Re: [PATCH] remove ide-scsi

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On Saturday 06 December 2008, Pete Zaitcev wrote:> On Wed, 03 Dec 2008 09:09:00 -0600, James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote:> > > git log tells me ide-scsi has been updated quite a bit recently, but it> > mostly looks to be fallout around the drivers/ide churn.  Can we get ide> > maintainer's buy in for this (I think they've been maintaining ide-tape> > and ide-cd in preference to ide-scsi)?> > They must be bonkers to do it. I fixed a couple of bugs in ide-tape> and it was one of the worst drivers I worked on, ever (worse than> floppy.c, I kid you not). It definitely must die before ide-scsi.> Fortunately, I solved this issue by hooking my tape to USB bridge,> or else I'd be up in arms and wanting Tomo's blood.
Pete, I don't mean any disrespect or to deny your credit for your pastcontributions but it must have been "quite a some" time ago since you werelast working on ide-tape. ;-)
[ To be sure I checked both Linus' tree (which goes back to Apr 2005,  2.6.12 timeframe) and Thomas' historical git tree (Feb 2002 / 2.4.1)  -- I don't see any IDE changes from you there. ]
In the recent years Borislav and me put substantial work into puttingide-tape into a sane state (mainly as a by-product of working on genericATAPI support) and although many improvements are still possible (BTWpatches are always warmly welcomed) it doesn't contain any horrors likeidescsi_eh_abort() / idescsi_eh_reset() in ide-scsi.  Moreover ide-tapeis of much less complexity than SCSI st driver (afterall ide-tape.c isnow almost half of the size / lines of code of st.c).
See for yourself, ide-tape.c from Linus' tree:
/* * IDE ATAPI streaming tape driver. * * Copyright (C) 1995-1999  Gadi Oxman <gadio@xxxxxxxxxxxxxxxx> * Copyright (C) 2003-2005  Bartlomiej Zolnierkiewicz * * This driver was constructed as a student project in the software laboratory * of the faculty of electrical engineering in the Technion - Israel's * Institute Of Technology, with the guide of Avner Lottem and Dr. Ilana David. * * It is hereby placed under the terms of the GNU general public license. * (See linux/COPYING). * * For a historical changelog see * Documentation/ide/ChangeLog.ide-tape.1995-2002 */
#define DRV_NAME "ide-tape"
#define IDETAPE_VERSION "1.20"
#include <linux/module.h>#include <linux/types.h>#include <linux/string.h>#include <linux/kernel.h>#include <linux/delay.h>#include <linux/timer.h>#include <linux/mm.h>#include <linux/interrupt.h>#include <linux/jiffies.h>#include <linux/major.h>#include <linux/errno.h>#include <linux/genhd.h>#include <linux/slab.h>#include <linux/pci.h>#include <linux/ide.h>#include <linux/smp_lock.h>#include <linux/completion.h>#include <linux/bitops.h>#include <linux/mutex.h>#include <scsi/scsi.h>
#include <asm/byteorder.h>#include <linux/irq.h>#include <linux/uaccess.h>#include <linux/io.h>#include <asm/unaligned.h>#include <linux/mtio.h>
enum {	/* output errors only */	DBG_ERR =		(1 << 0),	/* output all sense key/asc */	DBG_SENSE =		(1 << 1),	/* info regarding all chrdev-related procedures */	DBG_CHRDEV =		(1 << 2),	/* all remaining procedures */	DBG_PROCS =		(1 << 3),};
/* define to see debug info */#define IDETAPE_DEBUG_LOG		0
#if IDETAPE_DEBUG_LOG#define debug_log(lvl, fmt, args...)			\{							\	if (tape->debug_mask & lvl)			\	printk(KERN_INFO "ide-tape: " fmt, ## args);	\}#else#define debug_log(lvl, fmt, args...) do {} while (0)#endif
/**************************** Tunable parameters *****************************//* * After each failed packet command we issue a request sense command and retry * the packet command IDETAPE_MAX_PC_RETRIES times. * * Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries. */#define IDETAPE_MAX_PC_RETRIES		3
/* * The following parameter is used to select the point in the internal tape fifo * in which we will start to refill the buffer. Decreasing the following * parameter will improve the system's latency and interactive response, while * using a high value might improve system throughput. */#define IDETAPE_FIFO_THRESHOLD		2
/* * DSC polling parameters. * * Polling for DSC (a single bit in the status register) is a very important * function in ide-tape. There are two cases in which we poll for DSC: * * 1. Before a read/write packet command, to ensure that we can transfer data * from/to the tape's data buffers, without causing an actual media access. * In case the tape is not ready yet, we take out our request from the device * request queue, so that ide.c could service requests from the other device * on the same interface in the meantime. * * 2. After the successful initialization of a "media access packet command", * which is a command that can take a long time to complete (the interval can * range from several seconds to even an hour). Again, we postpone our request * in the middle to free the bus for the other device. The polling frequency * here should be lower than the read/write frequency since those media access * commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST * (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD * (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min). * * We also set a timeout for the timer, in case something goes wrong. The * timeout should be longer then the maximum execution time of a tape operation. */
/* DSC timings. */#define IDETAPE_DSC_RW_MIN		5*HZ/100	/* 50 msec */#define IDETAPE_DSC_RW_MAX		40*HZ/100	/* 400 msec */#define IDETAPE_DSC_RW_TIMEOUT		2*60*HZ		/* 2 minutes */#define IDETAPE_DSC_MA_FAST		2*HZ		/* 2 seconds */#define IDETAPE_DSC_MA_THRESHOLD	5*60*HZ		/* 5 minutes */#define IDETAPE_DSC_MA_SLOW		30*HZ		/* 30 seconds */#define IDETAPE_DSC_MA_TIMEOUT		2*60*60*HZ	/* 2 hours */
/*************************** End of tunable parameters ***********************/
/* tape directions */enum {	IDETAPE_DIR_NONE  = (1 << 0),	IDETAPE_DIR_READ  = (1 << 1),	IDETAPE_DIR_WRITE = (1 << 2),};
struct idetape_bh {	u32 b_size;	atomic_t b_count;	struct idetape_bh *b_reqnext;	char *b_data;};
/* Tape door status */#define DOOR_UNLOCKED			0#define DOOR_LOCKED			1#define DOOR_EXPLICITLY_LOCKED		2
/* Some defines for the SPACE command */#define IDETAPE_SPACE_OVER_FILEMARK	1#define IDETAPE_SPACE_TO_EOD		3
/* Some defines for the LOAD UNLOAD command */#define IDETAPE_LU_LOAD_MASK		1#define IDETAPE_LU_RETENSION_MASK	2#define IDETAPE_LU_EOT_MASK		4
/* Error codes returned in rq->errors to the higher part of the driver. */#define IDETAPE_ERROR_GENERAL		101#define IDETAPE_ERROR_FILEMARK		102#define IDETAPE_ERROR_EOD		103
/* Structures related to the SELECT SENSE / MODE SENSE packet commands. */#define IDETAPE_BLOCK_DESCRIPTOR	0#define IDETAPE_CAPABILITIES_PAGE	0x2a
/* * Most of our global data which we need to save even as we leave the driver due * to an interrupt or a timer event is stored in the struct defined below. */typedef struct ide_tape_obj {	ide_drive_t	*drive;	ide_driver_t	*driver;	struct gendisk	*disk;	struct kref	kref;
	/*	 *	failed_pc points to the last failed packet command, or contains	 *	NULL if we do not need to retry any packet command. This is	 *	required since an additional packet command is needed before the	 *	retry, to get detailed information on what went wrong.	 */	/* Last failed packet command */	struct ide_atapi_pc *failed_pc;	/* used by REQ_IDETAPE_{READ,WRITE} requests */	struct ide_atapi_pc queued_pc;
	/*	 * DSC polling variables.	 *	 * While polling for DSC we use postponed_rq to postpone the current	 * request so that ide.c will be able to service pending requests on the	 * other device. Note that at most we will have only one DSC (usually	 * data transfer) request in the device request queue.	 */	struct request *postponed_rq;	/* The time in which we started polling for DSC */	unsigned long dsc_polling_start;	/* Timer used to poll for dsc */	struct timer_list dsc_timer;	/* Read/Write dsc polling frequency */	unsigned long best_dsc_rw_freq;	unsigned long dsc_poll_freq;	unsigned long dsc_timeout;
	/* Read position information */	u8 partition;	/* Current block */	unsigned int first_frame;
	/* Last error information */	u8 sense_key, asc, ascq;
	/* Character device operation */	unsigned int minor;	/* device name */	char name[4];	/* Current character device data transfer direction */	u8 chrdev_dir;
	/* tape block size, usually 512 or 1024 bytes */	unsigned short blk_size;	int user_bs_factor;
	/* Copy of the tape's Capabilities and Mechanical Page */	u8 caps[20];
	/*	 * Active data transfer request parameters.	 *	 * At most, there is only one ide-tape originated data transfer request	 * in the device request queue. This allows ide.c to easily service	 * requests from the other device when we postpone our active request.	 */
	/* Data buffer size chosen based on the tape's recommendation */	int buffer_size;	/* merge buffer */	struct idetape_bh *merge_bh;	/* size of the merge buffer */	int merge_bh_size;	/* pointer to current buffer head within the merge buffer */	struct idetape_bh *bh;	char *b_data;	int b_count;
	int pages_per_buffer;	/* Wasted space in each stage */	int excess_bh_size;
	/* protects the ide-tape queue */	spinlock_t lock;
	/* Measures average tape speed */	unsigned long avg_time;	int avg_size;	int avg_speed;
	/* the door is currently locked */	int door_locked;	/* the tape hardware is write protected */	char drv_write_prot;	/* the tape is write protected (hardware or opened as read-only) */	char write_prot;
	u32 debug_mask;} idetape_tape_t;
static DEFINE_MUTEX(idetape_ref_mutex);
static struct class *idetape_sysfs_class;
static void ide_tape_release(struct kref *);
static struct ide_tape_obj *ide_tape_get(struct gendisk *disk){	struct ide_tape_obj *tape = NULL;
	mutex_lock(&idetape_ref_mutex);	tape = ide_drv_g(disk, ide_tape_obj);	if (tape) {		if (ide_device_get(tape->drive))			tape = NULL;		else			kref_get(&tape->kref);	}	mutex_unlock(&idetape_ref_mutex);	return tape;}
static void ide_tape_put(struct ide_tape_obj *tape){	ide_drive_t *drive = tape->drive;
	mutex_lock(&idetape_ref_mutex);	kref_put(&tape->kref, ide_tape_release);	ide_device_put(drive);	mutex_unlock(&idetape_ref_mutex);}
/* * The variables below are used for the character device interface. Additional * state variables are defined in our ide_drive_t structure. */static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i){	struct ide_tape_obj *tape = NULL;
	mutex_lock(&idetape_ref_mutex);	tape = idetape_devs[i];	if (tape)		kref_get(&tape->kref);	mutex_unlock(&idetape_ref_mutex);	return tape;}
static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,				  unsigned int bcount){	struct idetape_bh *bh = pc->bh;	int count;
	while (bcount) {		if (bh == NULL) {			printk(KERN_ERR "ide-tape: bh == NULL in "				"idetape_input_buffers\n");			ide_pad_transfer(drive, 0, bcount);			return;		}		count = min(			(unsigned int)(bh->b_size - atomic_read(&bh->b_count)),			bcount);		drive->hwif->tp_ops->input_data(drive, NULL, bh->b_data +					atomic_read(&bh->b_count), count);		bcount -= count;		atomic_add(count, &bh->b_count);		if (atomic_read(&bh->b_count) == bh->b_size) {			bh = bh->b_reqnext;			if (bh)				atomic_set(&bh->b_count, 0);		}	}	pc->bh = bh;}
static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,				   unsigned int bcount){	struct idetape_bh *bh = pc->bh;	int count;
	while (bcount) {		if (bh == NULL) {			printk(KERN_ERR "ide-tape: bh == NULL in %s\n",					__func__);			return;		}		count = min((unsigned int)pc->b_count, (unsigned int)bcount);		drive->hwif->tp_ops->output_data(drive, NULL, pc->b_data, count);		bcount -= count;		pc->b_data += count;		pc->b_count -= count;		if (!pc->b_count) {			bh = bh->b_reqnext;			pc->bh = bh;			if (bh) {				pc->b_data = bh->b_data;				pc->b_count = atomic_read(&bh->b_count);			}		}	}}
static void idetape_update_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc){	struct idetape_bh *bh = pc->bh;	int count;	unsigned int bcount = pc->xferred;
	if (pc->flags & PC_FLAG_WRITING)		return;	while (bcount) {		if (bh == NULL) {			printk(KERN_ERR "ide-tape: bh == NULL in %s\n",					__func__);			return;		}		count = min((unsigned int)bh->b_size, (unsigned int)bcount);		atomic_set(&bh->b_count, count);		if (atomic_read(&bh->b_count) == bh->b_size)			bh = bh->b_reqnext;		bcount -= count;	}	pc->bh = bh;}
/* * called on each failed packet command retry to analyze the request sense. We * currently do not utilize this information. */static void idetape_analyze_error(ide_drive_t *drive, u8 *sense){	idetape_tape_t *tape = drive->driver_data;	struct ide_atapi_pc *pc = tape->failed_pc;
	tape->sense_key = sense[2] & 0xF;	tape->asc       = sense[12];	tape->ascq      = sense[13];
	debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",		 pc->c[0], tape->sense_key, tape->asc, tape->ascq);
	/* Correct pc->xferred by asking the tape.	 */	if (pc->flags & PC_FLAG_DMA_ERROR) {		pc->xferred = pc->req_xfer -			tape->blk_size *			get_unaligned_be32(&sense[3]);		idetape_update_buffers(drive, pc);	}
	/*	 * If error was the result of a zero-length read or write command,	 * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives	 * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.	 */	if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)	    /* length == 0 */	    && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {		if (tape->sense_key == 5) {			/* don't report an error, everything's ok */			pc->error = 0;			/* don't retry read/write */			pc->flags |= PC_FLAG_ABORT;		}	}	if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {		pc->error = IDETAPE_ERROR_FILEMARK;		pc->flags |= PC_FLAG_ABORT;	}	if (pc->c[0] == WRITE_6) {		if ((sense[2] & 0x40) || (tape->sense_key == 0xd		     && tape->asc == 0x0 && tape->ascq == 0x2)) {			pc->error = IDETAPE_ERROR_EOD;			pc->flags |= PC_FLAG_ABORT;		}	}	if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {		if (tape->sense_key == 8) {			pc->error = IDETAPE_ERROR_EOD;			pc->flags |= PC_FLAG_ABORT;		}		if (!(pc->flags & PC_FLAG_ABORT) &&		    pc->xferred)			pc->retries = IDETAPE_MAX_PC_RETRIES + 1;	}}
/* Free data buffers completely. */static void ide_tape_kfree_buffer(idetape_tape_t *tape){	struct idetape_bh *prev_bh, *bh = tape->merge_bh;
	while (bh) {		u32 size = bh->b_size;
		while (size) {			unsigned int order = fls(size >> PAGE_SHIFT)-1;
			if (bh->b_data)				free_pages((unsigned long)bh->b_data, order);
			size &= (order-1);			bh->b_data += (1 << order) * PAGE_SIZE;		}		prev_bh = bh;		bh = bh->b_reqnext;		kfree(prev_bh);	}}
static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects){	struct request *rq = HWGROUP(drive)->rq;	idetape_tape_t *tape = drive->driver_data;	unsigned long flags;	int error;
	debug_log(DBG_PROCS, "Enter %s\n", __func__);
	switch (uptodate) {	case 0:	error = IDETAPE_ERROR_GENERAL; break;	case 1: error = 0; break;	default: error = uptodate;	}	rq->errors = error;	if (error)		tape->failed_pc = NULL;
	if (!blk_special_request(rq)) {		ide_end_request(drive, uptodate, nr_sects);		return 0;	}
	spin_lock_irqsave(&tape->lock, flags);
	ide_end_drive_cmd(drive, 0, 0);
	spin_unlock_irqrestore(&tape->lock, flags);	return 0;}
static void ide_tape_handle_dsc(ide_drive_t *);
static void ide_tape_callback(ide_drive_t *drive, int dsc){	idetape_tape_t *tape = drive->driver_data;	struct ide_atapi_pc *pc = drive->pc;	int uptodate = pc->error ? 0 : 1;
	debug_log(DBG_PROCS, "Enter %s\n", __func__);
	if (dsc)		ide_tape_handle_dsc(drive);
	if (tape->failed_pc == pc)		tape->failed_pc = NULL;
	if (pc->c[0] == REQUEST_SENSE) {		if (uptodate)			idetape_analyze_error(drive, pc->buf);		else			printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "					"itself - Aborting request!\n");	} else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {		struct request *rq = drive->hwif->hwgroup->rq;		int blocks = pc->xferred / tape->blk_size;
		tape->avg_size += blocks * tape->blk_size;
		if (time_after_eq(jiffies, tape->avg_time + HZ)) {			tape->avg_speed = tape->avg_size * HZ /				(jiffies - tape->avg_time) / 1024;			tape->avg_size = 0;			tape->avg_time = jiffies;		}
		tape->first_frame += blocks;		rq->current_nr_sectors -= blocks;
		if (pc->error)			uptodate = pc->error;	} else if (pc->c[0] == READ_POSITION && uptodate) {		u8 *readpos = pc->buf;
		debug_log(DBG_SENSE, "BOP - %s\n",				(readpos[0] & 0x80) ? "Yes" : "No");		debug_log(DBG_SENSE, "EOP - %s\n",				(readpos[0] & 0x40) ? "Yes" : "No");
		if (readpos[0] & 0x4) {			printk(KERN_INFO "ide-tape: Block location is unknown"					 "to the tape\n");			clear_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);			uptodate = 0;		} else {			debug_log(DBG_SENSE, "Block Location - %u\n",					be32_to_cpup((__be32 *)&readpos[4]));
			tape->partition = readpos[1];			tape->first_frame = be32_to_cpup((__be32 *)&readpos[4]);			set_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);		}	}
	idetape_end_request(drive, uptodate, 0);}
/* * Postpone the current request so that ide.c will be able to service requests * from another device on the same hwgroup while we are polling for DSC. */static void idetape_postpone_request(ide_drive_t *drive){	idetape_tape_t *tape = drive->driver_data;
	debug_log(DBG_PROCS, "Enter %s\n", __func__);
	tape->postponed_rq = HWGROUP(drive)->rq;	ide_stall_queue(drive, tape->dsc_poll_freq);}
static void ide_tape_handle_dsc(ide_drive_t *drive){	idetape_tape_t *tape = drive->driver_data;
	/* Media access command */	tape->dsc_polling_start = jiffies;	tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;	tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;	/* Allow ide.c to handle other requests */	idetape_postpone_request(drive);}
static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,				unsigned int bcount, int write){	if (write)		idetape_output_buffers(drive, pc, bcount);	else		idetape_input_buffers(drive, pc, bcount);
	return bcount;}
/* * Packet Command Interface * * The current Packet Command is available in drive->pc, and will not change * until we finish handling it. Each packet command is associated with a * callback function that will be called when the command is finished. * * The handling will be done in three stages: * * 1. idetape_issue_pc will send the packet command to the drive, and will set * the interrupt handler to ide_pc_intr. * * 2. On each interrupt, ide_pc_intr will be called. This step will be * repeated until the device signals us that no more interrupts will be issued. * * 3. ATAPI Tape media access commands have immediate status with a delayed * process. In case of a successful initiation of a media access packet command, * the DSC bit will be set when the actual execution of the command is finished. * Since the tape drive will not issue an interrupt, we have to poll for this * event. In this case, we define the request as "low priority request" by * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and * exit the driver. * * ide.c will then give higher priority to requests which originate from the * other device, until will change rq_status to RQ_ACTIVE. * * 4. When the packet command is finished, it will be checked for errors. * * 5. In case an error was found, we queue a request sense packet command in * front of the request queue and retry the operation up to * IDETAPE_MAX_PC_RETRIES times. * * 6. In case no error was found, or we decided to give up and not to retry * again, the callback function will be called and then we will handle the next * request. */
static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,		struct ide_atapi_pc *pc){	idetape_tape_t *tape = drive->driver_data;
	if (drive->pc->c[0] == REQUEST_SENSE &&	    pc->c[0] == REQUEST_SENSE) {		printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "			"Two request sense in serial were issued\n");	}
	if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)		tape->failed_pc = pc;
	/* Set the current packet command */	drive->pc = pc;
	if (pc->retries > IDETAPE_MAX_PC_RETRIES ||		(pc->flags & PC_FLAG_ABORT)) {		/*		 * We will "abort" retrying a packet command in case legitimate		 * error code was received (crossing a filemark, or end of the		 * media, for example).		 */		if (!(pc->flags & PC_FLAG_ABORT)) {			if (!(pc->c[0] == TEST_UNIT_READY &&			      tape->sense_key == 2 && tape->asc == 4 &&			     (tape->ascq == 1 || tape->ascq == 8))) {				printk(KERN_ERR "ide-tape: %s: I/O error, "						"pc = %2x, key = %2x, "						"asc = %2x, ascq = %2x\n",						tape->name, pc->c[0],						tape->sense_key, tape->asc,						tape->ascq);			}			/* Giving up */			pc->error = IDETAPE_ERROR_GENERAL;		}		tape->failed_pc = NULL;		drive->pc_callback(drive, 0);		return ide_stopped;	}	debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
	pc->retries++;
	return ide_issue_pc(drive, WAIT_TAPE_CMD, NULL);}
/* A mode sense command is used to "sense" tape parameters. */static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code){	ide_init_pc(pc);	pc->c[0] = MODE_SENSE;	if (page_code != IDETAPE_BLOCK_DESCRIPTOR)		/* DBD = 1 - Don't return block descriptors */		pc->c[1] = 8;	pc->c[2] = page_code;	/*	 * Changed pc->c[3] to 0 (255 will at best return unused info).	 *	 * For SCSI this byte is defined as subpage instead of high byte	 * of length and some IDE drives seem to interpret it this way	 * and return an error when 255 is used.	 */	pc->c[3] = 0;	/* We will just discard data in that case */	pc->c[4] = 255;	if (page_code == IDETAPE_BLOCK_DESCRIPTOR)		pc->req_xfer = 12;	else if (page_code == IDETAPE_CAPABILITIES_PAGE)		pc->req_xfer = 24;	else		pc->req_xfer = 50;}
static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive){	ide_hwif_t *hwif = drive->hwif;	idetape_tape_t *tape = drive->driver_data;	struct ide_atapi_pc *pc = drive->pc;	u8 stat;
	stat = hwif->tp_ops->read_status(hwif);
	if (stat & ATA_DSC) {		if (stat & ATA_ERR) {			/* Error detected */			if (pc->c[0] != TEST_UNIT_READY)				printk(KERN_ERR "ide-tape: %s: I/O error, ",						tape->name);			/* Retry operation */			ide_retry_pc(drive, tape->disk);			return ide_stopped;		}		pc->error = 0;	} else {		pc->error = IDETAPE_ERROR_GENERAL;		tape->failed_pc = NULL;	}	drive->pc_callback(drive, 0);	return ide_stopped;}
static void ide_tape_create_rw_cmd(idetape_tape_t *tape,				   struct ide_atapi_pc *pc, struct request *rq,				   u8 opcode){	struct idetape_bh *bh = (struct idetape_bh *)rq->special;	unsigned int length = rq->current_nr_sectors;
	ide_init_pc(pc);	put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);	pc->c[1] = 1;	pc->bh = bh;	pc->buf = NULL;	pc->buf_size = length * tape->blk_size;	pc->req_xfer = pc->buf_size;	if (pc->req_xfer == tape->buffer_size)		pc->flags |= PC_FLAG_DMA_OK;
	if (opcode == READ_6) {		pc->c[0] = READ_6;		atomic_set(&bh->b_count, 0);	} else if (opcode == WRITE_6) {		pc->c[0] = WRITE_6;		pc->flags |= PC_FLAG_WRITING;		pc->b_data = bh->b_data;		pc->b_count = atomic_read(&bh->b_count);	}
	memcpy(rq->cmd, pc->c, 12);}
static ide_startstop_t idetape_do_request(ide_drive_t *drive,					  struct request *rq, sector_t block){	ide_hwif_t *hwif = drive->hwif;	idetape_tape_t *tape = drive->driver_data;	struct ide_atapi_pc *pc = NULL;	struct request *postponed_rq = tape->postponed_rq;	u8 stat;
	debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %lu,"			" current_nr_sectors: %u\n",			(unsigned long long)rq->sector, rq->nr_sectors,			rq->current_nr_sectors);
	if (!blk_special_request(rq)) {		/* We do not support buffer cache originated requests. */		printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "			"request queue (%d)\n", drive->name, rq->cmd_type);		ide_end_request(drive, 0, 0);		return ide_stopped;	}
	/* Retry a failed packet command */	if (tape->failed_pc && drive->pc->c[0] == REQUEST_SENSE) {		pc = tape->failed_pc;		goto out;	}
	if (postponed_rq != NULL)		if (rq != postponed_rq) {			printk(KERN_ERR "ide-tape: ide-tape.c bug - "					"Two DSC requests were queued\n");			idetape_end_request(drive, 0, 0);			return ide_stopped;		}
	tape->postponed_rq = NULL;
	/*	 * If the tape is still busy, postpone our request and service	 * the other device meanwhile.	 */	stat = hwif->tp_ops->read_status(hwif);
	if ((drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) == 0 &&	    (rq->cmd[13] & REQ_IDETAPE_PC2) == 0)		set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
	if (drive->dev_flags & IDE_DFLAG_POST_RESET) {		set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);		drive->dev_flags &= ~IDE_DFLAG_POST_RESET;	}
	if (!test_and_clear_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags) &&	    (stat & ATA_DSC) == 0) {		if (postponed_rq == NULL) {			tape->dsc_polling_start = jiffies;			tape->dsc_poll_freq = tape->best_dsc_rw_freq;			tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;		} else if (time_after(jiffies, tape->dsc_timeout)) {			printk(KERN_ERR "ide-tape: %s: DSC timeout\n",				tape->name);			if (rq->cmd[13] & REQ_IDETAPE_PC2) {				idetape_media_access_finished(drive);				return ide_stopped;			} else {				return ide_do_reset(drive);			}		} else if (time_after(jiffies,					tape->dsc_polling_start +					IDETAPE_DSC_MA_THRESHOLD))			tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;		idetape_postpone_request(drive);		return ide_stopped;	}	if (rq->cmd[13] & REQ_IDETAPE_READ) {		pc = &tape->queued_pc;		ide_tape_create_rw_cmd(tape, pc, rq, READ_6);		goto out;	}	if (rq->cmd[13] & REQ_IDETAPE_WRITE) {		pc = &tape->queued_pc;		ide_tape_create_rw_cmd(tape, pc, rq, WRITE_6);		goto out;	}	if (rq->cmd[13] & REQ_IDETAPE_PC1) {		pc = (struct ide_atapi_pc *) rq->buffer;		rq->cmd[13] &= ~(REQ_IDETAPE_PC1);		rq->cmd[13] |= REQ_IDETAPE_PC2;		goto out;	}	if (rq->cmd[13] & REQ_IDETAPE_PC2) {		idetape_media_access_finished(drive);		return ide_stopped;	}	BUG();
out:	return idetape_issue_pc(drive, pc);}
/* * The function below uses __get_free_pages to allocate a data buffer of size * tape->buffer_size (or a bit more). We attempt to combine sequential pages as * much as possible. * * It returns a pointer to the newly allocated buffer, or NULL in case of * failure. */static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,						  int full, int clear){	struct idetape_bh *prev_bh, *bh, *merge_bh;	int pages = tape->pages_per_buffer;	unsigned int order, b_allocd;	char *b_data = NULL;
	merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);	bh = merge_bh;	if (bh == NULL)		goto abort;
	order = fls(pages) - 1;	bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);	if (!bh->b_data)		goto abort;	b_allocd = (1 << order) * PAGE_SIZE;	pages &= (order-1);
	if (clear)		memset(bh->b_data, 0, b_allocd);	bh->b_reqnext = NULL;	bh->b_size = b_allocd;	atomic_set(&bh->b_count, full ? bh->b_size : 0);
	while (pages) {		order = fls(pages) - 1;		b_data = (char *) __get_free_pages(GFP_KERNEL, order);		if (!b_data)			goto abort;		b_allocd = (1 << order) * PAGE_SIZE;
		if (clear)			memset(b_data, 0, b_allocd);
		/* newly allocated page frames below buffer header or ...*/		if (bh->b_data == b_data + b_allocd) {			bh->b_size += b_allocd;			bh->b_data -= b_allocd;			if (full)				atomic_add(b_allocd, &bh->b_count);			continue;		}		/* they are above the header */		if (b_data == bh->b_data + bh->b_size) {			bh->b_size += b_allocd;			if (full)				atomic_add(b_allocd, &bh->b_count);			continue;		}		prev_bh = bh;		bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);		if (!bh) {			free_pages((unsigned long) b_data, order);			goto abort;		}		bh->b_reqnext = NULL;		bh->b_data = b_data;		bh->b_size = b_allocd;		atomic_set(&bh->b_count, full ? bh->b_size : 0);		prev_bh->b_reqnext = bh;
		pages &= (order-1);	}
	bh->b_size -= tape->excess_bh_size;	if (full)		atomic_sub(tape->excess_bh_size, &bh->b_count);	return merge_bh;abort:	ide_tape_kfree_buffer(tape);	return NULL;}
static int idetape_copy_stage_from_user(idetape_tape_t *tape,					const char __user *buf, int n){	struct idetape_bh *bh = tape->bh;	int count;	int ret = 0;
	while (n) {		if (bh == NULL) {			printk(KERN_ERR "ide-tape: bh == NULL in %s\n",					__func__);			return 1;		}		count = min((unsigned int)				(bh->b_size - atomic_read(&bh->b_count)),				(unsigned int)n);		if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,				count))			ret = 1;		n -= count;		atomic_add(count, &bh->b_count);		buf += count;		if (atomic_read(&bh->b_count) == bh->b_size) {			bh = bh->b_reqnext;			if (bh)				atomic_set(&bh->b_count, 0);		}	}	tape->bh = bh;	return ret;}
static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,				      int n){	struct idetape_bh *bh = tape->bh;	int count;	int ret = 0;
	while (n) {		if (bh == NULL) {			printk(KERN_ERR "ide-tape: bh == NULL in %s\n",					__func__);			return 1;		}		count = min(tape->b_count, n);		if  (copy_to_user(buf, tape->b_data, count))			ret = 1;		n -= count;		tape->b_data += count;		tape->b_count -= count;		buf += count;		if (!tape->b_count) {			bh = bh->b_reqnext;			tape->bh = bh;			if (bh) {				tape->b_data = bh->b_data;				tape->b_count = atomic_read(&bh->b_count);			}		}	}	return ret;}
static void idetape_init_merge_buffer(idetape_tape_t *tape){	struct idetape_bh *bh = tape->merge_bh;	tape->bh = tape->merge_bh;
	if (tape->chrdev_dir == IDETAPE_DIR_WRITE)		atomic_set(&bh->b_count, 0);	else {		tape->b_data = bh->b_data;		tape->b_count = atomic_read(&bh->b_count);	}}
/* * Write a filemark if write_filemark=1. Flush the device buffers without * writing a filemark otherwise. */static void idetape_create_write_filemark_cmd(ide_drive_t *drive,		struct ide_atapi_pc *pc, int write_filemark){	ide_init_pc(pc);	pc->c[0] = WRITE_FILEMARKS;	pc->c[4] = write_filemark;	pc->flags |= PC_FLAG_WAIT_FOR_DSC;}
static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout){	idetape_tape_t *tape = drive->driver_data;	struct gendisk *disk = tape->disk;	int load_attempted = 0;
	/* Wait for the tape to become ready */	set_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);	timeout += jiffies;	while (time_before(jiffies, timeout)) {		if (ide_do_test_unit_ready(drive, disk) == 0)			return 0;		if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)		    || (tape->asc == 0x3A)) {			/* no media */			if (load_attempted)				return -ENOMEDIUM;			ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);			load_attempted = 1;		/* not about to be ready */		} else if (!(tape->sense_key == 2 && tape->asc == 4 &&			     (tape->ascq == 1 || tape->ascq == 8)))			return -EIO;		msleep(100);	}	return -EIO;}
static int idetape_flush_tape_buffers(ide_drive_t *drive){	struct ide_tape_obj *tape = drive->driver_data;	struct ide_atapi_pc pc;	int rc;
	idetape_create_write_filemark_cmd(drive, &pc, 0);	rc = ide_queue_pc_tail(drive, tape->disk, &pc);	if (rc)		return rc;	idetape_wait_ready(drive, 60 * 5 * HZ);	return 0;}
static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc){	ide_init_pc(pc);	pc->c[0] = READ_POSITION;	pc->req_xfer = 20;}
static int idetape_read_position(ide_drive_t *drive){	idetape_tape_t *tape = drive->driver_data;	struct ide_atapi_pc pc;	int position;
	debug_log(DBG_PROCS, "Enter %s\n", __func__);
	idetape_create_read_position_cmd(&pc);	if (ide_queue_pc_tail(drive, tape->disk, &pc))		return -1;	position = tape->first_frame;	return position;}
static void idetape_create_locate_cmd(ide_drive_t *drive,		struct ide_atapi_pc *pc,		unsigned int block, u8 partition, int skip){	ide_init_pc(pc);	pc->c[0] = POSITION_TO_ELEMENT;	pc->c[1] = 2;	put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);	pc->c[8] = partition;	pc->flags |= PC_FLAG_WAIT_FOR_DSC;}
static void __ide_tape_discard_merge_buffer(ide_drive_t *drive){	idetape_tape_t *tape = drive->driver_data;
	if (tape->chrdev_dir != IDETAPE_DIR_READ)		return;
	clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags);	tape->merge_bh_size = 0;	if (tape->merge_bh != NULL) {		ide_tape_kfree_buffer(tape);		tape->merge_bh = NULL;	}
	tape->chrdev_dir = IDETAPE_DIR_NONE;}
/* * Position the tape to the requested block using the LOCATE packet command. * A READ POSITION command is then issued to check where we are positioned. Like * all higher level operations, we queue the commands at the tail of the request * queue and wait for their completion. */static int idetape_position_tape(ide_drive_t *drive, unsigned int block,		u8 partition, int skip){	idetape_tape_t *tape = drive->driver_data;	struct gendisk *disk = tape->disk;	int retval;	struct ide_atapi_pc pc;
	if (tape->chrdev_dir == IDETAPE_DIR_READ)		__ide_tape_discard_merge_buffer(drive);	idetape_wait_ready(drive, 60 * 5 * HZ);	idetape_create_locate_cmd(drive, &pc, block, partition, skip);	retval = ide_queue_pc_tail(drive, disk, &pc);	if (retval)		return (retval);
	idetape_create_read_position_cmd(&pc);	return ide_queue_pc_tail(drive, disk, &pc);}
static void ide_tape_discard_merge_buffer(ide_drive_t *drive,					  int restore_position){	idetape_tape_t *tape = drive->driver_data;	int seek, position;
	__ide_tape_discard_merge_buffer(drive);	if (restore_position) {		position = idetape_read_position(drive);		seek = position > 0 ? position : 0;		if (idetape_position_tape(drive, seek, 0, 0)) {			printk(KERN_INFO "ide-tape: %s: position_tape failed in"					 " %s\n", tape->name, __func__);			return;		}	}}
/* * Generate a read/write request for the block device interface and wait for it * to be serviced. */static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,				 struct idetape_bh *bh){	idetape_tape_t *tape = drive->driver_data;	struct request *rq;	int ret, errors;
	debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
	rq = blk_get_request(drive->queue, READ, __GFP_WAIT);	rq->cmd_type = REQ_TYPE_SPECIAL;	rq->cmd[13] = cmd;	rq->rq_disk = tape->disk;	rq->special = (void *)bh;	rq->sector = tape->first_frame;	rq->nr_sectors = blocks;	rq->current_nr_sectors = blocks;	blk_execute_rq(drive->queue, tape->disk, rq, 0);
	errors = rq->errors;	ret = tape->blk_size * (blocks - rq->current_nr_sectors);	blk_put_request(rq);
	if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)		return 0;
	if (tape->merge_bh)		idetape_init_merge_buffer(tape);	if (errors == IDETAPE_ERROR_GENERAL)		return -EIO;	return ret;}
static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc){	ide_init_pc(pc);	pc->c[0] = INQUIRY;	pc->c[4] = 254;	pc->req_xfer = 254;}
static void idetape_create_rewind_cmd(ide_drive_t *drive,		struct ide_atapi_pc *pc){	ide_init_pc(pc);	pc->c[0] = REZERO_UNIT;	pc->flags |= PC_FLAG_WAIT_FOR_DSC;}
static void idetape_create_erase_cmd(struct ide_atapi_pc *pc){	ide_init_pc(pc);	pc->c[0] = ERASE;	pc->c[1] = 1;	pc->flags |= PC_FLAG_WAIT_FOR_DSC;}
static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd){	ide_init_pc(pc);	pc->c[0] = SPACE;	put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);	pc->c[1] = cmd;	pc->flags |= PC_FLAG_WAIT_FOR_DSC;}
/* Queue up a character device originated write request. */static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks){	idetape_tape_t *tape = drive->driver_data;
	debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
	return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,				     blocks, tape->merge_bh);}
static void ide_tape_flush_merge_buffer(ide_drive_t *drive){	idetape_tape_t *tape = drive->driver_data;	int blocks, min;	struct idetape_bh *bh;
	if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {		printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"				" but we are not writing.\n");		return;	}	if (tape->merge_bh_size > tape->buffer_size) {		printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");		tape->merge_bh_size = tape->buffer_size;	}	if (tape->merge_bh_size) {		blocks = tape->merge_bh_size / tape->blk_size;		if (tape->merge_bh_size % tape->blk_size) {			unsigned int i;
			blocks++;			i = tape->blk_size - tape->merge_bh_size %				tape->blk_size;			bh = tape->bh->b_reqnext;			while (bh) {				atomic_set(&bh->b_count, 0);				bh = bh->b_reqnext;			}			bh = tape->bh;			while (i) {				if (bh == NULL) {					printk(KERN_INFO "ide-tape: bug,"							 " bh NULL\n");					break;				}				min = min(i, (unsigned int)(bh->b_size -						atomic_read(&bh->b_count)));				memset(bh->b_data + atomic_read(&bh->b_count),						0, min);				atomic_add(min, &bh->b_count);				i -= min;				bh = bh->b_reqnext;			}		}		(void) idetape_add_chrdev_write_request(drive, blocks);		tape->merge_bh_size = 0;	}	if (tape->merge_bh != NULL) {		ide_tape_kfree_buffer(tape);		tape->merge_bh = NULL;	}	tape->chrdev_dir = IDETAPE_DIR_NONE;}
static int idetape_init_read(ide_drive_t *drive){	idetape_tape_t *tape = drive->driver_data;	int bytes_read;
	/* Initialize read operation */	if (tape->chrdev_dir != IDETAPE_DIR_READ) {		if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {			ide_tape_flush_merge_buffer(drive);			idetape_flush_tape_buffers(drive);		}		if (tape->merge_bh || tape->merge_bh_size) {			printk(KERN_ERR "ide-tape: merge_bh_size should be"					 " 0 now\n");			tape->merge_bh_size = 0;		}		tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);		if (!tape->merge_bh)			return -ENOMEM;		tape->chrdev_dir = IDETAPE_DIR_READ;
		/*		 * Issue a read 0 command to ensure that DSC handshake is		 * switched from completion mode to buffer available mode.		 * No point in issuing this if DSC overlap isn't supported, some		 * drives (Seagate STT3401A) will return an error.		 */		if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) {			bytes_read = idetape_queue_rw_tail(drive,							REQ_IDETAPE_READ, 0,							tape->merge_bh);			if (bytes_read < 0) {				ide_tape_kfree_buffer(tape);				tape->merge_bh = NULL;				tape->chrdev_dir = IDETAPE_DIR_NONE;				return bytes_read;			}		}	}
	return 0;}
/* called from idetape_chrdev_read() to service a chrdev read request. */static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks){	idetape_tape_t *tape = drive->driver_data;
	debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
	/* If we are at a filemark, return a read length of 0 */	if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))		return 0;
	idetape_init_read(drive);
	return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,				     tape->merge_bh);}
static void idetape_pad_zeros(ide_drive_t *drive, int bcount){	idetape_tape_t *tape = drive->driver_data;	struct idetape_bh *bh;	int blocks;
	while (bcount) {		unsigned int count;
		bh = tape->merge_bh;		count = min(tape->buffer_size, bcount);		bcount -= count;		blocks = count / tape->blk_size;		while (count) {			atomic_set(&bh->b_count,				   min(count, (unsigned int)bh->b_size));			memset(bh->b_data, 0, atomic_read(&bh->b_count));			count -= atomic_read(&bh->b_count);			bh = bh->b_reqnext;		}		idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,				      tape->merge_bh);	}}
/* * Rewinds the tape to the Beginning Of the current Partition (BOP). We * currently support only one partition. */static int idetape_rewind_tape(ide_drive_t *drive){	struct ide_tape_obj *tape = drive->driver_data;	struct gendisk *disk = tape->disk;	int retval;	struct ide_atapi_pc pc;
	debug_log(DBG_SENSE, "Enter %s\n", __func__);
	idetape_create_rewind_cmd(drive, &pc);	retval = ide_queue_pc_tail(drive, disk, &pc);	if (retval)		return retval;
	idetape_create_read_position_cmd(&pc);	retval = ide_queue_pc_tail(drive, disk, &pc);	if (retval)		return retval;	return 0;}
/* mtio.h compatible commands should be issued to the chrdev interface. */static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,				unsigned long arg){	idetape_tape_t *tape = drive->driver_data;	void __user *argp = (void __user *)arg;
	struct idetape_config {		int dsc_rw_frequency;		int dsc_media_access_frequency;		int nr_stages;	} config;
	debug_log(DBG_PROCS, "Enter %s\n", __func__);
	switch (cmd) {	case 0x0340:		if (copy_from_user(&config, argp, sizeof(config)))			return -EFAULT;		tape->best_dsc_rw_freq = config.dsc_rw_frequency;		break;	case 0x0350:		config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;		config.nr_stages = 1;		if (copy_to_user(argp, &config, sizeof(config)))			return -EFAULT;		break;	default:		return -EIO;	}	return 0;}
static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,					int mt_count){	idetape_tape_t *tape = drive->driver_data;	struct gendisk *disk = tape->disk;	struct ide_atapi_pc pc;	int retval, count = 0;	int sprev = !!(tape->caps[4] & 0x20);
	if (mt_count == 0)		return 0;	if (MTBSF == mt_op || MTBSFM == mt_op) {		if (!sprev)			return -EIO;		mt_count = -mt_count;	}
	if (tape->chrdev_dir == IDETAPE_DIR_READ) {		tape->merge_bh_size = 0;		if (test_and_clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))			++count;		ide_tape_discard_merge_buffer(drive, 0);	}
	switch (mt_op) {	case MTFSF:	case MTBSF:		idetape_create_space_cmd(&pc, mt_count - count,					 IDETAPE_SPACE_OVER_FILEMARK);		return ide_queue_pc_tail(drive, disk, &pc);	case MTFSFM:	case MTBSFM:		if (!sprev)			return -EIO;		retval = idetape_space_over_filemarks(drive, MTFSF,						      mt_count - count);		if (retval)			return retval;		count = (MTBSFM == mt_op ? 1 : -1);		return idetape_space_over_filemarks(drive, MTFSF, count);	default:		printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",				mt_op);		return -EIO;	}}
/* * Our character device read / write functions. * * The tape is optimized to maximize throughput when it is transferring an * integral number of the "continuous transfer limit", which is a parameter of * the specific tape (26kB on my particular tape, 32kB for Onstream). * * As of version 1.3 of the driver, the character device provides an abstract * continuous view of the media - any mix of block sizes (even 1 byte) on the * same backup/restore procedure is supported. The driver will internally * convert the requests to the recommended transfer unit, so that an unmatch * between the user's block size to the recommended size will only result in a * (slightly) increased driver overhead, but will no longer hit performance. * This is not applicable to Onstream. */static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,				   size_t count, loff_t *ppos){	struct ide_tape_obj *tape = file->private_data;	ide_drive_t *drive = tape->drive;	ssize_t bytes_read, temp, actually_read = 0, rc;	ssize_t ret = 0;	u16 ctl = *(u16 *)&tape->caps[12];
	debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
	if (tape->chrdev_dir != IDETAPE_DIR_READ) {		if (test_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags))			if (count > tape->blk_size &&			    (count % tape->blk_size) == 0)				tape->user_bs_factor = count / tape->blk_size;	}	rc = idetape_init_read(drive);	if (rc < 0)		return rc;	if (count == 0)		return (0);	if (tape->merge_bh_size) {		actually_read = min((unsigned int)(tape->merge_bh_size),				    (unsigned int)count);		if (idetape_copy_stage_to_user(tape, buf, actually_read))			ret = -EFAULT;		buf += actually_read;		tape->merge_bh_size -= actually_read;		count -= actually_read;	}	while (count >= tape->buffer_size) {		bytes_read = idetape_add_chrdev_read_request(drive, ctl);		if (bytes_read <= 0)			goto finish;		if (idetape_copy_stage_to_user(tape, buf, bytes_read))			ret = -EFAULT;		buf += bytes_read;		count -= bytes_read;		actually_read += bytes_read;	}	if (count) {		bytes_read = idetape_add_chrdev_read_request(drive, ctl);		if (bytes_read <= 0)			goto finish;		temp = min((unsigned long)count, (unsigned long)bytes_read);		if (idetape_copy_stage_to_user(tape, buf, temp))			ret = -EFAULT;		actually_read += temp;		tape->merge_bh_size = bytes_read-temp;	}finish:	if (!actually_read && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) {		debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
		idetape_space_over_filemarks(drive, MTFSF, 1);		return 0;	}
	return ret ? ret : actually_read;}
static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,				     size_t count, loff_t *ppos){	struct ide_tape_obj *tape = file->private_data;	ide_drive_t *drive = tape->drive;	ssize_t actually_written = 0;	ssize_t ret = 0;	u16 ctl = *(u16 *)&tape->caps[12];
	/* The drive is write protected. */	if (tape->write_prot)		return -EACCES;
	debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
	/* Initialize write operation */	if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {		if (tape->chrdev_dir == IDETAPE_DIR_READ)			ide_tape_discard_merge_buffer(drive, 1);		if (tape->merge_bh || tape->merge_bh_size) {			printk(KERN_ERR "ide-tape: merge_bh_size "				"should be 0 now\n");			tape->merge_bh_size = 0;		}		tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);		if (!tape->merge_bh)			return -ENOMEM;		tape->chrdev_dir = IDETAPE_DIR_WRITE;		idetape_init_merge_buffer(tape);
		/*		 * Issue a write 0 command to ensure that DSC handshake is		 * switched from completion mode to buffer available mode. No		 * point in issuing this if DSC overlap isn't supported, some		 * drives (Seagate STT3401A) will return an error.		 */		if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) {			ssize_t retval = idetape_queue_rw_tail(drive,							REQ_IDETAPE_WRITE, 0,							tape->merge_bh);			if (retval < 0) {				ide_tape_kfree_buffer(tape);				tape->merge_bh = NULL;				tape->chrdev_dir = IDETAPE_DIR_NONE;				return retval;			}		}	}	if (count == 0)		return (0);	if (tape->merge_bh_size) {		if (tape->merge_bh_size >= tape->buffer_size) {			printk(KERN_ERR "ide-tape: bug: merge buf too big\n");			tape->merge_bh_size = 0;		}		actually_written = min((unsigned int)				(tape->buffer_size - tape->merge_bh_size),				(unsigned int)count);		if (idetape_copy_stage_from_user(tape, buf, actually_written))				ret = -EFAULT;		buf += actually_written;		tape->merge_bh_size += actually_written;		count -= actually_written;
		if (tape->merge_bh_size == tape->buffer_size) {			ssize_t retval;			tape->merge_bh_size = 0;			retval = idetape_add_chrdev_write_request(drive, ctl);			if (retval <= 0)				return (retval);		}	}	while (count >= tape->buffer_size) {		ssize_t retval;		if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))			ret = -EFAULT;		buf += tape->buffer_size;		count -= tape->buffer_size;		retval = idetape_add_chrdev_write_request(drive, ctl);		actually_written += tape->buffer_size;		if (retval <= 0)			return (retval);	}	if (count) {		actually_written += count;		if (idetape_copy_stage_from_user(tape, buf, count))			ret = -EFAULT;		tape->merge_bh_size += count;	}	return ret ? ret : actually_written;}
static int idetape_write_filemark(ide_drive_t *drive){	struct ide_tape_obj *tape = drive->driver_data;	struct ide_atapi_pc pc;
	/* Write a filemark */	idetape_create_write_filemark_cmd(drive, &pc, 1);	if (ide_queue_pc_tail(drive, tape->disk, &pc)) {		printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");		return -EIO;	}	return 0;}
/* * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is * requested. * * Note: MTBSF and MTBSFM are not supported when the tape doesn't support * spacing over filemarks in the reverse direction. In this case, MTFSFM is also * usually not supported. * * The following commands are currently not supported: * * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS, * MT_ST_WRITE_THRESHOLD. */static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count){	idetape_tape_t *tape = drive->driver_data;	struct gendisk *disk = tape->disk;	struct ide_atapi_pc pc;	int i, retval;
	debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",			mt_op, mt_count);
	switch (mt_op) {	case MTFSF:	case MTFSFM:	case MTBSF:	case MTBSFM:		if (!mt_count)			return 0;		return idetape_space_over_filemarks(drive, mt_op, mt_count);	default:		break;	}
	switch (mt_op) {	case MTWEOF:		if (tape->write_prot)			return -EACCES;		ide_tape_discard_merge_buffer(drive, 1);		for (i = 0; i < mt_count; i++) {			retval = idetape_write_filemark(drive);			if (retval)				return retval;		}		return 0;	case MTREW:		ide_tape_discard_merge_buffer(drive, 0);		if (idetape_rewind_tape(drive))			return -EIO;		return 0;	case MTLOAD:		ide_tape_discard_merge_buffer(drive, 0);		return ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);	case MTUNLOAD:	case MTOFFL:		/*		 * If door is locked, attempt to unlock before		 * attempting to eject.		 */		if (tape->door_locked) {			if (!ide_set_media_lock(drive, disk, 0))				tape->door_locked = DOOR_UNLOCKED;		}		ide_tape_discard_merge_buffer(drive, 0);		retval = ide_do_start_stop(drive, disk, !IDETAPE_LU_LOAD_MASK);		if (!retval)			clear_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);		return retval;	case MTNOP:		ide_tape_discard_merge_buffer(drive, 0);		return idetape_flush_tape_buffers(drive);	case MTRETEN:		ide_tape_discard_merge_buffer(drive, 0);		return ide_do_start_stop(drive, disk,			IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);	case MTEOM:		idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);		return ide_queue_pc_tail(drive, disk, &pc);	case MTERASE:		(void)idetape_rewind_tape(drive);		idetape_create_erase_cmd(&pc);		return ide_queue_pc_tail(drive, disk, &pc);	case MTSETBLK:		if (mt_count) {			if (mt_count < tape->blk_size ||			    mt_count % tape->blk_size)				return -EIO;			tape->user_bs_factor = mt_count / tape->blk_size;			clear_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);		} else			set_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);		return 0;	case MTSEEK:		ide_tape_discard_merge_buffer(drive, 0);		return idetape_position_tape(drive,			mt_count * tape->user_bs_factor, tape->partition, 0);	case MTSETPART:		ide_tape_discard_merge_buffer(drive, 0);		return idetape_position_tape(drive, 0, mt_count, 0);	case MTFSR:	case MTBSR:	case MTLOCK:		retval = ide_set_media_lock(drive, disk, 1);		if (retval)			return retval;		tape->door_locked = DOOR_EXPLICITLY_LOCKED;		return 0;	case MTUNLOCK:		retval = ide_set_media_lock(drive, disk, 0);		if (retval)			return retval;		tape->door_locked = DOOR_UNLOCKED;		return 0;	default:		printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",				mt_op);		return -EIO;	}}
/* * Our character device ioctls. General mtio.h magnetic io commands are * supported here, and not in the corresponding block interface. Our own * ide-tape ioctls are supported on both interfaces. */static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,				unsigned int cmd, unsigned long arg){	struct ide_tape_obj *tape = file->private_data;	ide_drive_t *drive = tape->drive;	struct mtop mtop;	struct mtget mtget;	struct mtpos mtpos;	int block_offset = 0, position = tape->first_frame;	void __user *argp = (void __user *)arg;
	debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
	if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {		ide_tape_flush_merge_buffer(drive);		idetape_flush_tape_buffers(drive);	}	if (cmd == MTIOCGET || cmd == MTIOCPOS) {		block_offset = tape->merge_bh_size /			(tape->blk_size * tape->user_bs_factor);		position = idetape_read_position(drive);		if (position < 0)			return -EIO;	}	switch (cmd) {	case MTIOCTOP:		if (copy_from_user(&mtop, argp, sizeof(struct mtop)))			return -EFAULT;		return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);	case MTIOCGET:		memset(&mtget, 0, sizeof(struct mtget));		mtget.mt_type = MT_ISSCSI2;		mtget.mt_blkno = position / tape->user_bs_factor - block_offset;		mtget.mt_dsreg =			((tape->blk_size * tape->user_bs_factor)			 << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
		if (tape->drv_write_prot)			mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
		if (copy_to_user(argp, &mtget, sizeof(struct mtget)))			return -EFAULT;		return 0;	case MTIOCPOS:		mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;		if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))			return -EFAULT;		return 0;	default:		if (tape->chrdev_dir == IDETAPE_DIR_READ)			ide_tape_discard_merge_buffer(drive, 1);		return idetape_blkdev_ioctl(drive, cmd, arg);	}}
/* * Do a mode sense page 0 with block descriptor and if it succeeds set the tape * block size with the reported value. */static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive){	idetape_tape_t *tape = drive->driver_data;	struct ide_atapi_pc pc;
	idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);	if (ide_queue_pc_tail(drive, tape->disk, &pc)) {		printk(KERN_ERR "ide-tape: Can't get block descriptor\n");		if (tape->blk_size == 0) {			printk(KERN_WARNING "ide-tape: Cannot deal with zero "					    "block size, assuming 32k\n");			tape->blk_size = 32768;		}		return;	}	tape->blk_size = (pc.buf[4 + 5] << 16) +				(pc.buf[4 + 6] << 8)  +				 pc.buf[4 + 7];	tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;}
static int idetape_chrdev_open(struct inode *inode, struct file *filp){	unsigned int minor = iminor(inode), i = minor & ~0xc0;	ide_drive_t *drive;	idetape_tape_t *tape;	int retval;
	if (i >= MAX_HWIFS * MAX_DRIVES)		return -ENXIO;
	lock_kernel();	tape = ide_tape_chrdev_get(i);	if (!tape) {		unlock_kernel();		return -ENXIO;	}
	debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
	/*	 * We really want to do nonseekable_open(inode, filp); here, but some	 * versions of tar incorrectly call lseek on tapes and bail out if that	 * fails.  So we disallow pread() and pwrite(), but permit lseeks.	 */	filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
	drive = tape->drive;
	filp->private_data = tape;
	if (test_and_set_bit(IDE_AFLAG_BUSY, &drive->atapi_flags)) {		retval = -EBUSY;		goto out_put_tape;	}
	retval = idetape_wait_ready(drive, 60 * HZ);	if (retval) {		clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);		printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);		goto out_put_tape;	}
	idetape_read_position(drive);	if (!test_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags))		(void)idetape_rewind_tape(drive);
	/* Read block size and write protect status from drive. */	ide_tape_get_bsize_from_bdesc(drive);
	/* Set write protect flag if device is opened as read-only. */	if ((filp->f_flags & O_ACCMODE) == O_RDONLY)		tape->write_prot = 1;	else		tape->write_prot = tape->drv_write_prot;
	/* Make sure drive isn't write protected if user wants to write. */	if (tape->write_prot) {		if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||		    (filp->f_flags & O_ACCMODE) == O_RDWR) {			clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);			retval = -EROFS;			goto out_put_tape;		}	}
	/* Lock the tape drive door so user can't eject. */	if (tape->chrdev_dir == IDETAPE_DIR_NONE) {		if (!ide_set_media_lock(drive, tape->disk, 1)) {			if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)				tape->door_locked = DOOR_LOCKED;		}	}	unlock_kernel();	return 0;
out_put_tape:	ide_tape_put(tape);	unlock_kernel();	return retval;}
static void idetape_write_release(ide_drive_t *drive, unsigned int minor){	idetape_tape_t *tape = drive->driver_data;
	ide_tape_flush_merge_buffer(drive);	tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);	if (tape->merge_bh != NULL) {		idetape_pad_zeros(drive, tape->blk_size *				(tape->user_bs_factor - 1));		ide_tape_kfree_buffer(tape);		tape->merge_bh = NULL;	}	idetape_write_filemark(drive);	idetape_flush_tape_buffers(drive);	idetape_flush_tape_buffers(drive);}
static int idetape_chrdev_release(struct inode *inode, struct file *filp){	struct ide_tape_obj *tape = filp->private_data;	ide_drive_t *drive = tape->drive;	unsigned int minor = iminor(inode);
	lock_kernel();	tape = drive->driver_data;
	debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
	if (tape->chrdev_dir == IDETAPE_DIR_WRITE)		idetape_write_release(drive, minor);	if (tape->chrdev_dir == IDETAPE_DIR_READ) {		if (minor < 128)			ide_tape_discard_merge_buffer(drive, 1);	}
	if (minor < 128 && test_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags))		(void) idetape_rewind_tape(drive);	if (tape->chrdev_dir == IDETAPE_DIR_NONE) {		if (tape->door_locked == DOOR_LOCKED) {			if (!ide_set_media_lock(drive, tape->disk, 0))				tape->door_locked = DOOR_UNLOCKED;		}	}	clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);	ide_tape_put(tape);	unlock_kernel();	return 0;}
static void idetape_get_inquiry_results(ide_drive_t *drive){	idetape_tape_t *tape = drive->driver_data;	struct ide_atapi_pc pc;	char fw_rev[4], vendor_id[8], product_id[16];
	idetape_create_inquiry_cmd(&pc);	if (ide_queue_pc_tail(drive, tape->disk, &pc)) {		printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",				tape->name);		return;	}	memcpy(vendor_id, &pc.buf[8], 8);	memcpy(product_id, &pc.buf[16], 16);	memcpy(fw_rev, &pc.buf[32], 4);
	ide_fixstring(vendor_id, 8, 0);	ide_fixstring(product_id, 16, 0);	ide_fixstring(fw_rev, 4, 0);
	printk(KERN_INFO "ide-tape: %s <-> %s: %.8s %.16s rev %.4s\n",			drive->name, tape->name, vendor_id, product_id, fw_rev);}
/* * Ask the tape about its various parameters. In particular, we will adjust our * data transfer buffer	size to the recommended value as returned by the tape. */static void idetape_get_mode_sense_results(ide_drive_t *drive){	idetape_tape_t *tape = drive->driver_data;	struct ide_atapi_pc pc;	u8 *caps;	u8 speed, max_speed;
	idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);	if (ide_queue_pc_tail(drive, tape->disk, &pc)) {		printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"				" some default values\n");		tape->blk_size = 512;		put_unaligned(52,   (u16 *)&tape->caps[12]);		put_unaligned(540,  (u16 *)&tape->caps[14]);		put_unaligned(6*52, (u16 *)&tape->caps[16]);		return;	}	caps = pc.buf + 4 + pc.buf[3];
	/* convert to host order and save for later use */	speed = be16_to_cpup((__be16 *)&caps[14]);	max_speed = be16_to_cpup((__be16 *)&caps[8]);
	*(u16 *)&caps[8] = max_speed;	*(u16 *)&caps[12] = be16_to_cpup((__be16 *)&caps[12]);	*(u16 *)&caps[14] = speed;	*(u16 *)&caps[16] = be16_to_cpup((__be16 *)&caps[16]);
	if (!speed) {		printk(KERN_INFO "ide-tape: %s: invalid tape speed "				"(assuming 650KB/sec)\n", drive->name);		*(u16 *)&caps[14] = 650;	}	if (!max_speed) {		printk(KERN_INFO "ide-tape: %s: invalid max_speed "				"(assuming 650KB/sec)\n", drive->name);		*(u16 *)&caps[8] = 650;	}
	memcpy(&tape->caps, caps, 20);
	/* device lacks locking support according to capabilities page */	if ((caps[6] & 1) == 0)		drive->dev_flags &= ~IDE_DFLAG_DOORLOCKING;
	if (caps[7] & 0x02)		tape->blk_size = 512;	else if (caps[7] & 0x04)		tape->blk_size = 1024;}
#ifdef CONFIG_IDE_PROC_FS#define ide_tape_devset_get(name, field) \static int get_##name(ide_drive_t *drive) \{ \	idetape_tape_t *tape = drive->driver_data; \	return tape->field; \}
#define ide_tape_devset_set(name, field) \static int set_##name(ide_drive_t *drive, int arg) \{ \	idetape_tape_t *tape = drive->driver_data; \	tape->field = arg; \	return 0; \}
#define ide_tape_devset_rw_field(_name, _field) \ide_tape_devset_get(_name, _field) \ide_tape_devset_set(_name, _field) \IDE_DEVSET(_name, DS_SYNC, get_##_name, set_##_name)
#define ide_tape_devset_r_field(_name, _field) \ide_tape_devset_get(_name, _field) \IDE_DEVSET(_name, 0, get_##_name, NULL)
static int mulf_tdsc(ide_drive_t *drive)	{ return 1000; }static int divf_tdsc(ide_drive_t *drive)	{ return   HZ; }static int divf_buffer(ide_drive_t *drive)	{ return    2; }static int divf_buffer_size(ide_drive_t *drive)	{ return 1024; }
ide_devset_rw_flag(dsc_overlap, IDE_DFLAG_DSC_OVERLAP);
ide_tape_devset_rw_field(debug_mask, debug_mask);ide_tape_devset_rw_field(tdsc, best_dsc_rw_freq);
ide_tape_devset_r_field(avg_speed, avg_speed);ide_tape_devset_r_field(speed, caps[14]);ide_tape_devset_r_field(buffer, caps[16]);ide_tape_devset_r_field(buffer_size, buffer_size);
static const struct ide_proc_devset idetape_settings[] = {	__IDE_PROC_DEVSET(avg_speed,	0, 0xffff, NULL, NULL),	__IDE_PROC_DEVSET(buffer,	0, 0xffff, NULL, divf_buffer),	__IDE_PROC_DEVSET(buffer_size,	0, 0xffff, NULL, divf_buffer_size),	__IDE_PROC_DEVSET(debug_mask,	0, 0xffff, NULL, NULL),	__IDE_PROC_DEVSET(dsc_overlap,	0,      1, NULL, NULL),	__IDE_PROC_DEVSET(speed,	0, 0xffff, NULL, NULL),	__IDE_PROC_DEVSET(tdsc,		IDETAPE_DSC_RW_MIN, IDETAPE_DSC_RW_MAX,					mulf_tdsc, divf_tdsc),	{ 0 },};#endif
/* * The function below is called to: * * 1. Initialize our various state variables. * 2. Ask the tape for its capabilities. * 3. Allocate a buffer which will be used for data transfer. The buffer size * is chosen based on the recommendation which we received in step 2. * * Note that at this point ide.c already assigned us an irq, so that we can * queue requests here and wait for their completion. */static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor){	unsigned long t;	int speed;	int buffer_size;	u16 *ctl = (u16 *)&tape->caps[12];
	drive->pc_callback	 = ide_tape_callback;	drive->pc_update_buffers = idetape_update_buffers;	drive->pc_io_buffers	 = ide_tape_io_buffers;
	spin_lock_init(&tape->lock);
	drive->dev_flags |= IDE_DFLAG_DSC_OVERLAP;
	if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {		printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",				 tape->name);		drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;	}
	/* Seagate Travan drives do not support DSC overlap. */	if (strstr((char *)&drive->id[ATA_ID_PROD], "Seagate STT3401"))		drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
	tape->minor = minor;	tape->name[0] = 'h';	tape->name[1] = 't';	tape->name[2] = '0' + minor;	tape->chrdev_dir = IDETAPE_DIR_NONE;
	idetape_get_inquiry_results(drive);	idetape_get_mode_sense_results(drive);	ide_tape_get_bsize_from_bdesc(drive);	tape->user_bs_factor = 1;	tape->buffer_size = *ctl * tape->blk_size;	while (tape->buffer_size > 0xffff) {		printk(KERN_NOTICE "ide-tape: decreasing stage size\n");		*ctl /= 2;		tape->buffer_size = *ctl * tape->blk_size;	}	buffer_size = tape->buffer_size;	tape->pages_per_buffer = buffer_size / PAGE_SIZE;	if (buffer_size % PAGE_SIZE) {		tape->pages_per_buffer++;		tape->excess_bh_size = PAGE_SIZE - buffer_size % PAGE_SIZE;	}
	/* select the "best" DSC read/write polling freq */	speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
	t = (IDETAPE_FIFO_THRESHOLD * tape->buffer_size * HZ) / (speed * 1000);
	/*	 * Ensure that the number we got makes sense; limit it within	 * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.	 */	tape->best_dsc_rw_freq = clamp_t(unsigned long, t, IDETAPE_DSC_RW_MIN,					 IDETAPE_DSC_RW_MAX);	printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "		"%lums tDSC%s\n",		drive->name, tape->name, *(u16 *)&tape->caps[14],		(*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,		tape->buffer_size / 1024,		tape->best_dsc_rw_freq * 1000 / HZ,		(drive->dev_flags & IDE_DFLAG_USING_DMA) ? ", DMA" : "");
	ide_proc_register_driver(drive, tape->driver);}
static void ide_tape_remove(ide_drive_t *drive){	idetape_tape_t *tape = drive->driver_data;
	ide_proc_unregister_driver(drive, tape->driver);
	ide_unregister_region(tape->disk);
	ide_tape_put(tape);}
static void ide_tape_release(struct kref *kref){	struct ide_tape_obj *tape = to_ide_drv(kref, ide_tape_obj);	ide_drive_t *drive = tape->drive;	struct gendisk *g = tape->disk;
	BUG_ON(tape->merge_bh_size);
	drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;	drive->driver_data = NULL;	device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));	device_destroy(idetape_sysfs_class,			MKDEV(IDETAPE_MAJOR, tape->minor + 128));	idetape_devs[tape->minor] = NULL;	g->private_data = NULL;	put_disk(g);	kfree(tape);}
#ifdef CONFIG_IDE_PROC_FSstatic int proc_idetape_read_name	(char *page, char **start, off_t off, int count, int *eof, void *data){	ide_drive_t	*drive = (ide_drive_t *) data;	idetape_tape_t	*tape = drive->driver_data;	char		*out = page;	int		len;
	len = sprintf(out, "%s\n", tape->name);	PROC_IDE_READ_RETURN(page, start, off, count, eof, len);}
static ide_proc_entry_t idetape_proc[] = {	{ "capacity",	S_IFREG|S_IRUGO,	proc_ide_read_capacity, NULL },	{ "name",	S_IFREG|S_IRUGO,	proc_idetape_read_name,	NULL },	{ NULL, 0, NULL, NULL }};
static ide_proc_entry_t *ide_tape_proc_entries(ide_drive_t *drive){	return idetape_proc;}
static const struct ide_proc_devset *ide_tape_proc_devsets(ide_drive_t *drive){	return idetape_settings;}#endif
static int ide_tape_probe(ide_drive_t *);
static ide_driver_t idetape_driver = {	.gen_driver = {		.owner		= THIS_MODULE,		.name		= "ide-tape",		.bus		= &ide_bus_type,	},	.probe			= ide_tape_probe,	.remove			= ide_tape_remove,	.version		= IDETAPE_VERSION,	.do_request		= idetape_do_request,	.end_request		= idetape_end_request,	.error			= __ide_error,#ifdef CONFIG_IDE_PROC_FS	.proc_entries		= ide_tape_proc_entries,	.proc_devsets		= ide_tape_proc_devsets,#endif};
/* Our character device supporting functions, passed to register_chrdev. */static const struct file_operations idetape_fops = {	.owner		= THIS_MODULE,	.read		= idetape_chrdev_read,	.write		= idetape_chrdev_write,	.ioctl		= idetape_chrdev_ioctl,	.open		= idetape_chrdev_open,	.release	= idetape_chrdev_release,};
static int idetape_open(struct block_device *bdev, fmode_t mode){	struct ide_tape_obj *tape = ide_tape_get(bdev->bd_disk);
	if (!tape)		return -ENXIO;
	return 0;}
static int idetape_release(struct gendisk *disk, fmode_t mode){	struct ide_tape_obj *tape = ide_drv_g(disk, ide_tape_obj);
	ide_tape_put(tape);	return 0;}
static int idetape_ioctl(struct block_device *bdev, fmode_t mode,			unsigned int cmd, unsigned long arg){	struct ide_tape_obj *tape = ide_drv_g(bdev->bd_disk, ide_tape_obj);	ide_drive_t *drive = tape->drive;	int err = generic_ide_ioctl(drive, bdev, cmd, arg);	if (err == -EINVAL)		err = idetape_blkdev_ioctl(drive, cmd, arg);	return err;}
static struct block_device_operations idetape_block_ops = {	.owner		= THIS_MODULE,	.open		= idetape_open,	.release	= idetape_release,	.locked_ioctl	= idetape_ioctl,};
static int ide_tape_probe(ide_drive_t *drive){	idetape_tape_t *tape;	struct gendisk *g;	int minor;
	if (!strstr("ide-tape", drive->driver_req))		goto failed;
	if (drive->media != ide_tape)		goto failed;
	if ((drive->dev_flags & IDE_DFLAG_ID_READ) &&	    ide_check_atapi_device(drive, DRV_NAME) == 0) {		printk(KERN_ERR "ide-tape: %s: not supported by this version of"				" the driver\n", drive->name);		goto failed;	}	tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);	if (tape == NULL) {		printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",				drive->name);		goto failed;	}
	g = alloc_disk(1 << PARTN_BITS);	if (!g)		goto out_free_tape;
	ide_init_disk(g, drive);
	kref_init(&tape->kref);
	tape->drive = drive;	tape->driver = &idetape_driver;	tape->disk = g;
	g->private_data = &tape->driver;
	drive->driver_data = tape;
	mutex_lock(&idetape_ref_mutex);	for (minor = 0; idetape_devs[minor]; minor++)		;	idetape_devs[minor] = tape;	mutex_unlock(&idetape_ref_mutex);
	idetape_setup(drive, tape, minor);
	device_create(idetape_sysfs_class, &drive->gendev,		      MKDEV(IDETAPE_MAJOR, minor), NULL, "%s", tape->name);	device_create(idetape_sysfs_class, &drive->gendev,		      MKDEV(IDETAPE_MAJOR, minor + 128), NULL,		      "n%s", tape->name);
	g->fops = &idetape_block_ops;	ide_register_region(g);
	return 0;
out_free_tape:	kfree(tape);failed:	return -ENODEV;}
static void __exit idetape_exit(void){	driver_unregister(&idetape_driver.gen_driver);	class_destroy(idetape_sysfs_class);	unregister_chrdev(IDETAPE_MAJOR, "ht");}
static int __init idetape_init(void){	int error = 1;	idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");	if (IS_ERR(idetape_sysfs_class)) {		idetape_sysfs_class = NULL;		printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");		error = -EBUSY;		goto out;	}
	if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {		printk(KERN_ERR "ide-tape: Failed to register chrdev"				" interface\n");		error = -EBUSY;		goto out_free_class;	}
	error = driver_register(&idetape_driver.gen_driver);	if (error)		goto out_free_driver;
	return 0;
out_free_driver:	driver_unregister(&idetape_driver.gen_driver);out_free_class:	class_destroy(idetape_sysfs_class);out:	return error;}
MODULE_ALIAS("ide:*m-tape*");module_init(idetape_init);module_exit(idetape_exit);MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");MODULE_LICENSE("GPL");ÿôèº{.nÇ+?·?®?­?+%?Ëÿ±éݶ¥?wÿº{.nÇ+?·¥?{±þ'^þ)í?æèw*jg¬±¨¶????Ý¢jÿ¾«þG«?éÿ¢¸¢·¦j:+v?¨?wèjØm¶?ÿþø¯ù®w¥þ?àþf£¢·h??â?úÿ?Ù¥


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