Add a SG_SET_GET_EXTENDED ioctl control for whether commands
will be queued_at_head or queued_at_tail by the block layer
(together with the scsi mid-level). It has file scope.
Also add a read_value integer the can be used by write a
value from the SG_SEIRV_* group then the corresponding value
will be returned.
Signed-off-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
---
The user can still override the new file scope setting on a
a per command basis with the SG_FLAG_Q_AT_HEAD and
SG_FLAG_Q_AT_TAIL in the sg v3 and v4 structures.
An example of read_value usage is to write the value
SG_SEIRV_FL_RQS to the read_value field. Then after the
SG_SET_GET_EXTENDED ioctl is run, the number of (inactive)
requests currently on this file descriptor's request free
list is placed in the read_value field.
drivers/scsi/sg.c | 73 +++++++++++++++++++++++++++++++++++++-----
include/scsi/sg.h | 32 ++++--------------
include/uapi/scsi/sg.h | 48 ++++++++++++---------------
3 files changed, 92 insertions(+), 61 deletions(-)
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 1a63b0a9279a..31f6c364f60f 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -59,7 +59,7 @@ static int sg_version_num = 30901; /* 2 digits for each component */
#ifdef CONFIG_SCSI_PROC_FS
#include <linux/proc_fs.h>
-static char *sg_version_date = "20181019";
+static char *sg_version_date = "20181020";
static int sg_proc_init(void);
#endif
@@ -95,6 +95,10 @@ enum sg_rq_state {
#define SG_DEF_TIME_UNIT SG_TIME_UNIT_MS
#define SG_DEFAULT_TIMEOUT mult_frac(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ)
+#define SG_FD_Q_AT_TAIL true
+#define SG_FD_Q_AT_HEAD false
+#define SG_DEFAULT_Q_AT SG_FD_Q_AT_HEAD /* for backward compatibility */
+
int sg_big_buff = SG_DEF_RESERVED_SIZE;
/* N.B. This variable is readable and writeable via
/proc/scsi/sg/def_reserved_size . Each time sg_open() is called a buffer
@@ -187,6 +191,7 @@ struct sg_fd { /* holds the state of a file descriptor */
bool keep_orphan;/* false -> drop (def), true -> keep for read() */
bool mmap_called; /* false -> mmap() never called on this fd */
bool time_in_ns; /* report times in nanoseconds */
+ bool q_at_tail; /* queue at tail if true, head when false */
u8 next_cmd_len; /* 0: automatic, >0: use on next write() */
struct sg_request *reserve_srp; /* allocate on open(), starts on fl */
struct fasync_struct *async_qp; /* used by asynchronous notification */
@@ -896,9 +901,13 @@ sg_common_write(struct sg_fd *sfp, const struct sg_io_hdr *hi_p,
srp->start_ts = ktime_get_with_offset(TK_OFFS_BOOT);
else
hp->duration = jiffies_to_msecs(jiffies);
- /* at tail if v3 or later interface and tail flag set */
- at_head = !(hp->interface_id != '\0' &&
- (SG_FLAG_Q_AT_TAIL & hp->flags));
+
+ if (hp->interface_id == '\0') /* v1 and v2 interface */
+ at_head = true; /* backward compatibility */
+ else if (sfp->q_at_tail) /* cmd flags can override sfd setting */
+ at_head = (SG_FLAG_Q_AT_HEAD & hp->flags);
+ else /* this sfd is defaulting to head */
+ at_head = !(SG_FLAG_Q_AT_TAIL & hp->flags);
srp->rq->timeout = timeout;
kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */
@@ -1176,11 +1185,12 @@ static int
sg_set_get_extended(struct sg_fd *sfp, void __user *p)
{
int result = 0;
- u32 uv;
+ unsigned long iflags;
+ u32 uv, or_masks;
struct sg_device *sdp = sfp->parentdp;
struct sg_extended_info *seip;
+ struct sg_request *srp;
struct sg_extended_info sei;
- u32 or_masks;
seip = &sei;
if (!access_ok(VERIFY_READ, p, SZ_SG_EXTENDED_INFO))
@@ -1194,8 +1204,10 @@ sg_set_get_extended(struct sg_fd *sfp, void __user *p)
}
SG_LOG(3, sdp, "%s: wr_mask=0x%x rd_mask=0x%x\n", __func__,
seip->valid_wr_mask, seip->valid_rd_mask);
+ /* reserved_sz (u32), read-write */
if (or_masks & SG_SEIM_RESERVED_SIZE)
result = sg_reserved_sz(sfp, seip);
+ /* rq_rem_sgat_threshold (u32), read-write [impacts re-use only] */
if (or_masks & SG_SEIM_RQ_REM_THRESH) {
if (seip->valid_wr_mask & SG_SEIM_RQ_REM_THRESH) {
uv = seip->rq_rem_sgat_thresh;
@@ -1206,6 +1218,7 @@ sg_set_get_extended(struct sg_fd *sfp, void __user *p)
if (seip->valid_rd_mask & SG_SEIM_RQ_REM_THRESH)
seip->rq_rem_sgat_thresh = sfp->rem_sgat_thresh;
}
+ /* tot_fd_thresh (u32), read-write [sum of active cmd dlen_s] */
if (or_masks & SG_SEIM_TOT_FD_THRESH) {
if (seip->valid_wr_mask & SG_SEIM_TOT_FD_THRESH) {
uv = seip->tot_fd_thresh;
@@ -1216,8 +1229,9 @@ sg_set_get_extended(struct sg_fd *sfp, void __user *p)
if (seip->valid_rd_mask & SG_SEIM_TOT_FD_THRESH)
seip->tot_fd_thresh = sfp->tot_fd_thresh;
}
+ /* check all boolean flags if either wr or rd mask set in or_mask */
if (or_masks & SG_SEIM_CTL_FLAGS) {
- /* don't care whether wr or rd mask set in or_mask */
+ /* TIME_IN_NS boolean, read-write */
if (seip->ctl_flags_wr_mask & SG_CTL_FLAGM_TIME_IN_NS)
sfp->time_in_ns =
!!(seip->ctl_flags & SG_CTL_FLAGM_TIME_IN_NS);
@@ -1227,19 +1241,32 @@ sg_set_get_extended(struct sg_fd *sfp, void __user *p)
else
seip->ctl_flags &= ~SG_CTL_FLAGM_TIME_IN_NS;
}
+ /* ORPHANS boolean, read-only */
if (seip->ctl_flags_rd_mask & SG_CTL_FLAGM_ORPHANS) {
if (sg_any_persistent_orphans(sfp))
seip->ctl_flags |= SG_CTL_FLAGM_ORPHANS;
else
seip->ctl_flags &= ~SG_CTL_FLAGM_ORPHANS;
}
+ /* OTHER_OPENS boolean, read-only */
if (seip->ctl_flags_rd_mask & SG_CTL_FLAGM_OTHER_OPENS) {
if (sdp->open_cnt > 1)
seip->ctl_flags |= SG_CTL_FLAGM_OTHER_OPENS;
else
seip->ctl_flags &= ~SG_CTL_FLAGM_OTHER_OPENS;
}
+ /* Q_TAIL boolean, read-write */
+ if (seip->ctl_flags_wr_mask & SG_CTL_FLAGM_Q_TAIL)
+ sfp->q_at_tail =
+ !!(seip->ctl_flags & SG_CTL_FLAGM_Q_TAIL);
+ if (seip->ctl_flags_rd_mask & SG_CTL_FLAGM_Q_TAIL) {
+ if (sfp->q_at_tail)
+ seip->ctl_flags |= SG_CTL_FLAGM_Q_TAIL;
+ else
+ seip->ctl_flags &= ~SG_CTL_FLAGM_Q_TAIL;
+ }
}
+ /* minor_index u32, read-only */
if (or_masks & SG_SEIM_MINOR_INDEX) {
if (seip->valid_wr_mask & SG_SEIM_MINOR_INDEX)
SG_LOG(2, sdp, "%s: writing to minor_index ignored\n",
@@ -1247,7 +1274,36 @@ sg_set_get_extended(struct sg_fd *sfp, void __user *p)
if (seip->valid_rd_mask & SG_SEIM_MINOR_INDEX)
seip->minor_index = sdp->index;
}
- /* send object back to user space if any read mask set */
+ if ((seip->valid_rd_mask & SG_SEIM_READ_VAL) &&
+ (seip->valid_wr_mask & SG_SEIM_READ_VAL)) {
+ switch (seip->read_value) {
+ case SG_SEIRV_INT_MASK:
+ seip->read_value = SG_SEIM_ALL_BITS;
+ break;
+ case SG_SEIRV_BOOL_MASK:
+ seip->read_value = SG_CTL_FLAGM_ALL_BITS;
+ break;
+ case SG_SEIRV_VERS_NUM:
+ seip->read_value = sg_version_num;
+ break;
+ case SG_SEIRV_FL_RQS:
+ uv = 0;
+ read_lock_irqsave(&sfp->rq_list_lock, iflags);
+ list_for_each_entry(srp, &sfp->rq_free_list,
+ free_entry)
+ ++uv;
+ read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
+ seip->read_value = uv;
+ break;
+ default:
+ SG_LOG(6, sdp, "%s: can decode %d --> ::read_value\n",
+ __func__, seip->read_value);
+ seip->read_value = 0;
+ break;
+ }
+ }
+
+ /* finally send object back to user space if any read mask set */
if (seip->valid_rd_mask || seip->ctl_flags_rd_mask) {
if (access_ok(VERIFY_WRITE, p, SZ_SG_EXTENDED_INFO))
result = __copy_to_user(p, seip, SZ_SG_EXTENDED_INFO);
@@ -2816,6 +2872,7 @@ sg_add_sfp(struct sg_device *sdp)
sfp->tot_fd_thresh = SG_TOT_FD_THRESHOLD;
atomic_set(&sfp->sum_fd_dlens, 0);
sfp->time_in_ns = !!SG_DEF_TIME_UNIT;
+ sfp->q_at_tail = SG_DEFAULT_Q_AT;
sfp->parentdp = sdp;
if (atomic_read(&sdp->detaching)) {
kfree(sfp);
diff --git a/include/scsi/sg.h b/include/scsi/sg.h
index 596f68746f66..46fc7cbffd78 100644
--- a/include/scsi/sg.h
+++ b/include/scsi/sg.h
@@ -4,41 +4,21 @@
#include <linux/compiler.h>
-/*
- * History:
- * Started: Aug 9 by Lawrence Foard (entropy@xxxxxxxxxxxxx), to allow user
- * process control of SCSI devices.
- * Development Sponsored by Killy Corp. NY NY
- *
- * Original driver (sg.h):
- * Copyright (C) 1992 Lawrence Foard
- * Version 2 and 3 extensions to driver:
- * Copyright (C) 1998 - 2018 Douglas Gilbert
- *
- * Version: 3.9.01 (20181016)
- * This version is for 2.6, 3 and 4 series kernels.
- *
- * Documentation
- * =============
- * A web site for the SG device driver can be found at:
- * http://sg.danny.cz/sg [alternatively check the MAINTAINERS file]
- * The documentation for the sg version 3 driver can be found at:
- * http://sg.danny.cz/sg/p/sg_v3_ho.html
- * Also see: <kernel_source>/Documentation/scsi/scsi-generic.txt
- *
- * For utility and test programs see: http://sg.danny.cz/sg/sg3_utils.html
- */
-
#ifdef __KERNEL__
extern int sg_big_buff; /* for sysctl */
#endif
+/*
+ * In version 3.9.01 of the sg driver, this file was spilt in two, with the
+ * bulk of the user space interface being placed in the file being included
+ * in the following line.
+ */
#include <uapi/scsi/sg.h>
#ifdef __KERNEL__
#define SG_DEFAULT_TIMEOUT_USER (60*USER_HZ) /* HZ == 'jiffies in 1 second' */
#endif
-#undef SG_DEFAULT_TIMEOUT /* cause define in sg.c */
+#undef SG_DEFAULT_TIMEOUT /* because of conflicting define in sg.c */
#endif /* end of ifndef _SCSI_GENERIC_H guard */
diff --git a/include/uapi/scsi/sg.h b/include/uapi/scsi/sg.h
index 0bc652402bd9..c0ee00573921 100644
--- a/include/uapi/scsi/sg.h
+++ b/include/uapi/scsi/sg.h
@@ -2,27 +2,6 @@
#ifndef _UAPI_SCSI_SG_H
#define _UAPI_SCSI_SG_H
-/*
- * Want to block the original sg.h header from also being included. That
- * causes lots of multiple definition errors. This will only work if this
- * header is included _before_ the original sg.h header .
- */
-#define _SCSI_GENERIC_H /* original kernel header guard */
-#define _SCSI_SG_H /* glibc header guard */
-
-/*
- * Other UAPI headers include linux/compiler.h to resolve "__" types but that
- * doesn't always work, perhaps in the future. Fall back to linux/types.h .
- */
-/* #include <linux/compiler.h> */
-#include <linux/types.h>
-#include <linux/major.h>
-
-/* Still problems with __user so define to nothing */
-#define __user
-
-#include <linux/bsg.h>
-
/*
* History:
* Started: Aug 9 by Lawrence Foard (entropy@xxxxxxxxxxxxx), to allow user
@@ -48,6 +27,11 @@
* For utility and test programs see: http://sg.danny.cz/sg/sg3_utils.html
*/
+#include <linux/types.h>
+#include <linux/major.h>
+
+/* bsg.h contains the sg v4 use space interface structure. */
+#include <linux/bsg.h>
/*
* Same structure as used by readv() call. It defines one scatter-gather
@@ -109,7 +93,7 @@ typedef struct sg_io_hdr {
#define SG_FLAG_MMAP_IO 4 /* request memory mapped IO */
/* no transfer of kernel buffers to/from user space; to debug indirect IO */
#define SG_FLAG_NO_DXFER 0x10000
-/* defaults: for sg driver: Q_AT_HEAD; for block layer: Q_AT_TAIL */
+/* defaults: for sg driver (v3): Q_AT_HEAD; for block layer: Q_AT_TAIL */
#define SG_FLAG_Q_AT_TAIL 0x10
#define SG_FLAG_Q_AT_HEAD 0x20
@@ -186,12 +170,21 @@ typedef struct sg_req_info { /* used by SG_GET_REQUEST_TABLE ioctl() */
#define SG_SEIM_TOT_FD_THRESH 0x4 /* tot_fd_thresh field valid */
#define SG_SEIM_CTL_FLAGS 0x8 /* ctl_flags_mask bits in ctl_flags */
#define SG_SEIM_MINOR_INDEX 0x10 /* sg device minor index number */
-#define SG_SEIM_ALL_BITS 0x1f /* should be OR of previous items */
+#define SG_SEIM_READ_VAL 0x20 /* write SG_SEIRV, read related */
+#define SG_SEIM_ALL_BITS 0x3f /* should be OR of previous items */
#define SG_CTL_FLAGM_TIME_IN_NS 0x1 /* time: nanosecs (def: millisecs) */
#define SG_CTL_FLAGM_TAG_FOR_PACK_ID 0x2
#define SG_CTL_FLAGM_OTHER_OPENS 0x4 /* rd: other sg fd_s on this dev */
#define SG_CTL_FLAGM_ORPHANS 0x8 /* rd: orphaned requests on this fd */
+#define SG_CTL_FLAGM_Q_TAIL 0x10 /* used for future cmds on this fd */
+#define SG_CTL_FLAGM_ALL_BITS 0x1f /* should be OR of previous items */
+
+/* Write one of the following values to sg_extended_info::read_value, get... */
+#define SG_SEIRV_INT_MASK 0x0 /* get SG_SEIM_ALL_BITS */
+#define SG_SEIRV_BOOL_MASK 0x1 /* get SG_CTL_FLAGM_ALL_BITS */
+#define SG_SEIRV_VERS_NUM 0x2 /* get driver version number as int */
+#define SG_SEIRV_FL_RQS 0x3 /* number of requests in free list */
/*
* A pointer to the following structure is passed as the third argument to
@@ -203,11 +196,11 @@ typedef struct sg_req_info { /* used by SG_GET_REQUEST_TABLE ioctl() */
* back to the user space. If the same bit is set in both the *_wr_mask and
* corresponding *_rd_mask fields, then the write action takes place before
* the read action and no other operation will split the two. This structure
- * is padded to 64 bytes to allow for new values to be added in the future.
+ * is padded to 96 bytes to allow for new values to be added in the future.
*/
struct sg_extended_info {
- __u32 valid_wr_mask; /* OR-ed SG_SEIM_* values */
- __u32 valid_rd_mask; /* OR-ed SG_SEIM_* values */
+ __u32 valid_wr_mask; /* OR-ed SG_SEIM_* user->driver values */
+ __u32 valid_rd_mask; /* OR-ed SG_SEIM_* driver->user values */
__u32 reserved_sz; /* data/sgl size of pre-allocated request */
__u32 rq_rem_sgat_thresh;/* request re-use: clear data/sgat if > */
__u32 tot_fd_thresh; /* total data/sgat for this fd, 0: no limit */
@@ -215,7 +208,8 @@ struct sg_extended_info {
__u32 ctl_flags_rd_mask; /* OR-ed SG_CTL_FLAGM_* values */
__u32 ctl_flags; /* bit values OR-ed, see SG_CTL_FLAGM_* */
__u32 minor_index; /* rd: kernel's sg device minor number */
- __u8 pad_to_64[28]; /* pad so struct is 64 bytes long */
+ __u32 read_value; /* write known value, read back related */
+ __u8 pad_to_96[56]; /* pad so struct is 96 bytes long */
};
/*
--
2.17.1
