Any reason this patch hasn't been merged into scsi-misc yet?
On Wed, Dec 31, 2008 at 06:51:42AM -0700, Matthew Wilcox wrote:
> On Wed, Dec 31, 2008 at 06:50:15AM -0700, Matthew Wilcox wrote:
> > 2005), so I'm OK with this change. I'll send updated patches (the first
> > patch now needs an extra NULL argument to scsi_execute_request).
>
> commit 039f215a451eaa0cb04ae75e7506f178759e24e3
> Author: Matthew Wilcox <matthew@xxxxxx>
> Date: Wed Dec 31 07:30:12 2008 -0500
>
> sd: Refactor sd_read_capacity()
>
> The sd_read_capacity() function was about 180 lines long and
> included a backwards goto and a tricky state variable. Splitting out
> read_capacity_10() and read_capacity_16() (about 50 lines each) reduces
> sd_read_capacity to about 100 lines and gets rid of the backwards goto
> and the state variable. I've tried to avoid any behaviour change with
> this patch.
>
> Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
>
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index 62b28d5..06bb638 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -1275,42 +1275,61 @@ disable:
> sdkp->capacity = 0;
> }
>
> -/*
> - * read disk capacity
> - */
> -static void
> -sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer)
> +static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device *sdp,
> + struct scsi_sense_hdr *sshdr, int sense_valid,
> + int the_result)
> +{
> + sd_print_result(sdkp, the_result);
> + if (driver_byte(the_result) & DRIVER_SENSE)
> + sd_print_sense_hdr(sdkp, sshdr);
> + else
> + sd_printk(KERN_NOTICE, sdkp, "Sense not available.\n");
> +
> + /*
> + * Set dirty bit for removable devices if not ready -
> + * sometimes drives will not report this properly.
> + */
> + if (sdp->removable &&
> + sense_valid && sshdr->sense_key == NOT_READY)
> + sdp->changed = 1;
> +
> + /*
> + * We used to set media_present to 0 here to indicate no media
> + * in the drive, but some drives fail read capacity even with
> + * media present, so we can't do that.
> + */
> + sdkp->capacity = 0; /* unknown mapped to zero - as usual */
> +}
> +
> +#define RC16_LEN 13
> +#if RC16_LEN > SD_BUF_SIZE
> +#error RC16_LEN must not be more than SD_BUF_SIZE
> +#endif
> +
> +static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
> + unsigned char *buffer)
> {
> unsigned char cmd[16];
> - int the_result, retries;
> - int sector_size = 0;
> - /* Force READ CAPACITY(16) when PROTECT=1 */
> - int longrc = scsi_device_protection(sdkp->device) ? 1 : 0;
> struct scsi_sense_hdr sshdr;
> int sense_valid = 0;
> - struct scsi_device *sdp = sdkp->device;
> + int the_result;
> + int retries = 3;
> + unsigned long long lba;
> + unsigned sector_size;
>
> -repeat:
> - retries = 3;
> do {
> - if (longrc) {
> - memset((void *) cmd, 0, 16);
> - cmd[0] = SERVICE_ACTION_IN;
> - cmd[1] = SAI_READ_CAPACITY_16;
> - cmd[13] = 13;
> - memset((void *) buffer, 0, 13);
> - } else {
> - cmd[0] = READ_CAPACITY;
> - memset((void *) &cmd[1], 0, 9);
> - memset((void *) buffer, 0, 8);
> - }
> -
> + memset(cmd, 0, 16);
> + cmd[0] = SERVICE_ACTION_IN;
> + cmd[1] = SAI_READ_CAPACITY_16;
> + cmd[13] = RC16_LEN;
> + memset(buffer, 0, RC16_LEN);
> +
> the_result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
> - buffer, longrc ? 13 : 8, &sshdr,
> - SD_TIMEOUT, SD_MAX_RETRIES, NULL);
> + buffer, RC16_LEN, &sshdr,
> + SD_TIMEOUT, SD_MAX_RETRIES, NULL);
>
> if (media_not_present(sdkp, &sshdr))
> - return;
> + return -ENODEV;
>
> if (the_result)
> sense_valid = scsi_sense_valid(&sshdr);
> @@ -1318,72 +1337,122 @@ repeat:
>
> } while (the_result && retries);
>
> - if (the_result && !longrc) {
> + if (the_result) {
> + sd_printk(KERN_NOTICE, sdkp, "READ CAPACITY(16) failed\n");
> + read_capacity_error(sdkp, sdp, &sshdr, sense_valid, the_result);
> + return -EINVAL;
> + }
> +
> + sector_size = (buffer[8] << 24) | (buffer[9] << 16) |
> + (buffer[10] << 8) | buffer[11];
> + lba = (((u64)buffer[0] << 56) | ((u64)buffer[1] << 48) |
> + ((u64)buffer[2] << 40) | ((u64)buffer[3] << 32) |
> + ((u64)buffer[4] << 24) | ((u64)buffer[5] << 16) |
> + ((u64)buffer[6] << 8) | (u64)buffer[7]);
> +
> + sd_read_protection_type(sdkp, buffer);
> +
> + if ((sizeof(sdkp->capacity) == 4) && (lba >= 0xffffffffULL)) {
> + sd_printk(KERN_ERR, sdkp, "Too big for this kernel. Use a "
> + "kernel compiled with support for large block "
> + "devices.\n");
> + sdkp->capacity = 0;
> + return -EOVERFLOW;
> + }
> +
> + sdkp->capacity = lba + 1;
> + return sector_size;
> +}
> +
> +static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp,
> + unsigned char *buffer)
> +{
> + unsigned char cmd[16];
> + struct scsi_sense_hdr sshdr;
> + int sense_valid = 0;
> + int the_result;
> + int retries = 3;
> + sector_t lba;
> + unsigned sector_size;
> +
> + do {
> + cmd[0] = READ_CAPACITY;
> + memset(&cmd[1], 0, 9);
> + memset(buffer, 0, 8);
> +
> + the_result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
> + buffer, 8, &sshdr,
> + SD_TIMEOUT, SD_MAX_RETRIES, NULL);
> +
> + if (media_not_present(sdkp, &sshdr))
> + return -ENODEV;
> +
> + if (the_result)
> + sense_valid = scsi_sense_valid(&sshdr);
> + retries--;
> +
> + } while (the_result && retries);
> +
> + if (the_result) {
> sd_printk(KERN_NOTICE, sdkp, "READ CAPACITY failed\n");
> - sd_print_result(sdkp, the_result);
> - if (driver_byte(the_result) & DRIVER_SENSE)
> - sd_print_sense_hdr(sdkp, &sshdr);
> - else
> - sd_printk(KERN_NOTICE, sdkp, "Sense not available.\n");
> + read_capacity_error(sdkp, sdp, &sshdr, sense_valid, the_result);
> + return -EINVAL;
> + }
>
> - /* Set dirty bit for removable devices if not ready -
> - * sometimes drives will not report this properly. */
> - if (sdp->removable &&
> - sense_valid && sshdr.sense_key == NOT_READY)
> - sdp->changed = 1;
> + sector_size = (buffer[4] << 24) | (buffer[5] << 16) |
> + (buffer[6] << 8) | buffer[7];
> + lba = (buffer[0] << 24) | (buffer[1] << 16) |
> + (buffer[2] << 8) | buffer[3];
>
> - /* Either no media are present but the drive didn't tell us,
> - or they are present but the read capacity command fails */
> - /* sdkp->media_present = 0; -- not always correct */
> - sdkp->capacity = 0; /* unknown mapped to zero - as usual */
> + if ((sizeof(sdkp->capacity) == 4) && (lba == 0xffffffff)) {
> + sd_printk(KERN_ERR, sdkp, "Too big for this kernel. Use a "
> + "kernel compiled with support for large block "
> + "devices.\n");
> + sdkp->capacity = 0;
> + return -EOVERFLOW;
> + }
>
> - return;
> - } else if (the_result && longrc) {
> - /* READ CAPACITY(16) has been failed */
> - sd_printk(KERN_NOTICE, sdkp, "READ CAPACITY(16) failed\n");
> - sd_print_result(sdkp, the_result);
> - sd_printk(KERN_NOTICE, sdkp, "Use 0xffffffff as device size\n");
> + sdkp->capacity = lba + 1;
> + return sector_size;
> +}
>
> - sdkp->capacity = 1 + (sector_t) 0xffffffff;
> - goto got_data;
> - }
> -
> - if (!longrc) {
> - sector_size = (buffer[4] << 24) |
> - (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
> - if (buffer[0] == 0xff && buffer[1] == 0xff &&
> - buffer[2] == 0xff && buffer[3] == 0xff) {
> - if(sizeof(sdkp->capacity) > 4) {
> - sd_printk(KERN_NOTICE, sdkp, "Very big device. "
> - "Trying to use READ CAPACITY(16).\n");
> - longrc = 1;
> - goto repeat;
> - }
> - sd_printk(KERN_ERR, sdkp, "Too big for this kernel. Use "
> - "a kernel compiled with support for large "
> - "block devices.\n");
> - sdkp->capacity = 0;
> +/*
> + * read disk capacity
> + */
> +static void
> +sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer)
> +{
> + int sector_size;
> + struct scsi_device *sdp = sdkp->device;
> +
> + /* Force READ CAPACITY(16) when PROTECT=1 */
> + if (scsi_device_protection(sdp)) {
> + sector_size = read_capacity_16(sdkp, sdp, buffer);
> + if (sector_size == -EOVERFLOW)
> goto got_data;
> - }
> - sdkp->capacity = 1 + (((sector_t)buffer[0] << 24) |
> - (buffer[1] << 16) |
> - (buffer[2] << 8) |
> - buffer[3]);
> + if (sector_size < 0)
> + return;
> } else {
> - sdkp->capacity = 1 + (((u64)buffer[0] << 56) |
> - ((u64)buffer[1] << 48) |
> - ((u64)buffer[2] << 40) |
> - ((u64)buffer[3] << 32) |
> - ((sector_t)buffer[4] << 24) |
> - ((sector_t)buffer[5] << 16) |
> - ((sector_t)buffer[6] << 8) |
> - (sector_t)buffer[7]);
> -
> - sector_size = (buffer[8] << 24) |
> - (buffer[9] << 16) | (buffer[10] << 8) | buffer[11];
> -
> - sd_read_protection_type(sdkp, buffer);
> - }
> + sector_size = read_capacity_10(sdkp, sdp, buffer);
> + if (sector_size == -EOVERFLOW)
> + goto got_data;
> + if (sector_size < 0)
> + return;
> + if ((sizeof(sdkp->capacity) > 4) &&
> + (sdkp->capacity > 0xffffffffULL)) {
> + int old_sector_size = sector_size;
> + sd_printk(KERN_NOTICE, sdkp, "Very big device. "
> + "Trying to use READ CAPACITY(16).\n");
> + sector_size = read_capacity_16(sdkp, sdp, buffer);
> + if (sector_size < 0) {
> + sd_printk(KERN_NOTICE, sdkp,
> + "Using 0xffffffff as device size\n");
> + sdkp->capacity = 1 + (sector_t) 0xffffffff;
> + sector_size = old_sector_size;
> + goto got_data;
> + }
> + }
> + }
>
> /* Some devices return the total number of sectors, not the
> * highest sector number. Make the necessary adjustment. */
>
> --
> Matthew Wilcox Intel Open Source Technology Centre
> "Bill, look, we understand that you're interested in selling us this
> operating system, but compare it to ours. We can't possibly take such
> a retrograde step."
--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
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