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[SCSI] sd: Implement support for WRITE SAME

Implement support for WRITE SAME(10) and WRITE SAME(16) in the SCSI disk
driver.

 - We set the default maximum to 0xFFFF because there are several
   devices out there that only support two-byte block counts even with
   WRITE SAME(16). We only enable transfers bigger than 0xFFFF if the
   device explicitly reports MAXIMUM WRITE SAME LENGTH in the BLOCK
   LIMITS VPD.

 - max_write_same_blocks can be overriden per-device basis in sysfs.

 - The UNMAP discovery heuristics remain unchanged but the discard
   limits are tweaked to match the "real" WRITE SAME commands.

 - In the error handling logic we now distinguish between WRITE SAME
   with and without UNMAP set.

The discovery process heuristics are:

 - If the device reports a SCSI level of SPC-3 or greater we'll issue
   READ SUPPORTED OPERATION CODES to find out whether WRITE SAME(16) is
   supported. If that's the case we will use it.

 - If the device supports the block limits VPD and reports a MAXIMUM
   WRITE SAME LENGTH bigger than 0xFFFF we will use WRITE SAME(16).

 - Otherwise we will use WRITE SAME(10) unless the target LBA is beyond
   0xFFFFFFFF or the block count exceeds 0xFFFF.

 - no_write_same is set for ATA, FireWire and USB.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
  • Loading branch information...
commit 5db44863b6ebbb400c5e61d56ebe8f21ef48b1bd 1 parent 26e85fc
Martin K. Petersen authored jejb committed
View
1  drivers/ata/libata-scsi.c
@@ -1053,6 +1053,7 @@ static void ata_scsi_sdev_config(struct scsi_device *sdev)
sdev->use_10_for_rw = 1;
sdev->use_10_for_ms = 1;
sdev->no_report_opcodes = 1;
+ sdev->no_write_same = 1;
/* Schedule policy is determined by ->qc_defer() callback and
* it needs to see every deferred qc. Set dev_blocked to 1 to
View
1  drivers/firewire/sbp2.c
@@ -1547,6 +1547,7 @@ static int sbp2_scsi_slave_configure(struct scsi_device *sdev)
sdev->use_10_for_rw = 1;
sdev->no_report_opcodes = 1;
+ sdev->no_write_same = 1;
if (sbp2_param_exclusive_login)
sdev->manage_start_stop = 1;
View
22 drivers/scsi/scsi_lib.c
@@ -900,11 +900,23 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
action = ACTION_FAIL;
error = -EILSEQ;
/* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
- } else if ((sshdr.asc == 0x20 || sshdr.asc == 0x24) &&
- (cmd->cmnd[0] == UNMAP ||
- cmd->cmnd[0] == WRITE_SAME_16 ||
- cmd->cmnd[0] == WRITE_SAME)) {
- description = "Discard failure";
+ } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
+ switch (cmd->cmnd[0]) {
+ case UNMAP:
+ description = "Discard failure";
+ break;
+ case WRITE_SAME:
+ case WRITE_SAME_16:
+ if (cmd->cmnd[1] & 0x8)
+ description = "Discard failure";
+ else
+ description =
+ "Write same failure";
+ break;
+ default:
+ description = "Invalid command failure";
+ break;
+ }
action = ACTION_FAIL;
error = -EREMOTEIO;
} else
View
172 drivers/scsi/sd.c
@@ -99,6 +99,7 @@ MODULE_ALIAS_SCSI_DEVICE(TYPE_RBC);
#endif
static void sd_config_discard(struct scsi_disk *, unsigned int);
+static void sd_config_write_same(struct scsi_disk *);
static int sd_revalidate_disk(struct gendisk *);
static void sd_unlock_native_capacity(struct gendisk *disk);
static int sd_probe(struct device *);
@@ -395,6 +396,45 @@ sd_store_max_medium_access_timeouts(struct device *dev,
return err ? err : count;
}
+static ssize_t
+sd_show_write_same_blocks(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct scsi_disk *sdkp = to_scsi_disk(dev);
+
+ return snprintf(buf, 20, "%u\n", sdkp->max_ws_blocks);
+}
+
+static ssize_t
+sd_store_write_same_blocks(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct scsi_disk *sdkp = to_scsi_disk(dev);
+ struct scsi_device *sdp = sdkp->device;
+ unsigned long max;
+ int err;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EACCES;
+
+ if (sdp->type != TYPE_DISK)
+ return -EINVAL;
+
+ err = kstrtoul(buf, 10, &max);
+
+ if (err)
+ return err;
+
+ if (max == 0)
+ sdp->no_write_same = 1;
+ else if (max <= SD_MAX_WS16_BLOCKS)
+ sdkp->max_ws_blocks = max;
+
+ sd_config_write_same(sdkp);
+
+ return count;
+}
+
static struct device_attribute sd_disk_attrs[] = {
__ATTR(cache_type, S_IRUGO|S_IWUSR, sd_show_cache_type,
sd_store_cache_type),
@@ -410,6 +450,8 @@ static struct device_attribute sd_disk_attrs[] = {
__ATTR(thin_provisioning, S_IRUGO, sd_show_thin_provisioning, NULL),
__ATTR(provisioning_mode, S_IRUGO|S_IWUSR, sd_show_provisioning_mode,
sd_store_provisioning_mode),
+ __ATTR(max_write_same_blocks, S_IRUGO|S_IWUSR,
+ sd_show_write_same_blocks, sd_store_write_same_blocks),
__ATTR(max_medium_access_timeouts, S_IRUGO|S_IWUSR,
sd_show_max_medium_access_timeouts,
sd_store_max_medium_access_timeouts),
@@ -561,19 +603,23 @@ static void sd_config_discard(struct scsi_disk *sdkp, unsigned int mode)
return;
case SD_LBP_UNMAP:
- max_blocks = min_not_zero(sdkp->max_unmap_blocks, 0xffffffff);
+ max_blocks = min_not_zero(sdkp->max_unmap_blocks,
+ (u32)SD_MAX_WS16_BLOCKS);
break;
case SD_LBP_WS16:
- max_blocks = min_not_zero(sdkp->max_ws_blocks, 0xffffffff);
+ max_blocks = min_not_zero(sdkp->max_ws_blocks,
+ (u32)SD_MAX_WS16_BLOCKS);
break;
case SD_LBP_WS10:
- max_blocks = min_not_zero(sdkp->max_ws_blocks, (u32)0xffff);
+ max_blocks = min_not_zero(sdkp->max_ws_blocks,
+ (u32)SD_MAX_WS10_BLOCKS);
break;
case SD_LBP_ZERO:
- max_blocks = min_not_zero(sdkp->max_ws_blocks, (u32)0xffff);
+ max_blocks = min_not_zero(sdkp->max_ws_blocks,
+ (u32)SD_MAX_WS10_BLOCKS);
q->limits.discard_zeroes_data = 1;
break;
}
@@ -667,6 +713,83 @@ static int sd_setup_discard_cmnd(struct scsi_device *sdp, struct request *rq)
return ret;
}
+static void sd_config_write_same(struct scsi_disk *sdkp)
+{
+ struct request_queue *q = sdkp->disk->queue;
+ unsigned int logical_block_size = sdkp->device->sector_size;
+ unsigned int blocks = 0;
+
+ if (sdkp->device->no_write_same) {
+ sdkp->max_ws_blocks = 0;
+ goto out;
+ }
+
+ /* Some devices can not handle block counts above 0xffff despite
+ * supporting WRITE SAME(16). Consequently we default to 64k
+ * blocks per I/O unless the device explicitly advertises a
+ * bigger limit.
+ */
+ if (sdkp->max_ws_blocks == 0)
+ sdkp->max_ws_blocks = SD_MAX_WS10_BLOCKS;
+
+ if (sdkp->ws16 || sdkp->max_ws_blocks > SD_MAX_WS10_BLOCKS)
+ blocks = min_not_zero(sdkp->max_ws_blocks,
+ (u32)SD_MAX_WS16_BLOCKS);
+ else
+ blocks = min_not_zero(sdkp->max_ws_blocks,
+ (u32)SD_MAX_WS10_BLOCKS);
+
+out:
+ blk_queue_max_write_same_sectors(q, blocks * (logical_block_size >> 9));
+}
+
+/**
+ * sd_setup_write_same_cmnd - write the same data to multiple blocks
+ * @sdp: scsi device to operate one
+ * @rq: Request to prepare
+ *
+ * Will issue either WRITE SAME(10) or WRITE SAME(16) depending on
+ * preference indicated by target device.
+ **/
+static int sd_setup_write_same_cmnd(struct scsi_device *sdp, struct request *rq)
+{
+ struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
+ struct bio *bio = rq->bio;
+ sector_t sector = blk_rq_pos(rq);
+ unsigned int nr_sectors = blk_rq_sectors(rq);
+ unsigned int nr_bytes = blk_rq_bytes(rq);
+ int ret;
+
+ if (sdkp->device->no_write_same)
+ return BLKPREP_KILL;
+
+ BUG_ON(bio_offset(bio) || bio_iovec(bio)->bv_len != sdp->sector_size);
+
+ sector >>= ilog2(sdp->sector_size) - 9;
+ nr_sectors >>= ilog2(sdp->sector_size) - 9;
+
+ rq->__data_len = sdp->sector_size;
+ rq->timeout = SD_WRITE_SAME_TIMEOUT;
+ memset(rq->cmd, 0, rq->cmd_len);
+
+ if (sdkp->ws16 || sector > 0xffffffff || nr_sectors > 0xffff) {
+ rq->cmd_len = 16;
+ rq->cmd[0] = WRITE_SAME_16;
+ put_unaligned_be64(sector, &rq->cmd[2]);
+ put_unaligned_be32(nr_sectors, &rq->cmd[10]);
+ } else {
+ rq->cmd_len = 10;
+ rq->cmd[0] = WRITE_SAME;
+ put_unaligned_be32(sector, &rq->cmd[2]);
+ put_unaligned_be16(nr_sectors, &rq->cmd[7]);
+ }
+
+ ret = scsi_setup_blk_pc_cmnd(sdp, rq);
+ rq->__data_len = nr_bytes;
+
+ return ret;
+}
+
static int scsi_setup_flush_cmnd(struct scsi_device *sdp, struct request *rq)
{
rq->timeout = SD_FLUSH_TIMEOUT;
@@ -712,6 +835,9 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
if (rq->cmd_flags & REQ_DISCARD) {
ret = sd_setup_discard_cmnd(sdp, rq);
goto out;
+ } else if (rq->cmd_flags & REQ_WRITE_SAME) {
+ ret = sd_setup_write_same_cmnd(sdp, rq);
+ goto out;
} else if (rq->cmd_flags & REQ_FLUSH) {
ret = scsi_setup_flush_cmnd(sdp, rq);
goto out;
@@ -1484,8 +1610,9 @@ static int sd_done(struct scsi_cmnd *SCpnt)
int sense_valid = 0;
int sense_deferred = 0;
unsigned char op = SCpnt->cmnd[0];
+ unsigned char unmap = SCpnt->cmnd[1] & 8;
- if (req->cmd_flags & REQ_DISCARD) {
+ if (req->cmd_flags & REQ_DISCARD || req->cmd_flags & REQ_WRITE_SAME) {
if (!result) {
good_bytes = blk_rq_bytes(req);
scsi_set_resid(SCpnt, 0);
@@ -1542,9 +1669,25 @@ static int sd_done(struct scsi_cmnd *SCpnt)
if (sshdr.asc == 0x10) /* DIX: Host detected corruption */
good_bytes = sd_completed_bytes(SCpnt);
/* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
- if ((sshdr.asc == 0x20 || sshdr.asc == 0x24) &&
- (op == UNMAP || op == WRITE_SAME_16 || op == WRITE_SAME))
- sd_config_discard(sdkp, SD_LBP_DISABLE);
+ if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
+ switch (op) {
+ case UNMAP:
+ sd_config_discard(sdkp, SD_LBP_DISABLE);
+ break;
+ case WRITE_SAME_16:
+ case WRITE_SAME:
+ if (unmap)
+ sd_config_discard(sdkp, SD_LBP_DISABLE);
+ else {
+ sdkp->device->no_write_same = 1;
+ sd_config_write_same(sdkp);
+
+ good_bytes = 0;
+ req->__data_len = blk_rq_bytes(req);
+ req->cmd_flags |= REQ_QUIET;
+ }
+ }
+ }
break;
default:
break;
@@ -2380,9 +2523,7 @@ static void sd_read_block_limits(struct scsi_disk *sdkp)
if (buffer[3] == 0x3c) {
unsigned int lba_count, desc_count;
- sdkp->max_ws_blocks =
- (u32) min_not_zero(get_unaligned_be64(&buffer[36]),
- (u64)0xffffffff);
+ sdkp->max_ws_blocks = (u32)get_unaligned_be64(&buffer[36]);
if (!sdkp->lbpme)
goto out;
@@ -2475,6 +2616,13 @@ static void sd_read_block_provisioning(struct scsi_disk *sdkp)
kfree(buffer);
}
+static void sd_read_write_same(struct scsi_disk *sdkp, unsigned char *buffer)
+{
+ if (scsi_report_opcode(sdkp->device, buffer, SD_BUF_SIZE,
+ WRITE_SAME_16))
+ sdkp->ws16 = 1;
+}
+
static int sd_try_extended_inquiry(struct scsi_device *sdp)
{
/*
@@ -2534,6 +2682,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
sd_read_write_protect_flag(sdkp, buffer);
sd_read_cache_type(sdkp, buffer);
sd_read_app_tag_own(sdkp, buffer);
+ sd_read_write_same(sdkp, buffer);
}
sdkp->first_scan = 0;
@@ -2551,6 +2700,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
blk_queue_flush(sdkp->disk->queue, flush);
set_capacity(disk, sdkp->capacity);
+ sd_config_write_same(sdkp);
kfree(buffer);
out:
View
7 drivers/scsi/sd.h
@@ -14,6 +14,7 @@
#define SD_TIMEOUT (30 * HZ)
#define SD_MOD_TIMEOUT (75 * HZ)
#define SD_FLUSH_TIMEOUT (60 * HZ)
+#define SD_WRITE_SAME_TIMEOUT (120 * HZ)
/*
* Number of allowed retries
@@ -39,6 +40,11 @@ enum {
};
enum {
+ SD_MAX_WS10_BLOCKS = 0xffff,
+ SD_MAX_WS16_BLOCKS = 0x7fffff,
+};
+
+enum {
SD_LBP_FULL = 0, /* Full logical block provisioning */
SD_LBP_UNMAP, /* Use UNMAP command */
SD_LBP_WS16, /* Use WRITE SAME(16) with UNMAP bit */
@@ -77,6 +83,7 @@ struct scsi_disk {
unsigned lbpws : 1;
unsigned lbpws10 : 1;
unsigned lbpvpd : 1;
+ unsigned ws16 : 1;
};
#define to_scsi_disk(obj) container_of(obj,struct scsi_disk,dev)
View
3  drivers/usb/storage/scsiglue.c
@@ -189,6 +189,9 @@ static int slave_configure(struct scsi_device *sdev)
/* Do not attempt to use REPORT SUPPORTED OPERATION CODES */
sdev->no_report_opcodes = 1;
+ /* Do not attempt to use WRITE SAME */
+ sdev->no_write_same = 1;
+
/* Some disks return the total number of blocks in response
* to READ CAPACITY rather than the highest block number.
* If this device makes that mistake, tell the sd driver. */
View
1  include/scsi/scsi_device.h
@@ -136,6 +136,7 @@ struct scsi_device {
unsigned use_10_for_rw:1; /* first try 10-byte read / write */
unsigned use_10_for_ms:1; /* first try 10-byte mode sense/select */
unsigned no_report_opcodes:1; /* no REPORT SUPPORTED OPERATION CODES */
+ unsigned no_write_same:1; /* no WRITE SAME command */
unsigned skip_ms_page_8:1; /* do not use MODE SENSE page 0x08 */
unsigned skip_ms_page_3f:1; /* do not use MODE SENSE page 0x3f */
unsigned skip_vpd_pages:1; /* do not read VPD pages */
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