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authorMartin K. Petersen <martin.petersen@oracle.com>2012-09-18 20:19:32 +0400
committerJames Bottomley <JBottomley@Parallels.com>2012-11-14 10:45:42 +0400
commit5db44863b6ebbb400c5e61d56ebe8f21ef48b1bd (patch)
treea352bab202b6cb40f234bd2fd306b54776543e8b /drivers/scsi/sd.h
parent26e85fcd15f68b57d9ba645cd3591117a8ac0e05 (diff)
downloadlinux-5db44863b6ebbb400c5e61d56ebe8f21ef48b1bd.tar.xz
[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>
Diffstat (limited to 'drivers/scsi/sd.h')
-rw-r--r--drivers/scsi/sd.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 47c52a6d733c..74a1e4ca5401 100644
--- a/drivers/scsi/sd.h
+++ b/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)