From 5db44863b6ebbb400c5e61d56ebe8f21ef48b1bd Mon Sep 17 00:00:00 2001 From: "Martin K. Petersen" Date: Tue, 18 Sep 2012 12:19:32 -0400 Subject: [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 Reviewed-by: Mike Snitzer Reviewed-by: Jeff Garzik Signed-off-by: James Bottomley --- drivers/scsi/sd.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'drivers/scsi/sd.h') 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 @@ -38,6 +39,11 @@ enum { SD_MEMPOOL_SIZE = 2, /* CDB pool size */ }; +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 */ @@ -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) -- cgit v1.2.3