3.16.52-rc1 review patch. If anyone has any objections, please let me know.
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From: "Martin K. Petersen" martin.petersen@oracle.com
commit 28a0bc4120d38a394499382ba21d6965a67a3703 upstream.
SBC-4 states:
"A MAXIMUM UNMAP LBA COUNT field set to a non-zero value indicates the maximum number of LBAs that may be unmapped by an UNMAP command"
"A MAXIMUM WRITE SAME LENGTH field set to a non-zero value indicates the maximum number of contiguous logical blocks that the device server allows to be unmapped or written in a single WRITE SAME command."
Despite the spec being clear on the topic, some devices incorrectly expect WRITE SAME commands with the UNMAP bit set to be limited to the value reported in MAXIMUM UNMAP LBA COUNT in the Block Limits VPD.
Implement a blacklist option that can be used to accommodate devices with this behavior.
Reported-by: Bill Kuzeja William.Kuzeja@stratus.com Reported-by: Ewan D. Milne emilne@redhat.com Reviewed-by: Ewan D. Milne emilne@redhat.com Tested-by: Laurence Oberman loberman@redhat.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/scsi/scsi_scan.c | 3 +++ drivers/scsi/sd.c | 16 ++++++++++++---- include/scsi/scsi_device.h | 1 + include/scsi/scsi_devinfo.h | 1 + 4 files changed, 17 insertions(+), 4 deletions(-)
--- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -962,6 +962,9 @@ static int scsi_add_lun(struct scsi_devi if (*bflags & BLIST_NO_DIF) sdev->no_dif = 1;
+ if (*bflags & BLIST_UNMAP_LIMIT_WS) + sdev->unmap_limit_for_ws = 1; + sdev->eh_timeout = SCSI_DEFAULT_EH_TIMEOUT;
if (*bflags & BLIST_TRY_VPD_PAGES) --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -651,13 +651,21 @@ static void sd_config_discard(struct scs break;
case SD_LBP_WS16: - max_blocks = min_not_zero(sdkp->max_ws_blocks, - (u32)SD_MAX_WS16_BLOCKS); + if (sdkp->device->unmap_limit_for_ws) + max_blocks = sdkp->max_unmap_blocks; + else + max_blocks = sdkp->max_ws_blocks; + + max_blocks = min_not_zero(max_blocks, (u32)SD_MAX_WS16_BLOCKS); break;
case SD_LBP_WS10: - max_blocks = min_not_zero(sdkp->max_ws_blocks, - (u32)SD_MAX_WS10_BLOCKS); + if (sdkp->device->unmap_limit_for_ws) + max_blocks = sdkp->max_unmap_blocks; + else + max_blocks = sdkp->max_ws_blocks; + + max_blocks = min_not_zero(max_blocks, (u32)SD_MAX_WS10_BLOCKS); break;
case SD_LBP_ZERO: --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -175,6 +175,7 @@ struct scsi_device { unsigned wce_default_on:1; /* Cache is ON by default */ unsigned no_dif:1; /* T10 PI (DIF) should be disabled */ unsigned broken_fua:1; /* Don't set FUA bit */ + unsigned unmap_limit_for_ws:1; /* Use the UNMAP limit for WRITE SAME */
atomic_t disk_events_disable_depth; /* disable depth for disk events */
--- a/include/scsi/scsi_devinfo.h +++ b/include/scsi/scsi_devinfo.h @@ -37,5 +37,6 @@ #define BLIST_TRY_VPD_PAGES 0x10000000 /* Attempt to read VPD pages */ #define BLIST_NO_RSOC 0x20000000 /* don't try to issue RSOC */ #define BLIST_MAX_1024 0x40000000 /* maximum 1024 sector cdb length */ +#define BLIST_UNMAP_LIMIT_WS 0x80000000 /* Use UNMAP limit for WRITE SAME */
#endif