scsi: block: Introduce BLK_STS_DURATION_LIMIT

Introduce the new block I/O status BLK_STS_DURATION_LIMIT for LLDDs to
report command that failed due to a command duration limit being
exceeded. This new status is mapped to the ETIME error code to allow users
to differentiate "soft" duration limit failures from other more serious
hardware related errors.

If we compare BLK_STS_DURATION_LIMIT with BLK_STS_TIMEOUT:
-BLK_STS_DURATION_LIMIT means that the drive gave a reply indicating that
the command duration limit was exceeded before the command could be
completed. This I/O status is mapped to ETIME for user space.

-BLK_STS_TIMEOUT means that the drive never gave a reply at all.
This I/O status is mapped to ETIMEDOUT for user space.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Co-developed-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
Link: https://lore.kernel.org/r/20230511011356.227789-4-nks@flawful.orgSigned-off-by: Martin K. Petersen <martin.petersen@oracle.com>

block/blk-core.c

@@ -170,6 +170,9 @@ static const struct {
 	[BLK_STS_ZONE_OPEN_RESOURCE]	= { -ETOOMANYREFS, "open zones exceeded" },
 	[BLK_STS_ZONE_ACTIVE_RESOURCE]	= { -EOVERFLOW, "active zones exceeded" },
 
+	/* Command duration limit device-side timeout */
+	[BLK_STS_DURATION_LIMIT]	= { -ETIME, "duration limit exceeded" },
+
 	/* everything else not covered above: */
 	[BLK_STS_IOERR]		= { -EIO,	"I/O" },
 };

include/linux/blk_types.h

@@ -171,6 +171,12 @@ typedef u16 blk_short_t;
  */
 #define BLK_STS_OFFLINE		((__force blk_status_t)17)
 
+/*
+ * BLK_STS_DURATION_LIMIT is returned from the driver when the target device
+ * aborted the command because it exceeded one of its Command Duration Limits.
+ */
+#define BLK_STS_DURATION_LIMIT	((__force blk_status_t)18)
+
 /**
  * blk_path_error - returns true if error may be path related
  * @error: status the request was completed with