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Subject[PATCH 6 of 7] scsi: Support devices with protection information (DIF)
Date
From
5 files changed, 90 insertions(+)
drivers/scsi/Kconfig | 15 +++++++++++++++
drivers/scsi/scsi_lib.c | 42 ++++++++++++++++++++++++++++++++++++++++++
drivers/scsi/scsi_scan.c | 3 +++
include/scsi/scsi_cmnd.h | 29 +++++++++++++++++++++++++++++
include/scsi/scsi_device.h | 1 +

- Add support for an extra scatter-gather list containing protection
information.

- Remember devices with protection information turned on in INQUIRY.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

---
diff -r 5be7c534c954 -r ad65bfde4e05 drivers/scsi/Kconfig
--- a/drivers/scsi/Kconfig Sat Jun 07 00:45:15 2008 -0400
+++ b/drivers/scsi/Kconfig Sat Jun 07 00:45:15 2008 -0400
@@ -260,6 +260,21 @@
default m
depends on SCSI
depends on MODULES
+
+config SCSI_PROTECTION
+ bool "SCSI Data Integrity Protection"
+ depends on SCSI
+ depends on BLK_DEV_INTEGRITY
+ help
+ Some SCSI devices support data protection features above and
+ beyond those implemented in the transport. Select this
+ option to enable protection information to be transferred to
+ and from a device. Specifically, this option will enable DIF
+ (Data Integrity Field) for SCSI disks.
+
+ The SCSI protection features depend on the block layer data
+ integrity infrastructure so the latter must be enabled for
+ this option to work.

menu "SCSI Transports"
depends on SCSI
diff -r 5be7c534c954 -r ad65bfde4e05 drivers/scsi/scsi_lib.c
--- a/drivers/scsi/scsi_lib.c Sat Jun 07 00:45:15 2008 -0400
+++ b/drivers/scsi/scsi_lib.c Sat Jun 07 00:45:15 2008 -0400
@@ -778,6 +778,13 @@
kmem_cache_free(scsi_sdb_cache, bidi_sdb);
cmd->request->next_rq->special = NULL;
}
+
+#if defined(CONFIG_SCSI_PROTECTION)
+ if (scsi_prot_sg_count(cmd)) {
+ scsi_free_sgtable(cmd->prot_sdb);
+ kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
+ }
+#endif
}
EXPORT_SYMBOL(scsi_release_buffers);

@@ -1031,6 +1038,32 @@
return BLKPREP_OK;
}

+#if defined(CONFIG_SCSI_PROTECTION)
+static int scsi_protect_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
+{
+ struct request *req = cmd->request;
+ struct scsi_data_buffer *pdb;
+ int ivecs, count;
+
+ pdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
+ if (unlikely(pdb == NULL))
+ return BLKPREP_DEFER;
+
+ ivecs = blk_rq_count_integrity_sg(req);
+
+ if (unlikely(scsi_alloc_sgtable(pdb, ivecs, gfp_mask)))
+ return BLKPREP_DEFER;
+
+ count = blk_rq_map_integrity_sg(req, pdb->table.sgl);
+ BUG_ON(unlikely(count > ivecs));
+
+ cmd->prot_sdb = pdb;
+ cmd->prot_sdb->table.nents = count;
+
+ return BLKPREP_OK;
+}
+#endif
+
/*
* Function: scsi_init_io()
*
@@ -1062,6 +1095,15 @@
if (error)
goto err_exit;
}
+
+#if defined(CONFIG_SCSI_PROTECTION)
+ if (blk_integrity_rq(cmd->request)) {
+ error = scsi_protect_io(cmd, gfp_mask);
+
+ if (error != BLKPREP_OK)
+ goto err_exit;
+ }
+#endif

return BLKPREP_OK ;

diff -r 5be7c534c954 -r ad65bfde4e05 drivers/scsi/scsi_scan.c
--- a/drivers/scsi/scsi_scan.c Sat Jun 07 00:45:15 2008 -0400
+++ b/drivers/scsi/scsi_scan.c Sat Jun 07 00:45:15 2008 -0400
@@ -882,6 +882,9 @@

if (*bflags & BLIST_USE_10_BYTE_MS)
sdev->use_10_for_ms = 1;
+
+ if (inq_result[5] & 0x1)
+ sdev->protection = 1;

/* set the device running here so that slave configure
* may do I/O */
diff -r 5be7c534c954 -r ad65bfde4e05 include/scsi/scsi_cmnd.h
--- a/include/scsi/scsi_cmnd.h Sat Jun 07 00:45:15 2008 -0400
+++ b/include/scsi/scsi_cmnd.h Sat Jun 07 00:45:15 2008 -0400
@@ -88,6 +88,9 @@

/* These elements define the operation we ultimately want to perform */
struct scsi_data_buffer sdb;
+#if defined(CONFIG_SCSI_PROTECTION)
+ struct scsi_data_buffer *prot_sdb;
+#endif
unsigned underflow; /* Return error if less than
this amount is transferred */

@@ -209,4 +212,30 @@
buf, buflen);
}

+#if defined(CONFIG_SCSI_PROTECTION)
+
+static inline unsigned scsi_prot_sg_count(struct scsi_cmnd *cmd)
+{
+ return cmd->prot_sdb ? cmd->prot_sdb->table.nents : 0;
+}
+
+static inline struct scatterlist *scsi_prot_sglist(struct scsi_cmnd *cmd)
+{
+ return cmd->prot_sdb ? cmd->prot_sdb->table.sgl : NULL;
+}
+
+static inline struct scsi_data_buffer *scsi_prot(struct scsi_cmnd *cmd)
+{
+ return cmd->prot_sdb;
+}
+
+#define scsi_for_each_prot_sg(cmd, sg, nseg, __i) \
+ for_each_sg(scsi_prot_sglist(cmd), sg, nseg, __i)
+
+#else /* CONFIG_SCSI_PROTECTION */
+
+#define scsi_prot_sg_count(a) (0)
+
+#endif /* CONFIG_SCSI_PROTECTION */
+
#endif /* _SCSI_SCSI_CMND_H */
diff -r 5be7c534c954 -r ad65bfde4e05 include/scsi/scsi_device.h
--- a/include/scsi/scsi_device.h Sat Jun 07 00:45:15 2008 -0400
+++ b/include/scsi/scsi_device.h Sat Jun 07 00:45:15 2008 -0400
@@ -140,6 +140,7 @@
unsigned guess_capacity:1; /* READ_CAPACITY might be too high by 1 */
unsigned retry_hwerror:1; /* Retry HARDWARE_ERROR */
unsigned last_sector_bug:1; /* Always read last sector in a 1 sector read */
+ unsigned protection:1; /* Data Integrity Field */

DECLARE_BITMAP(supported_events, SDEV_EVT_MAXBITS); /* supported events */
struct list_head event_list; /* asserted events */



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