[SCSI] Support devices with protection information

Implement support for DMA of protection information for devices that
are data integrity capable.

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

 - Allocate protection scsi_data_buffer if host is DIX (integrity DMA)
   capable.

 - Accessor function for checking whether a device has protection
   enabled.

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

diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 5276e73..ee6be59 100644 (file)
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -197,11 +197,43 @@ static void
 scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
                         struct scsi_cmnd *cmd)
 {
+       if (cmd->prot_sdb)
+               kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
+
        kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
        kmem_cache_free(pool->cmd_slab, cmd);
 }
 
 /**
+ * scsi_host_alloc_command - internal function to allocate command
+ * @shost:     SCSI host whose pool to allocate from
+ * @gfp_mask:  mask for the allocation
+ *
+ * Returns a fully allocated command with sense buffer and protection
+ * data buffer (where applicable) or NULL on failure
+ */
+static struct scsi_cmnd *
+scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
+{
+       struct scsi_cmnd *cmd;
+
+       cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
+       if (!cmd)
+               return NULL;
+
+       if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
+               cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
+
+               if (!cmd->prot_sdb) {
+                       scsi_pool_free_command(shost->cmd_pool, cmd);
+                       return NULL;
+               }
+       }
+
+       return cmd;
+}
+
+/**
  * __scsi_get_command - Allocate a struct scsi_cmnd
  * @shost: host to transmit command
  * @gfp_mask: allocation mask
@@ -214,7 +246,7 @@ struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
        struct scsi_cmnd *cmd;
        unsigned char *buf;
 
-       cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
+       cmd = scsi_host_alloc_command(shost, gfp_mask);
 
        if (unlikely(!cmd)) {
                unsigned long flags;
@@ -457,7 +489,7 @@ int scsi_setup_command_freelist(struct Scsi_Host *shost)
        /*
         * Get one backup command for this host.
         */
-       cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
+       cmd = scsi_host_alloc_command(shost, gfp_mask);
        if (!cmd) {
                scsi_put_host_cmd_pool(gfp_mask);
                shost->cmd_pool = NULL;

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index fe77cca..a47c05d 100644 (file)
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -65,7 +65,7 @@ static struct scsi_host_sg_pool scsi_sg_pools[] = {
 };
 #undef SP
 
-static struct kmem_cache *scsi_sdb_cache;
+struct kmem_cache *scsi_sdb_cache;
 
 static void scsi_run_queue(struct request_queue *q);
 
@@ -787,6 +787,9 @@ void scsi_release_buffers(struct scsi_cmnd *cmd)
                kmem_cache_free(scsi_sdb_cache, bidi_sdb);
                cmd->request->next_rq->special = NULL;
        }
+
+       if (scsi_prot_sg_count(cmd))
+               scsi_free_sgtable(cmd->prot_sdb);
 }
 EXPORT_SYMBOL(scsi_release_buffers);
 
@@ -1072,6 +1075,26 @@ int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
                        goto err_exit;
        }
 
+       if (blk_integrity_rq(cmd->request)) {
+               struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
+               int ivecs, count;
+
+               BUG_ON(prot_sdb == NULL);
+               ivecs = blk_rq_count_integrity_sg(cmd->request);
+
+               if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) {
+                       error = BLKPREP_DEFER;
+                       goto err_exit;
+               }
+
+               count = blk_rq_map_integrity_sg(cmd->request,
+                                               prot_sdb->table.sgl);
+               BUG_ON(unlikely(count > ivecs));
+
+               cmd->prot_sdb = prot_sdb;
+               cmd->prot_sdb->table.nents = count;
+       }
+
        return BLKPREP_OK ;
 
 err_exit:

diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
index b33e725..79f0f75 100644 (file)
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -77,6 +77,7 @@ extern void scsi_exit_queue(void);
 struct request_queue;
 struct request;
 extern int scsi_prep_fn(struct request_queue *, struct request *);
+extern struct kmem_cache *scsi_sdb_cache;
 
 /* scsi_proc.c */
 #ifdef CONFIG_SCSI_PROC_FS

diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 402c107..f9f6e79 100644 (file)
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -90,6 +90,8 @@ struct scsi_cmnd {
 
        /* These elements define the operation we ultimately want to perform */
        struct scsi_data_buffer sdb;
+       struct scsi_data_buffer *prot_sdb;
+
        unsigned underflow;     /* Return error if less than
                                   this amount is transferred */
 
@@ -274,4 +276,22 @@ static inline sector_t scsi_get_lba(struct scsi_cmnd *scmd)
        return scmd->request->sector;
 }
 
+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)
+
 #endif /* _SCSI_SCSI_CMND_H */

diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 4deb934..9cecc40 100644 (file)
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -423,6 +423,11 @@ static inline int scsi_device_enclosure(struct scsi_device *sdev)
        return sdev->inquiry[6] & (1<<6);
 }
 
+static inline int scsi_device_protection(struct scsi_device *sdev)
+{
+       return sdev->inquiry[5] & (1<<0);
+}
+
 #define MODULE_ALIAS_SCSI_DEVICE(type) \
        MODULE_ALIAS("scsi:t-" __stringify(type) "*")
 #define SCSI_DEVICE_MODALIAS_FMT "scsi:t-0x%02x"