[SCSI] simplify command allocation and freeing a bit

Just have one level of alloc/free functions that take a host instead
of two levels for the allocation and different calling conventions
for the free.

[fengguang.wu@intel.com: docbook problems spotted, now fixed]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/scsi.c

@@ -161,47 +161,20 @@ static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
 static DEFINE_MUTEX(host_cmd_pool_mutex);
 
 /**
- * scsi_pool_alloc_command - internal function to get a fully allocated command
- * @pool:	slab pool to allocate the command from
- * @gfp_mask:	mask for the allocation
- *
- * Returns a fully allocated command (with the allied sense buffer) or
- * NULL on failure
- */
-static struct scsi_cmnd *
-scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
-{
-	struct scsi_cmnd *cmd;
-
-	cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
-	if (!cmd)
-		return NULL;
-
-	cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
-					     gfp_mask | pool->gfp_mask);
-	if (!cmd->sense_buffer) {
-		kmem_cache_free(pool->cmd_slab, cmd);
-		return NULL;
-	}
-
-	return cmd;
-}
-
-/**
- * scsi_pool_free_command - internal function to release a command
- * @pool:	slab pool to allocate the command from
+ * scsi_host_free_command - internal function to release a command
+ * @shost:	host to free the command for
  * @cmd:	command to release
  *
  * the command must previously have been allocated by
- * scsi_pool_alloc_command.
+ * scsi_host_alloc_command.
  */
 static void
-scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
-			 struct scsi_cmnd *cmd)
+scsi_host_free_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
 {
+	struct scsi_host_cmd_pool *pool = shost->cmd_pool;
+
 	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);
 }
@@ -217,22 +190,32 @@ scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
 static struct scsi_cmnd *
 scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
 {
+	struct scsi_host_cmd_pool *pool = shost->cmd_pool;
 	struct scsi_cmnd *cmd;
 
-	cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
+	cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
 	if (!cmd)
-		return NULL;
+		goto fail;
+
+	cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
+					     gfp_mask | pool->gfp_mask);
+	if (!cmd->sense_buffer)
+		goto fail_free_cmd;
 
 	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;
-		}
+		if (!cmd->prot_sdb)
+			goto fail_free_sense;
 	}
 
 	return cmd;
+
+fail_free_sense:
+	kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
+fail_free_cmd:
+	kmem_cache_free(pool->cmd_slab, cmd);
+fail:
+	return NULL;
 }
 
 /**
@@ -320,7 +303,7 @@ void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
 	}
 
 	if (likely(cmd != NULL))
-		scsi_pool_free_command(shost->cmd_pool, cmd);
+		scsi_host_free_command(shost, cmd);
 }
 EXPORT_SYMBOL(__scsi_put_command);
 
@@ -456,7 +439,7 @@ void scsi_destroy_command_freelist(struct Scsi_Host *shost)
 
 		cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
 		list_del_init(&cmd->list);
-		scsi_pool_free_command(shost->cmd_pool, cmd);
+		scsi_host_free_command(shost, cmd);
 	}
 	shost->cmd_pool = NULL;
 	scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);