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Commit e507e30b authored by James Bottomley's avatar James Bottomley
Browse files

[SCSI] consolidate command allocation in a single place 



Since the way we allocate commands with a separate sense buffer is
getting complicated, we should isolate setup and teardown to a single
routine so that if it gets even more complex, there's only one place
in the code that needs to be altered.

Signed-off-by: default avatarJames Bottomley <James.Bottomley@HansenPartnership.com>
parent 035f5e06

drivers/scsi/scsi.c

+50 −32
Original line number Diff line number Diff line
@@ -165,6 +165,51 @@ 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_alloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);

	if (!cmd)

		return NULL;



	memset(cmd, 0, sizeof(*cmd));



	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

 * @cmd:	command to release

 *

 * the command must previously have been allocated by

 * scsi_pool_alloc_command.

 */

static void

scsi_pool_free_command(struct scsi_host_cmd_pool *pool,

			 struct scsi_cmnd *cmd)

{

	kmem_cache_free(pool->sense_slab, cmd->sense_buffer);

	kmem_cache_free(pool->cmd_slab, cmd);

}



/**

 * __scsi_get_command - Allocate a struct scsi_cmnd

 * @shost: host to transmit command
@@ -178,20 +223,7 @@ struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask) 
	struct scsi_cmnd *cmd;

	unsigned char *buf;



	cmd = kmem_cache_alloc(shost->cmd_pool->cmd_slab,

			       gfp_mask | shost->cmd_pool->gfp_mask);



	if (likely(cmd)) {

		buf = kmem_cache_alloc(shost->cmd_pool->sense_slab,

				       gfp_mask | shost->cmd_pool->gfp_mask);

		if (likely(buf)) {

			memset(cmd, 0, sizeof(*cmd));

			cmd->sense_buffer = buf;

		} else {

			kmem_cache_free(shost->cmd_pool->cmd_slab, cmd);

			cmd = NULL;

		}

	}

	cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);



	if (unlikely(!cmd)) {

		unsigned long flags;
@@ -268,11 +300,8 @@ void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd, 
	}

	spin_unlock_irqrestore(&shost->free_list_lock, flags);



	if (likely(cmd != NULL)) {

		kmem_cache_free(shost->cmd_pool->sense_slab,

				cmd->sense_buffer);

		kmem_cache_free(shost->cmd_pool->cmd_slab, cmd);

	}

	if (likely(cmd != NULL))

		scsi_pool_free_command(shost->cmd_pool, cmd);



	put_device(dev);

}
@@ -348,23 +377,14 @@ int scsi_setup_command_freelist(struct Scsi_Host *shost) 
	/*

	 * Get one backup command for this host.

	 */

	cmd = kmem_cache_alloc(shost->cmd_pool->cmd_slab,

			       GFP_KERNEL | shost->cmd_pool->gfp_mask);

	cmd = scsi_pool_alloc_command(shost->cmd_pool, GFP_KERNEL);

	if (!cmd)

		goto fail2;



	cmd->sense_buffer = kmem_cache_alloc(shost->cmd_pool->sense_slab,

					     GFP_KERNEL |

					     shost->cmd_pool->gfp_mask);

	if (!cmd->sense_buffer)

		goto fail2;



	list_add(&cmd->list, &shost->free_list);

	return 0;



 fail2:

	if (cmd)

		kmem_cache_free(shost->cmd_pool->cmd_slab, cmd);

	mutex_lock(&host_cmd_pool_mutex);

	if (!--pool->users) {

		kmem_cache_destroy(pool->cmd_slab);
@@ -386,9 +406,7 @@ 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);

		kmem_cache_free(shost->cmd_pool->sense_slab,

				cmd->sense_buffer);

		kmem_cache_free(shost->cmd_pool->cmd_slab, cmd);

		scsi_pool_free_command(shost->cmd_pool, cmd);

	}



	mutex_lock(&host_cmd_pool_mutex);