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[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: James Bottomley <James.Bottomley@HansenPartnership.com>
This commit is contained in:
James Bottomley 2008-03-13 11:16:33 -05:00
parent 035f5e0651
commit e507e30b80
1 changed files with 50 additions and 32 deletions
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82
drivers/scsi/scsi.c
View File

@ -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);