[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>
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index c78b836..2cf9a62 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -166,6 +166,51 @@
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
* @gfp_mask: allocation mask
@@ -178,20 +223,7 @@
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 @@
}
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 @@
/*
* 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 @@
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);