Now that no low level driver relies on ISA DMAable scsi_cmnds anymore
it is safe to always use the same static slab for them.
Signed-off-by: Andi Kleen <ak@xxxxxxx>
Signed-off-by: Andi Kleen <andi@xxxxxxxxxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
drivers/scsi/scsi.c | 58 +++++++++++++++++++++++++++-------------------------
1 file changed, 31 insertions(+), 27 deletions(-)
Index: linux/drivers/scsi/scsi.c
===================================================================
--- linux.orig/drivers/scsi/scsi.c
+++ linux/drivers/scsi/scsi.c
@@ -131,24 +131,24 @@ const char * scsi_device_type(unsigned t
EXPORT_SYMBOL(scsi_device_type);
+/* Writing of both protected by host_cmd_pool_mutex */
+static struct kmem_cache *scsi_cmd_slab;
+static int cmd_pool_users;
+
struct scsi_host_cmd_pool {
- struct kmem_cache *cmd_slab;
struct kmem_cache *sense_slab;
unsigned int users;
- char *cmd_name;
char *sense_name;
unsigned int slab_flags;
gfp_t gfp_mask;
};
-static struct scsi_host_cmd_pool scsi_cmd_pool = {
- .cmd_name = "scsi_cmd_cache",
+static struct scsi_host_cmd_pool scsi_sense_pool = {
.sense_name = "scsi_sense_cache",
.slab_flags = SLAB_HWCACHE_ALIGN,
};
-static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
- .cmd_name = "scsi_cmd_cache(DMA)",
+static struct scsi_host_cmd_pool scsi_sense_dma_pool = {
.sense_name = "scsi_sense_cache(DMA)",
.slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
.gfp_mask = __GFP_DMA,
@@ -169,7 +169,7 @@ scsi_pool_alloc_command(struct scsi_host
{
struct scsi_cmnd *cmd;
- cmd = kmem_cache_alloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
+ cmd = kmem_cache_alloc(scsi_cmd_slab, gfp_mask);
if (!cmd)
return NULL;
@@ -178,7 +178,7 @@ scsi_pool_alloc_command(struct scsi_host
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);
+ kmem_cache_free(scsi_cmd_slab, cmd);
return NULL;
}
@@ -201,7 +201,7 @@ scsi_pool_free_command(struct scsi_host_
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);
+ kmem_cache_free(scsi_cmd_slab, cmd);
}
/**
@@ -362,21 +362,26 @@ scsi_get_host_cmd_pool(struct Scsi_Host
* yet existent.
*/
mutex_lock(&host_cmd_pool_mutex);
- pool = &scsi_cmd_pool;
- if (shost && (shost->unchecked_isa_dma || shost->sense_buffer_isa))
- pool = &scsi_cmd_dma_pool;
+ if (!scsi_cmd_slab) {
+ scsi_cmd_slab = kmem_cache_create("scsi_cmd_pool",
+ sizeof(struct scsi_cmnd), 0,
+ 0, NULL);
+ }
+ if (!scsi_cmd_slab)
+ goto fail;
+ cmd_pool_users++;
+
+ pool = &scsi_sense_pool;
+ if (shost && shost->sense_buffer_isa)
+ pool = &scsi_sense_dma_pool;
if (!pool->users) {
- pool->cmd_slab = kmem_cache_create(pool->cmd_name,
- sizeof(struct scsi_cmnd), 0,
- pool->slab_flags, NULL);
- if (!pool->cmd_slab)
- goto fail;
-
pool->sense_slab = kmem_cache_create(pool->sense_name,
SCSI_SENSE_BUFFERSIZE, 0,
pool->slab_flags, NULL);
if (!pool->sense_slab) {
- kmem_cache_destroy(pool->cmd_slab);
+ kmem_cache_destroy(scsi_cmd_slab);
+ scsi_cmd_slab = NULL;
+ cmd_pool_users--;
goto fail;
}
}
@@ -393,8 +398,8 @@ static void scsi_put_host_cmd_pool(struc
struct scsi_host_cmd_pool *pool;
mutex_lock(&host_cmd_pool_mutex);
- pool = (shost && (shost->unchecked_isa_dma || shost->sense_buffer_isa)) ?
- &scsi_cmd_dma_pool : &scsi_cmd_pool;
+ pool = (shost && shost->sense_buffer_isa) ?
+ &scsi_sense_dma_pool : &scsi_sense_pool;
/*
* This may happen if a driver has a mismatched get and put
* of the command pool; the driver should be implicated in
@@ -402,9 +407,11 @@ static void scsi_put_host_cmd_pool(struc
*/
BUG_ON(pool->users == 0);
- if (!--pool->users) {
- kmem_cache_destroy(pool->cmd_slab);
+ if (!--pool->users)
kmem_cache_destroy(pool->sense_slab);
+ if (!--cmd_pool_users) {
+ kmem_cache_destroy(scsi_cmd_slab);
+ scsi_cmd_slab = NULL;
}
mutex_unlock(&host_cmd_pool_mutex);
}
@@ -489,9 +496,6 @@ EXPORT_SYMBOL(scsi_free_command);
int scsi_setup_command_freelist(struct Scsi_Host *shost)
{
struct scsi_cmnd *cmd;
- gfp_t gfp_mask = GFP_KERNEL;
- if (shost->unchecked_isa_dma || shost->sense_buffer_isa)
- gfp_mask = GFP_DMA;
spin_lock_init(&shost->free_list_lock);
INIT_LIST_HEAD(&shost->free_list);
@@ -504,7 +508,7 @@ int scsi_setup_command_freelist(struct S
/*
* Get one backup command for this host.
*/
- cmd = scsi_host_alloc_command(shost, gfp_mask);
+ cmd = scsi_host_alloc_command(shost, 0);
if (!cmd) {
scsi_put_host_cmd_pool(shost);
shost->cmd_pool = NULL;
--
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