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[SCSI] don't use __GFP_DMA for sense buffers if not required
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Only hosts which actually have ISA DMA requirements need sense buffers
coming out of ZONE_DMA, so only use the __GFP_DMA flag for that case
to avoid allocating this scarce resource if it's not necessary.

[tomo: fixed slab leak in failure case]
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
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James Bottomley authored and James Bottomley committed Jan 23, 2008
1 parent de25deb commit 5b7f168
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Showing 3 changed files with 51 additions and 71 deletions.
9 changes: 1 addition & 8 deletions drivers/scsi/hosts.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -268,7 +268,6 @@ static void scsi_host_dev_release(struct device *dev)
}

scsi_destroy_command_freelist(shost);
scsi_destroy_command_sense_buffer(shost);
if (shost->bqt)
blk_free_tags(shost->bqt);

Expand Down Expand Up @@ -373,13 +372,9 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
else
shost->dma_boundary = 0xffffffff;

rval = scsi_setup_command_sense_buffer(shost);
if (rval)
goto fail_kfree;

rval = scsi_setup_command_freelist(shost);
if (rval)
goto fail_destroy_sense;
goto fail_kfree;

device_initialize(&shost->shost_gendev);
snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
Expand All @@ -404,8 +399,6 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)

fail_destroy_freelist:
scsi_destroy_command_freelist(shost);
fail_destroy_sense:
scsi_destroy_command_sense_buffer(shost);
fail_kfree:
kfree(shost);
return NULL;
Expand Down
111 changes: 50 additions & 61 deletions drivers/scsi/scsi.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -141,29 +141,30 @@ const char * scsi_device_type(unsigned type)
EXPORT_SYMBOL(scsi_device_type);

struct scsi_host_cmd_pool {
struct kmem_cache *slab;
unsigned int users;
char *name;
unsigned int slab_flags;
gfp_t gfp_mask;
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 = {
.name = "scsi_cmd_cache",
.cmd_name = "scsi_cmd_cache",
.sense_name = "scsi_sense_cache",
.slab_flags = SLAB_HWCACHE_ALIGN,
};

static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
.name = "scsi_cmd_cache(DMA)",
.cmd_name = "scsi_cmd_cache(DMA)",
.sense_name = "scsi_sense_cache(DMA)",
.slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
.gfp_mask = __GFP_DMA,
};

static DEFINE_MUTEX(host_cmd_pool_mutex);

static struct kmem_cache *sense_buffer_slab;
static int sense_buffer_slab_users;

/**
* __scsi_get_command - Allocate a struct scsi_cmnd
* @shost: host to transmit command
Expand All @@ -177,8 +178,8 @@ 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->slab,
gfp_mask | shost->cmd_pool->gfp_mask);
cmd = kmem_cache_alloc(shost->cmd_pool->cmd_slab,
gfp_mask | shost->cmd_pool->gfp_mask);

if (unlikely(!cmd)) {
unsigned long flags;
Expand All @@ -197,12 +198,13 @@ struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
cmd->sense_buffer = buf;
}
} else {
buf = kmem_cache_alloc(sense_buffer_slab, __GFP_DMA|gfp_mask);
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->slab, cmd);
kmem_cache_free(shost->cmd_pool->cmd_slab, cmd);
cmd = NULL;
}
}
Expand Down Expand Up @@ -265,8 +267,9 @@ 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(sense_buffer_slab, cmd->sense_buffer);
kmem_cache_free(shost->cmd_pool->slab, cmd);
kmem_cache_free(shost->cmd_pool->sense_slab,
cmd->sense_buffer);
kmem_cache_free(shost->cmd_pool->cmd_slab, cmd);
}

put_device(dev);
Expand Down Expand Up @@ -310,7 +313,6 @@ int scsi_setup_command_freelist(struct Scsi_Host *shost)
{
struct scsi_host_cmd_pool *pool;
struct scsi_cmnd *cmd;
unsigned char *sense_buffer;

spin_lock_init(&shost->free_list_lock);
INIT_LIST_HEAD(&shost->free_list);
Expand All @@ -322,11 +324,19 @@ int scsi_setup_command_freelist(struct Scsi_Host *shost)
mutex_lock(&host_cmd_pool_mutex);
pool = (shost->unchecked_isa_dma ? &scsi_cmd_dma_pool : &scsi_cmd_pool);
if (!pool->users) {
pool->slab = kmem_cache_create(pool->name,
sizeof(struct scsi_cmnd), 0,
pool->slab_flags, NULL);
if (!pool->slab)
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);
goto fail;
}
}

pool->users++;
Expand All @@ -336,26 +346,28 @@ int scsi_setup_command_freelist(struct Scsi_Host *shost)
/*
* Get one backup command for this host.
*/
cmd = kmem_cache_alloc(shost->cmd_pool->slab,
GFP_KERNEL | shost->cmd_pool->gfp_mask);
cmd = kmem_cache_alloc(shost->cmd_pool->cmd_slab,
GFP_KERNEL | shost->cmd_pool->gfp_mask);
if (!cmd)
goto fail2;

sense_buffer = kmem_cache_alloc(sense_buffer_slab,
GFP_KERNEL | __GFP_DMA);
if (!sense_buffer)
goto destroy_backup;
cmd->sense_buffer = kmem_cache_alloc(shost->cmd_pool->sense_slab,
GFP_KERNEL |
shost->cmd_pool->gfp_mask);
if (!cmd->sense_buffer)
goto fail2;

cmd->sense_buffer = sense_buffer;
list_add(&cmd->list, &shost->free_list);
return 0;

destroy_backup:
kmem_cache_free(shost->cmd_pool->slab, cmd);
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->slab);
if (!--pool->users) {
kmem_cache_destroy(pool->cmd_slab);
kmem_cache_destroy(pool->sense_slab);
}
fail:
mutex_unlock(&host_cmd_pool_mutex);
return -ENOMEM;
Expand All @@ -372,39 +384,16 @@ 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(sense_buffer_slab, cmd->sense_buffer);
kmem_cache_free(shost->cmd_pool->slab, cmd);
kmem_cache_free(shost->cmd_pool->sense_slab,
cmd->sense_buffer);
kmem_cache_free(shost->cmd_pool->cmd_slab, cmd);
}

mutex_lock(&host_cmd_pool_mutex);
if (!--shost->cmd_pool->users)
kmem_cache_destroy(shost->cmd_pool->slab);
mutex_unlock(&host_cmd_pool_mutex);
}

int scsi_setup_command_sense_buffer(struct Scsi_Host *shost)
{
mutex_lock(&host_cmd_pool_mutex);
if (!sense_buffer_slab_users) {
sense_buffer_slab = kmem_cache_create("scsi_sense_buffer",
SCSI_SENSE_BUFFERSIZE,
0, SLAB_CACHE_DMA, NULL);
if (!sense_buffer_slab) {
mutex_unlock(&host_cmd_pool_mutex);
return -ENOMEM;
}
if (!--shost->cmd_pool->users) {
kmem_cache_destroy(shost->cmd_pool->cmd_slab);
kmem_cache_destroy(shost->cmd_pool->sense_slab);
}
sense_buffer_slab_users++;
mutex_unlock(&host_cmd_pool_mutex);

return 0;
}

void scsi_destroy_command_sense_buffer(struct Scsi_Host *shost)
{
mutex_lock(&host_cmd_pool_mutex);
if (!--sense_buffer_slab_users)
kmem_cache_destroy(sense_buffer_slab);
mutex_unlock(&host_cmd_pool_mutex);
}

Expand Down
2 changes: 0 additions & 2 deletions drivers/scsi/scsi_priv.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,8 +27,6 @@ extern void scsi_exit_hosts(void);
extern int scsi_dispatch_cmd(struct scsi_cmnd *cmd);
extern int scsi_setup_command_freelist(struct Scsi_Host *shost);
extern void scsi_destroy_command_freelist(struct Scsi_Host *shost);
extern int scsi_setup_command_sense_buffer(struct Scsi_Host *shost);
extern void scsi_destroy_command_sense_buffer(struct Scsi_Host *shost);
extern void __scsi_done(struct scsi_cmnd *cmd);
#ifdef CONFIG_SCSI_LOGGING
void scsi_log_send(struct scsi_cmnd *cmd);
Expand Down

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