This removes static array sense_buffer in scsi_cmnd and uses
dynamically allocated sense_buffer (with GFP_DMA).
scsi_add_host allocates as many buffers as
scsi_host->can_queue. __scsi_get_command attaches sense_buffer to a
scsi_cmnd and __scsi_put_command detaches the sense_buffer from it.
There is a small possibility that a host need more sense buffers than
can_queue. The failure of the buffer allocation works just like the
failure of scsi_cmnd allocation. So everything should work as before.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
---
drivers/scsi/hosts.c | 10 ++++++-
drivers/scsi/scsi.c | 67 +++++++++++++++++++++++++++++++++++++++++++++-
drivers/scsi/scsi_priv.h | 2 +
include/scsi/scsi_cmnd.h | 2 +-
include/scsi/scsi_host.h | 3 ++
5 files changed, 81 insertions(+), 3 deletions(-)
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 9a10b43..35c5f0e 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -205,10 +205,14 @@ int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
if (!shost->shost_gendev.parent)
shost->shost_gendev.parent = dev ? dev : &platform_bus;
- error = device_add(&shost->shost_gendev);
+ error = scsi_setup_command_sense_buffer(shost);
if (error)
goto out;
+ error = device_add(&shost->shost_gendev);
+ if (error)
+ goto destroy_pool;
+
scsi_host_set_state(shost, SHOST_RUNNING);
get_device(shost->shost_gendev.parent);
@@ -248,6 +252,8 @@ int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
class_device_del(&shost->shost_classdev);
out_del_gendev:
device_del(&shost->shost_gendev);
+ destroy_pool:
+ scsi_destroy_command_sense_buffer(shost);
out:
return error;
}
@@ -267,6 +273,8 @@ static void scsi_host_dev_release(struct device *dev)
scsi_free_queue(shost->uspace_req_q);
}
+ scsi_destroy_command_sense_buffer(shost);
+
scsi_destroy_command_freelist(shost);
if (shost->bqt)
blk_free_tags(shost->bqt);
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index ebc0193..91306a5 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -161,6 +161,9 @@ static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
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
@@ -172,6 +175,11 @@ static DEFINE_MUTEX(host_cmd_pool_mutex);
struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
{
struct scsi_cmnd *cmd;
+ unsigned char *buf;
+
+ buf = mempool_alloc(shost->sense_buffer_pool, __GFP_DMA|gfp_mask);
+ if (!buf)
+ return NULL;
cmd = kmem_cache_alloc(shost->cmd_pool->slab,
gfp_mask | shost->cmd_pool->gfp_mask);
@@ -188,6 +196,14 @@ struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
spin_unlock_irqrestore(&shost->free_list_lock, flags);
}
+ if (cmd) {
+ memset(cmd, 0, sizeof(*cmd));
+ cmd->sense_buffer = buf;
+ /* probably unnecessary */
+ memset(buf, 0, SCSI_SENSE_BUFFERSIZE);
+ } else
+ mempool_free(buf, shost->sense_buffer_pool);
+
return cmd;
}
EXPORT_SYMBOL_GPL(__scsi_get_command);
@@ -212,7 +228,6 @@ struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
if (likely(cmd != NULL)) {
unsigned long flags;
- memset(cmd, 0, sizeof(*cmd));
cmd->device = dev;
init_timer(&cmd->eh_timeout);
INIT_LIST_HEAD(&cmd->list);
@@ -238,6 +253,8 @@ void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
{
unsigned long flags;
+ mempool_free(cmd->sense_buffer, shost->sense_buffer_pool);
+
/* changing locks here, don't need to restore the irq state */
spin_lock_irqsave(&shost->free_list_lock, flags);
if (unlikely(list_empty(&shost->free_list))) {
@@ -352,6 +369,54 @@ void scsi_destroy_command_freelist(struct Scsi_Host *shost)
mutex_unlock(&host_cmd_pool_mutex);
}
+int scsi_setup_command_sense_buffer(struct Scsi_Host *shost)
+{
+ int ret;
+
+ mutex_lock(&host_cmd_pool_mutex);
+ if (!sense_buffer_slab) {
+ 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;
+ }
+ }
+ sense_buffer_slab_users++;
+ mutex_unlock(&host_cmd_pool_mutex);
+
+ shost->sense_buffer_pool =
+ mempool_create_slab_pool(0, sense_buffer_slab);
+ if (!shost->sense_buffer_pool)
+ goto fail;
+
+ ret = mempool_resize(shost->sense_buffer_pool, shost->can_queue,
+ __GFP_DMA|GFP_KERNEL);
+ if (ret) {
+ mempool_destroy(shost->sense_buffer_pool);
+ goto fail;
+ }
+
+ return 0;
+fail:
+ mutex_lock(&host_cmd_pool_mutex);
+ if (!--sense_buffer_slab_users)
+ kmem_cache_destroy(sense_buffer_slab);
+ mutex_unlock(&host_cmd_pool_mutex);
+ return -ENOMEM;
+}
+
+void scsi_destroy_command_sense_buffer(struct Scsi_Host *shost)
+{
+ mempool_destroy(shost->sense_buffer_pool);
+
+ mutex_lock(&host_cmd_pool_mutex);
+ if (!--sense_buffer_slab_users)
+ kmem_cache_destroy(sense_buffer_slab);
+ mutex_unlock(&host_cmd_pool_mutex);
+}
+
#ifdef CONFIG_SCSI_LOGGING
void scsi_log_send(struct scsi_cmnd *cmd)
{
diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
index eff0059..88b20f0 100644
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -27,6 +27,8 @@ 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);
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index a7be605..753da55 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -88,7 +88,7 @@ struct scsi_cmnd {
working on */
#define SCSI_SENSE_BUFFERSIZE 96
- unsigned char sense_buffer[SCSI_SENSE_BUFFERSIZE];
+ unsigned char *sense_buffer;
/* obtained by REQUEST SENSE when
* CHECK CONDITION is received on original
* command (auto-sense) */
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 0fd4746..3f4bae3 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -6,6 +6,7 @@
#include <linux/types.h>
#include <linux/workqueue.h>
#include <linux/mutex.h>
+#include <linux/mempool.h>
struct request_queue;
struct block_device;
@@ -520,6 +521,8 @@ struct Scsi_Host {
struct list_head free_list; /* backup store of cmd structs */
struct list_head starved_list;
+ mempool_t *sense_buffer_pool;
+
spinlock_t default_lock;
spinlock_t *host_lock;
--
1.5.3.4
-
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