Commit de25deb1 authored by FUJITA Tomonori's avatar FUJITA Tomonori Committed by James Bottomley

[SCSI] use dynamically allocated sense buffer

This removes static array sense_buffer in scsi_cmnd and uses
dynamically allocated sense_buffer (with GFP_DMA).

The reason for doing this is that some architectures need cacheline
aligned buffer for DMA:

http://lkml.org/lkml/2007/11/19/2

The problems are that scsi_eh_prep_cmnd puts scsi_cmnd::sense_buffer
to sglist and some LLDs directly DMA to scsi_cmnd::sense_buffer. It's
necessary to DMA to scsi_cmnd::sense_buffer safely. This patch solves
these issues.

__scsi_get_command allocates sense_buffer via kmem_cache_alloc and
attaches it to a scsi_cmnd so everything just work as before.
Signed-off-by: default avatarFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@HansenPartnership.com>
parent b30c2fc1
......@@ -268,6 +268,7 @@ 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);
......@@ -372,10 +373,14 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
else
shost->dma_boundary = 0xffffffff;
rval = scsi_setup_command_freelist(shost);
rval = scsi_setup_command_sense_buffer(shost);
if (rval)
goto fail_kfree;
rval = scsi_setup_command_freelist(shost);
if (rval)
goto fail_destroy_sense;
device_initialize(&shost->shost_gendev);
snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
shost->host_no);
......@@ -399,6 +404,8 @@ 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;
......
......@@ -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 +175,7 @@ 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;
cmd = kmem_cache_alloc(shost->cmd_pool->slab,
gfp_mask | shost->cmd_pool->gfp_mask);
......@@ -186,6 +190,21 @@ struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
list_del_init(&cmd->list);
}
spin_unlock_irqrestore(&shost->free_list_lock, flags);
if (cmd) {
buf = cmd->sense_buffer;
memset(cmd, 0, sizeof(*cmd));
cmd->sense_buffer = buf;
}
} else {
buf = kmem_cache_alloc(sense_buffer_slab, __GFP_DMA|gfp_mask);
if (likely(buf)) {
memset(cmd, 0, sizeof(*cmd));
cmd->sense_buffer = buf;
} else {
kmem_cache_free(shost->cmd_pool->slab, cmd);
cmd = NULL;
}
}
return cmd;
......@@ -212,7 +231,6 @@ 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);
......@@ -246,8 +264,10 @@ void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
}
spin_unlock_irqrestore(&shost->free_list_lock, flags);
if (likely(cmd != NULL))
if (likely(cmd != NULL)) {
kmem_cache_free(sense_buffer_slab, cmd->sense_buffer);
kmem_cache_free(shost->cmd_pool->slab, cmd);
}
put_device(dev);
}
......@@ -290,6 +310,7 @@ 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);
......@@ -319,9 +340,18 @@ int scsi_setup_command_freelist(struct Scsi_Host *shost)
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 = sense_buffer;
list_add(&cmd->list, &shost->free_list);
return 0;
destroy_backup:
kmem_cache_free(shost->cmd_pool->slab, cmd);
fail2:
mutex_lock(&host_cmd_pool_mutex);
if (!--pool->users)
......@@ -342,6 +372,7 @@ 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(sense_buffer_slab, cmd->sense_buffer);
kmem_cache_free(shost->cmd_pool->slab, cmd);
}
......@@ -351,6 +382,32 @@ 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)
{
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;
}
}
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);
}
#ifdef CONFIG_SCSI_LOGGING
void scsi_log_send(struct scsi_cmnd *cmd)
{
......
......@@ -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);
......
......@@ -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) */
......
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