On Thu, 2008-03-13 at 12:15 -0500, James Bottomley wrote:
> On Thu, 2008-03-13 at 11:09 -0600, Matthew Wilcox wrote:
> > On Thu, Mar 13, 2008 at 11:53:11AM -0500, James Bottomley wrote:
> > > 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.
> >
> > > +static struct scsi_cmnd *
> > > +scsi_get_command_from_pool(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
> > > +static void
> > > +scsi_put_command_to_pool(struct scsi_host_cmd_pool *pool,
> > > + struct scsi_cmnd *cmd)
> >
> > The names are a bit clunky ... 'put command to pool'? How about
> > alloc/free instead of get/put? or:
> >
> > scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
> > scsi_pool_free_command(struct scsi_host_cmd_pool *pool, struct scsi_cmnd *cmd)
> >
> > or even:
> >
> > scsi_command_pool_alloc(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
> > scsi_command_pool_free(struct scsi_host_cmd_pool *pool, struct scsi_cmnd *cmd)
> >
> > (i also wouldn't object to use 'cmnd' or 'cmd' in place of 'command').
>
> Yes, but it's following the naming convention in the file. OK, I don't
> like it as well, that's why the new functions in the following patch
> have alloc/free.
Actually, I reconsidered this. Since I don't use the get/put
terminology in the second patch, it really doesn't make sense to stick
with it in the first one. The naming convention still seems to be
scsi_<action>_command, so I picked
scsi_pool_alloc_command
scsi_pool_free_command
I also swept up one last place where the kmem_cache_allocs were being
used in the destroy freelist.
James
---
From: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Date: Thu, 13 Mar 2008 11:16:33 -0500
Subject: 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@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/scsi/scsi.c | 80 ++++++++++++++++++++++++++++++++-------------------
1 files changed, 50 insertions(+), 30 deletions(-)
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index e5c6f6a..2cf9a62 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -166,6 +166,51 @@ static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
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
@@ -178,8 +223,7 @@ 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->cmd_slab,
- gfp_mask | shost->cmd_pool->gfp_mask);
+ cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
if (unlikely(!cmd)) {
unsigned long flags;
@@ -197,16 +241,6 @@ struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
memset(cmd, 0, sizeof(*cmd));
cmd->sense_buffer = buf;
}
- } else {
- 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;
- }
}
return cmd;
@@ -266,11 +300,8 @@ 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(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);
}
@@ -346,23 +377,14 @@ int scsi_setup_command_freelist(struct Scsi_Host *shost)
/*
* 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);
@@ -384,9 +406,7 @@ 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(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);
--
1.5.4.3
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