[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: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 9a10b4335e76..f5d3fbb55717 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -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;