Re: [patch] [SCSI] scsi_transport_sas: check for allocation failure
From: Douglas Gilbert
Date: Mon Mar 11 2013 - 10:49:23 EST
On 13-03-11 09:10 AM, Dan Carpenter wrote:
On Fri, Mar 08, 2013 at 10:50:19PM +0000, James Bottomley wrote:
On Fri, 2013-03-08 at 12:57 -0500, Douglas Gilbert wrote:
On 13-03-08 07:02 AM, Dan Carpenter wrote:
Static checkers complain that this allocation isn't checked. We
should return zero if the allocation fails.
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c
index 1b68142..a022997 100644
--- a/drivers/scsi/scsi_transport_sas.c
+++ b/drivers/scsi/scsi_transport_sas.c
@@ -379,9 +379,12 @@ sas_tlr_supported(struct scsi_device *sdev)
{
const int vpd_len = 32;
struct sas_end_device *rdev = sas_sdev_to_rdev(sdev);
- char *buffer = kzalloc(vpd_len, GFP_KERNEL);
+ char *buffer;
int ret = 0;
+ buffer = kzalloc(vpd_len, GFP_KERNEL);
+ if (!buffer)
+ goto out;
if (scsi_get_vpd_page(sdev, 0x90, buffer, vpd_len))
goto out;
For 32 bytes, why not use the stack?
Because the buffer is a DMA target. You can't DMA to stack because of
padding and cacheline issues.
I think stack data works here. scsi_execute() calls
blk_rq_map_kern() which handles stack memory and alignment issues.
That being the case, several other callers of
scsi_get_vpd_page() 9and friends) could be
simplified and sped up.
Also since VPD pages don't change and they can carry
a lot of disparate information (e.g. the Extended
Inquiry and Block Limits pages) perhaps they could
be cached by the appropriate level (e.g. Extended
Inquiry cached by mid-level; Block Limits cached
by sd driver).
Doug Gilbert
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