Re: [PATCH] ses: Use new scsi VPD helper

Matthew Wilcox
2008-12-31T19:11:33Z

On Wed, Dec 31, 2008 at 12:59:38PM -0600, James Bottomley wrote:
> This was actually wrong in the original code. It should be
>
> pd_len = (buf[2] << 8) | buf[3] + 4;
>
> to account for the header offset in the returned data length.

Ah yes. I got it right in the scsi_get_vpd_page() code, and then forgot
about it while changing the ses code. Thanks for spotting that.

vpd_len also needs to be unsigned int, as a u16 could wrap. Here's a
replacement patch:

diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c
index 7f0df29..95d16b3 100644
--- a/drivers/scsi/ses.c
+++ b/drivers/scsi/ses.c
@@ -345,44 +345,21 @@ static int ses_enclosure_find_by_addr(struct enclosure_device *edev,
return 0;
}

-#define VPD_INQUIRY_SIZE 36
-
static void ses_match_to_enclosure(struct enclosure_device *edev,
struct scsi_device *sdev)
{
- unsigned char *buf = kmalloc(VPD_INQUIRY_SIZE, GFP_KERNEL);
+ unsigned char *buf;
unsigned char *desc;
- u16 vpd_len;
+ unsigned int vpd_len;
struct efd efd = {
.addr = 0,
};
- unsigned char cmd[] = {
- INQUIRY,
- 1,
- 0x83,
- VPD_INQUIRY_SIZE >> 8,
- VPD_INQUIRY_SIZE & 0xff,
- 0
- };

+ buf = scsi_get_vpd_page(sdev, 0x83);
if (!buf)
return;

- if (scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buf,
- VPD_INQUIRY_SIZE, NULL, SES_TIMEOUT, SES_RETRIES,
- NULL))
- goto free;
-
- vpd_len = (buf[2] << 8) + buf[3];
- kfree(buf);
- buf = kmalloc(vpd_len, GFP_KERNEL);
- if (!buf)
- return;
- cmd[3] = vpd_len >> 8;
- cmd[4] = vpd_len & 0xff;
- if (scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buf,
- vpd_len, NULL, SES_TIMEOUT, SES_RETRIES, NULL))
- goto free;
+ vpd_len = ((buf[2] << 8) | buf[3]) + 4;

desc = buf + 4;
while (desc < buf + vpd_len) {

--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."