[ 22/68] cciss: Fix scsi tape io with more than 255 scatter gather elements

From: Greg KH
Date: Thu Apr 19 2012 - 17:16:29 EST

3.2-stable review patch. If anyone has any objections, please let me know.


From: "Stephen M. Cameron" <scameron@xxxxxxxxxxxxxxxxxx>

commit bc67f63650fad6b3478d9ddfd5406d45a95987c9 upstream.

The total number of scatter gather elements in the CISS command
used by the scsi tape code was being cast to a u8, which can hold
at most 255 scatter gather elements. It should have been cast to
a u16. Without this patch the command gets rejected by the controller
since the total scatter gather count did not add up to the right
value resulting in an i/o error.

Signed-off-by: Stephen M. Cameron <scameron@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/block/cciss_scsi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/block/cciss_scsi.c
+++ b/drivers/block/cciss_scsi.c
@@ -1411,7 +1411,7 @@ static void cciss_scatter_gather(ctlr_in
/* track how many SG entries we are using */
if (request_nsgs > h->maxSG)
h->maxSG = request_nsgs;
- c->Header.SGTotal = (__u8) request_nsgs + chained;
+ c->Header.SGTotal = (u16) request_nsgs + chained;
if (request_nsgs > h->max_cmd_sgentries)
c->Header.SGList = h->max_cmd_sgentries;

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