scsi: sr avoids useless buffer allocation
blk_rq_map_kern can handle the stack buffers correctly (avoid DMA
from/to the stack buffers by using the bounce buffer) so we don't need
to complicate the code by allocating just 8 bytes.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index c82df8b..27f5bfd 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -673,24 +673,20 @@
static void get_sectorsize(struct scsi_cd *cd)
{
unsigned char cmd[10];
- unsigned char *buffer;
+ unsigned char buffer[8];
int the_result, retries = 3;
int sector_size;
struct request_queue *queue;
- buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
- if (!buffer)
- goto Enomem;
-
do {
cmd[0] = READ_CAPACITY;
memset((void *) &cmd[1], 0, 9);
- memset(buffer, 0, 8);
+ memset(buffer, 0, sizeof(buffer));
/* Do the command and wait.. */
the_result = scsi_execute_req(cd->device, cmd, DMA_FROM_DEVICE,
- buffer, 8, NULL, SR_TIMEOUT,
- MAX_RETRIES);
+ buffer, sizeof(buffer), NULL,
+ SR_TIMEOUT, MAX_RETRIES);
retries--;
@@ -745,14 +741,8 @@
queue = cd->device->request_queue;
blk_queue_hardsect_size(queue, sector_size);
-out:
- kfree(buffer);
- return;
-Enomem:
- cd->capacity = 0x1fffff;
- cd->device->sector_size = 2048; /* A guess, just in case */
- goto out;
+ return;
}
static void get_capabilities(struct scsi_cd *cd)