The patch titled
scsi: sr avoids useless buffer allocation
has been added to the -mm tree. Its filename is
scsi-sr-avoids-useless-buffer-allocation.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: scsi: sr avoids useless buffer allocation
From: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx>
Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Tejun Heo <htejun@xxxxxxxxx>
Cc: Jens Axboe <jens.axboe@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/scsi/sr.c | 20 +++++---------------
1 file changed, 5 insertions(+), 15 deletions(-)
diff -puN drivers/scsi/sr.c~scsi-sr-avoids-useless-buffer-allocation drivers/scsi/sr.c
--- a/drivers/scsi/sr.c~scsi-sr-avoids-useless-buffer-allocation
+++ a/drivers/scsi/sr.c
@@ -670,24 +670,20 @@ fail:
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--;
@@ -742,14 +738,8 @@ static void get_sectorsize(struct scsi_c
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)
_
Patches currently in -mm which might be from fujita.tomonori@xxxxxxxxxxxxx are
linux-next.patch
block-add-blk_queue_update_dma_pad.patch
ide-use-the-dma-safe-check-for-req_type_ata_pc.patch
block-blk_rq_map_kern-uses-the-bounce-buffers-for-stack-buffers.patch
ide-avoid-dma-on-the-stack-for-req_type_ata_pc.patch
scsi-sr-avoids-useless-buffer-allocation.patch
cdrom-revert-commit-22a9189-cdrom-use-kmalloced-buffers-instead-of-buffers-on-stack.patch
dma-mapping-add-the-device-argument-to-dma_mapping_error.patch
dma-mapping-add-the-device-argument-to-dma_mapping_error-sge-fix.patch
dma-mapping-add-the-device-argument-to-dma_mapping_error-svc_rdma-fix.patch
dma-mapping-add-the-device-argument-to-dma_mapping_error-bnx2x.patch
dma-mapping-add-the-device-argument-to-dma_mapping_error-sparc32.patch
dma-mapping-x86-per-device-dma_mapping_ops-support.patch
dma-mapping-x86-per-device-dma_mapping_ops-support-fix.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
