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Commit 62858dac authored by FUJITA Tomonori's avatar FUJITA Tomonori Committed by Jens Axboe
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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: default avatarFUJITA 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 30c00eda

drivers/scsi/sr.c

+5 −15
Original line number Diff line number Diff line
@@ -673,24 +673,20 @@ 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--;
@@ -745,14 +741,8 @@ static void get_sectorsize(struct scsi_cd *cd) 


	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)