Commit d7e3c324 authored by FUJITA Tomonori's avatar FUJITA Tomonori Committed by Jens Axboe
Browse files

block: add large command support 



This patch changes rq->cmd from the static array to a pointer to
support large commands.

We rarely handle large commands. So for optimization, a struct request
still has a static array for a command. rq_init sets rq->cmd pointer
to the static array.

Signed-off-by: default avatarFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent d34c87e4

block/blk-core.c

+1 −0
Original line number Diff line number Diff line
@@ -117,6 +117,7 @@ void blk_rq_init(struct request_queue *q, struct request *rq) 
	rq->sector = rq->hard_sector = (sector_t) -1;

	INIT_HLIST_NODE(&rq->hash);

	RB_CLEAR_NODE(&rq->rb_node);

	rq->cmd = rq->__cmd;

	rq->tag = -1;

	rq->ref_count = 1;

}

include/linux/blkdev.h

+3 −2
Original line number Diff line number Diff line
@@ -215,8 +215,9 @@ struct request { 
	/*

	 * when request is used as a packet command carrier

	 */

	unsigned int cmd_len;

	unsigned char cmd[BLK_MAX_CDB];

	unsigned short cmd_len;

	unsigned char __cmd[BLK_MAX_CDB];

	unsigned char *cmd;



	unsigned int data_len;

	unsigned int extra_len;	/* length of alignment and padding */

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