From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH 3/5] block: implement request_queue->dma_drain_needed Date: Tue, 5 Feb 2008 16:53:03 +0900 Message-ID: <12021979863240-git-send-email-htejun@gmail.com> References: <12021979851743-git-send-email-htejun@gmail.com> Return-path: Received: from rv-out-0910.google.com ([209.85.198.186]:22908 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754321AbYBEHxR (ORCPT ); Tue, 5 Feb 2008 02:53:17 -0500 Received: by rv-out-0910.google.com with SMTP id k20so1647568rvb.1 for ; Mon, 04 Feb 2008 23:53:16 -0800 (PST) In-Reply-To: <12021979851743-git-send-email-htejun@gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: jeff@garzik.org, linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org, fujita.tomonori@lab.ntt.co.jp, Jens.Axboe@oracle.com Cc: Tejun Heo , James Bottomley Draining shouldn't be done for commands where overflow may indicate data integrity issues. Add dma_drain_needed callback to request_queue. Drain buffer is appened iff this function returns non-zero. Signed-off-by: Tejun Heo Cc: James Bottomley --- block/blk-merge.c | 2 +- block/blk-settings.c | 7 +++++-- include/linux/blkdev.h | 7 +++++-- 3 files changed, 11 insertions(+), 5 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index 480d2bc..d50cfc8 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -220,7 +220,7 @@ new_segment: bvprv = bvec; } /* segments in rq */ - if (q->dma_drain_size) { + if (q->dma_drain_size && q->dma_drain_needed(rq)) { sg->page_link &= ~0x02; sg = sg_next(sg); sg_set_page(sg, virt_to_page(q->dma_drain_buffer), diff --git a/block/blk-settings.c b/block/blk-settings.c index c8d0c57..0a0b3a4 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -296,6 +296,7 @@ EXPORT_SYMBOL(blk_queue_stack_limits); * blk_queue_dma_drain - Set up a drain buffer for excess dma. * * @q: the request queue for the device + * @dma_drain_needed: fn which returns non-zero if drain is necessary * @buf: physically contiguous buffer * @size: size of the buffer in bytes * @@ -315,14 +316,16 @@ EXPORT_SYMBOL(blk_queue_stack_limits); * device can support otherwise there won't be room for the drain * buffer. */ -int blk_queue_dma_drain(struct request_queue *q, void *buf, - unsigned int size) +extern int blk_queue_dma_drain(struct request_queue *q, + dma_drain_needed_fn *dma_drain_needed, + void *buf, unsigned int size) { if (q->max_hw_segments < 2 || q->max_phys_segments < 2) return -EINVAL; /* make room for appending the drain */ --q->max_hw_segments; --q->max_phys_segments; + q->dma_drain_needed = dma_drain_needed; q->dma_drain_buffer = buf; q->dma_drain_size = size; diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index ee0b021..3912c5d 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -257,6 +257,7 @@ struct bio_vec; typedef int (merge_bvec_fn) (struct request_queue *, struct bio *, struct bio_vec *); typedef void (prepare_flush_fn) (struct request_queue *, struct request *); typedef void (softirq_done_fn)(struct request *); +typedef int (dma_drain_needed_fn)(struct request *); enum blk_queue_state { Queue_down, @@ -293,6 +294,7 @@ struct request_queue merge_bvec_fn *merge_bvec_fn; prepare_flush_fn *prepare_flush_fn; softirq_done_fn *softirq_done_fn; + dma_drain_needed_fn *dma_drain_needed; /* * Dispatch queue sorting @@ -697,8 +699,9 @@ extern void blk_queue_max_hw_segments(struct request_queue *, unsigned short); extern void blk_queue_max_segment_size(struct request_queue *, unsigned int); extern void blk_queue_hardsect_size(struct request_queue *, unsigned short); extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b); -extern int blk_queue_dma_drain(struct request_queue *q, void *buf, - unsigned int size); +extern int blk_queue_dma_drain(struct request_queue *q, + dma_drain_needed_fn *dma_drain_needed, + void *buf, unsigned int size); extern void blk_queue_segment_boundary(struct request_queue *, unsigned long); extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn); extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *); -- 1.5.2.4