From: Tejun Heo <tj@kernel.org>
To: axboe@kernel.dk, bharrosh@panasas.com, linux-kernel@vger.kernel.org,
       fujita.tomonori@lab.ntt.co.jp
Cc: Tejun Heo <tj@kernel.org>
Subject: [PATCH 14/17] scsi: replace custom rq mapping with blk_rq_map_kern_sgl()
Date: Wed,  1 Apr 2009 22:44:29 +0900
Message-Id: <1238593472-30360-15-git-send-email-tj@kernel.org>
In-Reply-To: <1238593472-30360-1-git-send-email-tj@kernel.org>
References: <1238593472-30360-1-git-send-email-tj@kernel.org>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 3979
Lines: 150

Impact: hack removal

SCSI needs to map sgl into rq for kernel PC requests; however, block
API didn't have such feature so it used its own rq mapping function
which hooked into block/bio internals and is generally considered an
ugly hack.  The private function may also produce requests which are
bigger than queue per-rq limits.

Block blk_rq_map_kern_sgl().  Kill the private implementation and use
it.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
 drivers/scsi/scsi_lib.c |  108 +----------------------------------------------
 1 files changed, 1 insertions(+), 107 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 3196c83..3fa5589 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -296,112 +296,6 @@ static void scsi_end_async(struct request *req, int uptodate)
 	__blk_put_request(req->q, req);
 }
 
-static int scsi_merge_bio(struct request *rq, struct bio *bio)
-{
-	struct request_queue *q = rq->q;
-
-	bio->bi_flags &= ~(1 << BIO_SEG_VALID);
-	if (rq_data_dir(rq) == WRITE)
-		bio->bi_rw |= (1 << BIO_RW);
-	blk_queue_bounce(q, &bio);
-
-	return blk_rq_append_bio(q, rq, bio);
-}
-
-static void scsi_bi_endio(struct bio *bio, int error)
-{
-	bio_put(bio);
-}
-
-/**
- * scsi_req_map_sg - map a scatterlist into a request
- * @rq:		request to fill
- * @sgl:	scatterlist
- * @nsegs:	number of elements
- * @bufflen:	len of buffer
- * @gfp:	memory allocation flags
- *
- * scsi_req_map_sg maps a scatterlist into a request so that the
- * request can be sent to the block layer. We do not trust the scatterlist
- * sent to use, as some ULDs use that struct to only organize the pages.
- */
-static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
-			   int nsegs, unsigned bufflen, gfp_t gfp)
-{
-	struct request_queue *q = rq->q;
-	int nr_pages = (bufflen + sgl[0].offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
-	unsigned int data_len = bufflen, len, bytes, off;
-	struct scatterlist *sg;
-	struct page *page;
-	struct bio *bio = NULL;
-	int i, err, nr_vecs = 0;
-
-	for_each_sg(sgl, sg, nsegs, i) {
-		page = sg_page(sg);
-		off = sg->offset;
-		len = sg->length;
-
-		while (len > 0 && data_len > 0) {
-			/*
-			 * sg sends a scatterlist that is larger than
-			 * the data_len it wants transferred for certain
-			 * IO sizes
-			 */
-			bytes = min_t(unsigned int, len, PAGE_SIZE - off);
-			bytes = min(bytes, data_len);
-
-			if (!bio) {
-				nr_vecs = min_t(int, BIO_GUARANTEED_PAGES,
-						nr_pages);
-				nr_pages -= nr_vecs;
-
-				bio = bio_alloc(gfp, nr_vecs);
-				if (!bio) {
-					err = -ENOMEM;
-					goto free_bios;
-				}
-				bio->bi_end_io = scsi_bi_endio;
-			}
-
-			if (bio_add_pc_page(q, bio, page, bytes, off) !=
-			    bytes) {
-				bio_put(bio);
-				err = -EINVAL;
-				goto free_bios;
-			}
-
-			if (bio->bi_vcnt >= nr_vecs) {
-				err = scsi_merge_bio(rq, bio);
-				if (err) {
-					bio_endio(bio, 0);
-					goto free_bios;
-				}
-				bio = NULL;
-			}
-
-			page++;
-			len -= bytes;
-			data_len -=bytes;
-			off = 0;
-		}
-	}
-
-	rq->buffer = rq->data = NULL;
-	rq->data_len = bufflen;
-	return 0;
-
-free_bios:
-	while ((bio = rq->bio) != NULL) {
-		rq->bio = bio->bi_next;
-		/*
-		 * call endio instead of bio_put incase it was bounced
-		 */
-		bio_endio(bio, 0);
-	}
-
-	return err;
-}
-
 /**
  * scsi_execute_async - insert request
  * @sdev:	scsi device
@@ -438,7 +332,7 @@ int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd,
 	req->cmd_flags |= REQ_QUIET;
 
 	if (use_sg)
-		err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp);
+		err = blk_rq_map_kern_sg(req->q, req, buffer, use_sg, gfp);
 	else if (bufflen)
 		err = blk_rq_map_kern(req->q, req, buffer, bufflen, gfp);
 
-- 
1.6.0.2

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