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Commit 33204663 authored by Julien Grall's avatar Julien Grall Committed by David Vrabel
Browse files

block/xen-blkfront: Split blkif_queue_request in 2 



Currently, blkif_queue_request has 2 distinct execution path:
    - Send a discard request
    - Send a read/write request

The function is also allocating grants to use for generating the
request. Although, this is only used for read/write request.

Rather than having a function with 2 distinct execution path, separate
the function in 2. This will also remove one level of tabulation.

Signed-off-by: default avatarJulien Grall <julien.grall@citrix.com>
Reviewed-by: default avatarRoger Pau Monné <roger.pau@citrix.com>
Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
parent 3922f32c

drivers/block/xen-blkfront.c

+153 −124
Original line number Diff line number Diff line
@@ -394,13 +394,35 @@ static int blkif_ioctl(struct block_device *bdev, fmode_t mode, 
	return 0;

}



/*

 * Generate a Xen blkfront IO request from a blk layer request.  Reads

 * and writes are handled as expected.

 *

 * @req: a request struct

 */

static int blkif_queue_request(struct request *req)

static int blkif_queue_discard_req(struct request *req)

{

	struct blkfront_info *info = req->rq_disk->private_data;

	struct blkif_request *ring_req;

	unsigned long id;



	/* Fill out a communications ring structure. */

	ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);

	id = get_id_from_freelist(info);

	info->shadow[id].request = req;



	ring_req->operation = BLKIF_OP_DISCARD;

	ring_req->u.discard.nr_sectors = blk_rq_sectors(req);

	ring_req->u.discard.id = id;

	ring_req->u.discard.sector_number = (blkif_sector_t)blk_rq_pos(req);

	if ((req->cmd_flags & REQ_SECURE) && info->feature_secdiscard)

		ring_req->u.discard.flag = BLKIF_DISCARD_SECURE;

	else

		ring_req->u.discard.flag = 0;



	info->ring.req_prod_pvt++;



	/* Keep a private copy so we can reissue requests when recovering. */

	info->shadow[id].req = *ring_req;



	return 0;

}



static int blkif_queue_rw_req(struct request *req)

{

	struct blkfront_info *info = req->rq_disk->private_data;

	struct blkif_request *ring_req;
@@ -420,9 +442,6 @@ static int blkif_queue_request(struct request *req) 
	struct scatterlist *sg;

	int nseg, max_grefs;



	if (unlikely(info->connected != BLKIF_STATE_CONNECTED))

		return 1;



	max_grefs = req->nr_phys_segments;

	if (max_grefs > BLKIF_MAX_SEGMENTS_PER_REQUEST)

		/*
@@ -452,16 +471,6 @@ static int blkif_queue_request(struct request *req) 
	id = get_id_from_freelist(info);

	info->shadow[id].request = req;



	if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE))) {

		ring_req->operation = BLKIF_OP_DISCARD;

		ring_req->u.discard.nr_sectors = blk_rq_sectors(req);

		ring_req->u.discard.id = id;

		ring_req->u.discard.sector_number = (blkif_sector_t)blk_rq_pos(req);

		if ((req->cmd_flags & REQ_SECURE) && info->feature_secdiscard)

			ring_req->u.discard.flag = BLKIF_DISCARD_SECURE;

		else

			ring_req->u.discard.flag = 0;

	} else {

	BUG_ON(info->max_indirect_segments == 0 &&

	       req->nr_phys_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);

	BUG_ON(info->max_indirect_segments &&
@@ -487,11 +496,11 @@ static int blkif_queue_request(struct request *req) 
			BLKIF_OP_WRITE : BLKIF_OP_READ;

		if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) {

			/*

				 * Ideally we can do an unordered flush-to-disk. In case the

				 * backend onlysupports barriers, use that. A barrier request

				 * a superset of FUA, so we can implement it the same

				 * way.  (It's also a FLUSH+FUA, since it is

				 * guaranteed ordered WRT previous writes.)

			 * Ideally we can do an unordered flush-to-disk.

			 * In case the backend onlysupports barriers, use that.

			 * A barrier request a superset of FUA, so we can

			 * implement it the same way.  (It's also a FLUSH+FUA,

			 * since it is guaranteed ordered WRT previous writes.)

			 */

			switch (info->feature_flush &

				((REQ_FLUSH|REQ_FUA))) {
@@ -524,7 +533,10 @@ static int blkif_queue_request(struct request *req) 
			if (!info->feature_persistent) {

				struct page *indirect_page;



					/* Fetch a pre-allocated page to use for indirect grefs */

				/*

				 * Fetch a pre-allocated page to use for

				 * indirect grefs

				 */

				BUG_ON(list_empty(&info->indirect_pages));

				indirect_page = list_first_entry(&info->indirect_pages,

								 struct page, lru);
@@ -584,7 +596,6 @@ static int blkif_queue_request(struct request *req) 
	}

	if (segments)

		kunmap_atomic(segments);

	}



	info->ring.req_prod_pvt++;
@@ -597,6 +608,24 @@ static int blkif_queue_request(struct request *req) 
	return 0;

}



/*

 * Generate a Xen blkfront IO request from a blk layer request.  Reads

 * and writes are handled as expected.

 *

 * @req: a request struct

 */

static int blkif_queue_request(struct request *req)

{

	struct blkfront_info *info = req->rq_disk->private_data;



	if (unlikely(info->connected != BLKIF_STATE_CONNECTED))

		return 1;



	if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE)))

		return blkif_queue_discard_req(req);

	else

		return blkif_queue_rw_req(req);

}



static inline void flush_requests(struct blkfront_info *info)

{