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Commit fc53bf75 authored by Konrad Rzeszutek Wilk's avatar Konrad Rzeszutek Wilk
Browse files

xen/blkback: Squash the checking for operation into dispatch_rw_block_io 



We do a check for the operations right before calling dispatch_rw_block_io.
And then we do the same check in dispatch_rw_block_io. This patch
squashes those checks into the 'dispatch_rw_block_io' function.

Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 24f567f9

drivers/block/xen-blkback/blkback.c

+13 −32
Original line number Diff line number Diff line
@@ -123,7 +123,7 @@ static inline unsigned long vaddr(struct pending_req *req, int seg) 




static int do_block_io_op(struct blkif_st *blkif);

static void dispatch_rw_block_io(struct blkif_st *blkif,

static int dispatch_rw_block_io(struct blkif_st *blkif,

				struct blkif_request *req,

				struct pending_req *pending_req);

static void make_response(struct blkif_st *blkif, u64 id,
@@ -499,30 +499,8 @@ static int do_block_io_op(struct blkif_st *blkif) 
		/* Apply all sanity checks to /private copy/ of request. */

		barrier();



		switch (req.operation) {

		case BLKIF_OP_READ:

			blkif->st_rd_req++;

			dispatch_rw_block_io(blkif, &req, pending_req);

			break;

		case BLKIF_OP_FLUSH_DISKCACHE:

			blkif->st_f_req++;

			/* fall through */

		case BLKIF_OP_WRITE:

			blkif->st_wr_req++;

			dispatch_rw_block_io(blkif, &req, pending_req);

			break;

		case BLKIF_OP_WRITE_BARRIER:

		default:

			/* A good sign something is wrong: sleep for a while to

			 * avoid excessive CPU consumption by a bad guest. */

			msleep(1);

			DPRINTK("error: unknown block io operation [%d]\n",

				req.operation);

			make_response(blkif, req.id, req.operation,

				      BLKIF_RSP_ERROR);

			free_req(pending_req);

		if (dispatch_rw_block_io(blkif, &req, pending_req))

			break;

		}



		/* Yield point for this unbounded loop. */

		cond_resched();
@@ -535,7 +513,7 @@ static int do_block_io_op(struct blkif_st *blkif) 
 * Transumation of the 'struct blkif_request' to a proper 'struct bio'

 * and call the 'submit_bio' to pass it to the underlaying storage.

 */

static void dispatch_rw_block_io(struct blkif_st *blkif,

static int dispatch_rw_block_io(struct blkif_st *blkif,

				 struct blkif_request *req,

				 struct pending_req *pending_req)

{
@@ -550,22 +528,25 @@ static void dispatch_rw_block_io(struct blkif_st *blkif, 


	switch (req->operation) {

	case BLKIF_OP_READ:

		blkif->st_rd_req++;

		operation = READ;

		break;

	case BLKIF_OP_WRITE:

		blkif->st_wr_req++;

		operation = WRITE_ODIRECT;

		break;

	case BLKIF_OP_FLUSH_DISKCACHE:

		blkif->st_f_req++;

		operation = WRITE_FLUSH;

		/* The frontend likes to set this to -1, which vbd_translate

		 * is alergic too. */

		req->u.rw.sector_number = 0;

		break;

	case BLKIF_OP_WRITE_BARRIER:

		/* Should never get here. */

	default:

		operation = 0; /* make gcc happy */

		BUG();

		goto fail_response;

		break;

	}



	/* Check that the number of segments is sane. */
@@ -677,7 +658,7 @@ static void dispatch_rw_block_io(struct blkif_st *blkif, 
	else if (operation == WRITE || operation == WRITE_FLUSH)

		blkif->st_wr_sect += preq.nr_sects;



	return;

	return 0;



 fail_flush:

	xen_blkbk_unmap(pending_req);
@@ -686,14 +667,14 @@ static void dispatch_rw_block_io(struct blkif_st *blkif, 
	make_response(blkif, req->id, req->operation, BLKIF_RSP_ERROR);

	free_req(pending_req);

	msleep(1); /* back off a bit */

	return;

	return -EIO;



 fail_put_bio:

	for (i = 0; i < (nbio-1); i++)

		bio_put(biolist[i]);

	__end_block_io_op(pending_req, -EINVAL);

	msleep(1); /* back off a bit */

	return;

	return -EIO;

}