From fc53bf757ede292312eee10d64f4e691c8c8cebf Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Thu, 5 May 2011 13:37:23 -0400 Subject: [PATCH] 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: Konrad Rzeszutek Wilk --- drivers/block/xen-blkback/blkback.c | 45 +++++++++++-------------------------- 1 file changed, 13 insertions(+), 32 deletions(-) diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index 72ede0b..5f42847 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -123,9 +123,9 @@ 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, - struct blkif_request *req, - struct pending_req *pending_req); +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, unsigned short op, int st); @@ -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); + if (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); - 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; } -- 2.7.4