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 <konrad.wilk@oracle.com>
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 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 @@
/* 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);
+ if (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);
- break;
- }
/* Yield point for this unbounded loop. */
cond_resched();
@@ -535,7 +513,7 @@
* 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 @@
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 @@
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 @@
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;
}