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xen/blkback: Squash the checking for operation into dispatch_rw_block_io

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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>
This commit is contained in:
Konrad Rzeszutek Wilk 2011-05-05 13:37:23 -04:00
parent 24f567f952
commit fc53bf757e
1 changed files with 13 additions and 32 deletions
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45
drivers/block/xen-blkback/blkback.c
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@ -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);
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 @@ 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;
}