diff options
| author | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2010-11-01 14:32:27 -0400 |
|---|---|---|
| committer | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2010-11-02 10:43:51 -0400 |
| commit | c64e38ea17a81721da0393584fd807f8434050fa (patch) | |
| tree | b4c7203aa006fd618cb3477fcddf8c74b509da3f /drivers/block/xen-blkfront.c | |
| parent | c8ddb2713c624f432fa5fe3c7ecffcdda46ea0d4 (diff) | |
xen/blkfront: map REQ_FLUSH into a full barrier
Implement a flush as a full barrier, since we have nothing weaker.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'drivers/block/xen-blkfront.c')
| -rw-r--r-- | drivers/block/xen-blkfront.c | 19 |
1 files changed, 5 insertions, 14 deletions
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 06e2812ba12..3a318d8576c 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -245,14 +245,11 @@ static int blkif_ioctl(struct block_device *bdev, fmode_t mode, } /* - * blkif_queue_request + * Generate a Xen blkfront IO request from a blk layer request. Reads + * and writes are handled as expected. Since we lack a loose flush + * request, we map flushes into a full ordered barrier. * - * request block io - * - * id: for guest use only. - * operation: BLKIF_OP_{READ,WRITE,PROBE} - * buffer: buffer to read/write into. this should be a - * virtual address in the guest os. + * @req: a request struct */ static int blkif_queue_request(struct request *req) { @@ -289,7 +286,7 @@ static int blkif_queue_request(struct request *req) ring_req->operation = rq_data_dir(req) ? BLKIF_OP_WRITE : BLKIF_OP_READ; - if (req->cmd_flags & REQ_HARDBARRIER) + if (req->cmd_flags & REQ_FLUSH) ring_req->operation = BLKIF_OP_WRITE_BARRIER; ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg); @@ -1069,14 +1066,8 @@ static void blkfront_connect(struct blkfront_info *info) */ info->feature_flush = 0; - /* - * The driver doesn't properly handled empty flushes, so - * lets disable barrier support for now. - */ -#if 0 if (!err && barrier) info->feature_flush = REQ_FLUSH; -#endif err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size); if (err) { |