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authorJens Axboe <jaxboe@fusionio.com>2010-11-12 08:47:04 +0100
committerJens Axboe <jaxboe@fusionio.com>2010-11-12 08:47:04 +0100
commit1ff5125fb85a46279421350eeaf812f728784d35 (patch)
treee795ca6d427d136ea097f756eea8ea5cff1c4055 /drivers
parentcedb4a7d9f6aedb0dce94d6285b69dcb3c10fa05 (diff)
parentdcb8baeceaa1c629bbd06f472cea023ad08a0c33 (diff)
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Merge branch 'upstream/blkfront' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen into for-linus
Conflicts: drivers/block/xen-blkfront.c Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/block/xen-blkfront.c55
1 files changed, 33 insertions, 22 deletions
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 255035cfc88..4f9e22f2913 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -65,7 +65,7 @@ enum blkif_state {
struct blk_shadow {
struct blkif_request req;
- unsigned long request;
+ struct request *request;
unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST];
};
@@ -136,7 +136,7 @@ static void add_id_to_freelist(struct blkfront_info *info,
unsigned long id)
{
info->shadow[id].req.id = info->shadow_free;
- info->shadow[id].request = 0;
+ info->shadow[id].request = NULL;
info->shadow_free = id;
}
@@ -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)
{
@@ -281,7 +278,7 @@ static int blkif_queue_request(struct request *req)
/* Fill out a communications ring structure. */
ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
id = get_id_from_freelist(info);
- info->shadow[id].request = (unsigned long)req;
+ info->shadow[id].request = req;
ring_req->id = id;
ring_req->sector_number = (blkif_sector_t)blk_rq_pos(req);
@@ -290,6 +287,18 @@ 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_FLUSH | REQ_FUA)) {
+ /*
+ * Ideally we could just do an unordered
+ * flush-to-disk, but all we have is a full write
+ * barrier at the moment. However, a barrier write is
+ * a superset of FUA, so we can implement it the same
+ * way. (It's also a FLUSH+FUA, since it is
+ * guaranteed ordered WRT previous writes.)
+ */
+ ring_req->operation = BLKIF_OP_WRITE_BARRIER;
+ }
+
ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg);
BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
@@ -634,7 +643,7 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
bret = RING_GET_RESPONSE(&info->ring, i);
id = bret->id;
- req = (struct request *)info->shadow[id].request;
+ req = info->shadow[id].request;
blkif_completion(&info->shadow[id]);
@@ -647,6 +656,16 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
printk(KERN_WARNING "blkfront: %s: write barrier op failed\n",
info->gd->disk_name);
error = -EOPNOTSUPP;
+ }
+ if (unlikely(bret->status == BLKIF_RSP_ERROR &&
+ info->shadow[id].req.nr_segments == 0)) {
+ printk(KERN_WARNING "blkfront: %s: empty write barrier op failed\n",
+ info->gd->disk_name);
+ error = -EOPNOTSUPP;
+ }
+ if (unlikely(error)) {
+ if (error == -EOPNOTSUPP)
+ error = 0;
info->feature_flush = 0;
xlvbd_flush(info);
}
@@ -899,7 +918,7 @@ static int blkif_recover(struct blkfront_info *info)
/* Stage 3: Find pending requests and requeue them. */
for (i = 0; i < BLK_RING_SIZE; i++) {
/* Not in use? */
- if (copy[i].request == 0)
+ if (!copy[i].request)
continue;
/* Grab a request slot and copy shadow state into it. */
@@ -916,9 +935,7 @@ static int blkif_recover(struct blkfront_info *info)
req->seg[j].gref,
info->xbdev->otherend_id,
pfn_to_mfn(info->shadow[req->id].frame[j]),
- rq_data_dir(
- (struct request *)
- info->shadow[req->id].request));
+ rq_data_dir(info->shadow[req->id].request));
info->shadow[req->id].req = *req;
info->ring.req_prod_pvt++;
@@ -1067,14 +1084,8 @@ 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
+ info->feature_flush = REQ_FLUSH | REQ_FUA;
err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
if (err) {