|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH V4 2/3] xen-blkfront: teach blkfront driver to handle discard requests
The blkfront driver now will read discard related nodes from xenstore,
and set up the request queue, then we can forward the
discard requests to backend driver.
Signed-off-by: Li Dongyang <lidongyang@xxxxxxxxxx>
---
drivers/block/xen-blkfront.c | 111 +++++++++++++++++++++++++++++++++---------
1 files changed, 88 insertions(+), 23 deletions(-)
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 9ea8c25..86e2c63 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -98,6 +98,9 @@ struct blkfront_info
unsigned long shadow_free;
unsigned int feature_flush;
unsigned int flush_op;
+ unsigned int feature_discard;
+ unsigned int discard_granularity;
+ unsigned int discard_alignment;
int is_ready;
};
@@ -302,29 +305,36 @@ static int blkif_queue_request(struct request *req)
ring_req->operation = info->flush_op;
}
- ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg);
- BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
+ if (unlikely(req->cmd_flags & REQ_DISCARD)) {
+ /* id, sector_number and handle are set above. */
+ ring_req->operation = BLKIF_OP_DISCARD;
+ ring_req->nr_segments = 0;
+ ring_req->u.discard.nr_sectors = blk_rq_sectors(req);
+ } else {
+ ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg);
+ BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
- for_each_sg(info->sg, sg, ring_req->nr_segments, i) {
- buffer_mfn = pfn_to_mfn(page_to_pfn(sg_page(sg)));
- fsect = sg->offset >> 9;
- lsect = fsect + (sg->length >> 9) - 1;
- /* install a grant reference. */
- ref = gnttab_claim_grant_reference(&gref_head);
- BUG_ON(ref == -ENOSPC);
+ for_each_sg(info->sg, sg, ring_req->nr_segments, i) {
+ buffer_mfn = pfn_to_mfn(page_to_pfn(sg_page(sg)));
+ fsect = sg->offset >> 9;
+ lsect = fsect + (sg->length >> 9) - 1;
+ /* install a grant reference. */
+ ref = gnttab_claim_grant_reference(&gref_head);
+ BUG_ON(ref == -ENOSPC);
- gnttab_grant_foreign_access_ref(
- ref,
- info->xbdev->otherend_id,
- buffer_mfn,
- rq_data_dir(req) );
-
- info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn);
- ring_req->u.rw.seg[i] =
- (struct blkif_request_segment) {
- .gref = ref,
- .first_sect = fsect,
- .last_sect = lsect };
+ gnttab_grant_foreign_access_ref(
+ ref,
+ info->xbdev->otherend_id,
+ buffer_mfn,
+ rq_data_dir(req));
+
+ info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn);
+ ring_req->u.rw.seg[i] =
+ (struct blkif_request_segment) {
+ .gref = ref,
+ .first_sect = fsect,
+ .last_sect = lsect };
+ }
}
info->ring.req_prod_pvt++;
@@ -399,6 +409,7 @@ wait:
static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
{
struct request_queue *rq;
+ struct blkfront_info *info = gd->private_data;
rq = blk_init_queue(do_blkif_request, &blkif_io_lock);
if (rq == NULL)
@@ -406,6 +417,13 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16
sector_size)
queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
+ if (info->feature_discard) {
+ queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, rq);
+ blk_queue_max_discard_sectors(rq, get_capacity(gd));
+ rq->limits.discard_granularity = info->discard_granularity;
+ rq->limits.discard_alignment = info->discard_alignment;
+ }
+
/* Hard sector size and max sectors impersonate the equiv. hardware. */
blk_queue_logical_block_size(rq, sector_size);
blk_queue_max_hw_sectors(rq, 512);
@@ -722,6 +740,19 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
switch (bret->operation) {
+ case BLKIF_OP_DISCARD:
+ if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
+ struct request_queue *rq = info->rq;
+ printk(KERN_WARNING "blkfront: %s: discard op
failed\n",
+ info->gd->disk_name);
+ error = -EOPNOTSUPP;
+ info->feature_discard = 0;
+ spin_lock(rq->queue_lock);
+ queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
+ spin_unlock(rq->queue_lock);
+ }
+ __blk_end_request_all(req, error);
+ break;
case BLKIF_OP_FLUSH_DISKCACHE:
case BLKIF_OP_WRITE_BARRIER:
if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
@@ -1098,6 +1129,33 @@ blkfront_closing(struct blkfront_info *info)
bdput(bdev);
}
+static void blkfront_setup_discard(struct blkfront_info *info)
+{
+ int err;
+ char *type;
+ unsigned int discard_granularity;
+ unsigned int discard_alignment;
+
+ type = xenbus_read(XBT_NIL, info->xbdev->otherend, "type", NULL);
+ if (IS_ERR(type))
+ return;
+
+ if (strncmp(type, "phy", 3) == 0) {
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "discard-granularity", "%u", &discard_granularity,
+ "discard-alignment", "%u", &discard_alignment,
+ NULL);
+ if (!err) {
+ info->feature_discard = 1;
+ info->discard_granularity = discard_granularity;
+ info->discard_alignment = discard_alignment;
+ }
+ } else if (strncmp(type, "file", 4) == 0)
+ info->feature_discard = 1;
+
+ kfree(type);
+}
+
/*
* Invoked when the backend is finally 'ready' (and has told produced
* the details about the physical device - #sectors, size, etc).
@@ -1108,7 +1166,7 @@ static void blkfront_connect(struct blkfront_info *info)
unsigned long sector_size;
unsigned int binfo;
int err;
- int barrier, flush;
+ int barrier, flush, discard;
switch (info->connected) {
case BLKIF_STATE_CONNECTED:
@@ -1178,7 +1236,14 @@ static void blkfront_connect(struct blkfront_info *info)
info->feature_flush = REQ_FLUSH;
info->flush_op = BLKIF_OP_FLUSH_DISKCACHE;
}
-
+
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "feature-discard", "%d", &discard,
+ NULL);
+
+ if (!err && discard)
+ blkfront_setup_discard(info);
+
err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
if (err) {
xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
--
1.7.6
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |