Forgot to Cc stable for the Fixes tag. Doing it now.
On Tue, Jan 19, 2021 at 11:57:27AM +0100, Roger Pau Monne wrote:
This is inline with the specification described in blkif.h:
- discard-granularity: should be set to the physical block size if node is not present.
- discard-alignment, discard-secure: should be set to 0 if node not present.
This was detected as QEMU would only create the discard-granularity node but not discard-alignment, and thus the setup done in blkfront_setup_discard would fail.
Fix blkfront_setup_discard to not fail on missing nodes, and also fix blkif_set_queue_limits to set the discard granularity to the physical block size if none is specified in xenbus.
Fixes: ed30bf317c5ce ('xen-blkfront: Handle discard requests.') Reported-by: Arthur Borsboom arthurborsboom@gmail.com Signed-off-by: Roger Pau Monné roger.pau@citrix.com
Cc: Boris Ostrovsky boris.ostrovsky@oracle.com Cc: Juergen Gross jgross@suse.com Cc: Stefano Stabellini sstabellini@kernel.org Cc: Konrad Rzeszutek Wilk konrad.wilk@oracle.com Cc: "Roger Pau Monné" roger.pau@citrix.com Cc: Jens Axboe axboe@kernel.dk Cc: xen-devel@lists.xenproject.org Cc: linux-block@vger.kernel.org Cc: Arthur Borsboom arthurborsboom@gmail.com
Changes since v2:
- Allow all discard-* nodes to be optional.
drivers/block/xen-blkfront.c | 20 +++++++------------- 1 file changed, 7 insertions(+), 13 deletions(-)
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 5265975b3fba..e1c6798889f4 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -945,7 +945,8 @@ static void blkif_set_queue_limits(struct blkfront_info *info) if (info->feature_discard) { blk_queue_flag_set(QUEUE_FLAG_DISCARD, rq); blk_queue_max_discard_sectors(rq, get_capacity(gd));
rq->limits.discard_granularity = info->discard_granularity;
rq->limits.discard_granularity = info->discard_granularity ?:info->physical_sector_size;@@ -2179,19 +2180,12 @@ static void blkfront_closing(struct blkfront_info *info) static void blkfront_setup_discard(struct blkfront_info *info) {
- int err;
- unsigned int discard_granularity;
- unsigned int discard_alignment;
- info->feature_discard = 1;
- err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
"discard-granularity", "%u", &discard_granularity,"discard-alignment", "%u", &discard_alignment,NULL);- if (!err) {
info->discard_granularity = discard_granularity;info->discard_alignment = discard_alignment;- }
- info->discard_granularity = xenbus_read_unsigned(info->xbdev->otherend,
"discard-granularity",0);- info->discard_alignment = xenbus_read_unsigned(info->xbdev->otherend,
"discard-alignment", 0);-- 2.29.2