From: Roger Pau Monne roger.pau@citrix.com
commit 0549cd67b01016b579047bce045b386202a8bcfc upstream.
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 Reviewed-by: Juergen Gross jgross@suse.com Tested-By: Arthur Borsboom arthurborsboom@gmail.com Link: https://lore.kernel.org/r/20210119105727.95173-1-roger.pau@citrix.com Signed-off-by: Juergen Gross jgross@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/block/xen-blkfront.c | 20 +++++++------------- 1 file changed, 7 insertions(+), 13 deletions(-)
--- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -936,7 +936,8 @@ static void blkif_set_queue_limits(struc 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; rq->limits.discard_alignment = info->discard_alignment; if (info->feature_secdiscard) blk_queue_flag_set(QUEUE_FLAG_SECERASE, rq); @@ -2169,19 +2170,12 @@ static void blkfront_closing(struct blkf
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); info->feature_secdiscard = !!xenbus_read_unsigned(info->xbdev->otherend, "discard-secure", 0);