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From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Petr Vorel <pvorel@suse.cz>, Martijn Coenen <maco@android.com>,
	linux-block@vger.kernel.org, ltp@lists.linux.it
Subject: [PATCH 2/2] loop: Fix occasional uevent drop
Date: Thu, 12 Nov 2020 17:50:05 +0100	[thread overview]
Message-ID: <20201112165005.4022502-3-hch@lst.de> (raw)
In-Reply-To: <20201112165005.4022502-1-hch@lst.de>

From: Petr Vorel <pvorel@suse.cz>

Commit 716ad0986cbd ("loop: Switch to set_capacity_revalidate_and_notify")
causes an occasional drop of loop device uevent, which are no longer
triggered in loop_set_size() but in a different part of code.

Bug is reproducible with LTP test uevent01 [1]:

i=0; while true; do
    i=$((i+1)); echo "== $i =="
    lsmod |grep -q loop && rmmod -f loop
    ./uevent01 || break
done

Put back triggering through code called in loop_set_size().

Fix required to add yet another parameter to
set_capacity_revalidate_and_notify().

[1] https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/uevents/uevent01.c

Fixes: 716ad0986cbd ("loop: Switch to set_capacity_revalidate_and_notify")
Reported-by: <ltp@lists.linux.it>
Signed-off-by: Petr Vorel <pvorel@suse.cz>
[hch: rebased on a different change to the prototype of
 set_capacity_revalidate_and_notify]
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/loop.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index cb1191d6e945f2..a58084c2ed7ceb 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -255,7 +255,8 @@ static void loop_set_size(struct loop_device *lo, loff_t size)
 
 	bd_set_nr_sectors(bdev, size);
 
-	set_capacity_revalidate_and_notify(lo->lo_disk, size, false);
+	if (!set_capacity_revalidate_and_notify(lo->lo_disk, size, false))
+		kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
 }
 
 static inline int
-- 
2.28.0


WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: ltp@lists.linux.it
Subject: [LTP] [PATCH 2/2] loop: Fix occasional uevent drop
Date: Thu, 12 Nov 2020 17:50:05 +0100	[thread overview]
Message-ID: <20201112165005.4022502-3-hch@lst.de> (raw)
In-Reply-To: <20201112165005.4022502-1-hch@lst.de>

From: Petr Vorel <pvorel@suse.cz>

Commit 716ad0986cbd ("loop: Switch to set_capacity_revalidate_and_notify")
causes an occasional drop of loop device uevent, which are no longer
triggered in loop_set_size() but in a different part of code.

Bug is reproducible with LTP test uevent01 [1]:

i=0; while true; do
    i=$((i+1)); echo "== $i =="
    lsmod |grep -q loop && rmmod -f loop
    ./uevent01 || break
done

Put back triggering through code called in loop_set_size().

Fix required to add yet another parameter to
set_capacity_revalidate_and_notify().

[1] https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/uevents/uevent01.c

Fixes: 716ad0986cbd ("loop: Switch to set_capacity_revalidate_and_notify")
Reported-by: <ltp@lists.linux.it>
Signed-off-by: Petr Vorel <pvorel@suse.cz>
[hch: rebased on a different change to the prototype of
 set_capacity_revalidate_and_notify]
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/loop.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index cb1191d6e945f2..a58084c2ed7ceb 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -255,7 +255,8 @@ static void loop_set_size(struct loop_device *lo, loff_t size)
 
 	bd_set_nr_sectors(bdev, size);
 
-	set_capacity_revalidate_and_notify(lo->lo_disk, size, false);
+	if (!set_capacity_revalidate_and_notify(lo->lo_disk, size, false))
+		kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
 }
 
 static inline int
-- 
2.28.0


  parent reply	other threads:[~2020-11-12 16:50 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-12 16:50 loop uevent fix Christoph Hellwig
2020-11-12 16:50 ` [PATCH 1/2] block: add a return value to set_capacity_revalidate_and_notify Christoph Hellwig
2020-11-12 19:13   ` Petr Vorel
2020-11-12 16:50 ` Christoph Hellwig [this message]
2020-11-12 16:50   ` [LTP] [PATCH 2/2] loop: Fix occasional uevent drop Christoph Hellwig
2020-11-12 19:25   ` Petr Vorel
2020-11-12 19:25     ` [LTP] " Petr Vorel
2020-11-12 19:31 ` loop uevent fix Petr Vorel
2020-11-12 20:59 ` Jens Axboe

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