From:   Hou Tao <houtao@huaweicloud.com>
To:     dm-devel@redhat.com
Cc:     Alasdair Kergon <agk@redhat.com>,
        Mike Snitzer <snitzer@kernel.org>,
        Ignat Korchagin <ignat@cloudflare.com>,
        linux-kernel@vger.kernel.org, houtao1@huawei.com
Subject: [PATCH] dm crypt: initialize tasklet in crypt_io_init()
Date:   Mon,  6 Mar 2023 21:49:30 +0800
Message-Id: <20230306134930.2878660-1-houtao@huaweicloud.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Hou Tao <houtao1@huawei.com>

When neither no_read_workqueue nor no_write_workqueue are enabled,
tasklet_trylock() in crypt_dec_pending() may still return false due to
an uninitialized state, and dm-crypt will do io completion in io_queue
instead of current context unnecessarily.

Fix it by initializing io->tasklet in crypt_io_init().

Fixes: 8e14f610159d ("dm crypt: do not call bio_endio() from the dm-crypt tasklet")
Signed-off-by: Hou Tao <houtao1@huawei.com>
---
 drivers/md/dm-crypt.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 3aeeb8f2802f..caee6ce3b79f 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -238,6 +238,7 @@ static void crypt_endio(struct bio *clone);
 static void kcryptd_queue_crypt(struct dm_crypt_io *io);
 static struct scatterlist *crypt_get_sg_data(struct crypt_config *cc,
 					     struct scatterlist *sg);
+static void kcryptd_crypt_tasklet(unsigned long work);
 
 static bool crypt_integrity_aead(struct crypt_config *cc);
 
@@ -1725,6 +1726,7 @@ static void crypt_io_init(struct dm_crypt_io *io, struct crypt_config *cc,
 	io->sector = sector;
 	io->error = 0;
 	io->ctx.r.req = NULL;
+	tasklet_init(&io->tasklet, kcryptd_crypt_tasklet, (unsigned long)&io->work);
 	io->integrity_metadata = NULL;
 	io->integrity_metadata_from_pool = false;
 	atomic_set(&io->io_pending, 0);
@@ -2226,7 +2228,6 @@ static void kcryptd_queue_crypt(struct dm_crypt_io *io)
 		 * it is being executed with irqs disabled.
 		 */
 		if (in_hardirq() || irqs_disabled()) {
-			tasklet_init(&io->tasklet, kcryptd_crypt_tasklet, (unsigned long)&io->work);
 			tasklet_schedule(&io->tasklet);
 			return;
 		}
-- 
2.29.2