This reverts commit 5735a2671ffb70ea29ca83969fe01316ee2ed6fc which is
commit 0a9bab391e336489169b95cb0d4553d921302189 upstream.
Tasklet is thought to cause memory corruption [1], so it was disabled in
dm-crypt and dm-verity. However, memory corruption may not happen since
cc->io_queue is created without WQ_UNBOUND [2].
Revert commit 5735a2671ffb ("dm-crypt, dm-verity: disable tasklets") to
bring tasklet back.
[1] https://lore.kernel.org/all/d390d7ee-f142-44d3-822a-87949e14608b@xxxxxxx/T/
[2] https://lore.kernel.org/all/4d331659-badd-749d-fba1-271543631a8a@xxxxxxxxxx/
Signed-off-by: Li Lingfeng <lilingfeng3@xxxxxxxxxx>
---
drivers/md/dm-crypt.c | 38 +++++++++++++++++++++++++++++++++--
drivers/md/dm-verity-target.c | 26 ++++++++++++++++++++++--
drivers/md/dm-verity.h | 1 +
3 files changed, 61 insertions(+), 4 deletions(-)
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index aa6bb5b4704b..a60d91d02e28 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -75,8 +75,10 @@ struct dm_crypt_io {
struct bio *base_bio;
u8 *integrity_metadata;
bool integrity_metadata_from_pool:1;
+ bool in_tasklet:1;
struct work_struct work;
+ struct tasklet_struct tasklet;
struct convert_context ctx;
@@ -1775,6 +1777,7 @@ static void crypt_io_init(struct dm_crypt_io *io, struct crypt_config *cc,
io->ctx.r.req = NULL;
io->integrity_metadata = NULL;
io->integrity_metadata_from_pool = false;
+ io->in_tasklet = false;
atomic_set(&io->io_pending, 0);
}
@@ -1785,6 +1788,13 @@ static void crypt_inc_pending(struct dm_crypt_io *io)
static void kcryptd_queue_read(struct dm_crypt_io *io);
+static void kcryptd_io_bio_endio(struct work_struct *work)
+{
+ struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
+
+ bio_endio(io->base_bio);
+}
+
/*
* One of the bios was finished. Check for completion of
* the whole request and correctly clean up the buffer.
@@ -1817,6 +1827,20 @@ static void crypt_dec_pending(struct dm_crypt_io *io)
base_bio->bi_status = error;
+ /*
+ * If we are running this function from our tasklet,
+ * we can't call bio_endio() here, because it will call
+ * clone_endio() from dm.c, which in turn will
+ * free the current struct dm_crypt_io structure with
+ * our tasklet. In this case we need to delay bio_endio()
+ * execution to after the tasklet is done and dequeued.
+ */
+ if (io->in_tasklet) {
+ INIT_WORK(&io->work, kcryptd_io_bio_endio);
+ queue_work(cc->io_queue, &io->work);
+ return;
+ }
+
bio_endio(base_bio);
}
@@ -2291,6 +2315,11 @@ static void kcryptd_crypt(struct work_struct *work)
kcryptd_crypt_write_convert(io);
}
+static void kcryptd_crypt_tasklet(unsigned long work)
+{
+ kcryptd_crypt((struct work_struct *)work);
+}
+
static void kcryptd_queue_crypt(struct dm_crypt_io *io)
{
struct crypt_config *cc = io->cc;
@@ -2302,10 +2331,15 @@ static void kcryptd_queue_crypt(struct dm_crypt_io *io)
* irqs_disabled(): the kernel may run some IO completion from the idle thread, but
* it is being executed with irqs disabled.
*/
- if (!(in_hardirq() || irqs_disabled())) {
- kcryptd_crypt(&io->work);
+ if (in_hardirq() || irqs_disabled()) {
+ io->in_tasklet = true;
+ tasklet_init(&io->tasklet, kcryptd_crypt_tasklet, (unsigned long)&io->work);
+ tasklet_schedule(&io->tasklet);
return;
}
+
+ kcryptd_crypt(&io->work);
+ return;
}
INIT_WORK(&io->work, kcryptd_crypt);
diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index 49e4a35d7019..0bb126eadc0d 100644
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -701,6 +701,23 @@ static void verity_work(struct work_struct *w)
verity_finish_io(io, errno_to_blk_status(verity_verify_io(io)));
}
+static void verity_tasklet(unsigned long data)
+{
+ struct dm_verity_io *io = (struct dm_verity_io *)data;
+ int err;
+
+ io->in_tasklet = true;
+ err = verity_verify_io(io);
+ if (err == -EAGAIN || err == -ENOMEM) {
+ /* fallback to retrying with work-queue */
+ INIT_WORK(&io->work, verity_work);
+ queue_work(io->v->verify_wq, &io->work);
+ return;
+ }
+
+ verity_finish_io(io, errno_to_blk_status(err));
+}
+
static void verity_end_io(struct bio *bio)
{
struct dm_verity_io *io = bio->bi_private;
@@ -713,8 +730,13 @@ static void verity_end_io(struct bio *bio)
return;
}
- INIT_WORK(&io->work, verity_work);
- queue_work(io->v->verify_wq, &io->work);
+ if (static_branch_unlikely(&use_tasklet_enabled) && io->v->use_tasklet) {
+ tasklet_init(&io->tasklet, verity_tasklet, (unsigned long)io);
+ tasklet_schedule(&io->tasklet);
+ } else {
+ INIT_WORK(&io->work, verity_work);
+ queue_work(io->v->verify_wq, &io->work);
+ }
}
/*
diff --git a/drivers/md/dm-verity.h b/drivers/md/dm-verity.h
index db93a91169d5..7e495cc375b0 100644
--- a/drivers/md/dm-verity.h
+++ b/drivers/md/dm-verity.h
@@ -87,6 +87,7 @@ struct dm_verity_io {
bool in_tasklet;
struct work_struct work;
+ struct tasklet_struct tasklet;
char *recheck_buffer;
--
2.31.1
