Commit ba2cce82 authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm verity: conditionally enable branching for "try_verify_in_tasklet" 



Use jump_label to limit the need for branching unless the optional
"try_verify_in_tasklet" feature is used.

Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
parent 3c1c875d

drivers/md/dm-verity-target.c

+14 −5
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/module.h>

#include <linux/reboot.h>

#include <linux/scatterlist.h>

#include <linux/jump_label.h>



#define DM_MSG_PREFIX			"verity"
@@ -43,6 +44,8 @@ static unsigned dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE; 


module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, S_IRUGO | S_IWUSR);



static DEFINE_STATIC_KEY_FALSE(use_tasklet_enabled);



struct dm_verity_prefetch_work {

	struct work_struct work;

	struct dm_verity *v;
@@ -287,7 +290,7 @@ static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io, 


	verity_hash_at_level(v, block, level, &hash_block, &offset);



	if (io->in_tasklet) {

	if (static_branch_unlikely(&use_tasklet_enabled) && io->in_tasklet) {

		data = dm_bufio_get(v->bufio, hash_block, &buf);

		if (data == NULL) {

			/*
@@ -320,7 +323,8 @@ static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io, 
		if (likely(memcmp(verity_io_real_digest(v, io), want_digest,

				  v->digest_size) == 0))

			aux->hash_verified = 1;

		else if (io->in_tasklet) {

		else if (static_branch_unlikely(&use_tasklet_enabled) &&

			 io->in_tasklet) {

			/*

			 * Error handling code (FEC included) cannot be run in a

			 * tasklet since it may sleep, so fallback to work-queue.
@@ -553,7 +557,8 @@ static int verity_verify_io(struct dm_verity_io *io) 
			if (v->validated_blocks)

				set_bit(cur_block, v->validated_blocks);

			continue;

		} else if (io->in_tasklet) {

		} else if (static_branch_unlikely(&use_tasklet_enabled) &&

			   io->in_tasklet) {

			/*

			 * Error handling code (FEC included) cannot be run in a

			 * tasklet since it may sleep, so fallback to work-queue.
@@ -598,7 +603,7 @@ static void verity_finish_io(struct dm_verity_io *io, blk_status_t status) 
	bio->bi_end_io = io->orig_bi_end_io;

	bio->bi_status = status;



	if (!io->in_tasklet)

	if (!static_branch_unlikely(&use_tasklet_enabled) || !io->in_tasklet)

		verity_fec_finish_io(io);



	bio_endio(bio);
@@ -641,7 +646,7 @@ static void verity_end_io(struct bio *bio) 
		return;

	}



	if (io->v->use_tasklet) {

	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 {
@@ -949,6 +954,9 @@ static void verity_dtr(struct dm_target *ti) 


	kfree(v->signature_key_desc);



	if (v->use_tasklet)

		static_branch_dec(&use_tasklet_enabled);



	kfree(v);

}
@@ -1080,6 +1088,7 @@ static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v, 


		} else if (!strcasecmp(arg_name, DM_VERITY_OPT_TASKLET_VERIFY)) {

			v->use_tasklet = true;

			static_branch_inc(&use_tasklet_enabled);

			continue;



		} else if (verity_is_fec_opt_arg(arg_name)) {