dm verity: avoid deadlock

[platform/adaptation/renesas_rcar/renesas_kernel.git] / drivers / md / dm-verity.c

diff --git a/drivers/md/dm-verity.c b/drivers/md/dm-verity.c
index 6ad5383..a746f1d 100644 (file)
--- a/drivers/md/dm-verity.c
+++ b/drivers/md/dm-verity.c
@@ -93,6 +93,13 @@ struct dm_verity_io {
         */
 };
 
+struct dm_verity_prefetch_work {
+       struct work_struct work;
+       struct dm_verity *v;
+       sector_t block;
+       unsigned n_blocks;
+};
+
 static struct shash_desc *io_hash_desc(struct dm_verity *v, struct dm_verity_io *io)
 {
        return (struct shash_desc *)(io + 1);
@@ -424,15 +431,18 @@ static void verity_end_io(struct bio *bio, int error)
  * The root buffer is not prefetched, it is assumed that it will be cached
  * all the time.
  */
-static void verity_prefetch_io(struct dm_verity *v, struct dm_verity_io *io)
+static void verity_prefetch_io(struct work_struct *work)
 {
+       struct dm_verity_prefetch_work *pw =
+               container_of(work, struct dm_verity_prefetch_work, work);
+       struct dm_verity *v = pw->v;
        int i;
 
        for (i = v->levels - 2; i >= 0; i--) {
                sector_t hash_block_start;
                sector_t hash_block_end;
-               verity_hash_at_level(v, io->block, i, &hash_block_start, NULL);
-               verity_hash_at_level(v, io->block + io->n_blocks - 1, i, &hash_block_end, NULL);
+               verity_hash_at_level(v, pw->block, i, &hash_block_start, NULL);
+               verity_hash_at_level(v, pw->block + pw->n_blocks - 1, i, &hash_block_end, NULL);
                if (!i) {
                        unsigned cluster = ACCESS_ONCE(dm_verity_prefetch_cluster);
 
@@ -452,6 +462,25 @@ no_prefetch_cluster:
                dm_bufio_prefetch(v->bufio, hash_block_start,
                                  hash_block_end - hash_block_start + 1);
        }
+
+       kfree(pw);
+}
+
+static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io)
+{
+       struct dm_verity_prefetch_work *pw;
+
+       pw = kmalloc(sizeof(struct dm_verity_prefetch_work),
+               GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
+
+       if (!pw)
+               return;
+
+       INIT_WORK(&pw->work, verity_prefetch_io);
+       pw->v = v;
+       pw->block = io->block;
+       pw->n_blocks = io->n_blocks;
+       queue_work(v->verify_wq, &pw->work);
 }
 
 /*
@@ -498,7 +527,7 @@ static int verity_map(struct dm_target *ti, struct bio *bio)
        memcpy(io->io_vec, bio_iovec(bio),
               io->io_vec_size * sizeof(struct bio_vec));
 
-       verity_prefetch_io(v, io);
+       verity_submit_prefetch(v, io);
 
        generic_make_request(bio);
 
@@ -858,7 +887,7 @@ bad:
 
 static struct target_type verity_target = {
        .name           = "verity",
-       .version        = {1, 1, 1},
+       .version        = {1, 2, 0},
        .module         = THIS_MODULE,
        .ctr            = verity_ctr,
        .dtr            = verity_dtr,