1 files changed, 66 insertions, 43 deletions

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 13956437bc81..682ef9e6acd3 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -333,7 +333,6 @@ static void crypt_convert_init(struct crypt_config *cc,
         ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
         ctx->sector = sector + cc->iv_offset;
         init_completion(&ctx->restart);
-        atomic_set(&ctx->pending, 1);
 }
 
 static int crypt_convert_block(struct crypt_config *cc,
@@ -408,6 +407,8 @@ static int crypt_convert(struct crypt_config *cc,
 {
         int r;
 
+        atomic_set(&ctx->pending, 1);
+
         while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
               ctx->idx_out < ctx->bio_out->bi_vcnt) {
 
@@ -456,9 +457,11 @@ static void dm_crypt_bio_destructor(struct bio *bio)
 /*
  * Generate a new unfragmented bio with the given size
  * This should never violate the device limitations
- * May return a smaller bio when running out of pages
+ * May return a smaller bio when running out of pages, indicated by
+ * *out_of_pages set to 1.
  */
-static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
+static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size,
+                                      unsigned *out_of_pages)
 {
         struct crypt_config *cc = io->target->private;
         struct bio *clone;
@@ -472,11 +475,14 @@ static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
                 return NULL;
 
         clone_init(io, clone);
+        *out_of_pages = 0;
 
         for (i = 0; i < nr_iovecs; i++) {
                 page = mempool_alloc(cc->page_pool, gfp_mask);
-                if (!page)
+                if (!page) {
+                        *out_of_pages = 1;
                         break;
+                }
 
                 /*
                  * if additional pages cannot be allocated without waiting,
@@ -517,6 +523,27 @@ static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
         }
 }
 
+static struct dm_crypt_io *crypt_io_alloc(struct dm_target *ti,
+                                          struct bio *bio, sector_t sector)
+{
+        struct crypt_config *cc = ti->private;
+        struct dm_crypt_io *io;
+
+        io = mempool_alloc(cc->io_pool, GFP_NOIO);
+        io->target = ti;
+        io->base_bio = bio;
+        io->sector = sector;
+        io->error = 0;
+        atomic_set(&io->pending, 0);
+
+        return io;
+}
+
+static void crypt_inc_pending(struct dm_crypt_io *io)
+{
+        atomic_inc(&io->pending);
+}
+
 /*
  * One of the bios was finished. Check for completion of
  * the whole request and correctly clean up the buffer.
@@ -591,7 +618,7 @@ static void kcryptd_io_read(struct dm_crypt_io *io)
         struct bio *base_bio = io->base_bio;
         struct bio *clone;
 
-        atomic_inc(&io->pending);
+        crypt_inc_pending(io);
 
         /*
          * The block layer might modify the bvec array, so always
@@ -653,6 +680,7 @@ static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io,
                 crypt_free_buffer_pages(cc, clone);
                 bio_put(clone);
                 io->error = -EIO;
+                crypt_dec_pending(io);
                 return;
         }
 
@@ -664,28 +692,34 @@ static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io,
 
         if (async)
                 kcryptd_queue_io(io);
-        else {
-                atomic_inc(&io->pending);
+        else
                 generic_make_request(clone);
-        }
 }
 
-static void kcryptd_crypt_write_convert_loop(struct dm_crypt_io *io)
+static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
 {
         struct crypt_config *cc = io->target->private;
         struct bio *clone;
+        int crypt_finished;
+        unsigned out_of_pages = 0;
         unsigned remaining = io->base_bio->bi_size;
         int r;
 
         /*
+         * Prevent io from disappearing until this function completes.
+         */
+        crypt_inc_pending(io);
+        crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, io->sector);
+
+        /*
          * The allocated buffers can be smaller than the whole bio,
          * so repeat the whole process until all the data can be handled.
          */
         while (remaining) {
-                clone = crypt_alloc_buffer(io, remaining);
+                clone = crypt_alloc_buffer(io, remaining, &out_of_pages);
                 if (unlikely(!clone)) {
                         io->error = -ENOMEM;
-                        return;
+                        break;
                 }
 
                 io->ctx.bio_out = clone;
@@ -693,37 +727,32 @@ static void kcryptd_crypt_write_convert_loop(struct dm_crypt_io *io)
 
                 remaining -= clone->bi_size;
 
+                crypt_inc_pending(io);
                 r = crypt_convert(cc, &io->ctx);
+                crypt_finished = atomic_dec_and_test(&io->ctx.pending);
 
-                if (atomic_dec_and_test(&io->ctx.pending)) {
-                        /* processed, no running async crypto  */
+                /* Encryption was already finished, submit io now */
+                if (crypt_finished) {
                         kcryptd_crypt_write_io_submit(io, r, 0);
-                        if (unlikely(r < 0))
-                                return;
-                } else
-                        atomic_inc(&io->pending);
 
-                /* out of memory -> run queues */
-                if (unlikely(remaining)) {
-                        /* wait for async crypto then reinitialize pending */
-                        wait_event(cc->writeq, !atomic_read(&io->ctx.pending));
-                        atomic_set(&io->ctx.pending, 1);
-                        congestion_wait(WRITE, HZ/100);
+                        /*
+                         * If there was an error, do not try next fragments.
+                         * For async, error is processed in async handler.
+                         */
+                        if (unlikely(r < 0))
+                                break;
                 }
-        }
-}
 
-static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
-{
-        struct crypt_config *cc = io->target->private;
-
-        /*
-         * Prevent io from disappearing until this function completes.
-         */
-        atomic_inc(&io->pending);
+                /*
+                 * Out of memory -> run queues
+                 * But don't wait if split was due to the io size restriction
+                 */
+                if (unlikely(out_of_pages))
+                        congestion_wait(WRITE, HZ/100);
 
-        crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, io->sector);
-        kcryptd_crypt_write_convert_loop(io);
+                if (unlikely(remaining))
+                        wait_event(cc->writeq, !atomic_read(&io->ctx.pending));
+        }
 
         crypt_dec_pending(io);
 }
@@ -741,7 +770,7 @@ static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
         struct crypt_config *cc = io->target->private;
         int r = 0;
 
-        atomic_inc(&io->pending);
+        crypt_inc_pending(io);
 
         crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
                            io->sector);
@@ -1108,15 +1137,9 @@ static void crypt_dtr(struct dm_target *ti)
 static int crypt_map(struct dm_target *ti, struct bio *bio,
                      union map_info *map_context)
 {
-        struct crypt_config *cc = ti->private;
         struct dm_crypt_io *io;
 
-        io = mempool_alloc(cc->io_pool, GFP_NOIO);
-        io->target = ti;
-        io->base_bio = bio;
-        io->sector = bio->bi_sector - ti->begin;
-        io->error = 0;
-        atomic_set(&io->pending, 0);
+        io = crypt_io_alloc(ti, bio, bio->bi_sector - ti->begin);
 
         if (bio_data_dir(io->base_bio) == READ)
                 kcryptd_queue_io(io);