[PATCH] dm crypt: restructure write processing

Restructure the dm-crypt write processing in preparation for workqueue changes
in the next patches.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 76 insertions, 76 deletions

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 3783cf978850..946a9ebc89db 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -504,12 +504,14 @@ static void clone_init(struct crypt_io *io, struct bio *clone)
         clone->bi_rw      = io->base_bio->bi_rw;
 }
 
-static struct bio *clone_read(struct crypt_io *io,
-                              sector_t sector)
+static int process_read(struct crypt_io *io)
 {
         struct crypt_config *cc = io->target->private;
         struct bio *base_bio = io->base_bio;
         struct bio *clone;
+        sector_t sector = base_bio->bi_sector - io->target->begin;
+
+        atomic_inc(&io->pending);
 
         /*
          * The block layer might modify the bvec array, so always
@@ -517,47 +519,94 @@ static struct bio *clone_read(struct crypt_io *io,
          * one in order to decrypt the whole bio data *afterwards*.
          */
         clone = bio_alloc(GFP_NOIO, bio_segments(base_bio));
-        if (unlikely(!clone))
-                return NULL;
+        if (unlikely(!clone)) {
+                dec_pending(io, -ENOMEM);
+                return 0;
+        }
 
         clone_init(io, clone);
         clone->bi_idx = 0;
         clone->bi_vcnt = bio_segments(base_bio);
         clone->bi_size = base_bio->bi_size;
+        clone->bi_sector = cc->start + sector;
         memcpy(clone->bi_io_vec, bio_iovec(base_bio),
                sizeof(struct bio_vec) * clone->bi_vcnt);
-        clone->bi_sector = cc->start + sector;
 
-        return clone;
+        generic_make_request(clone);
+
+        return 0;
 }
 
-static struct bio *clone_write(struct crypt_io *io,
-                               sector_t sector,
-                               unsigned *bvec_idx,
-                               struct convert_context *ctx)
+static int process_write(struct crypt_io *io)
 {
         struct crypt_config *cc = io->target->private;
         struct bio *base_bio = io->base_bio;
         struct bio *clone;
+        struct convert_context ctx;
+        unsigned remaining = base_bio->bi_size;
+        sector_t sector = base_bio->bi_sector - io->target->begin;
+        unsigned bvec_idx = 0;
 
-        clone = crypt_alloc_buffer(cc, base_bio->bi_size,
-                                   io->first_clone, bvec_idx);
-        if (!clone)
-                return NULL;
+        atomic_inc(&io->pending);
 
-        ctx->bio_out = clone;
+        crypt_convert_init(cc, &ctx, NULL, base_bio, sector, 1);
 
-        if (unlikely(crypt_convert(cc, ctx) < 0)) {
-                crypt_free_buffer_pages(cc, clone,
-                                        clone->bi_size);
-                bio_put(clone);
-                return NULL;
+        /*
+         * 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(cc, base_bio->bi_size,
+                                           io->first_clone, &bvec_idx);
+                if (unlikely(!clone))
+                        goto cleanup;
+
+                ctx.bio_out = clone;
+
+                if (unlikely(crypt_convert(cc, &ctx) < 0)) {
+                        crypt_free_buffer_pages(cc, clone, clone->bi_size);
+                        bio_put(clone);
+                        goto cleanup;
+                }
+
+                clone_init(io, clone);
+                clone->bi_sector = cc->start + sector;
+
+                if (!io->first_clone) {
+                        /*
+                         * hold a reference to the first clone, because it
+                         * holds the bio_vec array and that can't be freed
+                         * before all other clones are released
+                         */
+                        bio_get(clone);
+                        io->first_clone = clone;
+                }
+
+                atomic_inc(&io->pending);
+
+                remaining -= clone->bi_size;
+                sector += bio_sectors(clone);
+
+                generic_make_request(clone);
+
+                /* out of memory -> run queues */
+                if (remaining)
+                        blk_congestion_wait(bio_data_dir(clone), HZ/100);
         }
 
-        clone_init(io, clone);
-        clone->bi_sector = cc->start + sector;
+        /* drop reference, clones could have returned before we reach this */
+        dec_pending(io, 0);
+        return 0;
 
-        return clone;
+cleanup:
+        if (io->first_clone) {
+                dec_pending(io, -ENOMEM);
+                return 0;
+        }
+
+         /* if no bio has been dispatched yet, we can directly return the error */
+        mempool_free(io, cc->io_pool);
+        return -ENOMEM;
 }
 
 static void process_read_endio(struct crypt_io *io)
@@ -838,68 +887,19 @@ static int crypt_map(struct dm_target *ti, struct bio *bio,
 {
         struct crypt_config *cc = ti->private;
         struct crypt_io *io;
-        struct convert_context ctx;
-        struct bio *clone;
-        unsigned int remaining = bio->bi_size;
-        sector_t sector = bio->bi_sector - ti->begin;
-        unsigned int bvec_idx = 0;
 
         io = mempool_alloc(cc->io_pool, GFP_NOIO);
+
         io->target = ti;
         io->base_bio = bio;
         io->first_clone = NULL;
         io->error = 0;
-        atomic_set(&io->pending, 1); /* hold a reference */
+        atomic_set(&io->pending, 0);
 
         if (bio_data_dir(bio) == WRITE)
-                crypt_convert_init(cc, &ctx, NULL, bio, sector, 1);
-
-        /*
-         * The allocated buffers can be smaller than the whole bio,
-         * so repeat the whole process until all the data can be handled.
-         */
-        while (remaining) {
-                if (bio_data_dir(bio) == WRITE)
-                        clone = clone_write(io, sector, &bvec_idx, &ctx);
-                else
-                        clone = clone_read(io, sector);
-                if (!clone)
-                        goto cleanup;
-
-                if (!io->first_clone) {
-                        /*
-                         * hold a reference to the first clone, because it
-                         * holds the bio_vec array and that can't be freed
-                         * before all other clones are released
-                         */
-                        bio_get(clone);
-                        io->first_clone = clone;
-                }
-                atomic_inc(&io->pending);
-
-                remaining -= clone->bi_size;
-                sector += bio_sectors(clone);
-
-                generic_make_request(clone);
-
-                /* out of memory -> run queues */
-                if (remaining)
-                        blk_congestion_wait(bio_data_dir(clone), HZ/100);
-        }
+                return process_write(io);
 
-        /* drop reference, clones could have returned before we reach this */
-        dec_pending(io, 0);
-        return 0;
-
-cleanup:
-        if (io->first_clone) {
-                dec_pending(io, -ENOMEM);
-                return 0;
-        }
-
-        /* if no bio has been dispatched yet, we can directly return the error */
-        mempool_free(io, cc->io_pool);
-        return -ENOMEM;
+        return process_read(io);
 }
 
 static int crypt_status(struct dm_target *ti, status_type_t type,