[PATCH] dm crypt: restructure for workqueue change

Restructure part of the dm-crypt code in preparation for workqueue changes.

Use 'base_bio' or 'clone' variable names consistently throughout.  No
functional changes are included in this patch.

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, 156 insertions, 123 deletions

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index e1e8040f451a..3783cf978850 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -30,7 +30,7 @@
  */
 struct crypt_io {
         struct dm_target *target;
-        struct bio *bio;
+        struct bio *base_bio;
         struct bio *first_clone;
         struct work_struct work;
         atomic_t pending;
@@ -319,7 +319,7 @@ static struct bio *
 crypt_alloc_buffer(struct crypt_config *cc, unsigned int size,
                    struct bio *base_bio, unsigned int *bio_vec_idx)
 {
-        struct bio *bio;
+        struct bio *clone;
         unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
         gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
         unsigned int i;
@@ -330,23 +330,23 @@ crypt_alloc_buffer(struct crypt_config *cc, unsigned int size,
          * FIXME: Is this really intelligent?
          */
         if (base_bio)
-                bio = bio_clone(base_bio, GFP_NOIO|__GFP_NOMEMALLOC);
+                clone = bio_clone(base_bio, GFP_NOIO|__GFP_NOMEMALLOC);
         else
-                bio = bio_alloc(GFP_NOIO|__GFP_NOMEMALLOC, nr_iovecs);
-        if (!bio)
+                clone = bio_alloc(GFP_NOIO|__GFP_NOMEMALLOC, nr_iovecs);
+        if (!clone)
                 return NULL;
 
         /* if the last bio was not complete, continue where that one ended */
-        bio->bi_idx = *bio_vec_idx;
-        bio->bi_vcnt = *bio_vec_idx;
-        bio->bi_size = 0;
-        bio->bi_flags &= ~(1 << BIO_SEG_VALID);
+        clone->bi_idx = *bio_vec_idx;
+        clone->bi_vcnt = *bio_vec_idx;
+        clone->bi_size = 0;
+        clone->bi_flags &= ~(1 << BIO_SEG_VALID);
 
-        /* bio->bi_idx pages have already been allocated */
-        size -= bio->bi_idx * PAGE_SIZE;
+        /* clone->bi_idx pages have already been allocated */
+        size -= clone->bi_idx * PAGE_SIZE;
 
-        for(i = bio->bi_idx; i < nr_iovecs; i++) {
-                struct bio_vec *bv = bio_iovec_idx(bio, i);
+        for (i = clone->bi_idx; i < nr_iovecs; i++) {
+                struct bio_vec *bv = bio_iovec_idx(clone, i);
 
                 bv->bv_page = mempool_alloc(cc->page_pool, gfp_mask);
                 if (!bv->bv_page)
@@ -357,7 +357,7 @@ crypt_alloc_buffer(struct crypt_config *cc, unsigned int size,
                  * return a partially allocated bio, the caller will then try
                  * to allocate additional bios while submitting this partial bio
                  */
-                if ((i - bio->bi_idx) == (MIN_BIO_PAGES - 1))
+                if ((i - clone->bi_idx) == (MIN_BIO_PAGES - 1))
                         gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
 
                 bv->bv_offset = 0;
@@ -366,13 +366,13 @@ crypt_alloc_buffer(struct crypt_config *cc, unsigned int size,
                 else
                         bv->bv_len = size;
 
-                bio->bi_size += bv->bv_len;
-                bio->bi_vcnt++;
+                clone->bi_size += bv->bv_len;
+                clone->bi_vcnt++;
                 size -= bv->bv_len;
         }
 
-        if (!bio->bi_size) {
-                bio_put(bio);
+        if (!clone->bi_size) {
+                bio_put(clone);
                 return NULL;
         }
 
@@ -380,13 +380,13 @@ crypt_alloc_buffer(struct crypt_config *cc, unsigned int size,
          * Remember the last bio_vec allocated to be able
          * to correctly continue after the splitting.
          */
-        *bio_vec_idx = bio->bi_vcnt;
+        *bio_vec_idx = clone->bi_vcnt;
 
-        return bio;
+        return clone;
 }
 
 static void crypt_free_buffer_pages(struct crypt_config *cc,
-                                    struct bio *bio, unsigned int bytes)
+                                    struct bio *clone, unsigned int bytes)
 {
         unsigned int i, start, end;
         struct bio_vec *bv;
@@ -400,19 +400,19 @@ static void crypt_free_buffer_pages(struct crypt_config *cc,
          * A fix to the bi_idx issue in the kernel is in the works, so
          * we will hopefully be able to revert to the cleaner solution soon.
          */
-        i = bio->bi_vcnt - 1;
-        bv = bio_iovec_idx(bio, i);
-        end = (i << PAGE_SHIFT) + (bv->bv_offset + bv->bv_len) - bio->bi_size;
+        i = clone->bi_vcnt - 1;
+        bv = bio_iovec_idx(clone, i);
+        end = (i << PAGE_SHIFT) + (bv->bv_offset + bv->bv_len) - clone->bi_size;
         start = end - bytes;
 
         start >>= PAGE_SHIFT;
-        if (!bio->bi_size)
-                end = bio->bi_vcnt;
+        if (!clone->bi_size)
+                end = clone->bi_vcnt;
         else
                 end >>= PAGE_SHIFT;
 
-        for(i = start; i < end; i++) {
-                bv = bio_iovec_idx(bio, i);
+        for (i = start; i < end; i++) {
+                bv = bio_iovec_idx(clone, i);
                 BUG_ON(!bv->bv_page);
                 mempool_free(bv->bv_page, cc->page_pool);
                 bv->bv_page = NULL;
@@ -436,7 +436,7 @@ static void dec_pending(struct crypt_io *io, int error)
         if (io->first_clone)
                 bio_put(io->first_clone);
 
-        bio_endio(io->bio, io->bio->bi_size, io->error);
+        bio_endio(io->base_bio, io->base_bio->bi_size, io->error);
 
         mempool_free(io, cc->io_pool);
 }
@@ -449,25 +449,133 @@ static void dec_pending(struct crypt_io *io, int error)
  * queued here.
  */
 static struct workqueue_struct *_kcryptd_workqueue;
+static void kcryptd_do_work(void *data);
 
-static void kcryptd_do_work(void *data)
+static void kcryptd_queue_io(struct crypt_io *io)
 {
-        struct crypt_io *io = (struct crypt_io *) data;
-        struct crypt_config *cc = (struct crypt_config *) io->target->private;
+        INIT_WORK(&io->work, kcryptd_do_work, io);
+        queue_work(_kcryptd_workqueue, &io->work);
+}
+
+static int crypt_endio(struct bio *clone, unsigned int done, int error)
+{
+        struct crypt_io *io = clone->bi_private;
+        struct crypt_config *cc = io->target->private;
+        unsigned read_io = bio_data_dir(clone) == READ;
+
+        /*
+         * free the processed pages, even if
+         * it's only a partially completed write
+         */
+        if (!read_io)
+                crypt_free_buffer_pages(cc, clone, done);
+
+        if (unlikely(clone->bi_size))
+                return 1;
+
+        /*
+         * successful reads are decrypted by the worker thread
+         */
+        if (!read_io)
+                goto out;
+
+        if (unlikely(!bio_flagged(clone, BIO_UPTODATE))) {
+                error = -EIO;
+                goto out;
+        }
+
+        bio_put(clone);
+        kcryptd_queue_io(io);
+        return 0;
+
+out:
+        bio_put(clone);
+        dec_pending(io, error);
+        return error;
+}
+
+static void clone_init(struct crypt_io *io, struct bio *clone)
+{
+        struct crypt_config *cc = io->target->private;
+
+        clone->bi_private = io;
+        clone->bi_end_io  = crypt_endio;
+        clone->bi_bdev    = cc->dev->bdev;
+        clone->bi_rw      = io->base_bio->bi_rw;
+}
+
+static struct bio *clone_read(struct crypt_io *io,
+                              sector_t sector)
+{
+        struct crypt_config *cc = io->target->private;
+        struct bio *base_bio = io->base_bio;
+        struct bio *clone;
+
+        /*
+         * The block layer might modify the bvec array, so always
+         * copy the required bvecs because we need the original
+         * one in order to decrypt the whole bio data *afterwards*.
+         */
+        clone = bio_alloc(GFP_NOIO, bio_segments(base_bio));
+        if (unlikely(!clone))
+                return NULL;
+
+        clone_init(io, clone);
+        clone->bi_idx = 0;
+        clone->bi_vcnt = bio_segments(base_bio);
+        clone->bi_size = base_bio->bi_size;
+        memcpy(clone->bi_io_vec, bio_iovec(base_bio),
+               sizeof(struct bio_vec) * clone->bi_vcnt);
+        clone->bi_sector = cc->start + sector;
+
+        return clone;
+}
+
+static struct bio *clone_write(struct crypt_io *io,
+                               sector_t sector,
+                               unsigned *bvec_idx,
+                               struct convert_context *ctx)
+{
+        struct crypt_config *cc = io->target->private;
+        struct bio *base_bio = io->base_bio;
+        struct bio *clone;
+
+        clone = crypt_alloc_buffer(cc, base_bio->bi_size,
+                                   io->first_clone, bvec_idx);
+        if (!clone)
+                return NULL;
+
+        ctx->bio_out = clone;
+
+        if (unlikely(crypt_convert(cc, ctx) < 0)) {
+                crypt_free_buffer_pages(cc, clone,
+                                        clone->bi_size);
+                bio_put(clone);
+                return NULL;
+        }
+
+        clone_init(io, clone);
+        clone->bi_sector = cc->start + sector;
+
+        return clone;
+}
+
+static void process_read_endio(struct crypt_io *io)
+{
+        struct crypt_config *cc = io->target->private;
         struct convert_context ctx;
-        int r;
 
-        crypt_convert_init(cc, &ctx, io->bio, io->bio,
-                           io->bio->bi_sector - io->target->begin, 0);
-        r = crypt_convert(cc, &ctx);
+        crypt_convert_init(cc, &ctx, io->base_bio, io->base_bio,
+                           io->base_bio->bi_sector - io->target->begin, 0);
 
-        dec_pending(io, r);
+        dec_pending(io, crypt_convert(cc, &ctx));
 }
 
-static void kcryptd_queue_io(struct crypt_io *io)
+static void kcryptd_do_work(void *data)
 {
-        INIT_WORK(&io->work, kcryptd_do_work, io);
-        queue_work(_kcryptd_workqueue, &io->work);
+        struct crypt_io *io = data;
+
+        process_read_endio(io);
 }
 
 /*
@@ -481,7 +589,7 @@ static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
 
         buffer[2] = '\0';
 
-        for(i = 0; i < size; i++) {
+        for (i = 0; i < size; i++) {
                 buffer[0] = *hex++;
                 buffer[1] = *hex++;
 
@@ -504,7 +612,7 @@ static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
 {
         unsigned int i;
 
-        for(i = 0; i < size; i++) {
+        for (i = 0; i < size; i++) {
                 sprintf(hex, "%02x", *key);
                 hex += 2;
                 key++;
@@ -725,88 +833,10 @@ static void crypt_dtr(struct dm_target *ti)
         kfree(cc);
 }
 
-static int crypt_endio(struct bio *bio, unsigned int done, int error)
-{
-        struct crypt_io *io = (struct crypt_io *) bio->bi_private;
-        struct crypt_config *cc = (struct crypt_config *) io->target->private;
-
-        if (bio_data_dir(bio) == WRITE) {
-                /*
-                 * free the processed pages, even if
-                 * it's only a partially completed write
-                 */
-                crypt_free_buffer_pages(cc, bio, done);
-        }
-
-        if (bio->bi_size)
-                return 1;
-
-        bio_put(bio);
-
-        /*
-         * successful reads are decrypted by the worker thread
-         */
-        if ((bio_data_dir(bio) == READ)
-            && bio_flagged(bio, BIO_UPTODATE)) {
-                kcryptd_queue_io(io);
-                return 0;
-        }
-
-        dec_pending(io, error);
-        return error;
-}
-
-static inline struct bio *
-crypt_clone(struct crypt_config *cc, struct crypt_io *io, struct bio *bio,
-            sector_t sector, unsigned int *bvec_idx,
-            struct convert_context *ctx)
-{
-        struct bio *clone;
-
-        if (bio_data_dir(bio) == WRITE) {
-                clone = crypt_alloc_buffer(cc, bio->bi_size,
-                                 io->first_clone, bvec_idx);
-                if (clone) {
-                        ctx->bio_out = clone;
-                        if (crypt_convert(cc, ctx) < 0) {
-                                crypt_free_buffer_pages(cc, clone,
-                                                        clone->bi_size);
-                                bio_put(clone);
-                                return NULL;
-                        }
-                }
-        } else {
-                /*
-                 * The block layer might modify the bvec array, so always
-                 * copy the required bvecs because we need the original
-                 * one in order to decrypt the whole bio data *afterwards*.
-                 */
-                clone = bio_alloc(GFP_NOIO, bio_segments(bio));
-                if (clone) {
-                        clone->bi_idx = 0;
-                        clone->bi_vcnt = bio_segments(bio);
-                        clone->bi_size = bio->bi_size;
-                        memcpy(clone->bi_io_vec, bio_iovec(bio),
-                               sizeof(struct bio_vec) * clone->bi_vcnt);
-                }
-        }
-
-        if (!clone)
-                return NULL;
-
-        clone->bi_private = io;
-        clone->bi_end_io = crypt_endio;
-        clone->bi_bdev = cc->dev->bdev;
-        clone->bi_sector = cc->start + sector;
-        clone->bi_rw = bio->bi_rw;
-
-        return clone;
-}
-
 static int crypt_map(struct dm_target *ti, struct bio *bio,
                      union map_info *map_context)
 {
-        struct crypt_config *cc = (struct crypt_config *) ti->private;
+        struct crypt_config *cc = ti->private;
         struct crypt_io *io;
         struct convert_context ctx;
         struct bio *clone;
@@ -816,7 +846,7 @@ static int crypt_map(struct dm_target *ti, struct bio *bio,
 
         io = mempool_alloc(cc->io_pool, GFP_NOIO);
         io->target = ti;
-        io->bio = bio;
+        io->base_bio = bio;
         io->first_clone = NULL;
         io->error = 0;
         atomic_set(&io->pending, 1); /* hold a reference */
@@ -829,7 +859,10 @@ static int crypt_map(struct dm_target *ti, struct bio *bio,
          * so repeat the whole process until all the data can be handled.
          */
         while (remaining) {
-                clone = crypt_clone(cc, io, bio, sector, &bvec_idx, &ctx);
+                if (bio_data_dir(bio) == WRITE)
+                        clone = clone_write(io, sector, &bvec_idx, &ctx);
+                else
+                        clone = clone_read(io, sector);
                 if (!clone)
                         goto cleanup;