From: olaf.kirch@xxxxxxxxxx
Get rid of first_clone in dm-crypt
This gets rid of first_clone, which is not really needed. Apparently,
cloned bios used to share their bvec some time way in the past - this is
no longer the case. Contrarily, this even hurts us if we try to create
a clone off first_clone after it has completed, and crypt_endio has
destroyed its bvec.
Signed-off-by: olaf.kirch@xxxxxxxxxx
Signed-off-by: Alasdair G Kergon <agk@xxxxxxxxxx>
---
drivers/md/dm-crypt.c | 34 ++++++----------------------------
1 files changed, 6 insertions(+), 28 deletions(-)
Index: linux-2.6.21/drivers/md/dm-crypt.c
===================================================================
--- linux-2.6.21.orig/drivers/md/dm-crypt.c 2007-05-01 17:40:48.000000000 +0100
+++ linux-2.6.21/drivers/md/dm-crypt.c 2007-05-01 17:40:48.000000000 +0100
@@ -33,7 +33,6 @@
struct crypt_io {
struct dm_target *target;
struct bio *base_bio;
- struct bio *first_clone;
struct work_struct work;
atomic_t pending;
int error;
@@ -380,9 +379,8 @@ static int crypt_convert(struct crypt_co
* This should never violate the device limitations
* May return a smaller bio when running out of pages
*/
-static struct bio *
-crypt_alloc_buffer(struct crypt_io *io, unsigned int size,
- struct bio *base_bio, unsigned int *bio_vec_idx)
+static struct bio *crypt_alloc_buffer(struct crypt_io *io, unsigned int size,
+ unsigned int *bio_vec_idx)
{
struct crypt_config *cc = io->target->private;
struct bio *clone;
@@ -390,12 +388,7 @@ crypt_alloc_buffer(struct crypt_io *io,
gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
unsigned int i;
- if (base_bio) {
- clone = bio_alloc_bioset(GFP_NOIO, base_bio->bi_max_vecs, cc->bs);
- __bio_clone(clone, base_bio);
- } else
- clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
-
+ clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
if (!clone)
return NULL;
@@ -498,9 +491,6 @@ static void dec_pending(struct crypt_io
if (!atomic_dec_and_test(&io->pending))
return;
- if (io->first_clone)
- bio_put(io->first_clone);
-
bio_endio(io->base_bio, io->base_bio->bi_size, io->error);
mempool_free(io, cc->io_pool);
@@ -618,8 +608,7 @@ static void process_write(struct crypt_i
* so repeat the whole process until all the data can be handled.
*/
while (remaining) {
- clone = crypt_alloc_buffer(io, base_bio->bi_size,
- io->first_clone, &bvec_idx);
+ clone = crypt_alloc_buffer(io, base_bio->bi_size, &bvec_idx);
if (unlikely(!clone)) {
dec_pending(io, -ENOMEM);
return;
@@ -635,21 +624,11 @@ static void process_write(struct crypt_i
}
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;
- }
-
remaining -= clone->bi_size;
sector += bio_sectors(clone);
- /* prevent bio_put of first_clone */
+ /* Grab another reference to the io struct
+ * before we kick off the request */
if (remaining)
atomic_inc(&io->pending);
@@ -965,7 +944,6 @@ static int crypt_map(struct dm_target *t
io = mempool_alloc(cc->io_pool, GFP_NOIO);
io->target = ti;
io->base_bio = bio;
- io->first_clone = NULL;
io->error = io->post_process = 0;
atomic_set(&io->pending, 0);
kcryptd_queue_io(io);
--
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