[patch 12/26] dm crypt: fix remove first_clone

Greg KH
2007-07-31T04:35:00Z

[-- Attachment #1: dm-crypt-fix-remove-first_clone.patch --]
[-- Type: text/plain, Size: 3799 bytes --]

-stable review patch. If anyone has any objections, please let us know.

------------------

From: Olaf Kirch <olaf.kirch@oracle.com>

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 <olaf.kirch@oracle.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
Gitweb: http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=2f9941b6c55d70103c1bc3f2c7676acd9f20bf8a

drivers/md/dm-crypt.c | 34 ++++++----------------------------
1 file changed, 6 insertions(+), 28 deletions(-)

--- linux-2.6.21.6.orig/drivers/md/dm-crypt.c
+++ linux-2.6.21.6/drivers/md/dm-crypt.c
@@ -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);

--