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Commit f97380bc authored by Olaf Kirch's avatar Olaf Kirch Committed by Linus Torvalds
Browse files

dm crypt: use smaller bvecs in clones 



Allocate smaller clones

With the previous dm-crypt fixes, there is no need for the clone bios to have
the same bvec size as the original - we just need to make them big enough for
the remaining number of pages.  The only requirement is that we clear the
"out" index in convert_context, so that crypt_convert starts storing data at
the right position within the clone bio.

Signed-off-by: default avatarOlaf Kirch <olaf.kirch@oracle.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2f9941b6

drivers/md/dm-crypt.c

+8 −21
Original line number Diff line number Diff line
@@ -379,8 +379,7 @@ static int crypt_convert(struct crypt_config *cc, 
 * 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,

				      unsigned int *bio_vec_idx)

static struct bio *crypt_alloc_buffer(struct crypt_io *io, unsigned int size)

{

	struct crypt_config *cc = io->target->private;

	struct bio *clone;
@@ -394,16 +393,7 @@ static struct bio *crypt_alloc_buffer(struct crypt_io *io, unsigned int size, 


	clone_init(io, clone);



	/* if the last bio was not complete, continue where that one ended */

	clone->bi_idx = *bio_vec_idx;

	clone->bi_vcnt = *bio_vec_idx;

	clone->bi_size = 0;

	clone->bi_flags &= ~(1 << BIO_SEG_VALID);



	/* clone->bi_idx pages have already been allocated */

	size -= clone->bi_idx * PAGE_SIZE;



	for (i = clone->bi_idx; i < nr_iovecs; i++) {

	for (i = 0; i < nr_iovecs; i++) {

		struct bio_vec *bv = bio_iovec_idx(clone, i);



		bv->bv_page = mempool_alloc(cc->page_pool, gfp_mask);
@@ -415,7 +405,7 @@ static struct bio *crypt_alloc_buffer(struct crypt_io *io, unsigned int size, 
		 * return a partially allocated bio, the caller will then try

		 * to allocate additional bios while submitting this partial bio

		 */

		if ((i - clone->bi_idx) == (MIN_BIO_PAGES - 1))

		if (i == (MIN_BIO_PAGES - 1))

			gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;



		bv->bv_offset = 0;
@@ -434,12 +424,6 @@ static struct bio *crypt_alloc_buffer(struct crypt_io *io, unsigned int size, 
		return NULL;

	}



	/*

	 * Remember the last bio_vec allocated to be able

	 * to correctly continue after the splitting.

	 */

	*bio_vec_idx = clone->bi_vcnt;



	return clone;

}
@@ -597,7 +581,6 @@ static void process_write(struct crypt_io *io) 
	struct convert_context ctx;

	unsigned remaining = base_bio->bi_size;

	sector_t sector = base_bio->bi_sector - io->target->begin;

	unsigned bvec_idx = 0;



	atomic_inc(&io->pending);
@@ -608,13 +591,14 @@ static void process_write(struct crypt_io *io) 
	 * so repeat the whole process until all the data can be handled.

	 */

	while (remaining) {

		clone = crypt_alloc_buffer(io, base_bio->bi_size, &bvec_idx);

		clone = crypt_alloc_buffer(io, remaining);

		if (unlikely(!clone)) {

			dec_pending(io, -ENOMEM);

			return;

		}



		ctx.bio_out = clone;

		ctx.idx_out = 0;



		if (unlikely(crypt_convert(cc, &ctx) < 0)) {

			crypt_free_buffer_pages(cc, clone, clone->bi_size);
@@ -623,6 +607,9 @@ static void process_write(struct crypt_io *io) 
			return;

		}



		/* crypt_convert should have filled the clone bio */

		BUG_ON(ctx.idx_out < clone->bi_vcnt);



		clone->bi_sector = cc->start + sector;

		remaining -= clone->bi_size;

		sector += bio_sectors(clone);