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Commit 6a24c718 authored by Milan Broz's avatar Milan Broz Committed by Linus Torvalds
Browse files

[PATCH] dm crypt: use private biosets 



In the low memory situation dm-crypt needs to use a private mempool of bios to
avoid blocking.

Signed-off-by: default avatarMilan Broz <mbroz@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 23541d2d

drivers/md/dm-crypt.c

+29 −12
Original line number Diff line number Diff line
@@ -77,6 +77,7 @@ struct crypt_config { 
	 */

	mempool_t *io_pool;

	mempool_t *page_pool;

	struct bio_set *bs;



	/*

	 * crypto related data
@@ -95,7 +96,7 @@ struct crypt_config { 
	u8 key[0];

};



#define MIN_IOS        256

#define MIN_IOS        16

#define MIN_POOL_PAGES 32

#define MIN_BIO_PAGES  8
@@ -311,6 +312,14 @@ static int crypt_convert(struct crypt_config *cc, 
	return r;

}



 static void dm_crypt_bio_destructor(struct bio *bio)

 {

	struct crypt_io *io = bio->bi_private;

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



	bio_free(bio, cc->bs);

 }



/*

 * Generate a new unfragmented bio with the given size

 * This should never violate the device limitations
@@ -325,18 +334,17 @@ crypt_alloc_buffer(struct crypt_config *cc, unsigned int size, 
	gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;

	unsigned int i;



	/*

	 * Use __GFP_NOMEMALLOC to tell the VM to act less aggressively and

	 * to fail earlier.  This is not necessary but increases throughput.

	 * FIXME: Is this really intelligent?

	 */

	if (base_bio)

		clone = bio_clone(base_bio, GFP_NOIO|__GFP_NOMEMALLOC);

	else

		clone = bio_alloc(GFP_NOIO|__GFP_NOMEMALLOC, nr_iovecs);

	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);



	if (!clone)

		return NULL;



	clone->bi_destructor = dm_crypt_bio_destructor;



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

	clone->bi_idx = *bio_vec_idx;

	clone->bi_vcnt = *bio_vec_idx;
@@ -517,13 +525,14 @@ static void process_read(struct crypt_io *io) 
	 * 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));

	clone = bio_alloc_bioset(GFP_NOIO, bio_segments(base_bio), cc->bs);

	if (unlikely(!clone)) {

		dec_pending(io, -ENOMEM);

		return;

	}



	clone_init(io, clone);

	clone->bi_destructor = dm_crypt_bio_destructor;

	clone->bi_idx = 0;

	clone->bi_vcnt = bio_segments(base_bio);

	clone->bi_size = base_bio->bi_size;
@@ -594,7 +603,6 @@ static void process_write(struct crypt_io *io) 
		/* out of memory -> run queues */

		if (remaining)

			blk_congestion_wait(bio_data_dir(clone), HZ/100);



	}

}
@@ -804,6 +812,12 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) 
		goto bad4;

	}



	cc->bs = bioset_create(MIN_IOS, MIN_IOS, 4);

	if (!cc->bs) {

		ti->error = "Cannot allocate crypt bioset";

		goto bad_bs;

	}



	if (crypto_blkcipher_setkey(tfm, cc->key, key_size) < 0) {

		ti->error = "Error setting key";

		goto bad5;
@@ -843,6 +857,8 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) 
	return 0;



bad5:

	bioset_free(cc->bs);

bad_bs:

	mempool_destroy(cc->page_pool);

bad4:

	mempool_destroy(cc->io_pool);
@@ -862,6 +878,7 @@ static void crypt_dtr(struct dm_target *ti) 
{

	struct crypt_config *cc = (struct crypt_config *) ti->private;



	bioset_free(cc->bs);

	mempool_destroy(cc->page_pool);

	mempool_destroy(cc->io_pool);