Commit 9793c269 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
Browse files

dm crypt: account large pages in cc->n_allocated_pages 



The commit 5054e778 ("dm crypt: allocate compound pages if
possible") changed dm-crypt to use compound pages to improve
performance. Unfortunately, there was an oversight: the allocation of
compound pages was not accounted at all. Normal pages are accounted in
a percpu counter cc->n_allocated_pages and dm-crypt is limited to
allocate at most 2% of memory. Because compound pages were not
accounted at all, dm-crypt could allocate memory over the 2% limit.

Fix this by adding the accounting of compound pages, so that memory
consumption of dm-crypt is properly limited.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Fixes: 5054e778 ("dm crypt: allocate compound pages if possible")
Cc: stable@vger.kernel.org	# v6.5+
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
parent 070bb43a

drivers/md/dm-crypt.c

+12 −3
Original line number Diff line number Diff line
@@ -1692,11 +1692,17 @@ static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned int size) 
		order = min(order, remaining_order);



		while (order > 0) {

			if (unlikely(percpu_counter_read_positive(&cc->n_allocated_pages) +

					(1 << order) > dm_crypt_pages_per_client))

				goto decrease_order;

			pages = alloc_pages(gfp_mask

				| __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN | __GFP_COMP,

				order);

			if (likely(pages != NULL))

			if (likely(pages != NULL)) {

				percpu_counter_add(&cc->n_allocated_pages, 1 << order);

				goto have_pages;

			}

decrease_order:

			order--;

		}
@@ -1734,13 +1740,16 @@ static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone) 


	if (clone->bi_vcnt > 0) { /* bio_for_each_folio_all crashes with an empty bio */

		bio_for_each_folio_all(fi, clone) {

			if (folio_test_large(fi.folio))

			if (folio_test_large(fi.folio)) {

				percpu_counter_sub(&cc->n_allocated_pages,

						1 << folio_order(fi.folio));

				folio_put(fi.folio);

			else

			} else {

				mempool_free(&fi.folio->page, &cc->page_pool);

			}

		}

	}

}



static void crypt_io_init(struct dm_crypt_io *io, struct crypt_config *cc,

			  struct bio *bio, sector_t sector)