Commit 2d45a7e8 authored Aug 10, 2017 by Stephan Mueller Committed by Herbert Xu Aug 22, 2017

crypto: af_alg - get_page upon reassignment to TX SGL



When a page is assigned to a TX SGL, call get_page to increment the
reference counter. It is possible that one page is referenced in
multiple SGLs:

- in the global TX SGL in case a previous af_alg_pull_tsgl only
reassigned parts of a page to a per-request TX SGL

- in the per-request TX SGL as assigned by af_alg_pull_tsgl

Note, multiple requests can be active at the same time whose TX SGLs all
point to different parts of the same page.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

parent 32e67b9a

crypto/af_alg.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -641,9 +641,9 @@ void af_alg_pull_tsgl(struct sock sk, size_t used, struct scatterlist dst,
		if (dst_offset >= plen) {
		/* discard page before offset */
		dst_offset -= plen;
		put_page(page);
		} else {
		/* reassign page to dst after offset */
		get_page(page);
		sg_set_page(dst + j, page,
		plen - dst_offset,
		sg[i].offset + dst_offset);
		@@ -661,9 +661,7 @@ void af_alg_pull_tsgl(struct sock sk, size_t used, struct scatterlist dst,
		if (sg[i].length)
		return;

		if (!dst)
		put_page(page);

		sg_assign_page(sg + i, NULL);
		}