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crypto: af_alg - get_page upon reassignment to TX SGL

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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>
This commit is contained in:
Stephan Mueller 2017-08-10 16:40:03 +02:00 committed by Herbert Xu
parent 32e67b9af0
commit 2d45a7e898
1 changed files with 2 additions and 4 deletions
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6
crypto/af_alg.c
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@ -641,9 +641,9 @@ void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
if (dst_offset >= plen) { if (dst_offset >= plen) {
/* discard page before offset */ /* discard page before offset */
dst_offset -= plen; dst_offset -= plen;
put_page(page);
} else { } else {
/* reassign page to dst after offset */ /* reassign page to dst after offset */
get_page(page);
sg_set_page(dst + j, page, sg_set_page(dst + j, page,
plen - dst_offset, plen - dst_offset,
sg[i].offset + 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) if (sg[i].length)
return; return;
if (!dst) put_page(page);
put_page(page);
sg_assign_page(sg + i, NULL); sg_assign_page(sg + i, NULL);
} }