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dm crypt: account large pages in cc->n_allocated_pages

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The commit 5054e778fc ("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: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 5054e778fc ("dm crypt: allocate compound pages if possible")
Cc: stable@vger.kernel.org	# v6.5+
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
This commit is contained in:
Mikulas Patocka 2023-10-31 19:12:54 +01:00 committed by Mike Snitzer
parent 070bb43ab0
commit 9793c269da
1 changed files with 12 additions and 3 deletions
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15
drivers/md/dm-crypt.c
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@ -1692,11 +1692,17 @@ retry:
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--;
}
@ -1734,10 +1740,13 @@ 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);
}
}
}
}