From: Barry Song <[email protected]>
We used to rely on the returned -ENOSPC of zpool_malloc() to increase
reject_compress_poor. But the code wouldn't get to there after commit
744e1885922a ("crypto: scomp - fix req->dst buffer overflow") as the
new code will goto out immediately after the special compression case
happens. So there might be no longer a chance to execute zpool_malloc
now. We are incorrectly increasing zswap_reject_compress_fail instead.
Thus, we need to fix the counters handling right after compressions
return ENOSPC. This patch also centralizes the counters handling for
all of compress_poor, compress_fail and alloc_fail.
Fixes: 744e1885922a ("crypto: scomp - fix req->dst buffer overflow")
Cc: Sergey Senozhatsky <[email protected]>
Signed-off-by: Barry Song <[email protected]>
Reviewed-by: Nhat Pham <[email protected]>
Acked-by: Yosry Ahmed <[email protected]>
Reviewed-by: Chengming Zhou <[email protected]>
---
-v3:
* rebase on top of mm-unstable according to Yosry and Andrew
* collect review and ack tags of Nhat, Yosry and Chengming, thanks!
mm/zswap.c | 27 +++++++++++++--------------
1 file changed, 13 insertions(+), 14 deletions(-)
diff --git a/mm/zswap.c b/mm/zswap.c
index 62fe307521c9..51de79aa8659 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -1021,12 +1021,12 @@ static bool zswap_compress(struct folio *folio, struct zswap_entry *entry)
{
struct crypto_acomp_ctx *acomp_ctx;
struct scatterlist input, output;
+ int comp_ret = 0, alloc_ret = 0;
unsigned int dlen = PAGE_SIZE;
unsigned long handle;
struct zpool *zpool;
char *buf;
gfp_t gfp;
- int ret;
u8 *dst;
acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx);
@@ -1057,26 +1057,18 @@ static bool zswap_compress(struct folio *folio, struct zswap_entry *entry)
* but in different threads running on different cpu, we have different
* acomp instance, so multiple threads can do (de)compression in parallel.
*/
- ret = crypto_wait_req(crypto_acomp_compress(acomp_ctx->req), &acomp_ctx->wait);
+ comp_ret = crypto_wait_req(crypto_acomp_compress(acomp_ctx->req), &acomp_ctx->wait);
dlen = acomp_ctx->req->dlen;
- if (ret) {
- zswap_reject_compress_fail++;
+ if (comp_ret)
goto unlock;
- }
zpool = zswap_find_zpool(entry);
gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM;
if (zpool_malloc_support_movable(zpool))
gfp |= __GFP_HIGHMEM | __GFP_MOVABLE;
- ret = zpool_malloc(zpool, dlen, gfp, &handle);
- if (ret == -ENOSPC) {
- zswap_reject_compress_poor++;
- goto unlock;
- }
- if (ret) {
- zswap_reject_alloc_fail++;
+ alloc_ret = zpool_malloc(zpool, dlen, gfp, &handle);
+ if (alloc_ret)
goto unlock;
- }
buf = zpool_map_handle(zpool, handle, ZPOOL_MM_WO);
memcpy(buf, dst, dlen);
@@ -1086,8 +1078,15 @@ static bool zswap_compress(struct folio *folio, struct zswap_entry *entry)
entry->length = dlen;
unlock:
+ if (comp_ret == -ENOSPC || alloc_ret == -ENOSPC)
+ zswap_reject_compress_poor++;
+ else if (comp_ret)
+ zswap_reject_compress_fail++;
+ else if (alloc_ret)
+ zswap_reject_alloc_fail++;
+
mutex_unlock(&acomp_ctx->mutex);
- return ret == 0;
+ return comp_ret == 0 && alloc_ret == 0;
}
static void zswap_decompress(struct zswap_entry *entry, struct page *page)
--
2.34.1