github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-12 16:18:45 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity

mm: zswap: remove redundant checks in zswap_cpu_comp_dead()

Browse Source 
Patch series "zswap pool per-CPU acomp_ctx simplifications", v3.

This patchset first removes redundant checks on the acomp_ctx and its
"req" member in zswap_cpu_comp_dead().

Next, it persists the zswap pool's per-CPU acomp_ctx resources to last
until the pool is destroyed.  It then simplifies the per-CPU acomp_ctx
mutex locking in zswap_compress()/zswap_decompress().

Code comments added after allocation and before checking to deallocate the
per-CPU acomp_ctx's members, based on expected crypto API return values
and zswap changes this patchset makes.

Patch 2 is an independent submission of patch 23 from [1], to
facilitate merging.


This patch (of 2):

There are presently redundant checks on the per-CPU acomp_ctx and it's
"req" member in zswap_cpu_comp_dead(): redundant because they are
inconsistent with zswap_pool_create() handling of failure in allocating
the acomp_ctx, and with the expected NULL return value from the
acomp_request_alloc() API when it fails to allocate an acomp_req.

Fix these by converting to them to be NULL checks.

Add comments in zswap_cpu_comp_prepare() clarifying the expected return
values of the crypto_alloc_acomp_node() and acomp_request_alloc() API.

Link: https://lore.kernel.org/20260331183351.29844-2-kanchanapsridhar2026@gmail.com
Link: https://patchwork.kernel.org/project/linux-mm/list/?series=1046677
Signed-off-by: Kanchana P. Sridhar <kanchanapsridhar2026@gmail.com>
Suggested-by: Yosry Ahmed <yosry@kernel.org>
Acked-by: Yosry Ahmed <yosry@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Kanchana P. Sridhar 2026-03-31 11:33:50 -07:00 committed by Andrew Morton
parent 6b1842775a
commit 1556478e9e
1 changed files with 10 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
mm/zswap.c
View File

@ -749,6 +749,10 @@ static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node)
goto fail;
}
/*
* In case of an error, crypto_alloc_acomp_node() returns an
* error pointer, never NULL.
*/
acomp = crypto_alloc_acomp_node(pool->tfm_name, 0, 0, cpu_to_node(cpu));
if (IS_ERR(acomp)) {
pr_err("could not alloc crypto acomp %s : %pe\n",
@ -757,6 +761,7 @@ static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node)
goto fail;
}
/* acomp_request_alloc() returns NULL in case of an error. */
req = acomp_request_alloc(acomp);
if (!req) {
pr_err("could not alloc crypto acomp_request %s\n",
@ -802,7 +807,7 @@ static int zswap_cpu_comp_dead(unsigned int cpu, struct hlist_node *node)
struct crypto_acomp *acomp;
u8 *buffer;
if (IS_ERR_OR_NULL(acomp_ctx))
if (!acomp_ctx)
return 0;
mutex_lock(&acomp_ctx->mutex);
@ -817,8 +822,11 @@ static int zswap_cpu_comp_dead(unsigned int cpu, struct hlist_node *node)
/*
* Do the actual freeing after releasing the mutex to avoid subtle
* locking dependencies causing deadlocks.
*
* If there was an error in allocating @acomp_ctx->req, it
* would be set to NULL.
*/
if (!IS_ERR_OR_NULL(req))
if (req)
acomp_request_free(req);
if (!IS_ERR_OR_NULL(acomp))
crypto_free_acomp(acomp);