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Tue, 31 Mar 2026 11:34:05 -0700 (PDT) Received: from penguin.lxd ([2601:647:6400:3ec0:216:3eff:fecd:e4ef]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-12ac4a0fa8dsm7961271c88.15.2026.03.31.11.34.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 31 Mar 2026 11:34:04 -0700 (PDT) From: "Kanchana P. Sridhar" To: hannes@cmpxchg.org, yosry@kernel.org, nphamcs@gmail.com, chengming.zhou@linux.dev, akpm@linux-foundation.org, kanchanapsridhar2026@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: herbert@gondor.apana.org.au, senozhatsky@chromium.org Subject: [PATCH v3 0/2] zswap pool per-CPU acomp_ctx simplifications Date: Tue, 31 Mar 2026 11:33:49 -0700 Message-Id: <20260331183351.29844-1-kanchanapsridhar2026@gmail.com> X-Mailer: git-send-email 2.39.5 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: AEAAD12000C X-Stat-Signature: hufo5rstpu1w6pdujbs7gtzw4c9yuz61 X-Rspam-User: X-HE-Tag: 1774982046-440294 X-HE-Meta: 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 N4WXd2b3 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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. [1]: https://patchwork.kernel.org/project/linux-mm/list/?series=1046677 Changes since v2: ================= 1) Rebased to mm-unstable as of 3-31-2026 (commit 24e341657c28). 2) Collected Acks. Changes since v1: ================= 1) Made the changes to eliminate redundant checks on acomp_ctx/acomp_ctx->req in zswap_cpu_comp_dead(), per Yosry. 2) Renamed acomp_ctx_dealloc() to acomp_ctx_free(), per Yosry. 3) Incorporated suggestions from Yosry and Sashiko to reset the acomp_ctx's members to NULL after freeing them, to prevent UAF and double free issues. 4) Replaced v1's patch 2 with v2's patch 1. Kanchana P. Sridhar (2): mm: zswap: Remove redundant checks in zswap_cpu_comp_dead(). mm: zswap: Tie per-CPU acomp_ctx lifetime to the pool. mm/zswap.c | 182 +++++++++++++++++++++++++---------------------------- 1 file changed, 85 insertions(+), 97 deletions(-) -- 2.39.5