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Tue, 18 Nov 2025 11:18:56 +0800 X-QQ-mid: xmsmtpt1763435936tgfvowgug Message-ID: X-QQ-XMAILINFO: MZtEYADUG4AgfdWAQf+qZ54lVhebfHhdDMGqPAgwFiuq0THzTSkCBhdmMX+SzQ 1SMlm3v0OKFNJFAywHUKrnww5srPjcJKEuNPl5ssQDpyPwRFYQFAyNWb+Hi2s8m8/upmOCtNGZWo MYFdkvoPZll66ZQWSoxSdb1MKDUN1Qb7u5ekc6t0/bA/151Hzwn4FDtNAgHCTRqn7h17cTuNm6/d aGQgL5VFUhc3+Nak/vIhzxIsrf6t7Ben2Bbzo3rqbjn6SC3/DyXyYgKLcsrb0iBmfa74TcMgQNUd JDIdSJyymmnksCOl2o+PVXLzbQJFZFW0rjI9n0fmD8zmO/E5dUTveZNx7sFl2hvKPNx+3Fjkoxja F7Oy5ud5aJpm/2ImpuNF9Ugl3MzRinRokeL3t7Ciw1Ie9Ki2QjilnsI82UOLogfxGQbSTKL1oDZR aqy26wiEF0aJJiw92pCiysZs7lVadk7dxhZPk5uXmlLYegvO1R0Ku7yr0UtjWKDbTqG+5nQ+vDHE Uo4bq3PepD28JYo0GimguFkNK6GqbZxZoGO9mNpmExkqm2xjjveRPjoVfrHmtMtnQv2KUxk3gACx C/x1DQZP2PoJ+M5B/qmb5X+WPjJBdg6o5C5+RXR1jpViwwS30oRO46bNk2TbuedQ74XSAw96oQQB w5jlrwlF8kziX3U3O6vd8RA/zqZoiToME5olPsKSlceYPpSvpE/QJZo+6B9MXgYKXFBroZ0CkWFs 3BTyKG2kCy0fAf2g69unnmGYoOrryIeWUZR7IHIqwKOLfK4+DdgOn01JpEb8H+FTU0UvURTp568+ KnUah8O+bw0dEvVczYY+oDlD067lJtAWTgfrnjNsQiIoIcNWh0M6S1US68rMv9l4YPzQMgRXEXBy Uoa2krF+hrMVlLlCCDjjBKr5Y/tkUfhSx1wPDaQH52XUGqm+XlweLMrxmnpVlo+pP844URwp4p9G MILv8NTKReA9a7vz7A8huLjGzCwiPEXYc3mW0gvAHX8/azugwb+Tgi/FqOESEyOSUIq/xf2BncZ9 9m26ENYI0ZrIB4E7YdytTSiU45cwzzzu1zZH3uLOpfuJPaSMgHjG9+f4If712p8XqGEJDF6w== X-QQ-XMRINFO: M/715EihBoGSf6IYSX1iLFg= From: Yuwen Chen To: senozhatsky@chromium.org Cc: akpm@linux-foundation.org, bgeffon@google.com, licayy@outlook.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, minchan@google.com, minchan@kernel.org, richardycc@google.com, ywen.chen@foxmail.com Subject: Re: [PATCHv3 1/4] zram: introduce writeback bio batching support Date: Tue, 18 Nov 2025 11:18:56 +0800 X-OQ-MSGID: <20251118031856.2800796-1-ywen.chen@foxmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <3nqzi2v72dsef2dte7iqe7wahrbzam33druh7klsh45zvefdm3@ab6stznzdxmh> References: <3nqzi2v72dsef2dte7iqe7wahrbzam33druh7klsh45zvefdm3@ab6stznzdxmh> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: rydtuwnukw6dprknwte8imhngjxf8gbk X-Rspam-User: X-Rspamd-Queue-Id: C2F7120002 X-Rspamd-Server: rspam01 X-HE-Tag: 1763435944-91301 X-HE-Meta: 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 3r8BpODC qUmKXBOwXe46FDoWS8p5ZmHCr8IgrF3eYu+kzsiF/aYtjg8Xkc5MzoM0lYe9NAtAxINPVfaR9AXstH3mQ3ss083hgXL0NzlQgATzJJi2gcX5zPsGD01rrxPnPzpTzCnxOBqamy6T2V6+Db3VENR4IAFrqZ5qu9GDaLSuJEjzEBhqBkEen8LzU11fldDJRzhwi+ZHlKO/71R1sdOv+YX72GUm4ow== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, 17 Nov 2025 10:19:22 -0500, Sergey Senozhatsky wrote: > +static int zram_writeback_complete(struct zram *zram, struct zram_wb_req *req) > +{ > + u32 index; > + int err; > + > + index = req->pps->index; > + release_pp_slot(zram, req->pps); > + req->pps = NULL; > + > + err = blk_status_to_errno(req->bio.bi_status); > + if (err) { > + /* > + * Failed wb requests should not be accounted in wb_limit > + * (if enabled). > + */ > + zram_account_writeback_rollback(zram); In this place, the index may be leaked. > + return err; > + } > + > + atomic64_inc(&zram->stats.bd_writes); > + zram_slot_lock(zram, index); > + /* > + * We release slot lock during writeback so slot can change under us: > + * slot_free() or slot_free() and zram_write_page(). In both cases > + * slot loses ZRAM_PP_SLOT flag. No concurrent post-processing can > + * set ZRAM_PP_SLOT on such slots until current post-processing > + * finishes. > + */ > + if (!zram_test_flag(zram, index, ZRAM_PP_SLOT)) > + goto out; In this place, the index may be leaked. > + > + zram_free_page(zram, index); > + zram_set_flag(zram, index, ZRAM_WB); > + zram_set_handle(zram, index, req->blk_idx); > + atomic64_inc(&zram->stats.pages_stored); > + > +out: > + zram_slot_unlock(zram, index); > + return 0; > +}