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Sat, 29 Aug 2026 05:13:40 -0700 (PDT) From: Wenjie Qi To: akpm@linux-foundation.org Cc: willy@infradead.org, jack@suse.cz, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, baohua@kernel.org, qiwenjie@xiaomi.com Subject: Re: [PATCH] mm: filemap: tighten dropbehind completion context check Date: Sat, 29 Aug 2026 20:13:35 +0800 Message-ID: <20260829121335.3491374-1-qwjhust@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260828181035.ce6e23970d37e38b64818f10@linux-foundation.org> References: <20260820142956.1414337-1-qiwenjie@xiaomi.com> <20260828181035.ce6e23970d37e38b64818f10@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 2F427160006 X-Stat-Signature: jt5yqsdwjkh7f88p4naoi34zpkbnsspr X-HE-Tag: 1788005622-518474 X-HE-Meta: U2FsdGVkX1/M/cMH/gtMb2v9piObxmUmp74uqUYBQt9y15SNKCoruh/SXZfoumwGP3IAPdPYJacRI5IoNMkrOqCe4xhbslQjXhbPhf/QICYXxlGL56ocwzz6hbXb7TIMT6bfBH9JkKCD1cLONmkYp2cO+Tws0bIJWk75TnKrzMF/ryx5X49DuhsJOpQYsklzjaSf4bLsOfkZol3qC/ap8gnWGBaAS9njeJesgCSDhAIzmc5elFYrKtwjQEYxQC3krAtF4UAfbvDavasDw6A0G/gPiG5Mn3S9+o1N5VCx705P+5CqXDMy9XxgP52S14svLLfYZv4B5plF5wRJ7GjqxYAASQjJIHPF8MTapHf3qfZdsBB5hy3hzvAaZemccKduPYpK+tpW0Mwn64ycpjJZn8epvYv1P5yhH1fbhAs8KAaL6NfYNv5oMkKGDUocvcPQ8KOXFJicxr6r3rXJPa+EgUufsiEUMed2HASKfFIVC3AyP+xPxFYWDFgzJarxEmBo8uFOJVrgXbNZ6ivqkzZbG6V8bMFs3+XfTIqmcQ05NzvWVl5j9MR1D19B1ef2NYmbncFMnFgm/veoibWRC5juULseKQG0WyOdgnZnbf+d6lRCYhiW5nn8RndtmQTB2t06UzfFjAifIN/VlMRFEpRWlMqfjbHGRqeUaCNvINzGUtr95KPqvPeOikye/miISQj25TQYlPvpr3AYfUVJ/zbA/P1HjzfggjrWVdGpm9X0SqZxUEdq7NrKU+RbwUa/p0tjbBiScdRvKBSNBiKAM1DnRzMtUCnYvK6T5A4blnIK5IJZsWIdb5zG4b/vAnFGq56WprNR5qx0VQsB1DrEeQUfHiE5QuwAhUddbliYzGuNcv6xbWxKfjzOp6KXhuQjDIbMVGgo7PQLYe+R9kW6TFhFxyK/AZis34EhY4FGOXBY1P8VT2P/6QXsT0uSs9he3KmZw2wBQrmUr7Vnt2fA1pZ rEcBRPCK u+pRq372pIuLQ+Fp+3lm27mVuWePTpHJ0eTrntyIoI9CX+oYUJimylkg3ECsF1gxZo9pWH8SCdsaC0aJdPsZDAsPBYd4hEuWxF52eAzh0xGcQGNuAYfMWnT4ufyzrvw3oYiZtW7/YG1vpm1RKiGyCftNtKp2NpgjZpS5KYG5iToGBwZntWoddvnUuenW8E4QYa+LqRxfhkl6xPrZ+aouJwkvgLG1kFMVPY8RT1+YNyNY6BUsxUezHrvV6xItSa3lZ/dwNi6Au2VhEqIQ1XDoS2s7uaxDsLrQ+2Y9pqaBLZT9lFJ68CJo/leMrOvjyjv+hP1dDflwq1aydQtZOzc2PzOk8pMyBcoAZdvhAXEJJxqE3V+JTpvjdb3GvBYNd9Xm1ugB1EX0JKuEDiU6tKiTBpNe5RAZ2tAnkdWv5RpkxxYfYDWo= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: I kept the helper private to avoid an MM dependency on . After looking further at the mapped-folio case Matthew raised, I think the better fix is to retain a dropbehind folio once it is mapped. A mapping represents a competing cached user, and retaining it avoids the sleeping unmap path, so filemap no longer needs a stricter context helper; the existing in_task() guard remains. I will respin the patch on that basis.