From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm2-f12.google.com (mail-wm2-f12.google.com [74.125.225.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 787C3562609 for ; Thu, 10 Sep 2026 18:22:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.225.140 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789064531; cv=none; b=V3CtT4w4d9WmZBwx+Cel4AkgbRndzzmyirWQOKkU9TSTNVgaW4AWnpm8ufxNDAI7XMjrUIlMNTw66nG2L0B9gXX1iAOkPDQ+DVd52NV14f2dbz/uj0D+M0Z7XYumKPk0slfi7QJQZtlFS+HpxN4RFO7QUTccG5HIn/0R+UVktIU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789064531; c=relaxed/simple; bh=xeBaVq34Fvm+F/zQVDvqjxr/qQQkcNW+NLJKAnQ0Gzk=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=jIY40F2hXq1w8kErKao1WhDbnwF/c+/03iJdArcBzYN8kiQ63IyZYNCR0HJvBF1Hv9RWRSaLawAmx81lSv1iEKc3zcMZdgkpuEfopa/nDZ3A22G5lXNY49ILDTrtBBAei2/Q3ViIl3cEjL//kicmYp99G/+gUy2sodd2eVfKWYU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=ionos.com; spf=pass smtp.mailfrom=ionos.com; dkim=pass (2048-bit key) header.d=ionos.com header.i=@ionos.com header.b=hiq9LTIH; arc=none smtp.client-ip=74.125.225.140 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=ionos.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ionos.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ionos.com header.i=@ionos.com header.b="hiq9LTIH" Received: by mail-wm2-f12.google.com with SMTP id 5b1f17b1804b1-49d097b4939so813965e9.0 for ; Thu, 10 Sep 2026 11:22:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ionos.com; s=google; t=1789064526; x=1789669326; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=GqDHIUprFGhLpfjoTtzfh0mDO50nuGrZXReIflYDQ28=; b=hiq9LTIHwK9bGox2e61Q5JkEOIfi+7XrnWER7D9SJLinSRQdrsBjxlA5spo7zgyAVa 7NYb7ST88F24ybJlmGl6mksaluXawXRSUr/HaVSdc6QDYpqeo4VKgTGz/th2wYgKZFvo QQzwAJa+3qc7MyKVYBaHba7QLHkuhZca0UWtBE9gkN/O08doU6OxkReN/DoVYsVWtu7W weEJ3ksB3WQC+JIhHBg0FbK+PrYk/W9kxYDp2Mmg/8xdU14P+HMFFpLcyOIcWk6NXy3E ayBUpZt5yP3Si/1PnXBfAGXs+ikXz45dEYYaQ4j1Pqxx1ByjqfLiakl+NUIVCZ5pN8J8 U+2g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1789064526; x=1789669326; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=GqDHIUprFGhLpfjoTtzfh0mDO50nuGrZXReIflYDQ28=; b=ovcwo6GHqEJfsEH3i45frrvV/sIXBFRY2OG0F9PKGmqGc1sEgZyVJJ0tVJM5sGsiUS MJLnTJ1riySQaw/Q3m8aBfbb9Cbtlddm4B67L9aP9veQbdDK/fY8Hadg7+1jBovF3hGb 1PNMQ4ITT+SGqGwGCLw/2tPPnqXVXpu+n6zU7dIYYcyIKYapRWvYCNhR9jmeyncUXiAZ ciDOPD/ceDo5G13lfRPI+KNrLZ8mrHBKCPR4YrOeqa/zdoKWziaHT3ZXoGWJgpQDHZVn rUBpEiDh5/r/oxHlmi5LneSCJkuPc50BYg2RBld49V2dHS86MVqrzELUgkt2LGdgMN7t IZ6Q== X-Forwarded-Encrypted: i=1; AKwUvBxHnkS+5Avzl400XUgovyPG7daaja1daef2a4WrKl+MGWqFpUMD3tkImaDgfo3CnyUymTgXYfuYEH1JNI8=@vger.kernel.org X-Gm-Message-State: AFuF++kitLdkVMtfXapv0AcHGyLrd8ULG9xrWPOyLHOC2CQYG8oAFJ5X mPS2fhsg5E4E96Ds5lseysA/c0AdDS6gj1OjL6IOR+bDKvq/REFPU0p4wHbDLMTUPw4= X-Gm-Gg: AYBFou1H1ydCbzx74u0FowB80l2Ba+2teltjCdRrffPDS6OKdafdC5W2WfIS0iS+AAk 8FIZz1kZ4LJD+IQAxyJ01TIaEAvQ6HgfNGrHiQSO7WzFNEvxP/NOLvoQeCJwUm2QeNa2xReoiqH Vvl1ovt3U1iZ7yXO5UUI+yTAOyZtFXjA8zhxk5yJFBKsYfgw389FpSKoFNB5gYkOXW8rT8xkSQs XkEp3tNYX8s/0ELT8HQcv4G6ydyeACPPdUXR7M7V+PeBDBaNB5t7NSo+tREaHQbFueuTCClLtoT XWPdBmc0rnRuwNYUeeJC8IwYP/sQEMMszF3EpqTVvdHNiWy/MxYenWSXKWnkzGgX5h70taoMzT0 xWemZ9e4UILf0jJNp+E0wgFfUg/ZhgwpxFkF0t7XqX9lrYBR1xM9RHN5QvFZOpFvcWxHiXdspUT rrPh3TzVwSPjf228fD3LLghcb/QdHiO53R3vlRYzc84QfnJ2UcWHyHXK7DTwZTCRkQuXOHusgW0 FhgnaqXCyg8JIDgVEbK68L5F+g5bARYGuwSBzgVBBM6/zKSt8b4L0a1WxPx0ELoE0UnsiVrVr0= X-Received: by 2002:a05:600d:6501:10b0:49c:fa21:e73b with SMTP id 5b1f17b1804b1-49e619c0bc0mr2423325e9.17.1789064526542; Thu, 10 Sep 2026 11:22:06 -0700 (PDT) Received: from raven.intern.cm-ag (p200300dc6f04b700023064fffe740809.dip0.t-ipconnect.de. [2003:dc:6f04:b700:230:64ff:fe74:809]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49e5765152asm40025455e9.11.2026.09.10.11.22.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Sep 2026 11:22:06 -0700 (PDT) From: Max Kellermann To: dhowells@redhat.com, steved@redhat.com, viro@zeniv.linux.org.uk, netfs@lists.linux.dev, linux-kernel@vger.kernel.org Cc: Max Kellermann , stable@vger.kernel.org Subject: [PATCH] cachefiles: pass a poll key when waking the daemon Date: Thu, 10 Sep 2026 20:22:00 +0200 Message-ID: <20260910182200.1272489-1-max.kellermann@ionos.com> X-Mailer: git-send-email 2.47.3 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Keyless wakeups bypass epoll's event-mask filtering. With only `EPOLLOUT` registered, any cachefiles_state_changed() call will wake up the epoll_wait() system call, but will not return any events, causing a busy loop. Pass the relevant poll events with each wakeup so `epoll` can filter out unwanted notifications. Fixes: a5b3a80b899b ("CacheFiles: Provide read-and-reset release counters for cachefilesd") Cc: stable@vger.kernel.org Signed-off-by: Max Kellermann --- Note: backports to older branches need to adjust ondemand.c as well like this: - wake_up_all(&cache->daemon_pollwq); + cachefiles_wake_poll(cache, EPOLLIN); --- fs/cachefiles/cache.c | 4 ++-- fs/cachefiles/internal.h | 15 +++++++++++++-- fs/cachefiles/namei.c | 2 +- 3 files changed, 16 insertions(+), 5 deletions(-) diff --git a/fs/cachefiles/cache.c b/fs/cachefiles/cache.c index 9fb06dc16520..08ca598618ac 100644 --- a/fs/cachefiles/cache.c +++ b/fs/cachefiles/cache.c @@ -255,7 +255,7 @@ int cachefiles_has_space(struct cachefiles_cache *cache, test_and_clear_bit(CACHEFILES_CULLING, &cache->flags) ) { _debug("cease culling"); - cachefiles_state_changed(cache); + cachefiles_state_changed(cache, EPOLLIN); } //_leave(" = 0"); @@ -275,7 +275,7 @@ int cachefiles_has_space(struct cachefiles_cache *cache, begin_cull: if (!test_and_set_bit(CACHEFILES_CULLING, &cache->flags)) { _debug("### CULL CACHE ###"); - cachefiles_state_changed(cache); + cachefiles_state_changed(cache, EPOLLIN | EPOLLOUT); } _leave(" = %d", ret); diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h index c93324e0f98c..b8a5ea4a5ced 100644 --- a/fs/cachefiles/internal.h +++ b/fs/cachefiles/internal.h @@ -15,6 +15,7 @@ #include #include #include +#include #define CACHEFILES_DIO_BLOCK_SIZE 4096 @@ -117,13 +118,23 @@ struct cachefiles_object *cachefiles_cres_object(struct netfs_cache_resources *c return fscache_cres_cookie(cres)->cache_priv; } +/* + * Wake up the daemon polling on /dev/cachefiles. + */ +static inline void cachefiles_wake_poll(struct cachefiles_cache *cache, + __poll_t mask) +{ + __wake_up(&cache->daemon_pollwq, TASK_NORMAL, 0, poll_to_key(mask)); +} + /* * note change of state for daemon */ -static inline void cachefiles_state_changed(struct cachefiles_cache *cache) +static inline void cachefiles_state_changed(struct cachefiles_cache *cache, + __poll_t mask) { set_bit(CACHEFILES_STATE_CHANGED, &cache->flags); - wake_up_all(&cache->daemon_pollwq); + cachefiles_wake_poll(cache, mask); } /* diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c index 88955249a1a6..52eb227f07e8 100644 --- a/fs/cachefiles/namei.c +++ b/fs/cachefiles/namei.c @@ -74,7 +74,7 @@ void cachefiles_unmark_inode_in_use(struct cachefiles_object *object, if (!test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags)) { atomic_long_add(inode->i_blocks, &cache->b_released); if (atomic_inc_return(&cache->f_released)) - cachefiles_state_changed(cache); + cachefiles_state_changed(cache, EPOLLIN); } } -- 2.47.3