From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 48E0F1581EB; Tue, 23 Jul 2024 18:26:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721759217; cv=none; b=AzLezXZ7elNC2Qvb/fjHSmB8XNWfho81UtA7JPejqpUlraoJuNo23dXjGJQN9bmGJqrW1glWGMZTyPzmDHfH0gzu9ZoEZoqT8hVMiKcDYoB3wh4FdWSVpMcqMsIoiQ1s6oowTBuxxHRoexe2AFStBeN4ThkmsNAkFBjm7ZqHrUw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721759217; c=relaxed/simple; bh=u7X2drtD++NWNTUf3mzL1JqxZbTSkb1ogM2qQUCaC2s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HdbfFVGlo21BXg08jF1Q7PxZLFXDxANbkhjDRpjASIx/oa6bv4P/gwtrQ+zVG2CN7z1gOEAJfUUh+FlNlMeF5aR9ZLUm1ht3/TPqI+6832fBbYC71IngBJCm8ALIA0ZE26LCnZlIv+I09IX+pFh0R390S1i3b5HMqvrh/8d1RJs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=LXNwpXeb; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="LXNwpXeb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BA43BC4AF09; Tue, 23 Jul 2024 18:26:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1721759217; bh=u7X2drtD++NWNTUf3mzL1JqxZbTSkb1ogM2qQUCaC2s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LXNwpXebHd60vHyvvn1C5G2X2O27HBF7cv4DTko0i/nEuImPcmp6SRaRCFQFp8qK2 Di7QNQCw72h1yXGCbfFvBo685Fzbw8N4fH0a7+sfZeO1Usmn35IQvvnuRvICQFGLNb 3aF1fOTXA6HOnOqf6Sr6ewBz4TXgBt4uhR/KPNL4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Hou Tao , Baokun Li , Jeff Layton , Jia Zhu , Christian Brauner , Sasha Levin Subject: [PATCH 6.1 042/105] cachefiles: make on-demand read killable Date: Tue, 23 Jul 2024 20:23:19 +0200 Message-ID: <20240723180404.867735110@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240723180402.490567226@linuxfoundation.org> References: <20240723180402.490567226@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Baokun Li [ Upstream commit bc9dde6155464e906e630a0a5c17a4cab241ffbb ] Replacing wait_for_completion() with wait_for_completion_killable() in cachefiles_ondemand_send_req() allows us to kill processes that might trigger a hunk_task if the daemon is abnormal. But now only CACHEFILES_OP_READ is killable, because OP_CLOSE and OP_OPEN is initiated from kworker context and the signal is prohibited in these kworker. Note that when the req in xas changes, i.e. xas_load(&xas) != req, it means that a process will complete the current request soon, so wait again for the request to be completed. In addition, add the cachefiles_ondemand_finish_req() helper function to simplify the code. Suggested-by: Hou Tao Signed-off-by: Baokun Li Link: https://lore.kernel.org/r/20240522114308.2402121-13-libaokun@huaweicloud.com Acked-by: Jeff Layton Reviewed-by: Jia Zhu Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin --- fs/cachefiles/ondemand.c | 40 ++++++++++++++++++++++++++++------------ 1 file changed, 28 insertions(+), 12 deletions(-) diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index 37489ca2e8571..2185e2908dba8 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -380,6 +380,20 @@ static struct cachefiles_req *cachefiles_ondemand_select_req(struct xa_state *xa return NULL; } +static inline bool cachefiles_ondemand_finish_req(struct cachefiles_req *req, + struct xa_state *xas, int err) +{ + if (unlikely(!xas || !req)) + return false; + + if (xa_cmpxchg(xas->xa, xas->xa_index, req, NULL, 0) != req) + return false; + + req->error = err; + complete(&req->done); + return true; +} + ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, char __user *_buffer, size_t buflen) { @@ -443,16 +457,8 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, out: cachefiles_put_object(req->object, cachefiles_obj_put_read_req); /* Remove error request and CLOSE request has no reply */ - if (ret || msg->opcode == CACHEFILES_OP_CLOSE) { - xas_reset(&xas); - xas_lock(&xas); - if (xas_load(&xas) == req) { - req->error = ret; - complete(&req->done); - xas_store(&xas, NULL); - } - xas_unlock(&xas); - } + if (ret || msg->opcode == CACHEFILES_OP_CLOSE) + cachefiles_ondemand_finish_req(req, &xas, ret); cachefiles_req_put(req); return ret ? ret : n; } @@ -557,8 +563,18 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object, goto out; wake_up_all(&cache->daemon_pollwq); - wait_for_completion(&req->done); - ret = req->error; +wait: + ret = wait_for_completion_killable(&req->done); + if (!ret) { + ret = req->error; + } else { + ret = -EINTR; + if (!cachefiles_ondemand_finish_req(req, &xas, ret)) { + /* Someone will complete it soon. */ + cpu_relax(); + goto wait; + } + } cachefiles_req_put(req); return ret; out: -- 2.43.0