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 2FF793CFF6C; Mon, 27 Apr 2026 13:47:42 +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=1777297662; cv=none; b=iP0Sn4Bz+gqtoYQszumiiSB+4zGvPmzmj6ox6p5Wiuxbb3ZeaQ1jmTwznvIrjSrpCTlxOLi6VQ9N0fh+S0hpbMH2hheWGXYASXriep+60BL57Vqgtumh5TWhXTKfxzAybdK7gB3bOcA6396xjS8gVNO8UYaT66+YbYwFKYiNGew= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777297662; c=relaxed/simple; bh=0BW7jfUeG88uxvNr1klqn1DDv2c8qcfaHXFDvi6YT2M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=aQvC72uvUuwdmZbZW8DSXhxwSg0kJaR72dFELomZMJ3OAmAeFOwGOvFYNSoxpwUPxHcFvpU5VATQ2SPYmVgNU7Z5zR6ECWhMgZwNmrhTa1yQBw2uMuWCyVSV1RCHZCnnkymCN5Tcxt/F5whaZxoBXME3Q0oN7glLpnbftLK+i3k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CfHwGx62; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="CfHwGx62" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D2F2AC19425; Mon, 27 Apr 2026 13:47:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777297660; bh=0BW7jfUeG88uxvNr1klqn1DDv2c8qcfaHXFDvi6YT2M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CfHwGx62/68RkUJXPK8KIFSMhPO7mljr/LfBkBU9uxQS31APzaZTi5xoOreWVV1Jk prBK9N+VyYpuRG2xo4KTW6uryEoyDSxGSyroylEN2dm4tHx93A4yM41ABfGnplRT0B 2urqVLMYO7Bdp1a7qGPOcD1xwluoJtG9wUXTHO1Dl0BosDTyf1eQRAJfM6MnQQY6ni yy5OI/r8dGHHfzx9IRnOarsw++jmKzzQVrAWH+L8JZ8cw9kpCcyRnvFgABocrJjBmR UgZEcr0XZ6TAEFksaWIWV9pSykHpL5jnA50DilEcx0FoBM+Jjx05CzGxEoW4zbj7q7 lDEi3t29zRPiQ== From: Tzung-Bi Shih To: Arnd Bergmann , Greg Kroah-Hartman Cc: Benson Leung , tzungbi@kernel.org, linux-kernel@vger.kernel.org, chrome-platform@lists.linux.dev, "Rafael J. Wysocki" , Danilo Krummrich , Jonathan Corbet , Shuah Khan , Laurent Pinchart , Wolfram Sang , Jason Gunthorpe , Johan Hovold , "Paul E . McKenney" , Dan Williams Subject: [PATCH 2/8] char: misc: Introduce misc_find() helper Date: Mon, 27 Apr 2026 21:46:53 +0800 Message-ID: <20260427134659.95181-3-tzungbi@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260427134659.95181-1-tzungbi@kernel.org> References: <20260427134659.95181-1-tzungbi@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Introduce misc_find() to search for a miscdevice by minor number in `misc_list`. This helper requires `misc_mtx` to be held. Use the new helper to reduce code duplication. Signed-off-by: Tzung-Bi Shih --- drivers/char/misc.c | 43 +++++++++++++++++++++++-------------------- 1 file changed, 23 insertions(+), 20 deletions(-) diff --git a/drivers/char/misc.c b/drivers/char/misc.c index e2bea4f01851..c26315577d65 100644 --- a/drivers/char/misc.c +++ b/drivers/char/misc.c @@ -116,22 +116,32 @@ static const struct seq_operations misc_seq_ops = { }; #endif +static struct miscdevice *misc_find(int minor) +{ + struct miscdevice *iter; + + lockdep_assert_held(&misc_mtx); + + list_for_each_entry(iter, &misc_list, list) { + if (iter->minor == minor) + return iter; + } + + return NULL; +} + static int misc_open(struct inode *inode, struct file *file) { int minor = iminor(inode); - struct miscdevice *c = NULL, *iter; + struct miscdevice *c = NULL; int err = -ENODEV; const struct file_operations *new_fops = NULL; mutex_lock(&misc_mtx); - list_for_each_entry(iter, &misc_list, list) { - if (iter->minor != minor) - continue; - c = iter; - new_fops = fops_get(iter->fops); - break; - } + c = misc_find(minor); + if (c) + new_fops = fops_get(c->fops); /* Only request module for fixed minor code */ if (!new_fops && minor < MISC_DYNAMIC_MINOR) { @@ -139,13 +149,9 @@ static int misc_open(struct inode *inode, struct file *file) request_module("char-major-%d-%d", MISC_MAJOR, minor); mutex_lock(&misc_mtx); - list_for_each_entry(iter, &misc_list, list) { - if (iter->minor != minor) - continue; - c = iter; - new_fops = fops_get(iter->fops); - break; - } + c = misc_find(minor); + if (c) + new_fops = fops_get(c->fops); } if (!new_fops) @@ -229,13 +235,10 @@ int misc_register(struct miscdevice *misc) return -EBUSY; misc->minor = i; } else { - struct miscdevice *c; int i; - list_for_each_entry(c, &misc_list, list) { - if (c->minor == misc->minor) - return -EBUSY; - } + if (misc_find(misc->minor)) + return -EBUSY; i = misc_minor_alloc(misc->minor); if (i < 0) -- 2.51.0