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smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=edn0AYPt; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AE858606DEBF; Mon, 2 Nov 2026 15:12:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=edn0AYPt Received: by smtp.kernel.org (Postfix) with ESMTPSA id D82CE1F00A16; Mon, 2 Nov 2026 15:12:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793632343; bh=RGxB3CLuL3hdMOFW6c8rETuQc0/Gu93ks+OA3zHK0Kk=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=edn0AYPt5jRwhzogids3xv0SIWD2ZJhmY0NQPvBljECs8aa0X00ejVbwi8wkj25C/ 2U5H4P82mtq9mk7Gq7o6e3/c1q4G3kbagk9jpohANeLaXrMVCD+eHlCpevZFWYYYSS zfdTR6xsYkavU1Yyn93mOd5uM9GVA/ziiwPly/tLPD8EKmEgx8k3MJ6ijWmLm10fQ5 aAJwWIQlFfdnqETK+vq3WSm6gSr6XKfcJMe7u/+KEhkto92jBEq1FJaT413U5aWoNC fX2qVLNTgmiFU3l4keyd4RISYlleq5zE0TOEd/g/8NAtAr7PPLpG0OuAXPXHvgwwGx A5koDE6WAQthg== From: Christian Brauner Date: Mon, 02 Nov 2026 16:07:14 +0100 Subject: [PATCH RFC 07/23] s390/dasd: let procfs copy in writes to /proc/dasd/statistics X-Mailing-List: linux-alpha@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261102-work-procfs-drivers-v1-7-a994bd4d3b1a@kernel.org> References: <20261102-work-procfs-drivers-v1-0-a994bd4d3b1a@kernel.org> In-Reply-To: <20261102-work-procfs-drivers-v1-0-a994bd4d3b1a@kernel.org> To: linux-fsdevel@vger.kernel.org Cc: Linus Torvalds , Jann Horn , Josef Bacik , Chris Mason , Jeff Layton , NeilBrown , Eric Dumazet , Thomas Gleixner , Al Viro , Jonathan Corbet , Christoph Hellwig , Greg Kroah-Hartman , Joel Granados , Kees Cook , Jan Kara , Jan Kara , linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-acpi@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, linux-um@lists.infradead.org, linux-wireless@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, ntfs3@lists.linux.dev, platform-driver-x86@vger.kernel.org, coreteam@netfilter.org, kexec@lists.infradead.org, linux-pci@vger.kernel.org, linux-sound@vger.kernel.org, netfilter-devel@vger.kernel.org, dri-devel@lists.freedesktop.org, ibm-acpi-devel@lists.sourceforge.net, jfs-discussion@lists.sourceforge.net, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-cifs@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-hwmon@vger.kernel.org, linux-mm@kvack.org, linux-sh@vger.kernel.org, linux-usb@vger.kernel.org, samba-technical@lists.samba.org, sparclinux@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-doc@vger.kernel.org, linux-serial@vger.kernel.org, linux-atm-general@lists.sourceforge.net, Takashi Iwai , linux-input@vger.kernel.org, linux-raid@vger.kernel.org, linux-ext4@vger.kernel.org, linux-modules@vger.kernel.org, linux-debuggers@vger.kernel.org, "Christian Brauner (Amutable)" , Chuck Lever X-Mailer: b4 0.17-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=2121; i=brauner@kernel.org; h=from:subject:message-id; bh=tPoM7KW2jugAI3HBgjDAkvMMKrMKVevq5gq8BMZsIqc=; b=kA0DAAoWkcYbwGV43KIByyZiAGropzCjfwupU8fn9+VxtZv2ThSIu2nz9SfrAQKMYBoRl89VB Ih1BAAWCgAdFiEEQIc0Vx6nDHizMmkokcYbwGV43KIFAmropzAACgkQkcYbwGV43KL3vwEA7DgZ qwKtRcRruUUjfm5rBcGQ2NDy+57vyMOGubX9wNEBAPGDTMKrc7NwpMTdmoTSB/UBaD6PA7NAvur lg4LjKr4D X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Implement ->proc_write_buf() so procfs copies in what is written before it pins the entry, and parse the command from that copy. Commands longer than PAGE_SIZE - 1 bytes are rejected now instead of cut at 64k. Signed-off-by: Christian Brauner (Amutable) --- drivers/s390/block/dasd_proc.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) diff --git a/drivers/s390/block/dasd_proc.c b/drivers/s390/block/dasd_proc.c index 86399427f01d..6c3bbb7dfe85 100644 --- a/drivers/s390/block/dasd_proc.c +++ b/drivers/s390/block/dasd_proc.c @@ -15,7 +15,6 @@ #include #include #include -#include #include #include @@ -247,17 +246,15 @@ static int dasd_stats_proc_show(struct seq_file *m, void *v) } static ssize_t dasd_stats_proc_write(struct file *file, - const char __user *user_buf, size_t user_len, loff_t *pos) + char *buffer, size_t user_len, loff_t *pos) { #ifdef CONFIG_DASD_PROFILE - char *buffer, *str; + char *str; int rc; - if (user_len > 65536) - user_len = 65536; - buffer = dasd_get_user_string(user_buf, user_len); - if (IS_ERR(buffer)) - return PTR_ERR(buffer); + /* strip linefeed */ + if (user_len && buffer[user_len - 1] == '\n') + buffer[user_len - 1] = 0; /* check for valid verbs */ str = skip_spaces(buffer); @@ -296,13 +293,11 @@ static ssize_t dasd_stats_proc_write(struct file *file, pr_info("The statistics have been reset\n"); } else goto out_parse_error; - vfree(buffer); return user_len; out_parse_error: rc = -EINVAL; pr_warn("%s is not a supported value for /proc/dasd/statistics\n", str); out_error: - vfree(buffer); return rc; #else pr_warn("/proc/dasd/statistics: is not activated in this kernel\n"); @@ -312,7 +307,7 @@ out_error: static const struct proc_ops dasd_stats_proc_ops = { .proc_show = dasd_stats_proc_show, - .proc_write = dasd_stats_proc_write, + .proc_write_buf = dasd_stats_proc_write, }; /* -- 2.53.0