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Mon, 2 Nov 2026 15:13:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793632421; bh=Rp3cBypvlPCLWQcsEgZutivLH7EPpJBFO75qhCW/oJM=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=inKajwEEAwMoHnDPteIsszpp+0/UJE+sH1dcRO3L/FVi7pG6bML9PLf7beknb8BdL 5MQTx4jDbN6vOHeJxw6i3QBTD/vaTRhHRSBDcIcLXd+3e9HF074pZjh8KpAt9SGtmt JOiGL6Tx8k0xhC/Euwa1o1K150jjjSE7j8GK34RKndNsCPhq4JCoa1y8V/FJaak7tQ sIo7pPqK3wIVaSyqVLUcMOS2/mUFkthHgMUSqu1fTag9cUMixxI0kmyYvEBaUL/61N /p62SUvaIR4X5tJTeFjC9esd/XuiBrsEJMh9ZeLl3eTyrN3FqEcwOKweqLGafV76hM GBi4RyeNSgR4Q== From: Christian Brauner Date: Mon, 02 Nov 2026 16:07:17 +0100 Subject: [PATCH RFC 10/23] scsi: core: let procfs copy in writes X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , Precedence: list X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261102-work-procfs-drivers-v1-10-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=5090; i=brauner@kernel.org; h=from:subject:message-id; bh=vGFrM/mDJbel5Ek/YnwRAY7y8jtd20EKftAALqu9TzI=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWS9WG6wbs9mk5mrv0xU3X+16EaLjJbetu1Tahw0NK74G XJYrLy2oqOUhUGMi0FWTJHFod0kXG45T8Vmo0wNmDmsTCBDGLg4BWAi9+8z/NP5dyTkr+Pqgvks tmYr2GzsdlxjWTkn2a8rR7w2gk/iwnaGf6oJ7vtUPv35vWtB+q7r99Z2c2x9l6Jyo+P0aQ5b7gu 905kA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Implement ->proc_write_buf() for /proc/scsi/scsi, /proc/scsi/device_info and the host files so procfs copies in what is written before it pins the entry, and parse what was written from that copy. /proc/scsi/scsi and device_info take up to PAGE_SIZE bytes like before. The host files pass the copy to ->write_info(), writes to them that are larger than PAGE_SIZE - 1 bytes fail with -EINVAL from procfs instead of -EOVERFLOW. Signed-off-by: Christian Brauner (Amutable) --- drivers/scsi/scsi_devinfo.c | 29 +++++----------------------- drivers/scsi/scsi_proc.c | 47 +++++++++++---------------------------------- 2 files changed, 16 insertions(+), 60 deletions(-) diff --git a/drivers/scsi/scsi_devinfo.c b/drivers/scsi/scsi_devinfo.c index 0b8f5ff40543..d9093851b23e 100644 --- a/drivers/scsi/scsi_devinfo.c +++ b/drivers/scsi/scsi_devinfo.c @@ -678,39 +678,20 @@ static const struct seq_operations scsi_devinfo_seq_ops = { * To use, echo "vendor:model:flag" > /proc/scsi/device_info */ static ssize_t proc_scsi_devinfo_write(struct file *file, - const char __user *buf, + char *buffer, size_t length, loff_t *ppos) { - char *buffer; - ssize_t err = length; - - if (!buf || length>PAGE_SIZE) + if (length == PAGE_SIZE && buffer[PAGE_SIZE-1]) return -EINVAL; - buffer = kmalloc(PAGE_SIZE, GFP_KERNEL); - if (!buffer) - return -ENOMEM; - if (copy_from_user(buffer, buf, length)) { - err =-EFAULT; - goto out; - } - - if (length < PAGE_SIZE) - buffer[length] = '\0'; - else if (buffer[PAGE_SIZE-1]) { - err = -EINVAL; - goto out; - } scsi_dev_info_list_add_str(buffer); - -out: - kfree(buffer); - return err; + return length; } static const struct proc_ops scsi_devinfo_proc_ops = { .proc_seq_ops = &scsi_devinfo_seq_ops, - .proc_write = proc_scsi_devinfo_write, + .proc_write_buf = proc_scsi_devinfo_write, + .proc_write_size = PAGE_SIZE, }; #endif /* CONFIG_SCSI_PROC_FS */ diff --git a/drivers/scsi/scsi_proc.c b/drivers/scsi/scsi_proc.c index 59229bf9938e..5962e671cc83 100644 --- a/drivers/scsi/scsi_proc.c +++ b/drivers/scsi/scsi_proc.c @@ -62,30 +62,18 @@ struct scsi_proc_entry { unsigned int present; }; -static ssize_t proc_scsi_host_write(struct file *file, const char __user *buf, +static ssize_t proc_scsi_host_write(struct file *file, char *buf, size_t count, loff_t *ppos) { struct Scsi_Host *shost = pde_data(file_inode(file)); - ssize_t ret = -ENOMEM; - char *page; - + if (count > PROC_BLOCK_SIZE) return -EOVERFLOW; if (!shost->hostt->write_info) return -EINVAL; - page = kmalloc(PAGE_SIZE, GFP_KERNEL); - if (page) { - ret = -EFAULT; - if (copy_from_user(page, buf, count)) - goto out; - page[count] = '\0'; - ret = shost->hostt->write_info(shost, page, count); - } -out: - kfree(page); - return ret; + return shost->hostt->write_info(shost, buf, count); } static int proc_scsi_show(struct seq_file *m, void *v) @@ -142,7 +130,7 @@ EXPORT_SYMBOL_GPL(scsi_template_proc_dir); static const struct proc_ops proc_scsi_ops = { .proc_show = proc_scsi_show, .proc_open = proc_scsi_host_open, - .proc_write = proc_scsi_host_write + .proc_write_buf = proc_scsi_host_write }; /** @@ -386,8 +374,8 @@ static int scsi_remove_single_device(uint host, uint channel, uint id, uint lun) /** * proc_scsi_write - handle writes to /proc/scsi/scsi * @file: not used - * @buf: buffer to write - * @length: length of buf, at most PAGE_SIZE + * @buffer: buffer to write + * @length: length of buffer, at most PAGE_SIZE * @ppos: not used * * Description: this provides a legacy mechanism to add or remove devices by @@ -402,32 +390,20 @@ static int scsi_remove_single_device(uint host, uint channel, uint id, uint lun) */ -static ssize_t proc_scsi_write(struct file *file, const char __user *buf, +static ssize_t proc_scsi_write(struct file *file, char *buffer, size_t length, loff_t *ppos) { int host, channel, id, lun; - char *buffer, *end, *p; + char *end, *p; int err; - if (!buf || length > PAGE_SIZE) - return -EINVAL; - - buffer = kmalloc(PAGE_SIZE, GFP_KERNEL); - if (!buffer) - return -ENOMEM; - - err = -EFAULT; - if (copy_from_user(buffer, buf, length)) - goto out; - err = -EINVAL; if (length < PAGE_SIZE) { end = buffer + length; - *end = '\0'; } else { end = buffer + PAGE_SIZE - 1; if (*end) - goto out; + return err; } /* @@ -466,8 +442,6 @@ static ssize_t proc_scsi_write(struct file *file, const char __user *buf, if (!err) err = length; - out: - kfree(buffer); return err; } @@ -521,7 +495,8 @@ static const struct seq_operations scsi_seq_ops = { static const struct proc_ops scsi_scsi_proc_ops = { .proc_seq_ops = &scsi_seq_ops, - .proc_write = proc_scsi_write, + .proc_write_buf = proc_scsi_write, + .proc_write_size = PAGE_SIZE, }; /** -- 2.53.0