From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752051AbWCGKm2 (ORCPT ); Tue, 7 Mar 2006 05:42:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752031AbWCGKm1 (ORCPT ); Tue, 7 Mar 2006 05:42:27 -0500 Received: from ozlabs.org ([203.10.76.45]:7078 "EHLO ozlabs.org") by vger.kernel.org with ESMTP id S1752051AbWCGKm1 (ORCPT ); Tue, 7 Mar 2006 05:42:27 -0500 To: Greg Kroah-Hartman , From: Michael Ellerman Date: Tue, 07 Mar 2006 21:41:59 +1100 Subject: [PATCH] debugfs: Add debugfs_create_blob() helper for exporting binary data Message-Id: <20060307104225.E0DDA679E6@ozlabs.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org I wanted to export a binary blob via debugfs, and although it was pretty easy it seems like it'd be easier if there was a helper for it. It's a pity we need the wrapper struct but I can't see a cleaner way to do it. Signed-off-by: Michael Ellerman --- fs/debugfs/file.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/debugfs.h | 15 +++++++++++++++ 2 files changed, 61 insertions(+) Index: kdump/fs/debugfs/file.c =================================================================== --- kdump.orig/fs/debugfs/file.c +++ kdump/fs/debugfs/file.c @@ -251,3 +251,49 @@ struct dentry *debugfs_create_bool(const } EXPORT_SYMBOL_GPL(debugfs_create_bool); +static ssize_t read_file_blob(struct file *file, char __user *user_buf, + size_t count, loff_t *ppos) +{ + struct debugfs_blob_wrapper *blob = file->private_data; + return simple_read_from_buffer(user_buf, count, ppos, blob->data, + blob->size); +} + +static struct file_operations fops_blob = { + .read = read_file_blob, + .open = default_open, +}; + +/** + * debugfs_create_blob - create a file in the debugfs filesystem that is + * used to read and write a binary blob. + * + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this paramater is NULL, then the + * file will be created in the root of the debugfs filesystem. + * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer + * to the blob data and the size of the data. + * + * This function creates a file in debugfs with the given name that exports + * @blob->data as a binary blob. If the @mode variable is so set it can be + * read from. Writing is not supported. + * + * This function will return a pointer to a dentry if it succeeds. This + * pointer must be passed to the debugfs_remove() function when the file is + * to be removed (no automatic cleanup happens if your module is unloaded, + * you are responsible here.) If an error occurs, NULL will be returned. + * + * If debugfs is not enabled in the kernel, the value -ENODEV will be + * returned. It is not wise to check for this value, but rather, check for + * NULL or !NULL instead as to eliminate the need for #ifdef in the calling + * code. + */ +struct dentry *debugfs_create_blob(const char *name, mode_t mode, + struct dentry *parent, + struct debugfs_blob_wrapper *blob) +{ + return debugfs_create_file(name, mode, parent, blob, &fops_blob); +} +EXPORT_SYMBOL_GPL(debugfs_create_blob); Index: kdump/include/linux/debugfs.h =================================================================== --- kdump.orig/include/linux/debugfs.h +++ kdump/include/linux/debugfs.h @@ -21,6 +21,11 @@ struct file_operations; +struct debugfs_blob_wrapper { + void *data; + unsigned long size; +}; + #if defined(CONFIG_DEBUG_FS) struct dentry *debugfs_create_file(const char *name, mode_t mode, struct dentry *parent, void *data, @@ -39,6 +44,9 @@ struct dentry *debugfs_create_u32(const struct dentry *debugfs_create_bool(const char *name, mode_t mode, struct dentry *parent, u32 *value); +struct dentry *debugfs_create_blob(const char *name, mode_t mode, + struct dentry *parent, + struct debugfs_blob_wrapper *blob); #else #include @@ -94,6 +102,13 @@ static inline struct dentry *debugfs_cre return ERR_PTR(-ENODEV); } +static inline struct dentry *debugfs_create_blob(const char *name, mode_t mode, + struct dentry *parent, + struct debugfs_blob_wrapper *blob) +{ + return ERR_PTR(-ENODEV); +} + #endif #endif