From: James Morse <james.morse@arm.com> maillist inclusion category: feature bugzilla: https://atomgit.com/openeuler/kernel/issues/9840 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git/commit/?h=mp... ------------------ debugfs has handy helpers to make a bool, integer or string available through debugfs. Add helpers to do the same for cpumasks. These are read only. CC: Ben Horgan <ben.horgan@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Zeng Heng <zengheng4@huawei.com> --- fs/debugfs/file.c | 64 +++++++++++++++++++++++++++++++++++++++++ include/linux/debugfs.h | 6 ++++ 2 files changed, 70 insertions(+) diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index 33676b8cf56c9..9bf45fe95aa37 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -1003,6 +1003,70 @@ void debugfs_create_str(const char *name, umode_t mode, } EXPORT_SYMBOL_GPL(debugfs_create_str); +static ssize_t debugfs_read_file_cpumask(struct file *file, + char __user *user_buf, + size_t count, loff_t *ppos) +{ + struct dentry *dentry = F_DENTRY(file); + struct cpumask *cpumask; + char *kernel_buf; + ssize_t ret; + int len; + + ret = debugfs_file_get(dentry); + if (unlikely(ret)) + return ret; + + /* How long is a piece of string? */ + kernel_buf = kmalloc(PAGE_SIZE, GFP_KERNEL); + if (!kernel_buf) { + debugfs_file_put(dentry); + return -ENOMEM; + } + + cpumask = (struct cpumask *)file->private_data; + len = scnprintf(kernel_buf, PAGE_SIZE, + "%*pb\n", cpumask_pr_args(cpumask)); + debugfs_file_put(dentry); + if (len + 1 >= PAGE_SIZE) { + kfree(kernel_buf); + return -EIO; + } + + ret = simple_read_from_buffer(user_buf, count, ppos, kernel_buf, len); + kfree(kernel_buf); + + return ret; +} + +static const struct file_operations fops_cpumask_ro = { + .read = debugfs_read_file_cpumask, + .open = simple_open, + .llseek = default_llseek, +}; + +/** + * debugfs_create_cpumask - create a read-only debugfs file that is used to read a cpumask + * @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 parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @value: a pointer to the variable that the file should read from. + * + * This function creates a file in debugfs with the given name that + * contains the value of the variable @value. + */ +void debugfs_create_cpumask(const char *name, umode_t mode, + struct dentry *parent, struct cpumask *value) +{ + /* Only read-only is supported */ + WARN_ON_ONCE(mode & S_IWUGO); + + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_cpumask_ro, + &fops_cpumask_ro, &fops_cpumask_ro); +} + static ssize_t read_file_blob(struct file *file, char __user *user_buf, size_t count, loff_t *ppos) { diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h index ea2d919fd9c79..4dfc67da0bb00 100644 --- a/include/linux/debugfs.h +++ b/include/linux/debugfs.h @@ -140,6 +140,8 @@ void debugfs_create_bool(const char *name, umode_t mode, struct dentry *parent, bool *value); void debugfs_create_str(const char *name, umode_t mode, struct dentry *parent, char **value); +void debugfs_create_cpumask(const char *name, umode_t mode, + struct dentry *parent, struct cpumask *value); struct dentry *debugfs_create_blob(const char *name, umode_t mode, struct dentry *parent, @@ -320,6 +322,10 @@ static inline void debugfs_create_str(const char *name, umode_t mode, char **value) { } +static inline void debugfs_create_cpumask(const char *name, umode_t mode, + struct dentry *parent, struct cpumask *value) +{ } + static inline struct dentry *debugfs_create_blob(const char *name, umode_t mode, struct dentry *parent, struct debugfs_blob_wrapper *blob) -- 2.43.0