diff options
| -rw-r--r-- | fs/sysfs/file.c | 103 |
1 files changed, 50 insertions, 53 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index b695b8b..2f849e8 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -267,61 +267,50 @@ static ssize_t kernfs_file_read(struct file *file, char __user *user_buf, return seq_read(file, user_buf, count, ppos); } -/** - * flush_write_buffer - push buffer to kobject - * @of: open file - * @buf: data buffer for file - * @off: file offset to write to - * @count: number of bytes - * - * Get the correct pointers for the kobject and the attribute we're dealing - * with, then call the store() method for it with @buf. - */ -static int flush_write_buffer(struct sysfs_open_file *of, char *buf, loff_t off, - size_t count) +/* kernfs write callback for regular sysfs files */ +static ssize_t sysfs_kf_write(struct sysfs_open_file *of, char *buf, + size_t count, loff_t pos) { + const struct sysfs_ops *ops = sysfs_file_ops(of->sd); struct kobject *kobj = of->sd->s_parent->priv; - int rc = 0; - /* - * Need @of->sd for attr and ops, its parent for kobj. @of->mutex - * nests outside active ref and is just to ensure that the ops - * aren't called concurrently for the same open file. - */ - mutex_lock(&of->mutex); - if (!sysfs_get_active(of->sd)) { - mutex_unlock(&of->mutex); - return -ENODEV; - } + if (!count) + return 0; - if (sysfs_is_bin(of->sd)) { - struct bin_attribute *battr = of->sd->priv; + return ops->store(kobj, of->sd->priv, buf, count); +} - rc = -EIO; - if (battr->write) - rc = battr->write(of->file, kobj, battr, buf, off, - count); - } else { - const struct sysfs_ops *ops = sysfs_file_ops(of->sd); +/* kernfs write callback for bin sysfs files */ +static ssize_t sysfs_kf_bin_write(struct sysfs_open_file *of, char *buf, + size_t count, loff_t pos) +{ + struct bin_attribute *battr = of->sd->priv; + struct kobject *kobj = of->sd->s_parent->priv; + loff_t size = file_inode(of->file)->i_size; - rc = ops->store(kobj, of->sd->priv, buf, count); + if (size) { + if (size <= pos) + return 0; + count = min_t(ssize_t, count, size - pos); } + if (!count) + return 0; - sysfs_put_active(of->sd); - mutex_unlock(&of->mutex); + if (!battr->write) + return -EIO; - return rc; + return battr->write(of->file, kobj, battr, buf, pos, count); } /** - * sysfs_write_file - write an attribute + * kernfs_file_write - kernfs vfs write callback * @file: file pointer * @user_buf: data to write * @count: number of bytes * @ppos: starting offset * - * Copy data in from userland and pass it to the matching - * sysfs_ops->store() by invoking flush_write_buffer(). + * Copy data in from userland and pass it to the matching kernfs write + * operation. * * There is no easy way for us to know if userspace is only doing a partial * write, so we don't support them. We expect the entire buffer to come on @@ -329,23 +318,13 @@ static int flush_write_buffer(struct sysfs_open_file *of, char *buf, loff_t off, * modify only the the value you're changing, then write entire buffer * back. */ -static ssize_t sysfs_write_file(struct file *file, const char __user *user_buf, - size_t count, loff_t *ppos) +static ssize_t kernfs_file_write(struct file *file, const char __user *user_buf, + size_t count, loff_t *ppos) { struct sysfs_open_file *of = sysfs_of(file); ssize_t len = min_t(size_t, count, PAGE_SIZE); - loff_t size = file_inode(file)->i_size; char *buf; - if (sysfs_is_bin(of->sd) && size) { - if (size <= *ppos) - return 0; - len = min_t(ssize_t, len, size - *ppos); - } - - if (!len) - return 0; - buf = kmalloc(len + 1, GFP_KERNEL); if (!buf) return -ENOMEM; @@ -356,7 +335,25 @@ static ssize_t sysfs_write_file(struct file *file, const char __user *user_buf, } buf[len] = '\0'; /* guarantee string termination */ - len = flush_write_buffer(of, buf, *ppos, len); + /* + * @of->mutex nests outside active ref and is just to ensure that + * the ops aren't called concurrently for the same open file. + */ + mutex_lock(&of->mutex); + if (!sysfs_get_active(of->sd)) { + mutex_unlock(&of->mutex); + len = -ENODEV; + goto out_free; + } + + if (sysfs_is_bin(of->sd)) + len = sysfs_kf_bin_write(of, buf, len, *ppos); + else + len = sysfs_kf_write(of, buf, len, *ppos); + + sysfs_put_active(of->sd); + mutex_unlock(&of->mutex); + if (len > 0) *ppos += len; out_free: @@ -878,7 +875,7 @@ EXPORT_SYMBOL_GPL(sysfs_notify); const struct file_operations sysfs_file_operations = { .read = kernfs_file_read, - .write = sysfs_write_file, + .write = kernfs_file_write, .llseek = generic_file_llseek, .open = sysfs_open_file, .release = sysfs_release, @@ -887,7 +884,7 @@ const struct file_operations sysfs_file_operations = { const struct file_operations sysfs_bin_operations = { .read = kernfs_file_read, - .write = sysfs_write_file, + .write = kernfs_file_write, .llseek = generic_file_llseek, .mmap = sysfs_bin_mmap, .open = sysfs_open_file, |
