From 7fe1e79b59ba02fb6bdc45d324f88f1ba97d3ab4 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Tue, 25 May 2021 10:30:21 +0200 Subject: configfs: implement the .read_iter and .write_iter methods Configfs is one of the few filesystems that does not yet support the .read_iter and .write_iter callbacks. This patch adds support for these methods in configfs. Signed-off-by: Bart Van Assche [hch: split out a separate fix] Signed-off-by: Christoph Hellwig --- fs/configfs/file.c | 84 +++++++++++++++++++++++++++--------------------------- 1 file changed, 42 insertions(+), 42 deletions(-) (limited to 'fs/configfs') diff --git a/fs/configfs/file.c b/fs/configfs/file.c index 2199690b4080..53913b84383a 100644 --- a/fs/configfs/file.c +++ b/fs/configfs/file.c @@ -14,7 +14,7 @@ #include #include #include - +#include #include #include "configfs_internal.h" @@ -77,9 +77,9 @@ static int fill_read_buffer(struct file *file, struct configfs_buffer *buffer) return 0; } -static ssize_t -configfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) +static ssize_t configfs_read_iter(struct kiocb *iocb, struct iov_iter *to) { + struct file *file = iocb->ki_filp; struct configfs_buffer *buffer = file->private_data; ssize_t retval = 0; @@ -89,23 +89,24 @@ configfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *pp if (retval) goto out; } - pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n", - __func__, count, *ppos, buffer->page); - retval = simple_read_from_buffer(buf, count, ppos, buffer->page, - buffer->count); + pr_debug("%s: count = %zd, pos = %lld, buf = %s\n", + __func__, iov_iter_count(to), iocb->ki_pos, buffer->page); + retval = copy_to_iter(buffer->page, buffer->count, to); + iocb->ki_pos += retval; + if (retval == 0) + retval = -EFAULT; out: mutex_unlock(&buffer->mutex); return retval; } -static ssize_t -configfs_read_bin_file(struct file *file, char __user *buf, - size_t count, loff_t *ppos) +static ssize_t configfs_bin_read_iter(struct kiocb *iocb, struct iov_iter *to) { + struct file *file = iocb->ki_filp; struct configfs_fragment *frag = to_frag(file); struct configfs_buffer *buffer = file->private_data; ssize_t retval = 0; - ssize_t len = min_t(size_t, count, PAGE_SIZE); + ssize_t len; mutex_lock(&buffer->mutex); @@ -161,31 +162,31 @@ configfs_read_bin_file(struct file *file, char __user *buf, buffer->needs_read_fill = 0; } - retval = simple_read_from_buffer(buf, count, ppos, buffer->bin_buffer, - buffer->bin_buffer_size); + retval = copy_to_iter(buffer->bin_buffer, buffer->bin_buffer_size, to); + iocb->ki_pos += retval; + if (retval == 0) + retval = -EFAULT; out: mutex_unlock(&buffer->mutex); return retval; } -static int -fill_write_buffer(struct configfs_buffer * buffer, const char __user * buf, size_t count) +static int fill_write_buffer(struct configfs_buffer *buffer, + struct iov_iter *from) { - int error; + int copied; if (!buffer->page) buffer->page = (char *)__get_free_pages(GFP_KERNEL, 0); if (!buffer->page) return -ENOMEM; - if (count >= SIMPLE_ATTR_SIZE) - count = SIMPLE_ATTR_SIZE - 1; - error = copy_from_user(buffer->page,buf,count); + copied = copy_from_iter(buffer->page, SIMPLE_ATTR_SIZE - 1, from); buffer->needs_read_fill = 1; /* if buf is assumed to contain a string, terminate it by \0, * so e.g. sscanf() can scan the string easily */ - buffer->page[count] = 0; - return error ? -EFAULT : count; + buffer->page[copied] = 0; + return copied ? : -EFAULT; } static int @@ -209,28 +210,29 @@ flush_write_buffer(struct file *file, struct configfs_buffer *buffer, size_t cou * Hint: if you're writing a value, first read the file, modify only the value * you're changing, then write entire buffer back. */ -static ssize_t -configfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos) +static ssize_t configfs_write_iter(struct kiocb *iocb, struct iov_iter *from) { + struct file *file = iocb->ki_filp; struct configfs_buffer *buffer = file->private_data; ssize_t len; mutex_lock(&buffer->mutex); - len = fill_write_buffer(buffer, buf, count); + len = fill_write_buffer(buffer, from); if (len > 0) len = flush_write_buffer(file, buffer, len); if (len > 0) - *ppos += len; + iocb->ki_pos += len; mutex_unlock(&buffer->mutex); return len; } -static ssize_t -configfs_write_bin_file(struct file *file, const char __user *buf, - size_t count, loff_t *ppos) +static ssize_t configfs_bin_write_iter(struct kiocb *iocb, + struct iov_iter *from) { + struct file *file = iocb->ki_filp; struct configfs_buffer *buffer = file->private_data; void *tbuf = NULL; + size_t end_offset; ssize_t len; mutex_lock(&buffer->mutex); @@ -243,15 +245,14 @@ configfs_write_bin_file(struct file *file, const char __user *buf, buffer->write_in_progress = true; /* buffer grows? */ - if (*ppos + count > buffer->bin_buffer_size) { - - if (buffer->cb_max_size && - *ppos + count > buffer->cb_max_size) { + end_offset = iocb->ki_pos + iov_iter_count(from); + if (end_offset > buffer->bin_buffer_size) { + if (buffer->cb_max_size && end_offset > buffer->cb_max_size) { len = -EFBIG; goto out; } - tbuf = vmalloc(*ppos + count); + tbuf = vmalloc(end_offset); if (tbuf == NULL) { len = -ENOMEM; goto out; @@ -266,16 +267,15 @@ configfs_write_bin_file(struct file *file, const char __user *buf, /* clear the new area */ memset(tbuf + buffer->bin_buffer_size, 0, - *ppos + count - buffer->bin_buffer_size); + end_offset - buffer->bin_buffer_size); buffer->bin_buffer = tbuf; - buffer->bin_buffer_size = *ppos + count; + buffer->bin_buffer_size = end_offset; } - len = simple_write_to_buffer(buffer->bin_buffer, - buffer->bin_buffer_size, ppos, buf, count); + len = copy_from_iter(buffer->bin_buffer, buffer->bin_buffer_size, from); out: mutex_unlock(&buffer->mutex); - return len; + return len ? : -EFAULT; } static int __configfs_open_file(struct inode *inode, struct file *file, int type) @@ -420,16 +420,16 @@ static int configfs_release_bin_file(struct inode *inode, struct file *file) const struct file_operations configfs_file_operations = { - .read = configfs_read_file, - .write = configfs_write_file, + .read_iter = configfs_read_iter, + .write_iter = configfs_write_iter, .llseek = generic_file_llseek, .open = configfs_open_file, .release = configfs_release, }; const struct file_operations configfs_bin_file_operations = { - .read = configfs_read_bin_file, - .write = configfs_write_bin_file, + .read_iter = configfs_bin_read_iter, + .write_iter = configfs_bin_write_iter, .llseek = NULL, /* bin file is not seekable */ .open = configfs_open_bin_file, .release = configfs_release_bin_file, -- cgit v1.2.3