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 <bvanassche@acm.org> [hch: split out a separate fix] Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Bart Van Assche
Christoph Hellwig
Родитель
44b9a000df
Коммит
7fe1e79b59
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@ -14,7 +14,7 @@
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#include <linux/mutex.h>
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#include <linux/vmalloc.h>
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#include <linux/uaccess.h>
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#include <linux/uio.h>
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#include <linux/configfs.h>
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#include "configfs_internal.h"
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@ -77,9 +77,9 @@ static int fill_read_buffer(struct file *file, struct configfs_buffer *buffer)
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return 0;
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}
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static ssize_t
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configfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos)
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static ssize_t configfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
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{
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struct file *file = iocb->ki_filp;
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struct configfs_buffer *buffer = file->private_data;
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ssize_t retval = 0;
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@ -89,23 +89,24 @@ configfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *pp
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if (retval)
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goto out;
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}
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pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n",
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__func__, count, *ppos, buffer->page);
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retval = simple_read_from_buffer(buf, count, ppos, buffer->page,
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buffer->count);
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pr_debug("%s: count = %zd, pos = %lld, buf = %s\n",
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__func__, iov_iter_count(to), iocb->ki_pos, buffer->page);
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retval = copy_to_iter(buffer->page, buffer->count, to);
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iocb->ki_pos += retval;
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if (retval == 0)
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retval = -EFAULT;
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out:
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mutex_unlock(&buffer->mutex);
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return retval;
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}
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static ssize_t
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configfs_read_bin_file(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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static ssize_t configfs_bin_read_iter(struct kiocb *iocb, struct iov_iter *to)
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{
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struct file *file = iocb->ki_filp;
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struct configfs_fragment *frag = to_frag(file);
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struct configfs_buffer *buffer = file->private_data;
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ssize_t retval = 0;
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ssize_t len = min_t(size_t, count, PAGE_SIZE);
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ssize_t len;
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mutex_lock(&buffer->mutex);
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@ -161,31 +162,31 @@ configfs_read_bin_file(struct file *file, char __user *buf,
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buffer->needs_read_fill = 0;
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}
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retval = simple_read_from_buffer(buf, count, ppos, buffer->bin_buffer,
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buffer->bin_buffer_size);
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retval = copy_to_iter(buffer->bin_buffer, buffer->bin_buffer_size, to);
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iocb->ki_pos += retval;
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if (retval == 0)
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retval = -EFAULT;
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out:
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mutex_unlock(&buffer->mutex);
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return retval;
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}
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static int
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fill_write_buffer(struct configfs_buffer * buffer, const char __user * buf, size_t count)
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static int fill_write_buffer(struct configfs_buffer *buffer,
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struct iov_iter *from)
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{
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int error;
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int copied;
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if (!buffer->page)
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buffer->page = (char *)__get_free_pages(GFP_KERNEL, 0);
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if (!buffer->page)
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return -ENOMEM;
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if (count >= SIMPLE_ATTR_SIZE)
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count = SIMPLE_ATTR_SIZE - 1;
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error = copy_from_user(buffer->page,buf,count);
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copied = copy_from_iter(buffer->page, SIMPLE_ATTR_SIZE - 1, from);
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buffer->needs_read_fill = 1;
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/* if buf is assumed to contain a string, terminate it by \0,
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* so e.g. sscanf() can scan the string easily */
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buffer->page[count] = 0;
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return error ? -EFAULT : count;
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buffer->page[copied] = 0;
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return copied ? : -EFAULT;
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}
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static int
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@ -209,28 +210,29 @@ flush_write_buffer(struct file *file, struct configfs_buffer *buffer, size_t cou
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* Hint: if you're writing a value, first read the file, modify only the value
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* you're changing, then write entire buffer back.
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*/
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static ssize_t
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configfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
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static ssize_t configfs_write_iter(struct kiocb *iocb, struct iov_iter *from)
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{
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struct file *file = iocb->ki_filp;
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struct configfs_buffer *buffer = file->private_data;
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ssize_t len;
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mutex_lock(&buffer->mutex);
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len = fill_write_buffer(buffer, buf, count);
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len = fill_write_buffer(buffer, from);
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if (len > 0)
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len = flush_write_buffer(file, buffer, len);
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if (len > 0)
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*ppos += len;
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iocb->ki_pos += len;
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mutex_unlock(&buffer->mutex);
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return len;
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}
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static ssize_t
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configfs_write_bin_file(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos)
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static ssize_t configfs_bin_write_iter(struct kiocb *iocb,
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struct iov_iter *from)
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{
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struct file *file = iocb->ki_filp;
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struct configfs_buffer *buffer = file->private_data;
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void *tbuf = NULL;
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size_t end_offset;
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ssize_t len;
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mutex_lock(&buffer->mutex);
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@ -243,15 +245,14 @@ configfs_write_bin_file(struct file *file, const char __user *buf,
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buffer->write_in_progress = true;
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/* buffer grows? */
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if (*ppos + count > buffer->bin_buffer_size) {
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if (buffer->cb_max_size &&
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*ppos + count > buffer->cb_max_size) {
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end_offset = iocb->ki_pos + iov_iter_count(from);
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if (end_offset > buffer->bin_buffer_size) {
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if (buffer->cb_max_size && end_offset > buffer->cb_max_size) {
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len = -EFBIG;
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goto out;
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}
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tbuf = vmalloc(*ppos + count);
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tbuf = vmalloc(end_offset);
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if (tbuf == NULL) {
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len = -ENOMEM;
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goto out;
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@ -266,16 +267,15 @@ configfs_write_bin_file(struct file *file, const char __user *buf,
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/* clear the new area */
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memset(tbuf + buffer->bin_buffer_size, 0,
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*ppos + count - buffer->bin_buffer_size);
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end_offset - buffer->bin_buffer_size);
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buffer->bin_buffer = tbuf;
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buffer->bin_buffer_size = *ppos + count;
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buffer->bin_buffer_size = end_offset;
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}
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len = simple_write_to_buffer(buffer->bin_buffer,
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buffer->bin_buffer_size, ppos, buf, count);
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len = copy_from_iter(buffer->bin_buffer, buffer->bin_buffer_size, from);
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out:
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mutex_unlock(&buffer->mutex);
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return len;
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return len ? : -EFAULT;
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}
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static int __configfs_open_file(struct inode *inode, struct file *file, int type)
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@ -420,16 +420,16 @@ static int configfs_release_bin_file(struct inode *inode, struct file *file)
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const struct file_operations configfs_file_operations = {
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.read = configfs_read_file,
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.write = configfs_write_file,
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.read_iter = configfs_read_iter,
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.write_iter = configfs_write_iter,
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.llseek = generic_file_llseek,
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.open = configfs_open_file,
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.release = configfs_release,
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};
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const struct file_operations configfs_bin_file_operations = {
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.read = configfs_read_bin_file,
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.write = configfs_write_bin_file,
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.read_iter = configfs_bin_read_iter,
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.write_iter = configfs_bin_write_iter,
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.llseek = NULL, /* bin file is not seekable */
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.open = configfs_open_bin_file,
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.release = configfs_release_bin_file,
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