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authorBart Van Assche <bvanassche@acm.org>2021-05-25 10:30:21 +0200
committerChristoph Hellwig <hch@lst.de>2021-05-25 10:30:56 +0200
commit7fe1e79b59ba02fb6bdc45d324f88f1ba97d3ab4 (patch)
tree2f889e5654a17432a219dadd9bb64a0d3226f08e /fs/configfs
parent44b9a000df5cc144c262a0da0d092dc04b93abca (diff)
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>
Diffstat (limited to 'fs/configfs')
-rw-r--r--fs/configfs/file.c84
1 files changed, 42 insertions, 42 deletions
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 <linux/mutex.h>
#include <linux/vmalloc.h>
#include <linux/uaccess.h>
-
+#include <linux/uio.h>
#include <linux/configfs.h>
#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,