@@ -1709,7 +1709,7 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
* Fault pages before locking them in prepare_pages
* to avoid recursive lock
*/
- if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
+ if (unlikely(fault_in_iov_iter_readable(i, write_bytes))) {
ret = -EFAULT;
break;
}
@@ -4279,7 +4279,7 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
size_t target_size = 0;
int err;
- if (iov_iter_fault_in_readable(from, iov_iter_count(from)))
+ if (fault_in_iov_iter_readable(from, iov_iter_count(from)))
set_inode_flag(inode, FI_NO_PREALLOC);
if ((iocb->ki_flags & IOCB_NOWAIT)) {
@@ -1164,7 +1164,7 @@ static ssize_t fuse_fill_write_pages(struct fuse_io_args *ia,
again:
err = -EFAULT;
- if (iov_iter_fault_in_readable(ii, bytes))
+ if (fault_in_iov_iter_readable(ii, bytes))
break;
err = -ENOMEM;
@@ -757,7 +757,7 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
* same page as we're writing to, without it being marked
* up-to-date.
*/
- if (unlikely(iov_iter_fault_in_readable(i, bytes))) {
+ if (unlikely(fault_in_iov_iter_readable(i, bytes))) {
status = -EFAULT;
break;
}
@@ -1829,7 +1829,7 @@ static ssize_t ntfs_perform_write(struct file *file, struct iov_iter *i,
* pages being swapped out between us bringing them into memory
* and doing the actual copying.
*/
- if (unlikely(iov_iter_fault_in_readable(i, bytes))) {
+ if (unlikely(fault_in_iov_iter_readable(i, bytes))) {
status = -EFAULT;
break;
}
@@ -989,7 +989,7 @@ static ssize_t ntfs_compress_write(struct kiocb *iocb, struct iov_iter *from)
frame_vbo = pos & ~(frame_size - 1);
index = frame_vbo >> PAGE_SHIFT;
- if (unlikely(iov_iter_fault_in_readable(from, bytes))) {
+ if (unlikely(fault_in_iov_iter_readable(from, bytes))) {
err = -EFAULT;
goto out;
}
@@ -133,7 +133,7 @@ size_t copy_page_from_iter_atomic(struct page *page, unsigned offset,
size_t bytes, struct iov_iter *i);
void iov_iter_advance(struct iov_iter *i, size_t bytes);
void iov_iter_revert(struct iov_iter *i, size_t bytes);
-int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes);
+size_t fault_in_iov_iter_readable(const struct iov_iter *i, size_t bytes);
size_t iov_iter_single_seg_count(const struct iov_iter *i);
size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i);
@@ -431,33 +431,42 @@ static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t by
}
/*
+ * fault_in_iov_iter_readable - fault in iov iterator for reading
+ * @i: iterator
+ * @size: maximum length
+ *
* Fault in one or more iovecs of the given iov_iter, to a maximum length of
- * bytes. For each iovec, fault in each page that constitutes the iovec.
+ * @size. For each iovec, fault in each page that constitutes the iovec.
+ *
+ * Returns the number of bytes not faulted in (like copy_to_user() and
+ * copy_from_user()).
*
- * Return 0 on success, or non-zero if the memory could not be accessed (i.e.
- * because it is an invalid address).
+ * Always returns 0 for non-userspace iterators.
*/
-int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes)
+size_t fault_in_iov_iter_readable(const struct iov_iter *i, size_t size)
{
if (iter_is_iovec(i)) {
+ size_t count = min(size, iov_iter_count(i));
const struct iovec *p;
size_t skip;
- if (bytes > i->count)
- bytes = i->count;
- for (p = i->iov, skip = i->iov_offset; bytes; p++, skip = 0) {
- size_t len = min(bytes, p->iov_len - skip);
+ size -= count;
+ for (p = i->iov, skip = i->iov_offset; count; p++, skip = 0) {
+ size_t len = min(count, p->iov_len - skip);
+ size_t ret;
if (unlikely(!len))
continue;
- if (fault_in_readable(p->iov_base + skip, len))
- return -EFAULT;
- bytes -= len;
+ ret = fault_in_readable(p->iov_base + skip, len);
+ count -= len - ret;
+ if (ret)
+ break;
}
+ return count + size;
}
return 0;
}
-EXPORT_SYMBOL(iov_iter_fault_in_readable);
+EXPORT_SYMBOL(fault_in_iov_iter_readable);
void iov_iter_init(struct iov_iter *i, unsigned int direction,
const struct iovec *iov, unsigned long nr_segs,
@@ -3760,7 +3760,7 @@ ssize_t generic_perform_write(struct file *file,
* same page as we're writing to, without it being marked
* up-to-date.
*/
- if (unlikely(iov_iter_fault_in_readable(i, bytes))) {
+ if (unlikely(fault_in_iov_iter_readable(i, bytes))) {
status = -EFAULT;
break;
}