Replacement is called copy_page_from_iter_atomic(); unlike the old primitive the
callers do *not* need to do iov_iter_advance() after it. In case when they end
up consuming less than they'd been given they need to do iov_iter_revert() on
everything they had not consumed. That, however, needs to be done only on slow
paths.
All in-tree callers converted. And that kills the last user of iterate_all_kinds()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
mnt_want_write_file() can now only be paired with mnt_drop_write_file(),
whereas previously it could be paired with mnt_drop_write() as well.
+
+---
+
+**mandatory**
+
+iov_iter_copy_from_user_atomic() is gone; use copy_page_from_iter_atomic().
+The difference is copy_page_from_iter_atomic() advances the iterator and
+you don't need iov_iter_advance() after it. However, if you decide to use
+only a part of obtained data, you should do iov_iter_revert().
/*
* Copy data from userspace to the current page
*/
- copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
+ copied = copy_page_from_iter_atomic(page, offset, count, i);
/* Flush processor's dcache for this page */
flush_dcache_page(page);
* The rest of the btrfs_file_write code will fall
* back to page at a time copies after we return 0.
*/
- if (!PageUptodate(page) && copied < count)
- copied = 0;
+ if (unlikely(copied < count)) {
+ if (!PageUptodate(page)) {
+ iov_iter_revert(i, copied);
+ copied = 0;
+ }
+ if (!copied)
+ break;
+ }
- iov_iter_advance(i, copied);
write_bytes -= copied;
total_copied += copied;
-
- /* Return to btrfs_file_write_iter to fault page */
- if (unlikely(copied == 0))
- break;
-
- if (copied < PAGE_SIZE - offset) {
- offset += copied;
- } else {
+ offset += copied;
+ if (offset == PAGE_SIZE) {
pg++;
offset = 0;
}
if (mapping_writably_mapped(mapping))
flush_dcache_page(page);
- tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
+ tmp = copy_page_from_iter_atomic(page, offset, bytes, ii);
flush_dcache_page(page);
- iov_iter_advance(ii, tmp);
if (!tmp) {
unlock_page(page);
put_page(page);
if (mapping_writably_mapped(inode->i_mapping))
flush_dcache_page(page);
- copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes);
+ copied = copy_page_from_iter_atomic(page, offset, bytes, i);
status = iomap_write_end(inode, pos, bytes, copied, page, iomap,
srcmap);
- cond_resched();
+ if (unlikely(copied != status))
+ iov_iter_revert(i, copied - status);
+ cond_resched();
if (unlikely(status == 0)) {
/*
* A short copy made iomap_write_end() reject the
bytes = copied;
goto again;
}
- copied = status;
- iov_iter_advance(i, copied);
- pos += copied;
- written += copied;
- length -= copied;
+ pos += status;
+ written += status;
+ length -= status;
balance_dirty_pages_ratelimited(inode->i_mapping);
} while (iov_iter_count(i) && length);
len = PAGE_SIZE - ofs;
if (len > bytes)
len = bytes;
- copied = iov_iter_copy_from_user_atomic(*pages, i, ofs,
- len);
- iov_iter_advance(i, copied);
+ copied = copy_page_from_iter_atomic(*pages, ofs, len, i);
total += copied;
bytes -= copied;
if (!bytes)
};
}
-size_t iov_iter_copy_from_user_atomic(struct page *page,
- struct iov_iter *i, unsigned long offset, size_t bytes);
+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);
n = wanted - n; \
}
-#define iterate_all_kinds(i, n, v, I, B, K, X) { \
- if (likely(n)) { \
- size_t skip = i->iov_offset; \
- if (likely(iter_is_iovec(i))) { \
- const struct iovec *iov; \
- struct iovec v; \
- iterate_iovec(i, n, v, iov, skip, (I)) \
- } else if (iov_iter_is_bvec(i)) { \
- struct bio_vec v; \
- struct bvec_iter __bi; \
- iterate_bvec(i, n, v, __bi, skip, (B)) \
- } else if (iov_iter_is_kvec(i)) { \
- const struct kvec *kvec; \
- struct kvec v; \
- iterate_kvec(i, n, v, kvec, skip, (K)) \
- } else if (iov_iter_is_xarray(i)) { \
- struct bio_vec v; \
- iterate_xarray(i, n, v, skip, (X)); \
- } \
- } \
-}
-
#define iterate_and_advance(i, n, v, I, B, K, X) { \
if (unlikely(i->count < n)) \
n = i->count; \
}
EXPORT_SYMBOL(iov_iter_zero);
-size_t iov_iter_copy_from_user_atomic(struct page *page,
- struct iov_iter *i, unsigned long offset, size_t bytes)
+size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes,
+ struct iov_iter *i)
{
char *kaddr = kmap_atomic(page), *p = kaddr + offset;
if (unlikely(!page_copy_sane(page, offset, bytes))) {
WARN_ON(1);
return 0;
}
- iterate_all_kinds(i, bytes, v,
+ iterate_and_advance(i, bytes, v,
copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len),
memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page,
v.bv_offset, v.bv_len),
kunmap_atomic(kaddr);
return bytes;
}
-EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
+EXPORT_SYMBOL(copy_page_from_iter_atomic);
static inline void pipe_truncate(struct iov_iter *i)
{
if (mapping_writably_mapped(mapping))
flush_dcache_page(page);
- copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes);
+ copied = copy_page_from_iter_atomic(page, offset, bytes, i);
flush_dcache_page(page);
status = a_ops->write_end(file, mapping, pos, bytes, copied,
page, fsdata);
- if (unlikely(status < 0))
- break;
-
+ if (unlikely(status != copied)) {
+ iov_iter_revert(i, copied - max(status, 0L));
+ if (unlikely(status < 0))
+ break;
+ }
cond_resched();
if (unlikely(status == 0)) {
bytes = copied;
goto again;
}
- copied = status;
- iov_iter_advance(i, copied);
- pos += copied;
- written += copied;
+ pos += status;
+ written += status;
balance_dirty_pages_ratelimited(mapping);
} while (iov_iter_count(i));