export generic_perform_write(), start getting rid of generic_file_buffer_write()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/mm/filemap.c b/mm/filemap.c
index 93e9cf5..09bfc9b 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2092,7 +2092,7 @@
}
EXPORT_SYMBOL(grab_cache_page_write_begin);
-static ssize_t generic_perform_write(struct file *file,
+ssize_t generic_perform_write(struct file *file,
struct iov_iter *i, loff_t pos)
{
struct address_space *mapping = file->f_mapping;
@@ -2180,6 +2180,7 @@
return written ? written : status;
}
+EXPORT_SYMBOL(generic_perform_write);
ssize_t
generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
@@ -2230,8 +2231,10 @@
size_t count; /* after file limit checks */
struct inode *inode = mapping->host;
loff_t pos = iocb->ki_pos;
- ssize_t written;
+ ssize_t written = 0;
ssize_t err;
+ ssize_t status;
+ struct iov_iter from;
ocount = 0;
err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
@@ -2242,8 +2245,6 @@
/* We can write back this queue in page reclaim */
current->backing_dev_info = mapping->backing_dev_info;
- written = 0;
-
err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
if (err)
goto out;
@@ -2259,44 +2260,47 @@
if (err)
goto out;
+ iov_iter_init(&from, iov, nr_segs, count, 0);
+
/* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
if (unlikely(file->f_flags & O_DIRECT)) {
loff_t endbyte;
- ssize_t written_buffered;
- written = generic_file_direct_write(iocb, iov, &nr_segs, pos,
+ written = generic_file_direct_write(iocb, iov, &from.nr_segs, pos,
count, ocount);
if (written < 0 || written == count)
goto out;
+ iov_iter_advance(&from, written);
+
/*
* direct-io write to a hole: fall through to buffered I/O
* for completing the rest of the request.
*/
pos += written;
count -= written;
- written_buffered = generic_file_buffered_write(iocb, iov,
- nr_segs, pos, count, written);
+
+ status = generic_perform_write(file, &from, pos);
/*
- * If generic_file_buffered_write() retuned a synchronous error
+ * If generic_perform_write() returned a synchronous error
* then we want to return the number of bytes which were
* direct-written, or the error code if that was zero. Note
* that this differs from normal direct-io semantics, which
* will return -EFOO even if some bytes were written.
*/
- if (written_buffered < 0) {
- err = written_buffered;
+ if (unlikely(status < 0) && !written) {
+ err = status;
goto out;
}
-
+ iocb->ki_pos = pos + status;
/*
* We need to ensure that the page cache pages are written to
* disk and invalidated to preserve the expected O_DIRECT
* semantics.
*/
- endbyte = pos + written_buffered - written - 1;
+ endbyte = pos + status - 1;
err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
if (err == 0) {
- written = written_buffered;
+ written += status;
invalidate_mapping_pages(mapping,
pos >> PAGE_CACHE_SHIFT,
endbyte >> PAGE_CACHE_SHIFT);
@@ -2307,8 +2311,9 @@
*/
}
} else {
- written = generic_file_buffered_write(iocb, iov, nr_segs,
- pos, count, written);
+ written = generic_perform_write(file, &from, pos);
+ if (likely(written >= 0))
+ iocb->ki_pos = pos + written;
}
out:
current->backing_dev_info = NULL;