[patch 1/6] revert "generic_file_buffered_write(): handle zero length iovec segments"

[Andrew Morton <akpm@osdl.org>]

Revert 81b0c8713385ce1b1b9058e916edcf9561ad76d6.

This was a bugfix against 6527c2bdf1f833cc18e8f42bd97973d583e4aa83, which we
also revert.


Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 mm/filemap.c |    9 +--------
 mm/filemap.h |    4 ++--
 2 files changed, 3 insertions(+), 10 deletions(-)

diff -puN mm/filemap.c~revert-generic_file_buffered_write-handle-zero-length-iovec-segments mm/filemap.c
--- a/mm/filemap.c~revert-generic_file_buffered_write-handle-zero-length-iovec-segments
+++ a/mm/filemap.c
@@ -2121,12 +2121,6 @@ generic_file_buffered_write(struct kiocb
 			break;
 		}
 
-		if (unlikely(bytes == 0)) {
-			status = 0;
-			copied = 0;
-			goto zero_length_segment;
-		}
-
 		status = a_ops->prepare_write(file, page, offset, offset+bytes);
 		if (unlikely(status)) {
 			loff_t isize = i_size_read(inode);
@@ -2156,8 +2150,7 @@ generic_file_buffered_write(struct kiocb
 			page_cache_release(page);
 			continue;
 		}
-zero_length_segment:
-		if (likely(copied >= 0)) {
+		if (likely(copied > 0)) {
 			if (!status)
 				status = copied;
 
diff -puN mm/filemap.h~revert-generic_file_buffered_write-handle-zero-length-iovec-segments mm/filemap.h
--- a/mm/filemap.h~revert-generic_file_buffered_write-handle-zero-length-iovec-segments
+++ a/mm/filemap.h
@@ -87,7 +87,7 @@ filemap_set_next_iovec(const struct iove
 	const struct iovec *iov = *iovp;
 	size_t base = *basep;
 
-	do {
+	while (bytes) {
 		int copy = min(bytes, iov->iov_len - base);
 
 		bytes -= copy;
@@ -96,7 +96,7 @@ filemap_set_next_iovec(const struct iove
 			iov++;
 			base = 0;
 		}
-	} while (bytes);
+	}
 	*iovp = iov;
 	*basep = base;
 }
_

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