Revert "[PATCH] generic_file_buffered_write(): handle zero-length iovec segments"

This reverts commit 81b0c8713385ce1b1b9058e916edcf9561ad76d6, which was
a bugfix against 6527c2bdf1f833cc18e8f42bd97973d583e4aa83 ("[PATCH]
generic_file_buffered_write(): deadlock on vectored write"), which we
also revert.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 3 insertions, 10 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index c504db18ac26..caaaa7adfdf9 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1895,12 +1895,6 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
                         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);
@@ -1930,8 +1924,7 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
                         page_cache_release(page);
                         continue;
                 }
-zero_length_segment:
-                if (likely(copied >= 0)) {
+                if (likely(copied > 0)) {
                         if (!status)
                                 status = copied;
 
diff --git a/mm/filemap.h b/mm/filemap.h
index c2bff04c84ed..a1e10a232e92 100644
--- a/mm/filemap.h
+++ b/mm/filemap.h
@@ -87,7 +87,7 @@ filemap_set_next_iovec(const struct iovec **iovp, size_t *basep, size_t bytes)
         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 iovec **iovp, size_t *basep, size_t bytes)
                         iov++;
                         base = 0;
                 }
-        } while (bytes);
+        }
         *iovp = iov;
         *basep = base;
 }