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-rw-r--r--mm/filemap.c9
-rw-r--r--mm/filemap.h4
2 files changed, 10 insertions, 3 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 4082b3b3cea7..648f2c0c8e18 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2125,6 +2125,12 @@ 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);
@@ -2154,7 +2160,8 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
page_cache_release(page);
continue;
}
- if (likely(copied > 0)) {
+zero_length_segment:
+ if (likely(copied >= 0)) {
if (!status)
status = copied;
diff --git a/mm/filemap.h b/mm/filemap.h
index 536979fb4ba7..3f2a343c6015 100644
--- a/mm/filemap.h
+++ b/mm/filemap.h
@@ -88,7 +88,7 @@ filemap_set_next_iovec(const struct iovec **iovp, size_t *basep, size_t bytes)
const struct iovec *iov = *iovp;
size_t base = *basep;
- while (bytes) {
+ do {
int copy = min(bytes, iov->iov_len - base);
bytes -= copy;
@@ -97,7 +97,7 @@ filemap_set_next_iovec(const struct iovec **iovp, size_t *basep, size_t bytes)
iov++;
base = 0;
}
- }
+ } while (bytes);
*iovp = iov;
*basep = base;
}