iomap: remove the length variable in iomap_seek_data

The length variable is rather pointless given that it can be trivially
deduced from offset and size.  Also the initial calculation can lead
to KASAN warnings.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Leizhen (ThunderTown) <thunder.leizhen@huawei.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>

diff --git a/fs/iomap/seek.c b/fs/iomap/seek.c
index dab1b02..50b8f14 100644 (file)
--- a/fs/iomap/seek.c
+++ b/fs/iomap/seek.c
@@ -83,27 +83,23 @@ loff_t
 iomap_seek_data(struct inode *inode, loff_t offset, const struct iomap_ops *ops)
 {
        loff_t size = i_size_read(inode);
-       loff_t length = size - offset;
        loff_t ret;
 
        /* Nothing to be found before or beyond the end of the file. */
        if (offset < 0 || offset >= size)
                return -ENXIO;
 
-       while (length > 0) {
-               ret = iomap_apply(inode, offset, length, IOMAP_REPORT, ops,
-                                 &offset, iomap_seek_data_actor);
+       while (offset < size) {
+               ret = iomap_apply(inode, offset, size - offset, IOMAP_REPORT,
+                                 ops, &offset, iomap_seek_data_actor);
                if (ret < 0)
                        return ret;
                if (ret == 0)
-                       break;
-
+                       return offset;
                offset += ret;
-               length -= ret;
        }
 
-       if (length <= 0)
-               return -ENXIO;
-       return offset;
+       /* We've reached the end of the file without finding data */
+       return -ENXIO;
 }
 EXPORT_SYMBOL_GPL(iomap_seek_data);