Re: [PATCH -next 1/1] iomap: Fix a false positive of UBSAN in iomap_seek_data()

From: Christoph Hellwig
Date: Fri Jul 02 2021 - 05:35:24 EST


We might as well just kill off the length variable while we're at it:


diff --git a/fs/iomap/seek.c b/fs/iomap/seek.c
index dab1b02eba5b7f..942e354e9e13e6 100644
--- a/fs/iomap/seek.c
+++ b/fs/iomap/seek.c
@@ -35,23 +35,21 @@ loff_t
iomap_seek_hole(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_hole_actor);
+ while (offset < size) {
+ ret = iomap_apply(inode, offset, size - offset, IOMAP_REPORT,
+ ops, &offset, iomap_seek_hole_actor);
if (ret < 0)
return ret;
if (ret == 0)
break;

offset += ret;
- length -= ret;
}

return offset;