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SubjectRe: [PATCH -next 1/1] iomap: Fix a false positive of UBSAN in iomap_seek_data()
On Mon, Jul 05, 2021 at 11:29:44AM +0800, Leizhen (ThunderTown) wrote:
> I've thought about it, and that "if" statement can be removed as follows:

I think this really misses Christoph's point. He's looking for
something more like this:

@@ -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) {
+ while (offset < size) {
ret = iomap_apply(inode, offset, length, 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;
+ return -ENXIO;
}
EXPORT_SYMBOL_GPL(iomap_seek_data);

(not even slightly tested)

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