On Wed, 2021-04-07 at 07:54 +0800, Gao Xiang wrote:
> Hi Colin,
>
> On Tue, Apr 06, 2021 at 05:27:18PM +0100, Colin King wrote:
> > From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> >
> > The while-loop iterates until src is non-null or i is 3, however, the
> > loop counter i is not intinitialied to zero, causing incorrect iteration
> > counts. Fix this by initializing it to zero.
> >
> > Addresses-Coverity: ("Uninitialized scalar variable")
> > Fixes: 1aa5f2e2feed ("erofs: support decompress big pcluster for lz4 backend")
> > Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> Thank you very much for catching this! It looks good to me,
> Reviewed-by: Gao Xiang <hsiangkao@xxxxxxxxxx>
>
> (btw, may I fold this into the original patchset? since such big pcluster
> patchset is just applied to for-next for further integration testing, and
> the commit id is not stable yet..)
>
> Thanks,
> Gao Xiang
I think this code is odd and would be more intelligible using
a for loop like:
---
fs/erofs/decompressor.c | 20 ++++++++------------
1 file changed, 8 insertions(+), 12 deletions(-)
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 27aa6a99b371..5a64f4649414 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -286,28 +286,24 @@ static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq,
}
ret = alg->prepare_destpages(rq, pagepool);
- if (ret < 0) {
+ if (ret < 0)
return ret;
- } else if (ret) {
+ if (ret) {
dst = page_address(*rq->out);
dst_maptype = 1;
goto dstmap_out;
}
- i = 0;
- while (1) {
+ for (i = 0; i < 3; i++) {
dst = vm_map_ram(rq->out, nrpages_out, -1);
-
+ if (dst) {
+ dst_maptype = 2;
+ goto dstmap_out;
+ }
/* retry two more times (totally 3 times) */
- if (dst || ++i >= 3)
- break;
vm_unmap_aliases();
}
-
- if (!dst)
- return -ENOMEM;
-
- dst_maptype = 2;
+ return -ENOMEM;
dstmap_out:
ret = alg->decompress(rq, dst + rq->pageofs_out);
