> -Original Message-
> From: Dan Carpenter [mailto:dan.carpen...@oracle.com]
> Sent: 17 May 2016 17:32
> To: Paul Durrant
> Cc: xen-de...@lists.xenproject.org
> Subject: re: xen-netback: add control protocol implementation
>
> Hello Paul Durrant,
>
> The patch 40d8abdee806: "xen-netback: add control protocol
> implementation" from May 13, 2016, leads to the following static
> checker warning:
>
> drivers/net/xen-netback/hash.c:362 xenvif_set_hash_mapping()
> warn: should this be 'len == -1'
>
> drivers/net/xen-netback/hash.c
>341 u32 xenvif_set_hash_mapping(struct xenvif *vif, u32 gref, u32 len,
>342 u32 off)
>343 {
>344 u32 *mapping = &vif->hash.mapping[off];
>345 struct gnttab_copy copy_op = {
>346 .source.u.ref = gref,
>347 .source.domid = vif->domid,
>348 .dest.u.gmfn = virt_to_gfn(mapping),
>349 .dest.domid = DOMID_SELF,
>350 .dest.offset = xen_offset_in_page(mapping),
>351 .len = len * sizeof(u32),
>352 .flags = GNTCOPY_source_gref
>353 };
>354
>355 if ((off + len > vif->hash.size) || copy_op.len >
> XEN_PAGE_SIZE)
>356 return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
>357
>358 while (len-- != 0)
>359 if (mapping[off++] >= vif->num_queues)
>360 return
> XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
>361
>362 if (len != 0) {
>
> We know that "len" is always UINT_MAX here meaning this is always true.
> What are trying to test?
>
Yes, that's clearly bogus. The test is supposed to be checking whether the
copy_op actually does something so it should be:
If (copy_op.len != 0)
I'll send a patch.
Paul
>363 gnttab_batch_copy(©_op, 1);
>364
>365 if (copy_op.status != GNTST_okay)
>366 return
> XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
>367 }
>368
>369 return XEN_NETIF_CTRL_STATUS_SUCCESS;
>370 }
>
> regards,
> dan carpenter
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