Hello Wan, thank you for this patch.
On Thu, 2021-10-14 at 03:56 -0400, Wan Jiabing wrote:
> Fix following coccicheck warning:
>
> ./arch/powerpc/platforms/pseries/iommu.c:924:1-28: WARNING: Function
> for_each_node_with_property should have of_node_put() before break
>
> Early exits from for_each_node_with_property should decrement the
> node reference counter.
Yeah, it makes sense to me.
for_each_node_with_property calls of_find_node_with_property() at each
step, which ends up calling of_node_put() after using each node.
Introducing this break caused this of_node_put not to happen to the
last node, so IIUC this patch fixes a possible issue if kzalloc() fails
in ddw_list_new_entry().
Another option would be s/break/continue here, but it does not make
sense to keep trying next nodes if there is no memory to allocate for a
struct dma_win (4 pointers).
On the other hard, failing on allocating such small space should not
happen often (if it will ever happen), so a 'continue' here makes code
simpler.
Anyway, FWIW:
Reviewed-by: Leonardo Bras <leobra...@gmail.com>
Best regards,
Leo
>
> Signed-off-by: Wan Jiabing <wanjiab...@vivo.com>
> ---
> arch/powerpc/platforms/pseries/iommu.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/platforms/pseries/iommu.c
> b/arch/powerpc/platforms/pseries/iommu.c
> index 269f61d519c2..c140aa683f66 100644
> --- a/arch/powerpc/platforms/pseries/iommu.c
> +++ b/arch/powerpc/platforms/pseries/iommu.c
> @@ -929,8 +929,10 @@ static void find_existing_ddw_windows_named(const
> char *name)
> }
>
> window = ddw_list_new_entry(pdn, dma64);
> - if (!window)
> + if (!window) {
> + of_node_put(pdn);
> break;
> + }
>
> spin_lock(&dma_win_list_lock);
> list_add(&window->list, &dma_win_list);
