On Fri, Apr 1, 2022 at 5:52 AM Jakob Koschel <jakobkoschel@xxxxxxxxx> wrote: > > When list_for_each_entry() completes the iteration over the whole list > without breaking the loop, the iterator value will be a bogus pointer > computed based on the head element. > > While it is safe to use the pointer to determine if it was computed > based on the head element, either with list_entry_is_head() or > &pos->member == head, using the iterator variable after the loop should > be avoided. > > In preparation to limiting the scope of a list iterator to the list > traversal loop, use a dedicated pointer to point to the found element [1]. > > Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@xxxxxxxxxxxxxx/ [1] > Signed-off-by: Jakob Koschel <jakobkoschel@xxxxxxxxx> LGTM. Thanks. Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> > sound/soc/sprd/sprd-mcdt.c | 13 ++++++------- > 1 file changed, 6 insertions(+), 7 deletions(-) > > diff --git a/sound/soc/sprd/sprd-mcdt.c b/sound/soc/sprd/sprd-mcdt.c > index f6a55fa60c1b..6e27789a0df5 100644 > --- a/sound/soc/sprd/sprd-mcdt.c > +++ b/sound/soc/sprd/sprd-mcdt.c > @@ -866,20 +866,19 @@ EXPORT_SYMBOL_GPL(sprd_mcdt_chan_dma_disable); > struct sprd_mcdt_chan *sprd_mcdt_request_chan(u8 channel, > enum sprd_mcdt_channel_type type) > { > - struct sprd_mcdt_chan *temp; > + struct sprd_mcdt_chan *temp = NULL; > + struct sprd_mcdt_chan *iter; > > mutex_lock(&sprd_mcdt_list_mutex); > > - list_for_each_entry(temp, &sprd_mcdt_chan_list, list) { > - if (temp->type == type && temp->id == channel) { > - list_del_init(&temp->list); > + list_for_each_entry(iter, &sprd_mcdt_chan_list, list) { > + if (iter->type == type && iter->id == channel) { > + list_del_init(&iter->list); > + temp = iter; > break; > } > } > > - if (list_entry_is_head(temp, &sprd_mcdt_chan_list, list)) > - temp = NULL; > - > mutex_unlock(&sprd_mcdt_list_mutex); > > return temp; > -- > 2.25.1 > -- Baolin Wang
