Hi Rafael, On Monday, August 05, 2019 17:59, Rafael J. Wysocki wrote: > > On Wednesday, July 24, 2019 9:47:20 AM CEST Ran Wang wrote: > > Some user might want to go through all registered wakeup sources and > > doing things accordingly. For example, SoC PM driver might need to do > > HW programming to prevent powering down specific IP which wakeup > > source depending on. So add this API to help walk through all > > registered wakeup source objects on that list and return them one by one. > > > > Signed-off-by: Ran Wang <ran.wan...@nxp.com> > > --- > > Change in v5: > > - Update commit message, add decription of walk through all wakeup > > source objects. > > - Add SCU protection in function wakeup_source_get_next(). > > - Rename wakeup_source member 'attached_dev' to 'dev' and move it > up > > (before wakeirq). > > > > Change in v4: > > - None. > > > > Change in v3: > > - Adjust indentation of *attached_dev;. > > > > Change in v2: > > - None. > > > > drivers/base/power/wakeup.c | 24 ++++++++++++++++++++++++ > > include/linux/pm_wakeup.h | 3 +++ > > 2 files changed, 27 insertions(+) > > > > diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c > > index ee31d4f..2fba891 100644 > > --- a/drivers/base/power/wakeup.c > > +++ b/drivers/base/power/wakeup.c > > @@ -14,6 +14,7 @@ > > #include <linux/suspend.h> > > #include <linux/seq_file.h> > > #include <linux/debugfs.h> > > +#include <linux/of_device.h> > > #include <linux/pm_wakeirq.h> > > #include <trace/events/power.h> > > > > @@ -226,6 +227,28 @@ void wakeup_source_unregister(struct > wakeup_source *ws) > > } > > } > > EXPORT_SYMBOL_GPL(wakeup_source_unregister); > > +/** > > + * wakeup_source_get_next - Get next wakeup source from the list > > + * @ws: Previous wakeup source object, null means caller want first one. > > + */ > > +struct wakeup_source *wakeup_source_get_next(struct wakeup_source > > +*ws) { > > + struct list_head *ws_head = &wakeup_sources; > > + struct wakeup_source *next_ws = NULL; > > + int idx; > > + > > + idx = srcu_read_lock(&wakeup_srcu); > > + if (ws) > > + next_ws = list_next_or_null_rcu(ws_head, &ws->entry, > > + struct wakeup_source, entry); > > + else > > + next_ws = list_entry_rcu(ws_head->next, > > + struct wakeup_source, entry); > > + srcu_read_unlock(&wakeup_srcu, idx); > > + > > This is incorrect. > > The SRCU cannot be unlocked until the caller of this is done with the object > returned by it, or that object can be freed while it is still being accessed.
Thanks for the comment. Looks like I was not fully understanding your point on v4 discussion. So I will implement 3 APIs by referring wakeup_sources_stats_seq_start/next/stop() > Besides, this patch conflicts with some general wakeup sources changes in the > works, so it needs to be deferred and rebased on top of those changes. Could you please tell me which is the right code base I should developing on? I just tried applying v5 patch on latest git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git branch master (d1abaeb Linux 5.3-rc5) and no conflict encountered. Thanks & Regards, Ran