On Thu, Feb 02, 2023 at 07:54:31AM +0000, Zhuo, Qiuxu wrote:
> > From: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
> > Sent: Wednesday, February 1, 2023 11:08 PM
> > To: LKML <linux-kernel@xxxxxxxxxxxxxxx>; RCU <rcu@xxxxxxxxxxxxxxx>; Paul E .
> > McKenney <paulmck@xxxxxxxxxx>
> > Cc: Uladzislau Rezki <urezki@xxxxxxxxx>; Oleksiy Avramchenko
> > <oleksiy.avramchenko@xxxxxxxx>; Jens Axboe <axboe@xxxxxxxxx>; Philipp
> > Reisner <philipp.reisner@xxxxxxxxxx>; Bryan Tan <bryantan@xxxxxxxxxx>;
> > Steven Rostedt <rostedt@xxxxxxxxxxx>; Eric Dumazet
> > <edumazet@xxxxxxxxxx>; Bob Pearson <rpearsonhpe@xxxxxxxxx>; Ariel
> > Levkovich <lariel@xxxxxxxxxx>; Theodore Ts'o <tytso@xxxxxxx>; Julian
> > Anastasov <ja@xxxxxx>
> > Subject: [PATCH 01/13] rcu/kvfree: Add kvfree_rcu_mightsleep() and
> > kfree_rcu_mightsleep()
> >
> > These two macroses will replace single-argument k[v]free_rcu() ones.
> > By adding an extra _mightsleep prefix we can avoid of situations when someone
>
> s/prefix/suffix
Good eyes, thank you!
Please see below for the version currently queued in the -rcu tree.
Thanx, Paul
> > intended to give a second argument but forgot to do it in a code where sleeping
> > is illegal.
> >
> > Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
> > ...
------------------------------------------------------------------------
commit d6b54a44de23c83944d042b6f6fd9d19ccd3f1b8
Author: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Date: Wed Feb 1 16:08:07 2023 +0100
rcu/kvfree: Add kvfree_rcu_mightsleep() and kfree_rcu_mightsleep()
The kvfree_rcu() and kfree_rcu() APIs are hazardous in that if you forget
the second argument, it works, but might sleep. This sleeping can be a
correctness bug from atomic contexts, and even in non-atomic contexts
it might introduce unacceptable latencies. This commit therefore adds
kvfree_rcu_mightsleep() and kfree_rcu_mightsleep(), which will replace
the single-argument kvfree_rcu() and kfree_rcu(), respectively.
This commit enables a series of commits that switch from single-argument
kvfree_rcu() and kfree_rcu() to their _mightsleep() counterparts. Once
all of these commits land, the single-argument versions will be removed.
Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 822ff7b4bb1ed..094321c17e48a 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -1013,6 +1013,9 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
#define kvfree_rcu(...) KVFREE_GET_MACRO(__VA_ARGS__, \
kvfree_rcu_arg_2, kvfree_rcu_arg_1)(__VA_ARGS__)
+#define kvfree_rcu_mightsleep(ptr) kvfree_rcu_arg_1(ptr)
+#define kfree_rcu_mightsleep(ptr) kvfree_rcu_mightsleep(ptr)
+
#define KVFREE_GET_MACRO(_1, _2, NAME, ...) NAME
#define kvfree_rcu_arg_2(ptr, rhf) \
do { \
