linux-kernel - Re: [PATCH 00/13] Rename k[v]free_rcu() single argument to k[v]free_rcu

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Date:   Thu, 23 Feb 2023 07:57:13 -0700
From:   Jens Axboe <axboe@...nel.dk>
To:     "Uladzislau Rezki (Sony)" <urezki@...il.com>,
        LKML <linux-kernel@...r.kernel.org>, RCU <rcu@...r.kernel.org>,
        "Paul E . McKenney" <paulmck@...nel.org>
Cc:     Oleksiy Avramchenko <oleksiy.avramchenko@...y.com>,
        Philipp Reisner <philipp.reisner@...bit.com>,
        Bryan Tan <bryantan@...are.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Eric Dumazet <edumazet@...gle.com>,
        Bob Pearson <rpearsonhpe@...il.com>,
        Ariel Levkovich <lariel@...dia.com>,
        Theodore Ts'o <tytso@....edu>, Julian Anastasov <ja@....bg>
Subject: Re: [PATCH 00/13] Rename k[v]free_rcu() single argument to
 k[v]free_rcu_mightsleep()

On 2/1/23 8:08 AM, Uladzislau Rezki (Sony) wrote:
> This small series is based on Paul's "dev" branch. Head is 6002817348a1c610dc1b1c01ff81654cdec12be4
> it renames a single argument of k[v]free_rcu() to its new k[v]free_rcu_mightsleep() name.
> 
> 1.
> The problem is that, recently we have run into a precedent when
> a user intended to give a second argument to kfree_rcu() API but
> forgot to do it in a code so a call became as a single argument
> of kfree_rcu() API.
> 
> 2.
> Such mistyping can lead to hidden bags where sleeping is forbidden.
> 
> 3.
> _mightsleep() prefix gives much more information for which contexts
> it can be used for.

This patchset seems weird to me. We have a LOT of calls that might
sleep, yet we don't suffix them all with _mightsleep(). Why is this
any different? Why isn't this just a might_sleep() call in the
actual helper, which will suffice for checkers and catch it at
runtime as well.

-- 
Jens Axboe