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Date: Fri, 16 Jan 2026 16:12:15 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	David Hildenbrand <david@kernel.org>,
	"Liam R . Howlett" <Liam.Howlett@oracle.com>,
	Vlastimil Babka <vbabka@suse.cz>, Mike Rapoport <rppt@kernel.org>,
	Suren Baghdasaryan <surenb@google.com>,
	Michal Hocko <mhocko@suse.com>,
	Shakeel Butt <shakeel.butt@linux.dev>, Jann Horn <jannh@google.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	linux-rt-devel@lists.linux.dev, Ingo Molnar <mingo@redhat.com>,
	Will Deacon <will@kernel.org>, Boqun Feng <boqun.feng@gmail.com>,
	Waiman Long <longman@redhat.com>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Clark Williams <clrkwllms@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH RESEND 1/3] locking: add rwsem_is_write_locked(), update
 non-lockdep asserts
Message-ID: <20260116151215.GH831050@noisy.programming.kicks-ass.net>
References: <cover.1768569863.git.lorenzo.stoakes@oracle.com>
 <8e343ccb9319433364f5949a69519f1bb521fc8a.1768569863.git.lorenzo.stoakes@oracle.com>
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In-Reply-To: <8e343ccb9319433364f5949a69519f1bb521fc8a.1768569863.git.lorenzo.stoakes@oracle.com>

On Fri, Jan 16, 2026 at 01:36:45PM +0000, Lorenzo Stoakes wrote:
> As part of adding some additional lock asserts in mm, we wish to be able to
> determine if a read/write semaphore is write-locked, so add
> rwsem_is_write_locked() to do the write-lock equivalent of
> rwsem_is_locked().
> 
> While we're here, update rwsem_assert_[write_]held_nolockdep() to utilise
> the rwsem_is_[write_]locked() helpers directly to reduce code duplication,
> and also update rwsem_is_locked() to take a const rwsem and return a
> boolean.

There is a long history of abuse of _is_locked() primitives. I don't
suppose you read the email thread that led to
rwsem_assert_held_*_nolockdep() by any chance?