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Received: from [50.53.2.24] (helo=[192.168.254.17]) by casper.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1tJlQM-0000000FMX3-1bIG; Sat, 07 Dec 2024 03:24:08 +0000 Message-ID: <9baeaab7-61d8-4121-8aa5-cf1c129daa40@infradead.org> Date: Fri, 6 Dec 2024 19:23:59 -0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 6/6] docs/mm: document latest changes to vm_lock To: Suren Baghdasaryan , akpm@linux-foundation.org Cc: willy@infradead.org, liam.howlett@oracle.com, lorenzo.stoakes@oracle.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mjguzik@gmail.com, oliver.sang@intel.com, mgorman@techsingularity.net, david@redhat.com, peterx@redhat.com, oleg@redhat.com, dave@stgolabs.net, paulmck@kernel.org, brauner@kernel.org, dhowells@redhat.com, hdanton@sina.com, hughd@google.com, minchan@google.com, jannh@google.com, shakeel.butt@linux.dev, souravpanda@google.com, pasha.tatashin@soleen.com, corbet@lwn.net, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@android.com References: <20241206225204.4008261-1-surenb@google.com> <20241206225204.4008261-7-surenb@google.com> Content-Language: en-US From: Randy Dunlap In-Reply-To: <20241206225204.4008261-7-surenb@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 61A6740013 X-Stat-Signature: ppupog79j66qfkexrqrg446i81p6jyed X-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1733541855-522338 X-HE-Meta: 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 NYtA38DE si5OlEKkKNuyU3QF0dbewZCurXfJMr5qqoK58XgvSbTYlaZvqmUc1UH42Mcz1Mepq0VTwDQqNN1xpuBa65Ux0eQiXpxoUBQnqxqKfQ9PTTIi/E+s8kjZ0KBzb1wwQ4kYEYmCF115/qA2lwuGRK8+ipCnF28ylmy4L4gufali81kN3/VoVGl9kqNzb4JTObYBQfl2vILBMRZoKrNd/efe/29aKmwov4V8JJdWU/vlJZqXVOTjq5Y+r1k1lxitTE2zA7kuTesG5hAB0vMWrEJ2rnDHHAxt3XiZjqnW+3BaZ0Bctv/Tqv3zmi7v+prXY+4tBDK3kMd2v2/V3E8NPHDdwQmKa0A== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi, Can someone explain what the (consistent) usage of '!' does in this file? This is the only file in Documentation/ that uses this syntax. E.g.: > diff --git a/Documentation/mm/process_addrs.rst b/Documentation/mm/process_addrs.rst > index 81417fa2ed20..92cf497a9e3c 100644 > --- a/Documentation/mm/process_addrs.rst > +++ b/Documentation/mm/process_addrs.rst > @@ -716,7 +716,11 @@ calls :c:func:`!rcu_read_lock` to ensure that the VMA is looked up in an RCU > critical section, then attempts to VMA lock it via :c:func:`!vma_start_read`, > before releasing the RCU lock via :c:func:`!rcu_read_unlock`. > > -VMA read locks hold the read lock on the :c:member:`!vma->vm_lock` semaphore for > +In cases when the user already holds mmap read lock, :c:func:`!vma_start_read_locked` > +and :c:func:`!vma_start_read_locked_nested` can be used. These functions always > +succeed in acquiring VMA read lock. thanks. -- ~Randy