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AJvYcCUm2NQ/keQL0k1FOxTlwgnJwJlpjfN8bwQ2GCER3J8DRAZHTATNsmBCJzDT8csU+4F6fRrGPoPxNQ==@kvack.org X-Gm-Message-State: AOJu0Yw6T0f1cdLQuj6MEi1ofgerjgArv2Rgr+H/quHsPnNyuiTRiuDz Or+xkky0tIrGhQ5YEosxrNE/ciJpVzJmmtjVkZfU4MXD8wtsj2dYlOZ5+lPrGceN9lN5g17M0SG SkbUUd/qfPxy6/7q7Q4tmlKCcMGmuWbeAq1iG X-Gm-Gg: ASbGncsimOBEVdKWNhHd7LNnQMEHCNNiQN8ET9xwOyb+o3DGWmQmWrHYXVVcGr4vSBJ +HtYVOWAVqZpNLwed6BcNeALdyHJrWvc= X-Google-Smtp-Source: AGHT+IF3WJ8kN8Ix9U0Qnr/PX5i4gdPvUR5eenqNxqgXSzETlC2SUkrWRpzKenUtPrjZAw3s3C92n+OXtqfTezUq44Y= X-Received: by 2002:a05:622a:909:b0:466:91fd:74c4 with SMTP id d75a77b69052e-46746d6677emr3351631cf.0.1733592847299; Sat, 07 Dec 2024 09:34:07 -0800 (PST) MIME-Version: 1.0 References: <9baeaab7-61d8-4121-8aa5-cf1c129daa40@infradead.org> In-Reply-To: From: Suren Baghdasaryan Date: Sat, 7 Dec 2024 09:33:56 -0800 Message-ID: Subject: Re: [PATCH v5 6/6] docs/mm: document latest changes to vm_lock To: Akira Yokosawa , lorenzo.stoakes@oracle.com Cc: rdunlap@infradead.org, akpm@linux-foundation.org, brauner@kernel.org, corbet@lwn.net, dave@stgolabs.net, david@redhat.com, dhowells@redhat.com, hannes@cmpxchg.org, hdanton@sina.com, hughd@google.com, jannh@google.com, kernel-team@android.com, liam.howlett@oracle.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mgorman@techsingularity.net, mhocko@suse.com, minchan@google.com, mjguzik@gmail.com, oleg@redhat.com, oliver.sang@intel.com, pasha.tatashin@soleen.com, paulmck@kernel.org, peterx@redhat.com, shakeel.butt@linux.dev, souravpanda@google.com, vbabka@suse.cz, willy@infradead.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: tr9dkua83qzrz9jchgm3udwgmjc691e4 X-Rspamd-Queue-Id: C34211A0011 X-Rspam-User: X-Rspamd-Server: rspam01 X-HE-Tag: 1733592828-481600 X-HE-Meta: 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 rS+qg++D hWRYAg6QdBEOz7ZA2o/CJfHJvTUG6adp2/BJomAdtcfSkA1UIdy+0f8IT6efifTxH0/qNGHeA4PdoQldCGCMAL2osLljD7kT5XMHpgg1jE1mzyKSC8mqQkhpg6qXhD0/SNIFK4eT/s7SBjtyQ1vIWwAiXJ3tHsEna1YUqX1vtRXcDp+2b3ZxugI9dPfyr9JekJUEJg/McOEaKwUXjAfffGpTVwOOvU/c8k7BqfvIE4ij6qfXK8leuqqXmCn10W0Gp1lVbt2M5jdIYP+QaSC6ESemK/ExdJeLHAafkkExHLbwDIgeUqbXbnfc5rHvOUWrzQLx8vIzqVHFh8yQwVP/zAptgf/e5wQjFRqcomRY9Qh6s8zEuv/atuvpLbg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000452, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Dec 6, 2024 at 8:24=E2=80=AFPM Akira Yokosawa wr= ote: > > On Fri, 6 Dec 2024 19:23:59 -0800, Randy Dunlap wrote: > > Hi, > > > > Can someone explain what the (consistent) usage of '!' does in this fil= e? > > This is the only file in Documentation/ that uses this syntax. > > > > > > E.g.: > > > >> diff --git a/Documentation/mm/process_addrs.rst b/Documentation/mm/pro= cess_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_star= t_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` se= maphore for > >> +In cases when the user already holds mmap read lock, :c:func:`!vma_st= art_read_locked` > >> +and :c:func:`!vma_start_read_locked_nested` can be used. These functi= ons always > >> +succeed in acquiring VMA read lock. > > > > Quoting from https://www.sphinx-doc.org/en/master/usage/referencing.html#= syntax > > * Suppressed link: Prefixing with an exclamation mark (!) prevents the > creation of a link but otherwise keeps the visual output of the role. > > For example, writing :py:func:`!target` displays target(), with no li= nk > generated. > > This is helpful for cases in which the link target does not exist; e.= g. > changelog entries that describe removed functionality, or third-party > libraries that don=E2=80=99t support intersphinx. Suppressing the lin= k prevents > warnings in nitpicky mode. > > But in kernel documentation, there is a preferred alternative. > Referencing by function names is the way to go. For example: > > calls rcu_read_lock() to ensure that the VMA is looked up in an RCU > critical section, then attempts to VMA lock it via vma_start_read(), > before releasing the RCU lock via rcu_read_unlock(). > > In cases when the user already holds mmap read lock, vma_start_read_loc= ked() > and vma_start_read_locked_nested() can be used. These functions always > succeed in acquiring VMA read lock. > > They work regardless of link target's existence. > Kernel-specific Sphinx extension named "automarkup" does conversions > for you. Thanks for the information. I was simply following the same style the document was written in. Sounds like converting it to the preferred alternative in a separate patch would be best. Lorenzo, WDYT? > > HTH, Akira > > > thanks. > > -- > > ~Randy >