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([2001:288:7001:2703:d6db:3ccc:88ed:bd6c]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2ef2705d42dsm1032243a91.8.2024.12.04.01.23.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Dec 2024 01:23:35 -0800 (PST) From: I Hsin Cheng To: viro@zeniv.linux.org.uk Cc: brauner@kernel.org, jack@suse.cz, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, I Hsin Cheng Subject: [RFC PATCH] file: Wrap locking mechanism for f_pos_lock Date: Wed, 4 Dec 2024 17:23:25 +0800 Message-ID: <20241204092325.170349-1-richard120310@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 As the implementation of "f->f_pos_lock" may change in the future, wrapping the actual implementation of locking and unlocking of it can provide better decoupling semantics. "__f_unlock_pos()" already exist and does that, adding "__f_lock_pos()" can provide full decoupling. Signed-off-by: I Hsin Cheng --- fs/file.c | 7 ++++++- include/linux/file.h | 1 + 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/file.c b/fs/file.c index fb1011cf6b4a..b93ac67d276d 100644 --- a/fs/file.c +++ b/fs/file.c @@ -1181,6 +1181,11 @@ static inline bool file_needs_f_pos_lock(struct file *file) (file_count(file) > 1 || file->f_op->iterate_shared); } +void __f_lock_pos(struct file *f) +{ + mutex_lock(&f->f_pos_lock); +} + struct fd fdget_pos(unsigned int fd) { struct fd f = fdget(fd); @@ -1188,7 +1193,7 @@ struct fd fdget_pos(unsigned int fd) if (file && file_needs_f_pos_lock(file)) { f.word |= FDPUT_POS_UNLOCK; - mutex_lock(&file->f_pos_lock); + __f_lock_pos(file); } return f; } diff --git a/include/linux/file.h b/include/linux/file.h index 302f11355b10..16292bd95499 100644 --- a/include/linux/file.h +++ b/include/linux/file.h @@ -67,6 +67,7 @@ extern struct file *fget(unsigned int fd); extern struct file *fget_raw(unsigned int fd); extern struct file *fget_task(struct task_struct *task, unsigned int fd); extern struct file *fget_task_next(struct task_struct *task, unsigned int *fd); +extern void __f_lock_pos(struct file *file); extern void __f_unlock_pos(struct file *); struct fd fdget(unsigned int fd);