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From: "Eric W. Biederman" <ebiederm@xmission.com>
To: linux-kernel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, criu@openvz.org,
	bpf@vger.kernel.org,
	"Linus Torvalds" <torvalds@linux-foundation.org>,
	"Alexander Viro" <viro@zeniv.linux.org.uk>,
	"Christian Brauner" <christian.brauner@ubuntu.com>,
	"Oleg Nesterov" <oleg@redhat.com>,
	"Cyrill Gorcunov" <gorcunov@gmail.com>,
	"Jann Horn" <jann@thejh.net>, "Kees Cook" <keescook@chromium.org>,
	"Daniel P . Berrangé" <berrange@redhat.com>,
	"Jeff Layton" <jlayton@redhat.com>,
	"Miklos Szeredi" <miklos@szeredi.hu>,
	"Matthew Wilcox" <willy@infradead.org>,
	"J. Bruce Fields" <bfields@fieldses.org>,
	"Trond Myklebust" <trond.myklebust@hammerspace.com>,
	"Chris Wright" <chrisw@redhat.com>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Martin KaFai Lau" <kafai@fb.com>,
	"Song Liu" <songliubraving@fb.com>, "Yonghong Song" <yhs@fb.com>,
	"Andrii Nakryiko" <andriin@fb.com>,
	"John Fastabend" <john.fastabend@gmail.com>,
	"KP Singh" <kpsingh@chromium.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>
Subject: [PATCH v2 10/24] file: Rename fcheck lookup_fd_rcu
Date: Fri, 20 Nov 2020 17:14:27 -0600	[thread overview]
Message-ID: <20201120231441.29911-10-ebiederm@xmission.com> (raw)
In-Reply-To: <87r1on1v62.fsf@x220.int.ebiederm.org>

Also remove the confusing comment about checking if a fd exists.  I
could not find one instance in the entire kernel that still matches
the description or the reason for the name fcheck.

The need for better names became apparent in the last round of
discussion of this set of changes[1].

[1] https://lkml.kernel.org/r/CAHk-=wj8BQbgJFLa+J0e=iT-1qpmCRTbPAJ8gd6MJQ=kbRPqyQ@mail.gmail.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 Documentation/filesystems/files.rst          | 6 +++---
 arch/powerpc/platforms/cell/spufs/coredump.c | 2 +-
 fs/notify/dnotify/dnotify.c                  | 2 +-
 include/linux/fdtable.h                      | 8 ++++----
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/Documentation/filesystems/files.rst b/Documentation/filesystems/files.rst
index ea75acdb632c..bcf84459917f 100644
--- a/Documentation/filesystems/files.rst
+++ b/Documentation/filesystems/files.rst
@@ -62,7 +62,7 @@ the fdtable structure -
    be held.
 
 4. To look up the file structure given an fd, a reader
-   must use either fcheck() or files_lookup_fd_rcu() APIs. These
+   must use either lookup_fd_rcu() or files_lookup_fd_rcu() APIs. These
    take care of barrier requirements due to lock-free lookup.
 
    An example::
@@ -70,7 +70,7 @@ the fdtable structure -
 	struct file *file;
 
 	rcu_read_lock();
-	file = fcheck(fd);
+	file = lookup_fd_rcu(fd);
 	if (file) {
 		...
 	}
@@ -104,7 +104,7 @@ the fdtable structure -
    lock-free, they must be installed using rcu_assign_pointer()
    API. If they are looked up lock-free, rcu_dereference()
    must be used. However it is advisable to use files_fdtable()
-   and fcheck()/files_lookup_fd_rcu() which take care of these issues.
+   and lookup_fd_rcu()/files_lookup_fd_rcu() which take care of these issues.
 
 7. While updating, the fdtable pointer must be looked up while
    holding files->file_lock. If ->file_lock is dropped, then
diff --git a/arch/powerpc/platforms/cell/spufs/coredump.c b/arch/powerpc/platforms/cell/spufs/coredump.c
index 026c181a98c5..60b5583e9eaf 100644
--- a/arch/powerpc/platforms/cell/spufs/coredump.c
+++ b/arch/powerpc/platforms/cell/spufs/coredump.c
@@ -74,7 +74,7 @@ static struct spu_context *coredump_next_context(int *fd)
 	*fd = n - 1;
 
 	rcu_read_lock();
-	file = fcheck(*fd);
+	file = lookup_fd_rcu(*fd);
 	ctx = SPUFS_I(file_inode(file))->i_ctx;
 	get_spu_context(ctx);
 	rcu_read_unlock();
diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c
index 5dcda8f20c04..5486aaca60b0 100644
--- a/fs/notify/dnotify/dnotify.c
+++ b/fs/notify/dnotify/dnotify.c
@@ -327,7 +327,7 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg)
 	}
 
 	rcu_read_lock();
-	f = fcheck(fd);
+	f = lookup_fd_rcu(fd);
 	rcu_read_unlock();
 
 	/* if (f != filp) means that we lost a race and another task/thread
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
index fa8c402a7790..2a4a8fed536e 100644
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -105,10 +105,10 @@ static inline struct file *files_lookup_fd_rcu(struct files_struct *files, unsig
 	return files_lookup_fd_raw(files, fd);
 }
 
-/*
- * Check whether the specified fd has an open file.
- */
-#define fcheck(fd)	files_lookup_fd_rcu(current->files, fd)
+static inline struct file *lookup_fd_rcu(unsigned int fd)
+{
+	return files_lookup_fd_rcu(current->files, fd);
+}
 
 struct task_struct;
 
-- 
2.25.0


  parent reply	other threads:[~2020-11-20 23:17 UTC|newest]

Thread overview: 77+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <87r1on1v62.fsf@x220.int.ebiederm.org>
2020-11-20 23:14 ` [PATCH v2 01/24] exec: Move unshare_files to fix posix file locking during exec Eric W. Biederman
2020-11-20 23:58   ` Linus Torvalds
2020-12-07 22:22   ` Al Viro
     [not found]     ` <87zh2pusdw.fsf@x220.int.ebiederm.org>
2020-12-07 23:35       ` Al Viro
2020-11-20 23:14 ` [PATCH v2 02/24] exec: Simplify unshare_files Eric W. Biederman
2020-11-23 17:50   ` Oleg Nesterov
2020-11-23 18:25     ` Linus Torvalds
     [not found]       ` <87im9vx08i.fsf@x220.int.ebiederm.org>
     [not found]         ` <87pn42r0n7.fsf@x220.int.ebiederm.org>
2020-11-24 19:58           ` Linus Torvalds
2020-11-24 20:14             ` Arnd Bergmann
2020-11-24 23:44               ` Geoff Levand
2020-11-25  1:16                 ` Eric W. Biederman
2020-11-27 20:29                   ` Arnd Bergmann
2020-11-30 21:37                     ` Eric W. Biederman
2020-12-01  9:46                     ` Michael Ellerman
2020-11-25 21:51                 ` [RFC][PATCH] coredump: Document coredump code exclusively used by cell spufs Eric W. Biederman
2020-12-02 15:20                   ` Eric W. Biederman
2020-12-02 15:58                     ` Arnd Bergmann
2020-12-07 22:32       ` [PATCH v2 02/24] exec: Simplify unshare_files Al Viro
2020-11-20 23:14 ` [PATCH v2 03/24] exec: Remove reset_files_struct Eric W. Biederman
2020-11-20 23:14 ` [PATCH v2 04/24] kcmp: In kcmp_epoll_target use fget_task Eric W. Biederman
2020-11-20 23:14 ` [PATCH v2 05/24] bpf: In bpf_task_fd_query " Eric W. Biederman
2020-11-20 23:14 ` [PATCH v2 06/24] proc/fd: In proc_fd_link " Eric W. Biederman
2020-11-20 23:14 ` [PATCH v2 07/24] file: Rename __fcheck_files to files_lookup_fd_raw Eric W. Biederman
2020-11-20 23:14 ` [PATCH v2 08/24] file: Factor files_lookup_fd_locked out of fcheck_files Eric W. Biederman
2020-11-20 23:14 ` [PATCH v2 09/24] file: Replace fcheck_files with files_lookup_fd_rcu Eric W. Biederman
2020-12-07 22:46   ` Al Viro
2020-12-07 22:49     ` Al Viro
2020-12-09 16:54       ` Al Viro
2020-12-09 17:44         ` Paul E. McKenney
2020-11-20 23:14 ` Eric W. Biederman [this message]
2020-11-20 23:14 ` [PATCH v2 11/24] file: Implement task_lookup_fd_rcu Eric W. Biederman
2020-11-21 18:19   ` Cyrill Gorcunov
     [not found]     ` <87blfp1r8b.fsf@x220.int.ebiederm.org>
2020-11-22 13:52       ` Cyrill Gorcunov
2020-11-20 23:14 ` [PATCH v2 12/24] proc/fd: In tid_fd_mode use task_lookup_fd_rcu Eric W. Biederman
2020-11-20 23:14 ` [PATCH v2 13/24] kcmp: In get_file_raw_ptr " Eric W. Biederman
2020-11-23 21:05   ` Cyrill Gorcunov
2020-11-20 23:14 ` [PATCH v2 14/24] file: Implement task_lookup_next_fd_rcu Eric W. Biederman
2020-11-20 23:14 ` [PATCH v2 15/24] proc/fd: In proc_readfd_common use task_lookup_next_fd_rcu Eric W. Biederman
2020-12-07 23:29   ` Al Viro
     [not found]     ` <877dprvs8e.fsf@x220.int.ebiederm.org>
2020-12-09  4:07       ` Al Viro
     [not found]         ` <877dprtxly.fsf@x220.int.ebiederm.org>
2020-12-09 14:23           ` Al Viro
2020-12-09 18:04             ` [PATCH] files: rcu free files_struct Eric W. Biederman
2020-12-09 19:13               ` Linus Torvalds
2020-12-09 19:50                 ` Al Viro
2020-12-09 21:32                   ` Eric W. Biederman
2020-12-10  6:13                     ` Al Viro
2020-12-10 19:29                       ` Eric W. Biederman
2020-12-10 21:36                         ` Al Viro
2020-12-10 22:30                           ` Christian Brauner
2020-12-10 22:54                             ` Al Viro
2020-12-10 23:10                               ` Al Viro
2020-12-09 21:42                   ` [PATCH -1/24] exec: Don't open code get_close_on_exec Eric W. Biederman
2020-12-09 22:04                 ` [PATCH] files: rcu free files_struct Eric W. Biederman
2020-12-09 19:49               ` Matthew Wilcox
2020-12-09 22:06                 ` Eric W. Biederman
2020-12-09 22:58                 ` Al Viro
2020-12-09 23:01                   ` Linus Torvalds
2020-12-09 23:04                     ` Linus Torvalds
2020-12-09 23:07                     ` Matthew Wilcox
2020-12-09 23:26                       ` Paul E. McKenney
2020-12-09 23:29                       ` Linus Torvalds
2020-12-10  0:39                         ` Paul E. McKenney
2020-12-10  0:41                           ` Linus Torvalds
2020-12-10  0:57                             ` Paul E. McKenney
2020-11-20 23:14 ` [PATCH v2 16/24] bpf/task_iter: In task_file_seq_get_next use task_lookup_next_fd_rcu Eric W. Biederman
2020-11-23 17:06   ` Yonghong Song
2020-11-20 23:14 ` [PATCH v2 17/24] proc/fd: In fdinfo seq_show don't use get_files_struct Eric W. Biederman
2020-11-20 23:14 ` [PATCH v2 18/24] file: Merge __fd_install into fd_install Eric W. Biederman
2020-11-20 23:14 ` [PATCH v2 19/24] file: In f_dupfd read RLIMIT_NOFILE once Eric W. Biederman
2020-11-20 23:14 ` [PATCH v2 20/24] file: Merge __alloc_fd into alloc_fd Eric W. Biederman
2020-11-20 23:14 ` [PATCH v2 21/24] file: Rename __close_fd to close_fd and remove the files parameter Eric W. Biederman
2020-11-20 23:14 ` [PATCH v2 22/24] file: Replace ksys_close with close_fd Eric W. Biederman
2020-11-20 23:14 ` [PATCH v2 23/24] file: Rename __close_fd_get_file close_fd_get_file Eric W. Biederman
2020-11-20 23:14 ` [PATCH v2 24/24] file: Remove get_files_struct Eric W. Biederman
2020-11-21  0:05 ` [PATCH v2 00/24] exec: Move unshare_files and guarantee files_struct.count is correct Linus Torvalds
2020-11-28  5:12   ` Al Viro
2020-12-07 23:56     ` Al Viro

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