This is a note to let you know that I've just added the patch titled
file: Rename fcheck lookup_fd_rcu
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
file-rename-fcheck-lookup_fd_rcu.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f9313dfc75a70fbce10206182f0b11a610dee433
Author: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Date: Fri Nov 20 17:14:27 2020 -0600
file: Rename fcheck lookup_fd_rcu
[ Upstream commit 460b4f812a9d473d4b39d87d37844f9fc30a9eb3 ]
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@xxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20201120231441.29911-10-ebiederm@xxxxxxxxxxxx
Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/Documentation/filesystems/files.rst b/Documentation/filesystems/files.rst
index ea75acdb632c0..bcf84459917f5 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 026c181a98c5d..60b5583e9eafc 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 e45ca6ecba959..e85e13c50d6d4 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 a45fa2ef723f5..695306cc5337a 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;
