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Commit af61b96b authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Ingo Molnar
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vfs: Abstract rcu_dereference_check for files-fdtable use 



Create an rcu_dereference_check_fdtable() that encapsulates the
rcu_dereference_check() condition for fcheck_files() use.  This
has the beneficial side-effect of getting rid of a very long
line.

Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1266887105-1528-9-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 7dc52157

include/linux/fdtable.h

+7 −4
Original line number Diff line number Diff line
@@ -57,11 +57,14 @@ struct files_struct { 
	struct file * fd_array[NR_OPEN_DEFAULT];

};



#define files_fdtable(files) \

	(rcu_dereference_check((files)->fdt, \

#define rcu_dereference_check_fdtable(files, fdtfd) \

	(rcu_dereference_check((fdtfd), \

			       rcu_read_lock_held() || \

			       lockdep_is_held(&(files)->file_lock) || \

			       atomic_read(&files->count) == 1))

			       atomic_read(&(files)->count) == 1))



#define files_fdtable(files) \

		(rcu_dereference_check_fdtable((files), (files)->fdt))



struct file_operations;

struct vfsmount;
@@ -82,7 +85,7 @@ static inline struct file * fcheck_files(struct files_struct *files, unsigned in 
	struct fdtable *fdt = files_fdtable(files);



	if (fd < fdt->max_fds)

		file = rcu_dereference_check(fdt->fd[fd], rcu_read_lock_held() || lockdep_is_held(&files->file_lock) || atomic_read(&files->count) == 1);

		file = rcu_dereference_check_fdtable(files, fdt->fd[fd]);

	return file;

}