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Commit 58939473 authored by Tony Battersby's avatar Tony Battersby Committed by Linus Torvalds
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vfs: improve comment describing fget_light() 



Improve the description of fget_light(), which is currently incorrect
about needing a prior refcnt (judging by the way it is actually used).

Signed-off-by: default avatarTony Battersby <tonyb@cybernetics.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5a19ae4b

fs/file_table.c

+14 −5
Original line number Diff line number Diff line
@@ -299,10 +299,19 @@ EXPORT_SYMBOL(fget); 


/*

 * Lightweight file lookup - no refcnt increment if fd table isn't shared.

 * You can use this only if it is guranteed that the current task already 

 * holds a refcnt to that file. That check has to be done at fget() only

 * and a flag is returned to be passed to the corresponding fput_light().

 * There must not be a cloning between an fget_light/fput_light pair.

 *

 * You can use this instead of fget if you satisfy all of the following

 * conditions:

 * 1) You must call fput_light before exiting the syscall and returning control

 *    to userspace (i.e. you cannot remember the returned struct file * after

 *    returning to userspace).

 * 2) You must not call filp_close on the returned struct file * in between

 *    calls to fget_light and fput_light.

 * 3) You must not clone the current task in between the calls to fget_light

 *    and fput_light.

 *

 * The fput_needed flag returned by fget_light should be passed to the

 * corresponding fput_light.

 */

struct file *fget_light(unsigned int fd, int *fput_needed)

{