diff options
Diffstat (limited to 'fs/file_table.c')
-rw-r--r-- | fs/file_table.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/fs/file_table.c b/fs/file_table.c index 5c7d10ead4ad..edecd36fed9b 100644 --- a/fs/file_table.c +++ b/fs/file_table.c | |||
@@ -289,11 +289,20 @@ struct file *fget(unsigned int fd) | |||
289 | EXPORT_SYMBOL(fget); | 289 | EXPORT_SYMBOL(fget); |
290 | 290 | ||
291 | /* | 291 | /* |
292 | * Lightweight file lookup - no refcnt increment if fd table isn't shared. | 292 | * Lightweight file lookup - no refcnt increment if fd table isn't shared. |
293 | * You can use this only if it is guranteed that the current task already | 293 | * |
294 | * holds a refcnt to that file. That check has to be done at fget() only | 294 | * You can use this instead of fget if you satisfy all of the following |
295 | * and a flag is returned to be passed to the corresponding fput_light(). | 295 | * conditions: |
296 | * There must not be a cloning between an fget_light/fput_light pair. | 296 | * 1) You must call fput_light before exiting the syscall and returning control |
297 | * to userspace (i.e. you cannot remember the returned struct file * after | ||
298 | * returning to userspace). | ||
299 | * 2) You must not call filp_close on the returned struct file * in between | ||
300 | * calls to fget_light and fput_light. | ||
301 | * 3) You must not clone the current task in between the calls to fget_light | ||
302 | * and fput_light. | ||
303 | * | ||
304 | * The fput_needed flag returned by fget_light should be passed to the | ||
305 | * corresponding fput_light. | ||
297 | */ | 306 | */ |
298 | struct file *fget_light(unsigned int fd, int *fput_needed) | 307 | struct file *fget_light(unsigned int fd, int *fput_needed) |
299 | { | 308 | { |