include/linux/file.h

   1 /*
   2  * Wrapper functions for accessing the file_struct fd array.
   3  */
   4
   5 #ifndef __LINUX_FILE_H
   6 #define __LINUX_FILE_H
   7
   8 extern void __fput(struct file *);
   9
  10 /*
  11  * Check whether the specified task has the fd open. Since the task
  12  * may not have a files_struct, we must test for p->files != NULL.
  13  */
  14 extern inline struct file * fcheck_task(struct task_struct *p, unsigned int fd)
  15 {
  16         struct file * file = NULL;
  17
  18         if (p->files && fd < p->files->max_fds)
  19                 file = p->files->fd[fd];
  20         return file;
  21 }
  22
  23 /*
  24  * Check whether the specified fd has an open file.
  25  */
  26 extern inline struct file * fcheck(unsigned int fd)
  27 {
  28         struct file * file = NULL;
  29
  30         if (fd < current->files->max_fds)
  31                 file = current->files->fd[fd];
  32         return file;
  33 }
  34
  35 extern inline struct file * fget(unsigned int fd)
  36 {
  37         struct file * file = fcheck(fd);
  38
  39         if (file)
  40                 file->f_count++;
  41         return file;
  42 }
  43
  44 /*
  45  * Install a file pointer in the fd array.
  46  */
  47 extern inline void fd_install(unsigned int fd, struct file * file)
  48 {
  49         current->files->fd[fd] = file;
  50 }
  51
  52 /*
  53  * 23/12/1998 Marcin Dalecki <dalecki@cs.net.pl>:
  54  *
  55  * Since those functions where calling other functions, it was compleatly
  56  * bogous to make them all "extern inline".
  57  *
  58  * The removal of this pseudo optimization saved me scandaleous:
  59  *
  60  *              3756 (i386 arch)
  61  *
  62  * precious bytes from my kernel, even without counting all the code compiled
  63  * as module!
  64  *
  65  * I suspect there are many other similar "optimizations" across the
  66  * kernel...
  67  */
  68 extern void fput(struct file *);
  69 extern void put_filp(struct file *);
  70
  71 #endif /* __LINUX_FILE_H */