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 extern void insert_file_free(struct file *file);
  10
  11 /*
  12  * Check whether the specified task has the fd open. Since the task
  13  * may not have a files_struct, we must test for p->files != NULL.
  14  */
  15 extern inline struct file * fcheck_task(struct task_struct *p, unsigned int fd)
  16 {
  17         struct file * file = NULL;
  18
  19         if (p->files && fd < p->files->max_fds)
  20                 file = p->files->fd[fd];
  21         return file;
  22 }
  23
  24 /*
  25  * Check whether the specified fd has an open file.
  26  */
  27 extern inline struct file * fcheck(unsigned int fd)
  28 {
  29         struct file * file = NULL;
  30
  31         if (fd < current->files->max_fds)
  32                 file = current->files->fd[fd];
  33         return file;
  34 }
  35
  36 extern inline struct file * fget(unsigned int fd)
  37 {
  38         struct file * file = fcheck(fd);
  39
  40         if (file)
  41                 file->f_count++;
  42         return file;
  43 }
  44
  45 /*
  46  * Install a file pointer in the fd array.
  47  */
  48 extern inline void fd_install(unsigned int fd, struct file *file)
  49 {
  50         current->files->fd[fd] = file;
  51 }
  52
  53 /* It does not matter which list it is on. */
  54 extern inline void remove_filp(struct file *file)
  55 {
  56         if(file->f_next)
  57                 file->f_next->f_pprev = file->f_pprev;
  58         *file->f_pprev = file->f_next;
  59 }
  60
  61 extern inline void fput(struct file *file)
  62 {
  63         int count = file->f_count-1;
  64
  65         if (!count) {
  66                 locks_remove_flock(file);
  67                 __fput(file);
  68                 file->f_count = 0;
  69                 remove_filp(file);
  70                 insert_file_free(file);
  71         } else
  72                 file->f_count = count;
  73 }
  74
  75 extern inline void put_filp(struct file *file)
  76 {
  77         if(--file->f_count == 0) {
  78                 remove_filp(file);
  79                 insert_file_free(file);
  80         }
  81 }
  82
  83 #endif