fs/aufs/wkq.h

   1 /*
   2  * Copyright (C) 2005-2016 Junjiro R. Okajima
   3  *
   4  * This program, aufs is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 /*
  19  * workqueue for asynchronous/super-io operations
  20  * todo: try new credentials management scheme
  21  */
  22
  23 #ifndef __AUFS_WKQ_H__
  24 #define __AUFS_WKQ_H__
  25
  26 #ifdef __KERNEL__
  27
  28 #include <linux/percpu_counter.h>
  29
  30 struct super_block;
  31
  32 /* ---------------------------------------------------------------------- */
  33
  34 /*
  35  * in the next operation, wait for the 'nowait' tasks in system-wide workqueue
  36  */
  37 struct au_nowait_tasks {
  38         atomic_t                nw_len;
  39         wait_queue_head_t       nw_wq;
  40 };
  41
  42 /* ---------------------------------------------------------------------- */
  43
  44 typedef void (*au_wkq_func_t)(void *args);
  45
  46 /* wkq flags */
  47 #define AuWkq_WAIT      1
  48 #define AuWkq_NEST      (1 << 1)
  49 #define au_ftest_wkq(flags, name)       ((flags) & AuWkq_##name)
  50 #define au_fset_wkq(flags, name) \
  51         do { (flags) |= AuWkq_##name; } while (0)
  52 #define au_fclr_wkq(flags, name) \
  53         do { (flags) &= ~AuWkq_##name; } while (0)
  54
  55 #ifndef CONFIG_AUFS_HNOTIFY
  56 #undef AuWkq_NEST
  57 #define AuWkq_NEST      0
  58 #endif
  59
  60 /* wkq.c */
  61 int au_wkq_do_wait(unsigned int flags, au_wkq_func_t func, void *args);
  62 int au_wkq_nowait(au_wkq_func_t func, void *args, struct super_block *sb,
  63                   unsigned int flags);
  64 void au_nwt_init(struct au_nowait_tasks *nwt);
  65 int __init au_wkq_init(void);
  66 void au_wkq_fin(void);
  67
  68 /* ---------------------------------------------------------------------- */
  69
  70 static inline int au_wkq_test(void)
  71 {
  72         return current->flags & PF_WQ_WORKER;
  73 }
  74
  75 static inline int au_wkq_wait(au_wkq_func_t func, void *args)
  76 {
  77         return au_wkq_do_wait(AuWkq_WAIT, func, args);
  78 }
  79
  80 static inline void au_nwt_done(struct au_nowait_tasks *nwt)
  81 {
  82         if (atomic_dec_and_test(&nwt->nw_len))
  83                 wake_up_all(&nwt->nw_wq);
  84 }
  85
  86 static inline int au_nwt_flush(struct au_nowait_tasks *nwt)
  87 {
  88         wait_event(nwt->nw_wq, !atomic_read(&nwt->nw_len));
  89         return 0;
  90 }
  91
  92 #endif /* __KERNEL__ */
  93 #endif /* __AUFS_WKQ_H__ */