fs/aufs/wkq.h

   1 /*
   2  * Copyright (C) 2005-2011 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, write to the Free Software
  16  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18
  19 /*
  20  * workqueue for asynchronous/super-io operations
  21  * todo: try new credentials management scheme
  22  */
  23
  24 #ifndef __AUFS_WKQ_H__
  25 #define __AUFS_WKQ_H__
  26
  27 #ifdef __KERNEL__
  28
  29 #include <linux/sched.h>
  30 #include <linux/wait.h>
  31 #include <linux/aufs_type.h>
  32
  33 struct super_block;
  34
  35 /* ---------------------------------------------------------------------- */
  36
  37 /*
  38  * in the next operation, wait for the 'nowait' tasks in system-wide workqueue
  39  */
  40 struct au_nowait_tasks {
  41         atomic_t                nw_len;
  42         wait_queue_head_t       nw_wq;
  43 };
  44
  45 /* ---------------------------------------------------------------------- */
  46
  47 typedef void (*au_wkq_func_t)(void *args);
  48
  49 /* wkq flags */
  50 #define AuWkq_WAIT      1
  51 #define AuWkq_PRE       (1 << 1)
  52 #ifdef CONFIG_AUFS_HNOTIFY
  53 #define AuWkq_NEST      (1 << 2)
  54 #else
  55 #define AuWkq_NEST      0
  56 #endif
  57 #define au_ftest_wkq(flags, name)       ((flags) & AuWkq_##name)
  58 #define au_fset_wkq(flags, name) \
  59         do { (flags) |= AuWkq_##name; } while (0)
  60 #define au_fclr_wkq(flags, name) \
  61         do { (flags) &= ~AuWkq_##name; } while (0)
  62
  63 /* wkq.c */
  64 int au_wkq_do_wait(unsigned int flags, au_wkq_func_t func, void *args);
  65 int au_wkq_nowait(au_wkq_func_t func, void *args, struct super_block *sb,
  66                   unsigned int flags);
  67 void au_nwt_init(struct au_nowait_tasks *nwt);
  68 int __init au_wkq_init(void);
  69 void au_wkq_fin(void);
  70
  71 /* ---------------------------------------------------------------------- */
  72
  73 static inline int au_wkq_test(void)
  74 {
  75         return current->flags & PF_WQ_WORKER;
  76 }
  77
  78 static inline int au_wkq_wait_pre(au_wkq_func_t func, void *args)
  79 {
  80         return au_wkq_do_wait(AuWkq_WAIT | AuWkq_PRE, func, args);
  81 }
  82
  83 static inline int au_wkq_wait(au_wkq_func_t func, void *args)
  84 {
  85         return au_wkq_do_wait(AuWkq_WAIT, func, args);
  86 }
  87
  88 static inline void au_nwt_done(struct au_nowait_tasks *nwt)
  89 {
  90         if (atomic_dec_and_test(&nwt->nw_len))
  91                 wake_up_all(&nwt->nw_wq);
  92 }
  93
  94 static inline int au_nwt_flush(struct au_nowait_tasks *nwt)
  95 {
  96         wait_event(nwt->nw_wq, !atomic_read(&nwt->nw_len));
  97         return 0;
  98 }
  99
 100 #endif /* __KERNEL__ */
 101 #endif /* __AUFS_WKQ_H__ */