fs/aufs/wkq.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (C) 2005-2019 Junjiro R. Okajima
   4  *
   5  * This program, aufs is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  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/wait.h>
  30
  31 struct super_block;
  32
  33 /* ---------------------------------------------------------------------- */
  34
  35 /*
  36  * in the next operation, wait for the 'nowait' tasks in system-wide workqueue
  37  */
  38 struct au_nowait_tasks {
  39         atomic_t                nw_len;
  40         wait_queue_head_t       nw_wq;
  41 };
  42
  43 /* ---------------------------------------------------------------------- */
  44
  45 typedef void (*au_wkq_func_t)(void *args);
  46
  47 /* wkq flags */
  48 #define AuWkq_WAIT      1
  49 #define AuWkq_NEST      (1 << 1)
  50 #define au_ftest_wkq(flags, name)       ((flags) & AuWkq_##name)
  51 #define au_fset_wkq(flags, name) \
  52         do { (flags) |= AuWkq_##name; } while (0)
  53 #define au_fclr_wkq(flags, name) \
  54         do { (flags) &= ~AuWkq_##name; } while (0)
  55
  56 /* wkq.c */
  57 int au_wkq_do_wait(unsigned int flags, au_wkq_func_t func, void *args);
  58 int au_wkq_nowait(au_wkq_func_t func, void *args, struct super_block *sb,
  59                   unsigned int flags);
  60 void au_nwt_init(struct au_nowait_tasks *nwt);
  61 int __init au_wkq_init(void);
  62 void au_wkq_fin(void);
  63
  64 /* ---------------------------------------------------------------------- */
  65
  66 static inline int au_wkq_test(void)
  67 {
  68         return current->flags & PF_WQ_WORKER;
  69 }
  70
  71 static inline int au_wkq_wait(au_wkq_func_t func, void *args)
  72 {
  73         return au_wkq_do_wait(AuWkq_WAIT, func, args);
  74 }
  75
  76 static inline void au_nwt_done(struct au_nowait_tasks *nwt)
  77 {
  78         if (atomic_dec_and_test(&nwt->nw_len))
  79                 wake_up_all(&nwt->nw_wq);
  80 }
  81
  82 static inline int au_nwt_flush(struct au_nowait_tasks *nwt)
  83 {
  84         wait_event(nwt->nw_wq, !atomic_read(&nwt->nw_len));
  85         return 0;
  86 }
  87
  88 #endif /* __KERNEL__ */
  89 #endif /* __AUFS_WKQ_H__ */