diff options
Diffstat (limited to 'fs/aufs/lcnt.h')
| -rw-r--r-- | fs/aufs/lcnt.h | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/fs/aufs/lcnt.h b/fs/aufs/lcnt.h new file mode 100644 index 000000000000..8afcabe55826 --- /dev/null +++ b/fs/aufs/lcnt.h @@ -0,0 +1,186 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2018-2020 Junjiro R. Okajima + * + * This program, aufs is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +/* + * simple long counter wrapper + */ + +#ifndef __AUFS_LCNT_H__ +#define __AUFS_LCNT_H__ + +#ifdef __KERNEL__ + +#include "debug.h" + +#define AuLCntATOMIC 1 +#define AuLCntPCPUCNT 2 +/* + * why does percpu_refcount require extra synchronize_rcu()s in + * au_br_do_free() + */ +#define AuLCntPCPUREF 3 + +/* #define AuLCntChosen AuLCntATOMIC */ +#define AuLCntChosen AuLCntPCPUCNT +/* #define AuLCntChosen AuLCntPCPUREF */ + +#if AuLCntChosen == AuLCntATOMIC +#include <linux/atomic.h> + +typedef atomic_long_t au_lcnt_t; + +static inline int au_lcnt_init(au_lcnt_t *cnt, void *release __maybe_unused) +{ + atomic_long_set(cnt, 0); + return 0; +} + +static inline void au_lcnt_wait_for_fin(au_lcnt_t *cnt __maybe_unused) +{ + /* empty */ +} + +static inline void au_lcnt_fin(au_lcnt_t *cnt __maybe_unused, + int do_sync __maybe_unused) +{ + /* empty */ +} + +static inline void au_lcnt_inc(au_lcnt_t *cnt) +{ + atomic_long_inc(cnt); +} + +static inline void au_lcnt_dec(au_lcnt_t *cnt) +{ + atomic_long_dec(cnt); +} + +static inline long au_lcnt_read(au_lcnt_t *cnt, int do_rev __maybe_unused) +{ + return atomic_long_read(cnt); +} +#endif + +#if AuLCntChosen == AuLCntPCPUCNT +#include <linux/percpu_counter.h> + +typedef struct percpu_counter au_lcnt_t; + +static inline int au_lcnt_init(au_lcnt_t *cnt, void *release __maybe_unused) +{ + return percpu_counter_init(cnt, 0, GFP_NOFS); +} + +static inline void au_lcnt_wait_for_fin(au_lcnt_t *cnt __maybe_unused) +{ + /* empty */ +} + +static inline void au_lcnt_fin(au_lcnt_t *cnt, int do_sync __maybe_unused) +{ + percpu_counter_destroy(cnt); +} + +static inline void au_lcnt_inc(au_lcnt_t *cnt) +{ + percpu_counter_inc(cnt); +} + +static inline void au_lcnt_dec(au_lcnt_t *cnt) +{ + percpu_counter_dec(cnt); +} + +static inline long au_lcnt_read(au_lcnt_t *cnt, int do_rev __maybe_unused) +{ + s64 n; + + n = percpu_counter_sum(cnt); + BUG_ON(n < 0); + if (LONG_MAX != LLONG_MAX + && n > LONG_MAX) + AuWarn1("%s\n", "wrap-around"); + + return n; +} +#endif + +#if AuLCntChosen == AuLCntPCPUREF +#include <linux/percpu-refcount.h> + +typedef struct percpu_ref au_lcnt_t; + +static inline int au_lcnt_init(au_lcnt_t *cnt, percpu_ref_func_t *release) +{ + if (!release) + release = percpu_ref_exit; + return percpu_ref_init(cnt, release, /*percpu mode*/0, GFP_NOFS); +} + +static inline void au_lcnt_wait_for_fin(au_lcnt_t *cnt __maybe_unused) +{ + synchronize_rcu(); +} + +static inline void au_lcnt_fin(au_lcnt_t *cnt, int do_sync) +{ + percpu_ref_kill(cnt); + if (do_sync) + au_lcnt_wait_for_fin(cnt); +} + +static inline void au_lcnt_inc(au_lcnt_t *cnt) +{ + percpu_ref_get(cnt); +} + +static inline void au_lcnt_dec(au_lcnt_t *cnt) +{ + percpu_ref_put(cnt); +} + +/* + * avoid calling this func as possible. + */ +static inline long au_lcnt_read(au_lcnt_t *cnt, int do_rev) +{ + long l; + + percpu_ref_switch_to_atomic_sync(cnt); + l = atomic_long_read(&cnt->count); + if (do_rev) + percpu_ref_switch_to_percpu(cnt); + + /* percpu_ref is initialized by 1 instead of 0 */ + return l - 1; +} +#endif + +#ifdef CONFIG_AUFS_DEBUG +#define AuLCntZero(val) do { \ + long l = val; \ + if (l) \ + AuDbg("%s = %ld\n", #val, l); \ +} while (0) +#else +#define AuLCntZero(val) do {} while (0) +#endif + +#endif /* __KERNEL__ */ +#endif /* __AUFS_LCNT_H__ */ |