diff options
Diffstat (limited to 'drivers/staging/lustre/lustre/llite/range_lock.h')
| -rw-r--r-- | drivers/staging/lustre/lustre/llite/range_lock.h | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/drivers/staging/lustre/lustre/llite/range_lock.h b/drivers/staging/lustre/lustre/llite/range_lock.h new file mode 100644 index 000000000000..c6d04a6f99fd --- /dev/null +++ b/drivers/staging/lustre/lustre/llite/range_lock.h @@ -0,0 +1,82 @@ +/* + * GPL HEADER START + * + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 only, + * as published by the Free Software Foundation. + * + * 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 version 2 for more details (a copy is included + * in the LICENSE file that accompanied this code). + * + * You should have received a copy of the GNU General Public License + * version 2 along with this program; If not, see + * http://www.gnu.org/licenses/gpl-2.0.html + * + * GPL HEADER END + */ +/* + * Range lock is used to allow multiple threads writing a single shared + * file given each thread is writing to a non-overlapping portion of the + * file. + * + * Refer to the possible upstream kernel version of range lock by + * Jan Kara <jack@suse.cz>: https://lkml.org/lkml/2013/1/31/480 + * + * This file could later replaced by the upstream kernel version. + */ +/* + * Author: Prakash Surya <surya1@llnl.gov> + * Author: Bobi Jam <bobijam.xu@intel.com> + */ +#ifndef _RANGE_LOCK_H +#define _RANGE_LOCK_H + +#include "../../include/linux/libcfs/libcfs.h" +#include "../include/interval_tree.h" + +struct range_lock { + struct interval_node rl_node; + /** + * Process to enqueue this lock. + */ + struct task_struct *rl_task; + /** + * List of locks with the same range. + */ + struct list_head rl_next_lock; + /** + * Number of locks in the list rl_next_lock + */ + unsigned int rl_lock_count; + /** + * Number of ranges which are blocking acquisition of the lock + */ + unsigned int rl_blocking_ranges; + /** + * Sequence number of range lock. This number is used to get to know + * the order the locks are queued; this is required for range_cancel(). + */ + __u64 rl_sequence; +}; + +static inline struct range_lock *node2rangelock(const struct interval_node *n) +{ + return container_of(n, struct range_lock, rl_node); +} + +struct range_lock_tree { + struct interval_node *rlt_root; + spinlock_t rlt_lock; /* protect range lock tree */ + __u64 rlt_sequence; +}; + +void range_lock_tree_init(struct range_lock_tree *tree); +void range_lock_init(struct range_lock *lock, __u64 start, __u64 end); +int range_lock(struct range_lock_tree *tree, struct range_lock *lock); +void range_unlock(struct range_lock_tree *tree, struct range_lock *lock); +#endif |