diff options
Diffstat (limited to 'drivers/staging/lustre/lustre/llite/range_lock.c')
-rw-r--r-- | drivers/staging/lustre/lustre/llite/range_lock.c | 241 |
1 files changed, 0 insertions, 241 deletions
diff --git a/drivers/staging/lustre/lustre/llite/range_lock.c b/drivers/staging/lustre/lustre/llite/range_lock.c deleted file mode 100644 index 008a8874118d..000000000000 --- a/drivers/staging/lustre/lustre/llite/range_lock.c +++ /dev/null @@ -1,241 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * 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> - */ -#include "range_lock.h" -#include <uapi/linux/lustre/lustre_idl.h> -#include <linux/libcfs/libcfs.h> - -/** - * Initialize a range lock tree - * - * \param tree [in] an empty range lock tree - * - * Pre: Caller should have allocated the range lock tree. - * Post: The range lock tree is ready to function. - */ -void range_lock_tree_init(struct range_lock_tree *tree) -{ - tree->rlt_root = NULL; - tree->rlt_sequence = 0; - spin_lock_init(&tree->rlt_lock); -} - -/** - * Initialize a range lock node - * - * \param lock [in] an empty range lock node - * \param start [in] start of the covering region - * \param end [in] end of the covering region - * - * Pre: Caller should have allocated the range lock node. - * Post: The range lock node is meant to cover [start, end] region - */ -int range_lock_init(struct range_lock *lock, __u64 start, __u64 end) -{ - int rc; - - memset(&lock->rl_node, 0, sizeof(lock->rl_node)); - if (end != LUSTRE_EOF) - end >>= PAGE_SHIFT; - rc = interval_set(&lock->rl_node, start >> PAGE_SHIFT, end); - if (rc) - return rc; - - INIT_LIST_HEAD(&lock->rl_next_lock); - lock->rl_task = NULL; - lock->rl_lock_count = 0; - lock->rl_blocking_ranges = 0; - lock->rl_sequence = 0; - return rc; -} - -static inline struct range_lock *next_lock(struct range_lock *lock) -{ - return list_entry(lock->rl_next_lock.next, typeof(*lock), rl_next_lock); -} - -/** - * Helper function of range_unlock() - * - * \param node [in] a range lock found overlapped during interval node - * search - * \param arg [in] the range lock to be tested - * - * \retval INTERVAL_ITER_CONT indicate to continue the search for next - * overlapping range node - * \retval INTERVAL_ITER_STOP indicate to stop the search - */ -static enum interval_iter range_unlock_cb(struct interval_node *node, void *arg) -{ - struct range_lock *lock = arg; - struct range_lock *overlap = node2rangelock(node); - struct range_lock *iter; - - list_for_each_entry(iter, &overlap->rl_next_lock, rl_next_lock) { - if (iter->rl_sequence > lock->rl_sequence) { - --iter->rl_blocking_ranges; - LASSERT(iter->rl_blocking_ranges > 0); - } - } - if (overlap->rl_sequence > lock->rl_sequence) { - --overlap->rl_blocking_ranges; - if (overlap->rl_blocking_ranges == 0) - wake_up_process(overlap->rl_task); - } - return INTERVAL_ITER_CONT; -} - -/** - * Unlock a range lock, wake up locks blocked by this lock. - * - * \param tree [in] range lock tree - * \param lock [in] range lock to be deleted - * - * If this lock has been granted, relase it; if not, just delete it from - * the tree or the same region lock list. Wake up those locks only blocked - * by this lock through range_unlock_cb(). - */ -void range_unlock(struct range_lock_tree *tree, struct range_lock *lock) -{ - spin_lock(&tree->rlt_lock); - if (!list_empty(&lock->rl_next_lock)) { - struct range_lock *next; - - if (interval_is_intree(&lock->rl_node)) { /* first lock */ - /* Insert the next same range lock into the tree */ - next = next_lock(lock); - next->rl_lock_count = lock->rl_lock_count - 1; - interval_erase(&lock->rl_node, &tree->rlt_root); - interval_insert(&next->rl_node, &tree->rlt_root); - } else { - /* find the first lock in tree */ - list_for_each_entry(next, &lock->rl_next_lock, - rl_next_lock) { - if (!interval_is_intree(&next->rl_node)) - continue; - - LASSERT(next->rl_lock_count > 0); - next->rl_lock_count--; - break; - } - } - list_del_init(&lock->rl_next_lock); - } else { - LASSERT(interval_is_intree(&lock->rl_node)); - interval_erase(&lock->rl_node, &tree->rlt_root); - } - - interval_search(tree->rlt_root, &lock->rl_node.in_extent, - range_unlock_cb, lock); - spin_unlock(&tree->rlt_lock); -} - -/** - * Helper function of range_lock() - * - * \param node [in] a range lock found overlapped during interval node - * search - * \param arg [in] the range lock to be tested - * - * \retval INTERVAL_ITER_CONT indicate to continue the search for next - * overlapping range node - * \retval INTERVAL_ITER_STOP indicate to stop the search - */ -static enum interval_iter range_lock_cb(struct interval_node *node, void *arg) -{ - struct range_lock *lock = arg; - struct range_lock *overlap = node2rangelock(node); - - lock->rl_blocking_ranges += overlap->rl_lock_count + 1; - return INTERVAL_ITER_CONT; -} - -/** - * Lock a region - * - * \param tree [in] range lock tree - * \param lock [in] range lock node containing the region span - * - * \retval 0 get the range lock - * \retval <0 error code while not getting the range lock - * - * If there exists overlapping range lock, the new lock will wait and - * retry, if later it find that it is not the chosen one to wake up, - * it wait again. - */ -int range_lock(struct range_lock_tree *tree, struct range_lock *lock) -{ - struct interval_node *node; - int rc = 0; - - spin_lock(&tree->rlt_lock); - /* - * We need to check for all conflicting intervals - * already in the tree. - */ - interval_search(tree->rlt_root, &lock->rl_node.in_extent, - range_lock_cb, lock); - /* - * Insert to the tree if I am unique, otherwise I've been linked to - * the rl_next_lock of another lock which has the same range as mine - * in range_lock_cb(). - */ - node = interval_insert(&lock->rl_node, &tree->rlt_root); - if (node) { - struct range_lock *tmp = node2rangelock(node); - - list_add_tail(&lock->rl_next_lock, &tmp->rl_next_lock); - tmp->rl_lock_count++; - } - lock->rl_sequence = ++tree->rlt_sequence; - - while (lock->rl_blocking_ranges > 0) { - lock->rl_task = current; - __set_current_state(TASK_INTERRUPTIBLE); - spin_unlock(&tree->rlt_lock); - schedule(); - - if (signal_pending(current)) { - range_unlock(tree, lock); - rc = -EINTR; - goto out; - } - spin_lock(&tree->rlt_lock); - } - spin_unlock(&tree->rlt_lock); -out: - return rc; -} |