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Subject[PATCH 04/11] staging: lustre: convert range_lock to linux interval_trees.
Linux has a fully-generic interval tree implementation
which can be tailored to different use cases.
Use it for range_lock rather than the lustre version.
This allows us to get rid of some call-backs and generally
simplifies the code.

We cannot use the pre-built version in lib/interval_tree.c
as we need 64bit endpoints and it only provides "unsigned long".

Signed-off-by: NeilBrown <neilb@suse.com>
---
drivers/staging/lustre/lustre/llite/file.c | 8 +-
drivers/staging/lustre/lustre/llite/range_lock.c | 94 ++++++++--------------
drivers/staging/lustre/lustre/llite/range_lock.h | 17 ++--
3 files changed, 47 insertions(+), 72 deletions(-)

diff --git a/drivers/staging/lustre/lustre/llite/file.c b/drivers/staging/lustre/lustre/llite/file.c
index 02295931883b..e888ed6e74bc 100644
--- a/drivers/staging/lustre/lustre/llite/file.c
+++ b/drivers/staging/lustre/lustre/llite/file.c
@@ -1086,8 +1086,8 @@ ll_file_io_generic(const struct lu_env *env, struct vvp_io_args *args,
(iot == CIT_READ && (file->f_flags & O_DIRECT))) &&
!(vio->vui_fd->fd_flags & LL_FILE_GROUP_LOCKED)) {
CDEBUG(D_VFSTRACE, "Range lock [%llu, %llu]\n",
- range.rl_node.in_extent.start,
- range.rl_node.in_extent.end);
+ range.rl_start,
+ range.rl_last);
rc = range_lock(&lli->lli_write_tree, &range);
if (rc < 0)
goto out;
@@ -1099,8 +1099,8 @@ ll_file_io_generic(const struct lu_env *env, struct vvp_io_args *args,
ll_cl_remove(file, env);
if (range_locked) {
CDEBUG(D_VFSTRACE, "Range unlock [%llu, %llu]\n",
- range.rl_node.in_extent.start,
- range.rl_node.in_extent.end);
+ range.rl_start,
+ range.rl_last);
range_unlock(&lli->lli_write_tree, &range);
}
} else {
diff --git a/drivers/staging/lustre/lustre/llite/range_lock.c b/drivers/staging/lustre/lustre/llite/range_lock.c
index eaa23f4c414e..acdb0dc00a89 100644
--- a/drivers/staging/lustre/lustre/llite/range_lock.c
+++ b/drivers/staging/lustre/lustre/llite/range_lock.c
@@ -37,7 +37,13 @@
#include "range_lock.h"
#include <uapi/linux/lustre/lustre_idl.h>
#include <linux/libcfs/libcfs.h>
+#include <linux/interval_tree_generic.h>

+#define START(node) ((node)->rl_start)
+#define LAST(node) ((node)->rl_last)
+
+INTERVAL_TREE_DEFINE(struct range_lock, rl_rb, __u64, __subtree_last,
+ START, LAST, static, range);
/**
* Initialize a range lock tree
*
@@ -48,7 +54,7 @@
*/
void range_lock_tree_init(struct range_lock_tree *tree)
{
- tree->rlt_root = NULL;
+ tree->rlt_root = RB_ROOT_CACHED;
tree->rlt_sequence = 0;
spin_lock_init(&tree->rlt_lock);
}
@@ -65,43 +71,19 @@ void range_lock_tree_init(struct range_lock_tree *tree)
*/
int range_lock_init(struct range_lock *lock, __u64 start, __u64 end)
{
- int rc;
+ RB_CLEAR_NODE(&lock->rl_rb);

- 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;
+ lock->rl_start = start >> PAGE_SHIFT;
+ lock->rl_last = end;
+ if (lock->rl_start > lock->rl_last)
+ return -ERANGE;

lock->rl_task = NULL;
lock->rl_blocking_ranges = 0;
lock->rl_sequence = 0;
- return rc;
-}
-
-/**
- * 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);
-
- 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;
+ return 0;
}

/**
@@ -112,36 +94,27 @@ static enum interval_iter range_unlock_cb(struct interval_node *node, void *arg)
*
* 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().
+ * by this lock.
*/
void range_unlock(struct range_lock_tree *tree, struct range_lock *lock)
{
- spin_lock(&tree->rlt_lock);
- LASSERT(interval_is_intree(&lock->rl_node));
- interval_erase(&lock->rl_node, &tree->rlt_root);
+ struct range_lock *overlap;

- interval_search(tree->rlt_root, &lock->rl_node.in_extent,
- range_unlock_cb, lock);
- spin_unlock(&tree->rlt_lock);
-}
+ spin_lock(&tree->rlt_lock);
+ LASSERT(!RB_EMPTY_NODE(&lock->rl_rb));
+ range_remove(lock, &tree->rlt_root);

-/**
- * 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;
+ for (overlap = range_iter_first(&tree->rlt_root,
+ lock->rl_start, lock->rl_last);
+ overlap;
+ overlap = range_iter_next(overlap, lock->rl_start, lock->rl_last))
+ if (overlap->rl_sequence > lock->rl_sequence) {
+ --overlap->rl_blocking_ranges;
+ if (overlap->rl_blocking_ranges == 0)
+ wake_up_process(overlap->rl_task);
+ }

- lock->rl_blocking_ranges++;
- return INTERVAL_ITER_CONT;
+ spin_unlock(&tree->rlt_lock);
}

/**
@@ -160,15 +133,20 @@ static enum interval_iter range_lock_cb(struct interval_node *node, void *arg)
int range_lock(struct range_lock_tree *tree, struct range_lock *lock)
{
int rc = 0;
+ struct range_lock *it;

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);
- interval_insert(&lock->rl_node, &tree->rlt_root);
+ for (it = range_iter_first(&tree->rlt_root,
+ lock->rl_start, lock->rl_last);
+ it;
+ it = range_iter_next(it, lock->rl_start, lock->rl_last))
+ lock->rl_blocking_ranges++;
+
+ range_insert(lock, &tree->rlt_root);
lock->rl_sequence = ++tree->rlt_sequence;

while (lock->rl_blocking_ranges > 0) {
diff --git a/drivers/staging/lustre/lustre/llite/range_lock.h b/drivers/staging/lustre/lustre/llite/range_lock.h
index 10ef1a995d26..2a0704d21481 100644
--- a/drivers/staging/lustre/lustre/llite/range_lock.h
+++ b/drivers/staging/lustre/lustre/llite/range_lock.h
@@ -38,10 +38,12 @@
#define _RANGE_LOCK_H

#include <linux/spinlock.h>
-#include <interval_tree.h>
+#include <linux/rbtree.h>

struct range_lock {
- struct interval_node rl_node;
+ struct rb_node rl_rb;
+ __u64 rl_start, rl_last;
+ __u64 __subtree_last;
/**
* Process to enqueue this lock.
*/
@@ -57,15 +59,10 @@ struct range_lock {
__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;
+ struct rb_root_cached rlt_root;
+ spinlock_t rlt_lock; /* protect range lock tree */
+ __u64 rlt_sequence;
};

void range_lock_tree_init(struct range_lock_tree *tree);

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