Module Name: src
Committed By: riastradh
Date: Mon Dec 30 04:52:11 UTC 2013
Modified Files:
src/sys/external/bsd/drm2/include/linux [riastradh-drm2]: idr.h
src/sys/external/bsd/drm2/linux [riastradh-drm2]: linux_idr.c
Log Message:
Rewrite idr to use a dumber algorithm that admits pserialized use.
drm2 doesn't use them with RCU, but it does use them under spin locks,
so an rwlock is not kosher.
This algorithm is super-dumb, but the idr API has changed upstream,
and this is not performance-critical, so it's not worth investing
time in a better algorithm at the moment.
To generate a diff of this commit:
cvs rdiff -u -r1.1.2.6 -r1.1.2.7 \
src/sys/external/bsd/drm2/include/linux/idr.h
cvs rdiff -u -r1.1.2.9 -r1.1.2.10 src/sys/external/bsd/drm2/linux/linux_idr.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/external/bsd/drm2/include/linux/idr.h
diff -u src/sys/external/bsd/drm2/include/linux/idr.h:1.1.2.6 src/sys/external/bsd/drm2/include/linux/idr.h:1.1.2.7
--- src/sys/external/bsd/drm2/include/linux/idr.h:1.1.2.6 Wed Jul 24 03:13:59 2013
+++ src/sys/external/bsd/drm2/include/linux/idr.h Mon Dec 30 04:52:11 2013
@@ -1,4 +1,4 @@
-/* $NetBSD: idr.h,v 1.1.2.6 2013/07/24 03:13:59 riastradh Exp $ */
+/* $NetBSD: idr.h,v 1.1.2.7 2013/12/30 04:52:11 riastradh Exp $ */
/*-
* Copyright (c) 2013 The NetBSD Foundation, Inc.
@@ -33,15 +33,16 @@
#define _LINUX_IDR_H_
#include <sys/types.h>
-#include <sys/rwlock.h>
-#include <sys/rbtree.h>
+#include <sys/mutex.h>
+#include <sys/pserialize.h>
/* XXX Stupid expedient algorithm should be replaced by something better. */
struct idr {
- krwlock_t idr_lock;
- rb_tree_t idr_tree;
- struct idr_node *idr_temp;
+ kmutex_t idr_lock;
+ pserialize_t idr_psz;
+ struct idr_state *idr_state;
+ struct idr_state *volatile idr_temp;
};
/* XXX Make the nm output a little more greppable... */
Index: src/sys/external/bsd/drm2/linux/linux_idr.c
diff -u src/sys/external/bsd/drm2/linux/linux_idr.c:1.1.2.9 src/sys/external/bsd/drm2/linux/linux_idr.c:1.1.2.10
--- src/sys/external/bsd/drm2/linux/linux_idr.c:1.1.2.9 Wed Jul 24 04:02:58 2013
+++ src/sys/external/bsd/drm2/linux/linux_idr.c Mon Dec 30 04:52:11 2013
@@ -1,4 +1,4 @@
-/* $NetBSD: linux_idr.c,v 1.1.2.9 2013/07/24 04:02:58 riastradh Exp $ */
+/* $NetBSD: linux_idr.c,v 1.1.2.10 2013/12/30 04:52:11 riastradh Exp $ */
/*-
* Copyright (c) 2013 The NetBSD Foundation, Inc.
@@ -30,215 +30,226 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_idr.c,v 1.1.2.9 2013/07/24 04:02:58 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_idr.c,v 1.1.2.10 2013/12/30 04:52:11 riastradh Exp $");
#include <sys/param.h>
#include <sys/atomic.h>
-#include <sys/kmem.h>
-#include <sys/rbtree.h>
+#include <sys/mutex.h>
+#include <sys/pserialize.h>
#include <linux/err.h>
#include <linux/idr.h>
+#include <linux/slab.h>
-struct idr_node {
- rb_node_t in_rb_node;
- int in_index;
- void *in_data;
+struct idr_state {
+ size_t is_n_allocated;
+ size_t is_n_used;
+ void **is_data;
};
-static signed int idr_tree_compare_nodes(void *, const void *, const void *);
-static signed int idr_tree_compare_key(void *, const void *, const void *);
-
-static const rb_tree_ops_t idr_rb_ops = {
- .rbto_compare_nodes = &idr_tree_compare_nodes,
- .rbto_compare_key = &idr_tree_compare_key,
- .rbto_node_offset = offsetof(struct idr_node, in_rb_node),
- .rbto_context = NULL,
-};
-
-static signed int
-idr_tree_compare_nodes(void *ctx __unused, const void *na, const void *nb)
+void
+idr_init(struct idr *idr)
{
- const int a = ((const struct idr_node *)na)->in_index;
- const int b = ((const struct idr_node *)nb)->in_index;
- if (a < b)
- return -1;
- else if (b < a)
- return +1;
- else
- return 0;
+ mutex_init(&idr->idr_lock, MUTEX_DEFAULT, IPL_VM);
+ idr->idr_psz = pserialize_create();
+ idr->idr_state = kmalloc(sizeof(*idr->idr_state), GFP_KERNEL);
+ KASSERT(idr->idr_state != NULL);
+ idr->idr_state->is_n_allocated = 1;
+ idr->idr_state->is_n_used = 0;
+ idr->idr_state->is_data = kcalloc(1, sizeof(void *), GFP_KERNEL);
+ KASSERT(idr->idr_state->is_data != NULL);
+ idr->idr_temp = NULL;
}
-static signed int
-idr_tree_compare_key(void *ctx __unused, const void *n, const void *key)
+static struct idr_state *
+idr_state(struct idr *idr)
{
- const int a = ((const struct idr_node *)n)->in_index;
- const int b = *(const int *)key;
+ struct idr_state *const is = idr->idr_state;
- if (a < b)
- return -1;
- else if (b < a)
- return +1;
- else
- return 0;
+ membar_consumer(); /* match state */
+
+ return is;
}
void
-idr_init(struct idr *idr)
+idr_destroy(struct idr *idr)
{
+ struct idr_state *const is = idr_state(idr);
- rw_init(&idr->idr_lock);
- rb_tree_init(&idr->idr_tree, &idr_rb_ops);
- idr->idr_temp = NULL;
+ kfree(is->is_data);
+ kfree(is);
+ KASSERT(idr->idr_temp == NULL);
+
+ pserialize_destroy(idr->idr_psz);
+ mutex_destroy(&idr->idr_lock);
}
-void
-idr_destroy(struct idr *idr)
+static void **
+idr_find_ptr(struct idr *idr, int id)
{
+ if (id < 0)
+ return NULL;
- if (idr->idr_temp != NULL) {
- /* XXX Probably shouldn't happen. */
- kmem_free(idr->idr_temp, sizeof(*idr->idr_temp));
- idr->idr_temp = NULL;
- }
-#if 0 /* XXX No rb_tree_destroy? */
- rb_tree_destroy(&idr->idr_tree);
-#endif
- rw_destroy(&idr->idr_lock);
+ struct idr_state *const is = idr_state(idr);
+ if (is->is_n_used <= id)
+ return NULL;
+
+ return &is->is_data[id];
}
void *
idr_find(struct idr *idr, int id)
{
- const struct idr_node *node;
- void *data;
+ void **const ptr = idr_find_ptr(idr, id);
+
+ if (ptr == NULL)
+ return NULL;
- rw_enter(&idr->idr_lock, RW_READER);
- node = rb_tree_find_node(&idr->idr_tree, &id);
- data = (node == NULL? NULL : node->in_data);
- rw_exit(&idr->idr_lock);
+ void *const datum = *ptr;
- return data;
+ membar_consumer(); /* match datum */
+ return datum;
}
void *
idr_replace(struct idr *idr, void *replacement, int id)
{
- struct idr_node *node;
- void *result;
+ void **const ptr = idr_find_ptr(idr, id);
- rw_enter(&idr->idr_lock, RW_WRITER);
- node = rb_tree_find_node(&idr->idr_tree, &id);
- if (node == NULL) {
- result = ERR_PTR(-ENOENT);
- } else {
- result = node->in_data;
- node->in_data = replacement;
- }
- rw_exit(&idr->idr_lock);
+ if (ptr == NULL)
+ return ERR_PTR(-ENOENT);
+
+ void *const datum = *ptr;
+
+ membar_producer(); /* match datum */
+ *ptr = replacement;
- return result;
+ return datum;
}
void
idr_remove(struct idr *idr, int id)
{
- struct idr_node *node;
+ if (id < 0)
+ return;
- rw_enter(&idr->idr_lock, RW_WRITER);
- node = rb_tree_find_node(&idr->idr_tree, &id);
- KASSERT(node != NULL);
- rb_tree_remove_node(&idr->idr_tree, node);
- rw_exit(&idr->idr_lock);
- kmem_free(node, sizeof(*node));
+ struct idr_state *const is = idr_state(idr);
+
+ if (is->is_n_used < id)
+ return;
+
+ is->is_data[id] = NULL;
+
+ if ((id + 1) == is->is_n_used) {
+ while ((0 < id--) && (is->is_data[id] == NULL))
+ continue;
+ is->is_n_used = id;
+ }
}
void
idr_remove_all(struct idr *idr)
{
- struct idr_node *node;
+ struct idr_state *const is = idr_state(idr);
- rw_enter(&idr->idr_lock, RW_WRITER);
- while ((node = RB_TREE_MIN(&idr->idr_tree)) != NULL) {
- rb_tree_remove_node(&idr->idr_tree, node);
- rw_exit(&idr->idr_lock);
- kmem_free(node, sizeof(*node));
- rw_enter(&idr->idr_lock, RW_WRITER);
- }
- rw_exit(&idr->idr_lock);
+ is->is_n_used = 0;
}
int
-idr_pre_get(struct idr *idr, int flags __unused /* XXX */)
+idr_pre_get(struct idr *idr, gfp_t gfp)
{
- struct idr_node *temp = kmem_alloc(sizeof(*temp), KM_SLEEP);
+ struct idr_state *old_is, *new_is, *temp_is;
+ size_t n_used;
- rw_enter(&idr->idr_lock, RW_WRITER);
- if (idr->idr_temp == NULL) {
- idr->idr_temp = temp;
- temp = NULL;
+ old_is = idr_state(idr);
+ n_used = old_is->is_n_used;
+
+ new_is = kmalloc(sizeof(*new_is), gfp);
+ if (new_is == NULL)
+ return 0;
+ new_is->is_data = kcalloc((n_used + 1), sizeof(*new_is->is_data), gfp);
+ if (new_is->is_data == NULL) {
+ kfree(new_is);
+ return 0;
}
- rw_exit(&idr->idr_lock);
- if (temp != NULL)
- kmem_free(temp, sizeof(*temp));
+ new_is->is_n_allocated = (n_used + 1);
+
+ membar_producer(); /* match temp */
+
+ /*
+ * If someone already put one in, replace it -- we're probably
+ * more up-to-date.
+ */
+ temp_is = atomic_swap_ptr(&idr->idr_temp, new_is);
+ if (temp_is != NULL) {
+ membar_consumer(); /* match temp */
+ kfree(temp_is->is_data);
+ kfree(temp_is);
+ }
return 1;
}
int
-idr_get_new_above(struct idr *idr, void *data, int min_id, int *id)
+idr_get_new_above(struct idr *idr, void *datum, int min_id, int *idp)
{
- struct idr_node *node, *search, *collision __unused;
- int want_id = min_id;
- int error;
-
- rw_enter(&idr->idr_lock, RW_WRITER);
-
- node = idr->idr_temp;
- if (node == NULL) {
- error = -EAGAIN;
- goto out;
- }
- idr->idr_temp = NULL;
-
- search = rb_tree_find_node_geq(&idr->idr_tree, &min_id);
- while ((search != NULL) && (search->in_index == want_id)) {
- if (want_id == INT_MAX) {
- error = -ENOSPC;
- goto out;
- }
- search = rb_tree_iterate(&idr->idr_tree, search, RB_DIR_RIGHT);
- want_id++;
- }
-
- node->in_index = want_id;
- node->in_data = data;
-
- collision = rb_tree_insert_node(&idr->idr_tree, node);
- KASSERT(collision == node);
-
- *id = want_id;
- error = 0;
-
-out: rw_exit(&idr->idr_lock);
- return error;
+ struct idr_state *is = idr_state(idr);
+ const size_t n_used = is->is_n_used;
+ const size_t n_allocated = is->is_n_allocated;
+ int id;
+
+ if (min_id < 0)
+ min_id = 0;
+
+ for (id = min_id; id < n_used; id++)
+ if (is->is_data[id] == NULL)
+ goto win;
+ if (id < n_allocated) {
+ is->is_n_used++;
+ goto win;
+ }
+
+ struct idr_state *const it = atomic_swap_ptr(&idr->idr_temp, NULL);
+ if (it == NULL)
+ return -EAGAIN;
+
+ membar_consumer(); /* match temp */
+ if (id < it->is_n_allocated) {
+ (void)memcpy(it->is_data, is->is_data, sizeof(void *) *
+ n_used);
+ it->is_n_used = (is->is_n_used + 1);
+ membar_producer(); /* match state */
+ idr->idr_state = it;
+ pserialize_perform(idr->idr_psz);
+ kfree(is->is_data);
+ kfree(is);
+ is = it;
+ goto win;
+ }
+
+win: membar_producer(); /* match datum */
+ is->is_data[id] = datum;
+ *idp = id;
+ return 0;
}
int
idr_for_each(struct idr *idr, int (*proc)(int, void *, void *), void *arg)
{
- struct idr_node *node;
+ struct idr_state *const is = idr_state(idr);
+ int id;
int error = 0;
- rw_enter(&idr->idr_lock, RW_READER);
- RB_TREE_FOREACH(node, &idr->idr_tree) {
- error = (*proc)(node->in_index, node->in_data, arg);
+ for (id = 0; id < is->is_n_used; id++) {
+ void *const datum = is->is_data[id];
+
+ membar_consumer(); /* match datum */
+ error = (*proc)(id, datum, arg);
if (error)
break;
}
- rw_exit(&idr->idr_lock);
return error;
}
