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-rw-r--r--drivers/dma-buf/reservation.c477
1 files changed, 477 insertions, 0 deletions
diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c
new file mode 100644
index 000000000000..3c97c8fa8d02
--- /dev/null
+++ b/drivers/dma-buf/reservation.c
@@ -0,0 +1,477 @@
+/*
+ * Copyright (C) 2012-2014 Canonical Ltd (Maarten Lankhorst)
+ *
+ * Based on bo.c which bears the following copyright notice,
+ * but is dual licensed:
+ *
+ * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+/*
+ * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
+ */
+
+#include <linux/reservation.h>
+#include <linux/export.h>
+
+DEFINE_WW_CLASS(reservation_ww_class);
+EXPORT_SYMBOL(reservation_ww_class);
+
+struct lock_class_key reservation_seqcount_class;
+EXPORT_SYMBOL(reservation_seqcount_class);
+
+const char reservation_seqcount_string[] = "reservation_seqcount";
+EXPORT_SYMBOL(reservation_seqcount_string);
+/*
+ * Reserve space to add a shared fence to a reservation_object,
+ * must be called with obj->lock held.
+ */
+int reservation_object_reserve_shared(struct reservation_object *obj)
+{
+ struct reservation_object_list *fobj, *old;
+ u32 max;
+
+ old = reservation_object_get_list(obj);
+
+ if (old && old->shared_max) {
+ if (old->shared_count < old->shared_max) {
+ /* perform an in-place update */
+ kfree(obj->staged);
+ obj->staged = NULL;
+ return 0;
+ } else
+ max = old->shared_max * 2;
+ } else
+ max = 4;
+
+ /*
+ * resize obj->staged or allocate if it doesn't exist,
+ * noop if already correct size
+ */
+ fobj = krealloc(obj->staged, offsetof(typeof(*fobj), shared[max]),
+ GFP_KERNEL);
+ if (!fobj)
+ return -ENOMEM;
+
+ obj->staged = fobj;
+ fobj->shared_max = max;
+ return 0;
+}
+EXPORT_SYMBOL(reservation_object_reserve_shared);
+
+static void
+reservation_object_add_shared_inplace(struct reservation_object *obj,
+ struct reservation_object_list *fobj,
+ struct fence *fence)
+{
+ u32 i;
+
+ fence_get(fence);
+
+ preempt_disable();
+ write_seqcount_begin(&obj->seq);
+
+ for (i = 0; i < fobj->shared_count; ++i) {
+ struct fence *old_fence;
+
+ old_fence = rcu_dereference_protected(fobj->shared[i],
+ reservation_object_held(obj));
+
+ if (old_fence->context == fence->context) {
+ /* memory barrier is added by write_seqcount_begin */
+ RCU_INIT_POINTER(fobj->shared[i], fence);
+ write_seqcount_end(&obj->seq);
+ preempt_enable();
+
+ fence_put(old_fence);
+ return;
+ }
+ }
+
+ /*
+ * memory barrier is added by write_seqcount_begin,
+ * fobj->shared_count is protected by this lock too
+ */
+ RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence);
+ fobj->shared_count++;
+
+ write_seqcount_end(&obj->seq);
+ preempt_enable();
+}
+
+static void
+reservation_object_add_shared_replace(struct reservation_object *obj,
+ struct reservation_object_list *old,
+ struct reservation_object_list *fobj,
+ struct fence *fence)
+{
+ unsigned i;
+ struct fence *old_fence = NULL;
+
+ fence_get(fence);
+
+ if (!old) {
+ RCU_INIT_POINTER(fobj->shared[0], fence);
+ fobj->shared_count = 1;
+ goto done;
+ }
+
+ /*
+ * no need to bump fence refcounts, rcu_read access
+ * requires the use of kref_get_unless_zero, and the
+ * references from the old struct are carried over to
+ * the new.
+ */
+ fobj->shared_count = old->shared_count;
+
+ for (i = 0; i < old->shared_count; ++i) {
+ struct fence *check;
+
+ check = rcu_dereference_protected(old->shared[i],
+ reservation_object_held(obj));
+
+ if (!old_fence && check->context == fence->context) {
+ old_fence = check;
+ RCU_INIT_POINTER(fobj->shared[i], fence);
+ } else
+ RCU_INIT_POINTER(fobj->shared[i], check);
+ }
+ if (!old_fence) {
+ RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence);
+ fobj->shared_count++;
+ }
+
+done:
+ preempt_disable();
+ write_seqcount_begin(&obj->seq);
+ /*
+ * RCU_INIT_POINTER can be used here,
+ * seqcount provides the necessary barriers
+ */
+ RCU_INIT_POINTER(obj->fence, fobj);
+ write_seqcount_end(&obj->seq);
+ preempt_enable();
+
+ if (old)
+ kfree_rcu(old, rcu);
+
+ if (old_fence)
+ fence_put(old_fence);
+}
+
+/*
+ * Add a fence to a shared slot, obj->lock must be held, and
+ * reservation_object_reserve_shared_fence has been called.
+ */
+void reservation_object_add_shared_fence(struct reservation_object *obj,
+ struct fence *fence)
+{
+ struct reservation_object_list *old, *fobj = obj->staged;
+
+ old = reservation_object_get_list(obj);
+ obj->staged = NULL;
+
+ if (!fobj) {
+ BUG_ON(old->shared_count >= old->shared_max);
+ reservation_object_add_shared_inplace(obj, old, fence);
+ } else
+ reservation_object_add_shared_replace(obj, old, fobj, fence);
+}
+EXPORT_SYMBOL(reservation_object_add_shared_fence);
+
+void reservation_object_add_excl_fence(struct reservation_object *obj,
+ struct fence *fence)
+{
+ struct fence *old_fence = reservation_object_get_excl(obj);
+ struct reservation_object_list *old;
+ u32 i = 0;
+
+ old = reservation_object_get_list(obj);
+ if (old)
+ i = old->shared_count;
+
+ if (fence)
+ fence_get(fence);
+
+ preempt_disable();
+ write_seqcount_begin(&obj->seq);
+ /* write_seqcount_begin provides the necessary memory barrier */
+ RCU_INIT_POINTER(obj->fence_excl, fence);
+ if (old)
+ old->shared_count = 0;
+ write_seqcount_end(&obj->seq);
+ preempt_enable();
+
+ /* inplace update, no shared fences */
+ while (i--)
+ fence_put(rcu_dereference_protected(old->shared[i],
+ reservation_object_held(obj)));
+
+ if (old_fence)
+ fence_put(old_fence);
+}
+EXPORT_SYMBOL(reservation_object_add_excl_fence);
+
+int reservation_object_get_fences_rcu(struct reservation_object *obj,
+ struct fence **pfence_excl,
+ unsigned *pshared_count,
+ struct fence ***pshared)
+{
+ unsigned shared_count = 0;
+ unsigned retry = 1;
+ struct fence **shared = NULL, *fence_excl = NULL;
+ int ret = 0;
+
+ while (retry) {
+ struct reservation_object_list *fobj;
+ unsigned seq;
+
+ seq = read_seqcount_begin(&obj->seq);
+
+ rcu_read_lock();
+
+ fobj = rcu_dereference(obj->fence);
+ if (fobj) {
+ struct fence **nshared;
+ size_t sz = sizeof(*shared) * fobj->shared_max;
+
+ nshared = krealloc(shared, sz,
+ GFP_NOWAIT | __GFP_NOWARN);
+ if (!nshared) {
+ rcu_read_unlock();
+ nshared = krealloc(shared, sz, GFP_KERNEL);
+ if (nshared) {
+ shared = nshared;
+ continue;
+ }
+
+ ret = -ENOMEM;
+ shared_count = 0;
+ break;
+ }
+ shared = nshared;
+ memcpy(shared, fobj->shared, sz);
+ shared_count = fobj->shared_count;
+ } else
+ shared_count = 0;
+ fence_excl = rcu_dereference(obj->fence_excl);
+
+ retry = read_seqcount_retry(&obj->seq, seq);
+ if (retry)
+ goto unlock;
+
+ if (!fence_excl || fence_get_rcu(fence_excl)) {
+ unsigned i;
+
+ for (i = 0; i < shared_count; ++i) {
+ if (fence_get_rcu(shared[i]))
+ continue;
+
+ /* uh oh, refcount failed, abort and retry */
+ while (i--)
+ fence_put(shared[i]);
+
+ if (fence_excl) {
+ fence_put(fence_excl);
+ fence_excl = NULL;
+ }
+
+ retry = 1;
+ break;
+ }
+ } else
+ retry = 1;
+
+unlock:
+ rcu_read_unlock();
+ }
+ *pshared_count = shared_count;
+ if (shared_count)
+ *pshared = shared;
+ else {
+ *pshared = NULL;
+ kfree(shared);
+ }
+ *pfence_excl = fence_excl;
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(reservation_object_get_fences_rcu);
+
+long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
+ bool wait_all, bool intr,
+ unsigned long timeout)
+{
+ struct fence *fence;
+ unsigned seq, shared_count, i = 0;
+ long ret = timeout;
+
+retry:
+ fence = NULL;
+ shared_count = 0;
+ seq = read_seqcount_begin(&obj->seq);
+ rcu_read_lock();
+
+ if (wait_all) {
+ struct reservation_object_list *fobj = rcu_dereference(obj->fence);
+
+ if (fobj)
+ shared_count = fobj->shared_count;
+
+ if (read_seqcount_retry(&obj->seq, seq))
+ goto unlock_retry;
+
+ for (i = 0; i < shared_count; ++i) {
+ struct fence *lfence = rcu_dereference(fobj->shared[i]);
+
+ if (test_bit(FENCE_FLAG_SIGNALED_BIT, &lfence->flags))
+ continue;
+
+ if (!fence_get_rcu(lfence))
+ goto unlock_retry;
+
+ if (fence_is_signaled(lfence)) {
+ fence_put(lfence);
+ continue;
+ }
+
+ fence = lfence;
+ break;
+ }
+ }
+
+ if (!shared_count) {
+ struct fence *fence_excl = rcu_dereference(obj->fence_excl);
+
+ if (read_seqcount_retry(&obj->seq, seq))
+ goto unlock_retry;
+
+ if (fence_excl &&
+ !test_bit(FENCE_FLAG_SIGNALED_BIT, &fence_excl->flags)) {
+ if (!fence_get_rcu(fence_excl))
+ goto unlock_retry;
+
+ if (fence_is_signaled(fence_excl))
+ fence_put(fence_excl);
+ else
+ fence = fence_excl;
+ }
+ }
+
+ rcu_read_unlock();
+ if (fence) {
+ ret = fence_wait_timeout(fence, intr, ret);
+ fence_put(fence);
+ if (ret > 0 && wait_all && (i + 1 < shared_count))
+ goto retry;
+ }
+ return ret;
+
+unlock_retry:
+ rcu_read_unlock();
+ goto retry;
+}
+EXPORT_SYMBOL_GPL(reservation_object_wait_timeout_rcu);
+
+
+static inline int
+reservation_object_test_signaled_single(struct fence *passed_fence)
+{
+ struct fence *fence, *lfence = passed_fence;
+ int ret = 1;
+
+ if (!test_bit(FENCE_FLAG_SIGNALED_BIT, &lfence->flags)) {
+ int ret;
+
+ fence = fence_get_rcu(lfence);
+ if (!fence)
+ return -1;
+
+ ret = !!fence_is_signaled(fence);
+ fence_put(fence);
+ }
+ return ret;
+}
+
+bool reservation_object_test_signaled_rcu(struct reservation_object *obj,
+ bool test_all)
+{
+ unsigned seq, shared_count;
+ int ret = true;
+
+retry:
+ shared_count = 0;
+ seq = read_seqcount_begin(&obj->seq);
+ rcu_read_lock();
+
+ if (test_all) {
+ unsigned i;
+
+ struct reservation_object_list *fobj = rcu_dereference(obj->fence);
+
+ if (fobj)
+ shared_count = fobj->shared_count;
+
+ if (read_seqcount_retry(&obj->seq, seq))
+ goto unlock_retry;
+
+ for (i = 0; i < shared_count; ++i) {
+ struct fence *fence = rcu_dereference(fobj->shared[i]);
+
+ ret = reservation_object_test_signaled_single(fence);
+ if (ret < 0)
+ goto unlock_retry;
+ else if (!ret)
+ break;
+ }
+
+ /*
+ * There could be a read_seqcount_retry here, but nothing cares
+ * about whether it's the old or newer fence pointers that are
+ * signaled. That race could still have happened after checking
+ * read_seqcount_retry. If you care, use ww_mutex_lock.
+ */
+ }
+
+ if (!shared_count) {
+ struct fence *fence_excl = rcu_dereference(obj->fence_excl);
+
+ if (read_seqcount_retry(&obj->seq, seq))
+ goto unlock_retry;
+
+ if (fence_excl) {
+ ret = reservation_object_test_signaled_single(fence_excl);
+ if (ret < 0)
+ goto unlock_retry;
+ }
+ }
+
+ rcu_read_unlock();
+ return ret;
+
+unlock_retry:
+ rcu_read_unlock();
+ goto retry;
+}
+EXPORT_SYMBOL_GPL(reservation_object_test_signaled_rcu);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-23 00:04:42 +0100