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-rw-r--r--drivers/dma-buf/dma-resv.c683
1 files changed, 683 insertions, 0 deletions
diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c
new file mode 100644
index 000000000..1187e5e80
--- /dev/null
+++ b/drivers/dma-buf/dma-resv.c
@@ -0,0 +1,683 @@
+/*
+ * 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/dma-resv.h>
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/sched/mm.h>
+#include <linux/mmu_notifier.h>
+
+/**
+ * DOC: Reservation Object Overview
+ *
+ * The reservation object provides a mechanism to manage shared and
+ * exclusive fences associated with a buffer. A reservation object
+ * can have attached one exclusive fence (normally associated with
+ * write operations) or N shared fences (read operations). The RCU
+ * mechanism is used to protect read access to fences from locked
+ * write-side updates.
+ */
+
+DEFINE_WD_CLASS(reservation_ww_class);
+EXPORT_SYMBOL(reservation_ww_class);
+
+/**
+ * dma_resv_list_alloc - allocate fence list
+ * @shared_max: number of fences we need space for
+ *
+ * Allocate a new dma_resv_list and make sure to correctly initialize
+ * shared_max.
+ */
+static struct dma_resv_list *dma_resv_list_alloc(unsigned int shared_max)
+{
+ struct dma_resv_list *list;
+
+ list = kmalloc(offsetof(typeof(*list), shared[shared_max]), GFP_KERNEL);
+ if (!list)
+ return NULL;
+
+ list->shared_max = (ksize(list) - offsetof(typeof(*list), shared)) /
+ sizeof(*list->shared);
+
+ return list;
+}
+
+/**
+ * dma_resv_list_free - free fence list
+ * @list: list to free
+ *
+ * Free a dma_resv_list and make sure to drop all references.
+ */
+static void dma_resv_list_free(struct dma_resv_list *list)
+{
+ unsigned int i;
+
+ if (!list)
+ return;
+
+ for (i = 0; i < list->shared_count; ++i)
+ dma_fence_put(rcu_dereference_protected(list->shared[i], true));
+
+ kfree_rcu(list, rcu);
+}
+
+#if IS_ENABLED(CONFIG_LOCKDEP)
+static int __init dma_resv_lockdep(void)
+{
+ struct mm_struct *mm = mm_alloc();
+ struct ww_acquire_ctx ctx;
+ struct dma_resv obj;
+ struct address_space mapping;
+ int ret;
+
+ if (!mm)
+ return -ENOMEM;
+
+ dma_resv_init(&obj);
+ address_space_init_once(&mapping);
+
+ mmap_read_lock(mm);
+ ww_acquire_init(&ctx, &reservation_ww_class);
+ ret = dma_resv_lock(&obj, &ctx);
+ if (ret == -EDEADLK)
+ dma_resv_lock_slow(&obj, &ctx);
+ fs_reclaim_acquire(GFP_KERNEL);
+ /* for unmap_mapping_range on trylocked buffer objects in shrinkers */
+ i_mmap_lock_write(&mapping);
+ i_mmap_unlock_write(&mapping);
+#ifdef CONFIG_MMU_NOTIFIER
+ lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
+ __dma_fence_might_wait();
+ lock_map_release(&__mmu_notifier_invalidate_range_start_map);
+#else
+ __dma_fence_might_wait();
+#endif
+ fs_reclaim_release(GFP_KERNEL);
+ ww_mutex_unlock(&obj.lock);
+ ww_acquire_fini(&ctx);
+ mmap_read_unlock(mm);
+
+ mmput(mm);
+
+ return 0;
+}
+subsys_initcall(dma_resv_lockdep);
+#endif
+
+/**
+ * dma_resv_init - initialize a reservation object
+ * @obj: the reservation object
+ */
+void dma_resv_init(struct dma_resv *obj)
+{
+ ww_mutex_init(&obj->lock, &reservation_ww_class);
+ seqcount_ww_mutex_init(&obj->seq, &obj->lock);
+
+ RCU_INIT_POINTER(obj->fence, NULL);
+ RCU_INIT_POINTER(obj->fence_excl, NULL);
+}
+EXPORT_SYMBOL(dma_resv_init);
+
+/**
+ * dma_resv_fini - destroys a reservation object
+ * @obj: the reservation object
+ */
+void dma_resv_fini(struct dma_resv *obj)
+{
+ struct dma_resv_list *fobj;
+ struct dma_fence *excl;
+
+ /*
+ * This object should be dead and all references must have
+ * been released to it, so no need to be protected with rcu.
+ */
+ excl = rcu_dereference_protected(obj->fence_excl, 1);
+ if (excl)
+ dma_fence_put(excl);
+
+ fobj = rcu_dereference_protected(obj->fence, 1);
+ dma_resv_list_free(fobj);
+ ww_mutex_destroy(&obj->lock);
+}
+EXPORT_SYMBOL(dma_resv_fini);
+
+/**
+ * dma_resv_reserve_shared - Reserve space to add shared fences to
+ * a dma_resv.
+ * @obj: reservation object
+ * @num_fences: number of fences we want to add
+ *
+ * Should be called before dma_resv_add_shared_fence(). Must
+ * be called with obj->lock held.
+ *
+ * RETURNS
+ * Zero for success, or -errno
+ */
+int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences)
+{
+ struct dma_resv_list *old, *new;
+ unsigned int i, j, k, max;
+
+ dma_resv_assert_held(obj);
+
+ old = dma_resv_get_list(obj);
+
+ if (old && old->shared_max) {
+ if ((old->shared_count + num_fences) <= old->shared_max)
+ return 0;
+ else
+ max = max(old->shared_count + num_fences,
+ old->shared_max * 2);
+ } else {
+ max = max(4ul, roundup_pow_of_two(num_fences));
+ }
+
+ new = dma_resv_list_alloc(max);
+ if (!new)
+ return -ENOMEM;
+
+ /*
+ * 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.
+ */
+ for (i = 0, j = 0, k = max; i < (old ? old->shared_count : 0); ++i) {
+ struct dma_fence *fence;
+
+ fence = rcu_dereference_protected(old->shared[i],
+ dma_resv_held(obj));
+ if (dma_fence_is_signaled(fence))
+ RCU_INIT_POINTER(new->shared[--k], fence);
+ else
+ RCU_INIT_POINTER(new->shared[j++], fence);
+ }
+ new->shared_count = j;
+
+ /*
+ * We are not changing the effective set of fences here so can
+ * merely update the pointer to the new array; both existing
+ * readers and new readers will see exactly the same set of
+ * active (unsignaled) shared fences. Individual fences and the
+ * old array are protected by RCU and so will not vanish under
+ * the gaze of the rcu_read_lock() readers.
+ */
+ rcu_assign_pointer(obj->fence, new);
+
+ if (!old)
+ return 0;
+
+ /* Drop the references to the signaled fences */
+ for (i = k; i < max; ++i) {
+ struct dma_fence *fence;
+
+ fence = rcu_dereference_protected(new->shared[i],
+ dma_resv_held(obj));
+ dma_fence_put(fence);
+ }
+ kfree_rcu(old, rcu);
+
+ return 0;
+}
+EXPORT_SYMBOL(dma_resv_reserve_shared);
+
+/**
+ * dma_resv_add_shared_fence - Add a fence to a shared slot
+ * @obj: the reservation object
+ * @fence: the shared fence to add
+ *
+ * Add a fence to a shared slot, obj->lock must be held, and
+ * dma_resv_reserve_shared() has been called.
+ */
+void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence)
+{
+ struct dma_resv_list *fobj;
+ struct dma_fence *old;
+ unsigned int i, count;
+
+ dma_fence_get(fence);
+
+ dma_resv_assert_held(obj);
+
+ fobj = dma_resv_get_list(obj);
+ count = fobj->shared_count;
+
+ write_seqcount_begin(&obj->seq);
+
+ for (i = 0; i < count; ++i) {
+
+ old = rcu_dereference_protected(fobj->shared[i],
+ dma_resv_held(obj));
+ if (old->context == fence->context ||
+ dma_fence_is_signaled(old))
+ goto replace;
+ }
+
+ BUG_ON(fobj->shared_count >= fobj->shared_max);
+ old = NULL;
+ count++;
+
+replace:
+ RCU_INIT_POINTER(fobj->shared[i], fence);
+ /* pointer update must be visible before we extend the shared_count */
+ smp_store_mb(fobj->shared_count, count);
+
+ write_seqcount_end(&obj->seq);
+ dma_fence_put(old);
+}
+EXPORT_SYMBOL(dma_resv_add_shared_fence);
+
+/**
+ * dma_resv_add_excl_fence - Add an exclusive fence.
+ * @obj: the reservation object
+ * @fence: the shared fence to add
+ *
+ * Add a fence to the exclusive slot. The obj->lock must be held.
+ */
+void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence)
+{
+ struct dma_fence *old_fence = dma_resv_get_excl(obj);
+ struct dma_resv_list *old;
+ u32 i = 0;
+
+ dma_resv_assert_held(obj);
+
+ old = dma_resv_get_list(obj);
+ if (old)
+ i = old->shared_count;
+
+ if (fence)
+ dma_fence_get(fence);
+
+ 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);
+
+ /* inplace update, no shared fences */
+ while (i--)
+ dma_fence_put(rcu_dereference_protected(old->shared[i],
+ dma_resv_held(obj)));
+
+ dma_fence_put(old_fence);
+}
+EXPORT_SYMBOL(dma_resv_add_excl_fence);
+
+/**
+* dma_resv_copy_fences - Copy all fences from src to dst.
+* @dst: the destination reservation object
+* @src: the source reservation object
+*
+* Copy all fences from src to dst. dst-lock must be held.
+*/
+int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src)
+{
+ struct dma_resv_list *src_list, *dst_list;
+ struct dma_fence *old, *new;
+ unsigned i;
+
+ dma_resv_assert_held(dst);
+
+ rcu_read_lock();
+ src_list = rcu_dereference(src->fence);
+
+retry:
+ if (src_list) {
+ unsigned shared_count = src_list->shared_count;
+
+ rcu_read_unlock();
+
+ dst_list = dma_resv_list_alloc(shared_count);
+ if (!dst_list)
+ return -ENOMEM;
+
+ rcu_read_lock();
+ src_list = rcu_dereference(src->fence);
+ if (!src_list || src_list->shared_count > shared_count) {
+ kfree(dst_list);
+ goto retry;
+ }
+
+ dst_list->shared_count = 0;
+ for (i = 0; i < src_list->shared_count; ++i) {
+ struct dma_fence *fence;
+
+ fence = rcu_dereference(src_list->shared[i]);
+ if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
+ &fence->flags))
+ continue;
+
+ if (!dma_fence_get_rcu(fence)) {
+ dma_resv_list_free(dst_list);
+ src_list = rcu_dereference(src->fence);
+ goto retry;
+ }
+
+ if (dma_fence_is_signaled(fence)) {
+ dma_fence_put(fence);
+ continue;
+ }
+
+ rcu_assign_pointer(dst_list->shared[dst_list->shared_count++], fence);
+ }
+ } else {
+ dst_list = NULL;
+ }
+
+ new = dma_fence_get_rcu_safe(&src->fence_excl);
+ rcu_read_unlock();
+
+ src_list = dma_resv_get_list(dst);
+ old = dma_resv_get_excl(dst);
+
+ write_seqcount_begin(&dst->seq);
+ /* write_seqcount_begin provides the necessary memory barrier */
+ RCU_INIT_POINTER(dst->fence_excl, new);
+ RCU_INIT_POINTER(dst->fence, dst_list);
+ write_seqcount_end(&dst->seq);
+
+ dma_resv_list_free(src_list);
+ dma_fence_put(old);
+
+ return 0;
+}
+EXPORT_SYMBOL(dma_resv_copy_fences);
+
+/**
+ * dma_resv_get_fences_rcu - Get an object's shared and exclusive
+ * fences without update side lock held
+ * @obj: the reservation object
+ * @pfence_excl: the returned exclusive fence (or NULL)
+ * @pshared_count: the number of shared fences returned
+ * @pshared: the array of shared fence ptrs returned (array is krealloc'd to
+ * the required size, and must be freed by caller)
+ *
+ * Retrieve all fences from the reservation object. If the pointer for the
+ * exclusive fence is not specified the fence is put into the array of the
+ * shared fences as well. Returns either zero or -ENOMEM.
+ */
+int dma_resv_get_fences_rcu(struct dma_resv *obj,
+ struct dma_fence **pfence_excl,
+ unsigned *pshared_count,
+ struct dma_fence ***pshared)
+{
+ struct dma_fence **shared = NULL;
+ struct dma_fence *fence_excl;
+ unsigned int shared_count;
+ int ret = 1;
+
+ do {
+ struct dma_resv_list *fobj;
+ unsigned int i, seq;
+ size_t sz = 0;
+
+ shared_count = i = 0;
+
+ rcu_read_lock();
+ seq = read_seqcount_begin(&obj->seq);
+
+ fence_excl = rcu_dereference(obj->fence_excl);
+ if (fence_excl && !dma_fence_get_rcu(fence_excl))
+ goto unlock;
+
+ fobj = rcu_dereference(obj->fence);
+ if (fobj)
+ sz += sizeof(*shared) * fobj->shared_max;
+
+ if (!pfence_excl && fence_excl)
+ sz += sizeof(*shared);
+
+ if (sz) {
+ struct dma_fence **nshared;
+
+ nshared = krealloc(shared, sz,
+ GFP_NOWAIT | __GFP_NOWARN);
+ if (!nshared) {
+ rcu_read_unlock();
+
+ dma_fence_put(fence_excl);
+ fence_excl = NULL;
+
+ nshared = krealloc(shared, sz, GFP_KERNEL);
+ if (nshared) {
+ shared = nshared;
+ continue;
+ }
+
+ ret = -ENOMEM;
+ break;
+ }
+ shared = nshared;
+ shared_count = fobj ? fobj->shared_count : 0;
+ for (i = 0; i < shared_count; ++i) {
+ shared[i] = rcu_dereference(fobj->shared[i]);
+ if (!dma_fence_get_rcu(shared[i]))
+ break;
+ }
+ }
+
+ if (i != shared_count || read_seqcount_retry(&obj->seq, seq)) {
+ while (i--)
+ dma_fence_put(shared[i]);
+ dma_fence_put(fence_excl);
+ goto unlock;
+ }
+
+ ret = 0;
+unlock:
+ rcu_read_unlock();
+ } while (ret);
+
+ if (pfence_excl)
+ *pfence_excl = fence_excl;
+ else if (fence_excl)
+ shared[shared_count++] = fence_excl;
+
+ if (!shared_count) {
+ kfree(shared);
+ shared = NULL;
+ }
+
+ *pshared_count = shared_count;
+ *pshared = shared;
+ return ret;
+}
+EXPORT_SYMBOL_GPL(dma_resv_get_fences_rcu);
+
+/**
+ * dma_resv_wait_timeout_rcu - Wait on reservation's objects
+ * shared and/or exclusive fences.
+ * @obj: the reservation object
+ * @wait_all: if true, wait on all fences, else wait on just exclusive fence
+ * @intr: if true, do interruptible wait
+ * @timeout: timeout value in jiffies or zero to return immediately
+ *
+ * RETURNS
+ * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or
+ * greater than zer on success.
+ */
+long dma_resv_wait_timeout_rcu(struct dma_resv *obj,
+ bool wait_all, bool intr,
+ unsigned long timeout)
+{
+ struct dma_fence *fence;
+ unsigned seq, shared_count;
+ long ret = timeout ? timeout : 1;
+ int i;
+
+retry:
+ shared_count = 0;
+ seq = read_seqcount_begin(&obj->seq);
+ rcu_read_lock();
+ i = -1;
+
+ fence = rcu_dereference(obj->fence_excl);
+ if (fence && !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
+ if (!dma_fence_get_rcu(fence))
+ goto unlock_retry;
+
+ if (dma_fence_is_signaled(fence)) {
+ dma_fence_put(fence);
+ fence = NULL;
+ }
+
+ } else {
+ fence = NULL;
+ }
+
+ if (wait_all) {
+ struct dma_resv_list *fobj = rcu_dereference(obj->fence);
+
+ if (fobj)
+ shared_count = fobj->shared_count;
+
+ for (i = 0; !fence && i < shared_count; ++i) {
+ struct dma_fence *lfence = rcu_dereference(fobj->shared[i]);
+
+ if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
+ &lfence->flags))
+ continue;
+
+ if (!dma_fence_get_rcu(lfence))
+ goto unlock_retry;
+
+ if (dma_fence_is_signaled(lfence)) {
+ dma_fence_put(lfence);
+ continue;
+ }
+
+ fence = lfence;
+ break;
+ }
+ }
+
+ rcu_read_unlock();
+ if (fence) {
+ if (read_seqcount_retry(&obj->seq, seq)) {
+ dma_fence_put(fence);
+ goto retry;
+ }
+
+ ret = dma_fence_wait_timeout(fence, intr, ret);
+ dma_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(dma_resv_wait_timeout_rcu);
+
+
+static inline int dma_resv_test_signaled_single(struct dma_fence *passed_fence)
+{
+ struct dma_fence *fence, *lfence = passed_fence;
+ int ret = 1;
+
+ if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &lfence->flags)) {
+ fence = dma_fence_get_rcu(lfence);
+ if (!fence)
+ return -1;
+
+ ret = !!dma_fence_is_signaled(fence);
+ dma_fence_put(fence);
+ }
+ return ret;
+}
+
+/**
+ * dma_resv_test_signaled_rcu - Test if a reservation object's
+ * fences have been signaled.
+ * @obj: the reservation object
+ * @test_all: if true, test all fences, otherwise only test the exclusive
+ * fence
+ *
+ * RETURNS
+ * true if all fences signaled, else false
+ */
+bool dma_resv_test_signaled_rcu(struct dma_resv *obj, bool test_all)
+{
+ unsigned seq, shared_count;
+ int ret;
+
+ rcu_read_lock();
+retry:
+ ret = true;
+ shared_count = 0;
+ seq = read_seqcount_begin(&obj->seq);
+
+ if (test_all) {
+ unsigned i;
+
+ struct dma_resv_list *fobj = rcu_dereference(obj->fence);
+
+ if (fobj)
+ shared_count = fobj->shared_count;
+
+ for (i = 0; i < shared_count; ++i) {
+ struct dma_fence *fence = rcu_dereference(fobj->shared[i]);
+
+ ret = dma_resv_test_signaled_single(fence);
+ if (ret < 0)
+ goto retry;
+ else if (!ret)
+ break;
+ }
+
+ if (read_seqcount_retry(&obj->seq, seq))
+ goto retry;
+ }
+
+ if (!shared_count) {
+ struct dma_fence *fence_excl = rcu_dereference(obj->fence_excl);
+
+ if (fence_excl) {
+ ret = dma_resv_test_signaled_single(fence_excl);
+ if (ret < 0)
+ goto retry;
+
+ if (read_seqcount_retry(&obj->seq, seq))
+ goto retry;
+ }
+ }
+
+ rcu_read_unlock();
+ return ret;
+}
+EXPORT_SYMBOL_GPL(dma_resv_test_signaled_rcu);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-28 23:02:02 +0000