path: root/common/recipes-kernel/linux/linux-yocto-4.14.71/2116-drm-amdkfd-Simplify-events-page-allocator.patch

From 187f24e703a35588437d2b1f6dbd528cd06a9bc8 Mon Sep 17 00:00:00 2001
From: Felix Kuehling <Felix.Kuehling@amd.com>
Date: Sat, 30 Sep 2017 20:46:03 -0400
Subject: [PATCH 2116/4131] drm/amdkfd: Simplify events page allocator

The first event page is always big enough to handle all events.
Handling of multiple events pages is not supported by user mode, and
not necessary.

Change-Id: I75f61dc90ff647e9c49208097307694ff699b38d
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_events.c | 227 ++++++++++----------------------
 drivers/gpu/drm/amd/amdkfd/kfd_events.h |   1 -
 drivers/gpu/drm/amd/amdkfd/kfd_priv.h   |   5 +-
 3 files changed, 73 insertions(+), 160 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_events.c b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
index 0baf130..9b76c38 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_events.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
@@ -57,12 +57,10 @@ struct kfd_event_waiter {
  * Individual signal events are then allocated a slot in a page.
  */
 
-struct signal_page {
-	struct list_head event_pages;	/* kfd_process.signal_event_pages */
+struct kfd_signal_page {
 	uint64_t *kernel_address;
 	uint64_t handle;
 	uint64_t __user *user_address;
-	uint32_t page_index;		/* Index into the mmap aperture. */
 	unsigned int free_slots;
 	unsigned long used_slot_bitmap[SLOT_BITMAP_LONGS];
 };
@@ -73,57 +71,48 @@ struct signal_page {
  */
 
 #define INTERRUPT_DATA_BITS 12
-#define SIGNAL_EVENT_ID_SLOT_SHIFT 0
 
-static uint64_t *page_slots(struct signal_page *page)
+static uint64_t *page_slots(struct kfd_signal_page *page)
 {
 	return page->kernel_address;
 }
 
 static bool allocate_free_slot(struct kfd_process *process,
-				struct signal_page **out_page,
-				unsigned int *out_slot_index)
+			       unsigned int *out_slot_index)
 {
-	struct signal_page *page;
+	struct kfd_signal_page *page = process->signal_page;
+	unsigned int slot;
 
-	list_for_each_entry(page, &process->signal_event_pages, event_pages) {
-		if (page->free_slots > 0) {
-			unsigned int slot =
-				find_first_zero_bit(page->used_slot_bitmap,
-							SLOTS_PER_PAGE);
+	if (!page || page->free_slots == 0) {
+		pr_debug("No free event signal slots were found for process %p\n",
+			 process);
 
-			__set_bit(slot, page->used_slot_bitmap);
-			page->free_slots--;
+		return false;
+	}
 
-			page_slots(page)[slot] = UNSIGNALED_EVENT_SLOT;
+	slot = find_first_zero_bit(page->used_slot_bitmap, SLOTS_PER_PAGE);
 
-			*out_page = page;
-			*out_slot_index = slot;
+	__set_bit(slot, page->used_slot_bitmap);
+	page->free_slots--;
 
-			pr_debug("Allocated event signal slot in page %p, slot %d\n",
-					page, slot);
+	page_slots(page)[slot] = UNSIGNALED_EVENT_SLOT;
 
-			return true;
-		}
-	}
+	*out_slot_index = slot;
 
-	pr_debug("No free event signal slots were found for process %p\n",
-			process);
+	pr_debug("Allocated event signal slot in page %p, slot %d\n",
+		 page, slot);
 
-	return false;
+	return true;
 }
 
-#define list_tail_entry(head, type, member) \
-	list_entry((head)->prev, type, member)
-
-static bool allocate_signal_page(struct file *devkfd, struct kfd_process *p)
+static struct kfd_signal_page *allocate_signal_page(struct kfd_process *p)
 {
 	void *backing_store;
-	struct signal_page *page;
+	struct kfd_signal_page *page;
 
 	page = kzalloc(sizeof(*page), GFP_KERNEL);
 	if (!page)
-		goto fail_alloc_signal_page;
+		return NULL;
 
 	page->free_slots = SLOTS_PER_PAGE;
 
@@ -132,99 +121,51 @@ static bool allocate_signal_page(struct file *devkfd, struct kfd_process *p)
 	if (!backing_store)
 		goto fail_alloc_signal_store;
 
-	/* prevent user-mode info leaks */
-	memset(backing_store, (uint8_t) UNSIGNALED_EVENT_SLOT,
-		KFD_SIGNAL_EVENT_LIMIT * 8);
-
 	page->kernel_address = backing_store;
-
-	if (list_empty(&p->signal_event_pages))
-		page->page_index = 0;
-	else
-		page->page_index = list_tail_entry(&p->signal_event_pages,
-						   struct signal_page,
-						   event_pages)->page_index + 1;
-
 	pr_debug("Allocated new event signal page at %p, for process %p\n",
 			page, p);
-	pr_debug("Page index is %d\n", page->page_index);
-
-	list_add(&page->event_pages, &p->signal_event_pages);
 
-	return true;
+	return page;
 
 fail_alloc_signal_store:
 	kfree(page);
-fail_alloc_signal_page:
-	return false;
+	return NULL;
 }
 
-static bool allocate_event_notification_slot(struct file *devkfd,
-					struct kfd_process *p,
-					struct signal_page **page,
-					unsigned int *signal_slot_index)
+static bool allocate_event_notification_slot(struct kfd_process *p,
+					     unsigned int *signal_slot_index)
 {
-	bool ret;
-
-	ret = allocate_free_slot(p, page, signal_slot_index);
-	if (!ret) {
-		ret = allocate_signal_page(devkfd, p);
-		if (ret)
-			ret = allocate_free_slot(p, page, signal_slot_index);
+	if (!p->signal_page) {
+		p->signal_page = allocate_signal_page(p);
+		if (!p->signal_page)
+			return false;
 	}
 
-	return ret;
+	return allocate_free_slot(p, signal_slot_index);
 }
 
-static bool allocate_signal_page_dgpu(struct kfd_process *p,
-				uint64_t *kernel_address, uint64_t handle)
+static struct kfd_signal_page *allocate_signal_page_dgpu(
+	struct kfd_process *p, uint64_t *kernel_address, uint64_t handle)
 {
-	struct signal_page *my_page;
+	struct kfd_signal_page *my_page;
 
 	my_page = kzalloc(sizeof(*my_page), GFP_KERNEL);
 	if (!my_page)
-		return false;
-
-	/* prevent user-mode info leaks */
-	memset(kernel_address, (uint8_t) UNSIGNALED_EVENT_SLOT,
-			KFD_SIGNAL_EVENT_LIMIT * 8);
+		return NULL;
 
 	my_page->kernel_address = kernel_address;
 	my_page->handle = handle;
 	my_page->user_address = NULL;
 	my_page->free_slots = SLOTS_PER_PAGE;
-	if (list_empty(&p->signal_event_pages))
-		my_page->page_index = 0;
-	else
-		my_page->page_index = list_tail_entry(&p->signal_event_pages,
-		   struct signal_page,
-		   event_pages)->page_index + 1;
 
 	pr_debug("Allocated new event signal page at %p, for process %p\n",
 			my_page, p);
-	pr_debug("Page index is %d\n", my_page->page_index);
-
-	list_add(&my_page->event_pages, &p->signal_event_pages);
-
-	return true;
-}
-
-void kfd_free_signal_page_dgpu(struct kfd_process *p, uint64_t handle)
-{
-	struct signal_page *page, *tmp;
 
-	list_for_each_entry_safe(page, tmp, &p->signal_event_pages,
-				event_pages) {
-		if (page->handle == handle) {
-			list_del(&page->event_pages);
-			kfree(page);
-			break;
-		}
-	}
+	return my_page;
 }
 
 /* Assumes that the process's event_mutex is locked. */
-static void release_event_notification_slot(struct signal_page *page,
+static void release_event_notification_slot(struct kfd_signal_page *page,
 						size_t slot_index)
 {
 	__clear_bit(slot_index, page->used_slot_bitmap);
@@ -235,22 +176,6 @@ static void release_event_notification_slot(struct signal_page *page,
 	 */
 }
 
-static struct signal_page *lookup_signal_page_by_index(struct kfd_process *p,
-						unsigned int page_index)
-{
-	struct signal_page *page;
-
-	/*
-	 * This is safe because we don't delete signal pages until the
-	 * process exits.
-	 */
-	list_for_each_entry(page, &p->signal_event_pages, event_pages)
-		if (page->page_index == page_index)
-			return page;
-
-	return NULL;
-}
-
 /*
  * Assumes that p->event_mutex is held and of course that p is not going
  * away (current or locked).
@@ -272,13 +197,6 @@ static struct kfd_event *lookup_event_by_id(struct kfd_process *p, uint32_t id)
 	return NULL;
 }
 
-static u32 make_signal_event_id(struct signal_page *page,
-					 unsigned int signal_slot_index)
-{
-	return page->page_index |
-			(signal_slot_index << SIGNAL_EVENT_ID_SLOT_SHIFT);
-}
-
 /*
  * Produce a kfd event id for a nonsignal event.
  * These are arbitrary numbers, so we do a sequential search through
@@ -324,10 +242,9 @@ static u32 make_nonsignal_event_id(struct kfd_process *p)
 }
 
 static struct kfd_event *lookup_event_by_page_slot(struct kfd_process *p,
-						struct signal_page *page,
 						unsigned int signal_slot)
 {
-	return lookup_event_by_id(p, make_signal_event_id(page, signal_slot));
+	return lookup_event_by_id(p, signal_slot);
 }
 
 static int create_signal_event(struct file *devkfd,
@@ -342,8 +259,7 @@ static int create_signal_event(struct file *devkfd,
 		return -ENOMEM;
 	}
 
-	if (!allocate_event_notification_slot(devkfd, p, &ev->signal_page,
-					      &ev->signal_slot_index)) {
+	if (!allocate_event_notification_slot(p, &ev->signal_slot_index)) {
 		pr_warn("Signal event wasn't created because out of kernel memory\n");
 		return -ENOMEM;
 	}
@@ -351,10 +267,9 @@ static int create_signal_event(struct file *devkfd,
 	p->signal_event_count++;
 
 	ev->user_signal_address =
-			&ev->signal_page->user_address[ev->signal_slot_index];
+			&p->signal_page->user_address[ev->signal_slot_index];
 
-	ev->event_id = make_signal_event_id(ev->signal_page,
-						ev->signal_slot_index);
+	ev->event_id = ev->signal_slot_index;
 
 	pr_debug("Signal event number %zu created with id %d, address %p\n",
 			p->signal_event_count, ev->event_id,
@@ -381,7 +296,7 @@ void kfd_event_init_process(struct kfd_process *p)
 {
 	mutex_init(&p->event_mutex);
 	hash_init(p->events);
-	INIT_LIST_HEAD(&p->signal_event_pages);
+	p->signal_page = NULL;
 	p->next_nonsignal_event_id = KFD_FIRST_NONSIGNAL_EVENT_ID;
 	p->signal_event_count = 0;
 }
@@ -395,8 +310,9 @@ static void destroy_event(struct kfd_process *p, struct kfd_event *ev)
 		waiter->event = NULL;
 	wake_up_all(&ev->wq);
 
-	if (ev->signal_page) {
-		release_event_notification_slot(ev->signal_page,
+	if ((ev->type == KFD_EVENT_TYPE_SIGNAL ||
+	     ev->type == KFD_EVENT_TYPE_DEBUG) && p->signal_page) {
+		release_event_notification_slot(p->signal_page,
 						ev->signal_slot_index);
 		p->signal_event_count--;
 	}
@@ -425,12 +341,11 @@ static void destroy_events(struct kfd_process *p)
  * We assume that the process is being destroyed and there is no need to
  * unmap the pages or keep bookkeeping data in order.
  */
-static void shutdown_signal_pages(struct kfd_process *p)
+static void shutdown_signal_page(struct kfd_process *p)
 {
-	struct signal_page *page, *tmp;
+	struct kfd_signal_page *page = p->signal_page;
 
-	list_for_each_entry_safe(page, tmp, &p->signal_event_pages,
-					event_pages) {
+	if (page) {
 		if (page->user_address)
 			free_pages((unsigned long)page->kernel_address,
 					get_order(KFD_SIGNAL_EVENT_LIMIT * 8));
@@ -441,7 +356,7 @@ static void shutdown_signal_pages(struct kfd_process *p)
 void kfd_event_free_process(struct kfd_process *p)
 {
 	destroy_events(p);
-	shutdown_signal_pages(p);
+	shutdown_signal_page(p);
 }
 
 static bool event_can_be_gpu_signaled(const struct kfd_event *ev)
@@ -475,8 +390,12 @@ int kfd_event_create(struct file *devkfd, struct kfd_process *p,
 
 	mutex_lock(&p->event_mutex);
 
-	if (kern_addr && list_empty(&p->signal_event_pages))
-		allocate_signal_page_dgpu(p, kern_addr, *event_page_offset);
+	if (kern_addr && !p->signal_page) {
+		p->signal_page = allocate_signal_page_dgpu(p, kern_addr,
+							   *event_page_offset);
+		if (!p->signal_page)
+			return -ENOMEM;
+	}
 
 	*event_page_offset = 0;
 
@@ -485,8 +404,7 @@ int kfd_event_create(struct file *devkfd, struct kfd_process *p,
 	case KFD_EVENT_TYPE_DEBUG:
 		ret = create_signal_event(devkfd, p, ev);
 		if (!ret) {
-			*event_page_offset = (ev->signal_page->page_index |
-					KFD_MMAP_TYPE_EVENTS);
+			*event_page_offset = KFD_MMAP_TYPE_EVENTS;
 			*event_page_offset <<= PAGE_SHIFT;
 			*event_slot_index = ev->signal_slot_index;
 		}
@@ -588,13 +506,17 @@ int kfd_reset_event(struct kfd_process *p, uint32_t event_id)
 
 static void acknowledge_signal(struct kfd_process *p, struct kfd_event *ev)
 {
-	page_slots(ev->signal_page)[ev->signal_slot_index] =
+	page_slots(p->signal_page)[ev->signal_slot_index] =
 						UNSIGNALED_EVENT_SLOT;
 }
 
-static bool is_slot_signaled(struct signal_page *page, unsigned int index)
+static bool is_slot_signaled(struct kfd_process *p, unsigned int index)
 {
-	return page_slots(page)[index] != UNSIGNALED_EVENT_SLOT;
+	if (!p->signal_page)
+		return false;
+	else
+		return page_slots(p->signal_page)[index] !=
+			UNSIGNALED_EVENT_SLOT;
 }
 
 static void set_event_from_interrupt(struct kfd_process *p,
@@ -627,22 +549,19 @@ void kfd_signal_event_interrupt(unsigned int pasid, uint32_t partial_id,
 		/* Partial ID is a full ID. */
 		ev = lookup_event_by_id(p, partial_id);
 		set_event_from_interrupt(p, ev);
-	} else {
+	} else if (p->signal_page) {
 		/*
 		 * Partial ID is in fact partial. For now we completely
 		 * ignore it, but we could use any bits we did receive to
 		 * search faster.
 		 */
-		struct signal_page *page;
 		unsigned int i;
 
-		list_for_each_entry(page, &p->signal_event_pages, event_pages)
-			for (i = 0; i < SLOTS_PER_PAGE; i++)
-				if (is_slot_signaled(page, i)) {
-					ev = lookup_event_by_page_slot(p,
-								page, i);
-					set_event_from_interrupt(p, ev);
-				}
+		for (i = 0; i < SLOTS_PER_PAGE; i++)
+			if (is_slot_signaled(p, i)) {
+				ev = lookup_event_by_page_slot(p, i);
+				set_event_from_interrupt(p, ev);
+			}
 	}
 
 	mutex_unlock(&p->event_mutex);
@@ -906,9 +825,8 @@ int kfd_wait_on_events(struct kfd_process *p,
 int kfd_event_mmap(struct kfd_process *p, struct vm_area_struct *vma)
 {
 
-	unsigned int page_index;
 	unsigned long pfn;
-	struct signal_page *page;
+	struct kfd_signal_page *page;
 
 	/* check required size is logical */
 	if (get_order(KFD_SIGNAL_EVENT_LIMIT * 8) !=
@@ -917,13 +835,10 @@ int kfd_event_mmap(struct kfd_process *p, struct vm_area_struct *vma)
 		return -EINVAL;
 	}
 
-	page_index = vma->vm_pgoff;
-
-	page = lookup_signal_page_by_index(p, page_index);
+	page = p->signal_page;
 	if (!page) {
 		/* Probably KFD bug, but mmap is user-accessible. */
-		pr_debug("Signal page could not be found for page_index %u\n",
-				page_index);
+		pr_debug("Signal page could not be found\n");
 		return -EINVAL;
 	}
 
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_events.h b/drivers/gpu/drm/amd/amdkfd/kfd_events.h
index 96f9122..f85fcee 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_events.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_events.h
@@ -60,7 +60,6 @@ struct kfd_event {
 	wait_queue_head_t wq; /* List of event waiters. */
 
 	/* Only for signal events. */
-	struct signal_page *signal_page;
 	unsigned int signal_slot_index;
 	uint64_t __user *user_signal_address;
 
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
index 1ac4db5..4fca10f 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
@@ -719,8 +719,8 @@ struct kfd_process {
 	struct mutex event_mutex;
 	/* All events in process hashed by ID, linked on kfd_event.events. */
 	DECLARE_HASHTABLE(events, 4);
-	/* struct slot_page_header.event_pages */
-	struct list_head signal_event_pages;
+	/* Event page */
+	struct kfd_signal_page *signal_page;
 	u32 next_nonsignal_event_id;
 	size_t signal_event_count;
 	bool signal_event_limit_reached;
@@ -1060,7 +1060,6 @@ int kfd_event_create(struct file *devkfd, struct kfd_process *p,
 		     uint64_t *event_page_offset, uint32_t *event_slot_index,
 		     void *kern_addr);
 int kfd_event_destroy(struct kfd_process *p, uint32_t event_id);
-void kfd_free_signal_page_dgpu(struct kfd_process *p, uint64_t handle);
 
 void kfd_signal_vm_fault_event(struct kfd_dev *dev, unsigned int pasid,
 				struct kfd_vm_fault_info *info);
-- 
2.7.4