3 files changed, 90 insertions, 67 deletions

diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index f15af2b55a62..e96659215f25 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -62,9 +62,9 @@ static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
 				       struct binder_buffer *buffer)
 {
 	if (list_is_last(&buffer->entry, &alloc->buffers))
-		return alloc->buffer +
-		       alloc->buffer_size - (void *)buffer->data;
-	return (size_t)binder_buffer_next(buffer) - (size_t)buffer->data;
+		return (u8 *)alloc->buffer +
+			alloc->buffer_size - (u8 *)buffer->data;
+	return (u8 *)binder_buffer_next(buffer)->data - (u8 *)buffer->data;
 }
 
 static void binder_insert_free_buffer(struct binder_alloc *alloc,
@@ -114,9 +114,9 @@ static void binder_insert_allocated_buffer_locked(
 		buffer = rb_entry(parent, struct binder_buffer, rb_node);
 		BUG_ON(buffer->free);
 
-		if (new_buffer < buffer)
+		if (new_buffer->data < buffer->data)
 			p = &parent->rb_left;
-		else if (new_buffer > buffer)
+		else if (new_buffer->data > buffer->data)
 			p = &parent->rb_right;
 		else
 			BUG();
@@ -131,18 +131,17 @@ static struct binder_buffer *binder_alloc_prepare_to_free_locked(
 {
 	struct rb_node *n = alloc->allocated_buffers.rb_node;
 	struct binder_buffer *buffer;
-	struct binder_buffer *kern_ptr;
+	void *kern_ptr;
 
-	kern_ptr = (struct binder_buffer *)(user_ptr - alloc->user_buffer_offset
-		- offsetof(struct binder_buffer, data));
+	kern_ptr = (void *)(user_ptr - alloc->user_buffer_offset);
 
 	while (n) {
 		buffer = rb_entry(n, struct binder_buffer, rb_node);
 		BUG_ON(buffer->free);
 
-		if (kern_ptr < buffer)
+		if (kern_ptr < buffer->data)
 			n = n->rb_left;
-		else if (kern_ptr > buffer)
+		else if (kern_ptr > buffer->data)
 			n = n->rb_right;
 		else {
 			/*
@@ -330,6 +329,9 @@ struct binder_buffer *binder_alloc_new_buf_locked(struct binder_alloc *alloc,
 		return ERR_PTR(-ENOSPC);
 	}
 
+	/* Pad 0-size buffers so they get assigned unique addresses */
+	size = max(size, sizeof(void *));
+
 	while (n) {
 		buffer = rb_entry(n, struct binder_buffer, rb_node);
 		BUG_ON(!buffer->free);
@@ -389,14 +391,9 @@ struct binder_buffer *binder_alloc_new_buf_locked(struct binder_alloc *alloc,
 
 	has_page_addr =
 		(void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK);
-	if (n == NULL) {
-		if (size + sizeof(struct binder_buffer) + 4 >= buffer_size)
-			buffer_size = size; /* no room for other buffers */
-		else
-			buffer_size = size + sizeof(struct binder_buffer);
-	}
+	WARN_ON(n && buffer_size != size);
 	end_page_addr =
-		(void *)PAGE_ALIGN((uintptr_t)buffer->data + buffer_size);
+		(void *)PAGE_ALIGN((uintptr_t)buffer->data + size);
 	if (end_page_addr > has_page_addr)
 		end_page_addr = has_page_addr;
 	ret = binder_update_page_range(alloc, 1,
@@ -404,17 +401,25 @@ struct binder_buffer *binder_alloc_new_buf_locked(struct binder_alloc *alloc,
 	if (ret)
 		return ERR_PTR(ret);
 
-	rb_erase(best_fit, &alloc->free_buffers);
-	buffer->free = 0;
-	buffer->free_in_progress = 0;
-	binder_insert_allocated_buffer_locked(alloc, buffer);
 	if (buffer_size != size) {
-		struct binder_buffer *new_buffer = (void *)buffer->data + size;
+		struct binder_buffer *new_buffer;
 
+		new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
+		if (!new_buffer) {
+			pr_err("%s: %d failed to alloc new buffer struct\n",
+			       __func__, alloc->pid);
+			goto err_alloc_buf_struct_failed;
+		}
+		new_buffer->data = (u8 *)buffer->data + size;
 		list_add(&new_buffer->entry, &buffer->entry);
 		new_buffer->free = 1;
 		binder_insert_free_buffer(alloc, new_buffer);
 	}
+
+	rb_erase(best_fit, &alloc->free_buffers);
+	buffer->free = 0;
+	buffer->free_in_progress = 0;
+	binder_insert_allocated_buffer_locked(alloc, buffer);
 	binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 		     "%d: binder_alloc_buf size %zd got %pK\n",
 		      alloc->pid, size, buffer);
@@ -429,6 +434,12 @@ struct binder_buffer *binder_alloc_new_buf_locked(struct binder_alloc *alloc,
 			      alloc->pid, size, alloc->free_async_space);
 	}
 	return buffer;
+
+err_alloc_buf_struct_failed:
+	binder_update_page_range(alloc, 0,
+				 (void *)PAGE_ALIGN((uintptr_t)buffer->data),
+				 end_page_addr, NULL);
+	return ERR_PTR(-ENOMEM);
 }
 
 /**
@@ -463,56 +474,59 @@ struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 
 static void *buffer_start_page(struct binder_buffer *buffer)
 {
-	return (void *)((uintptr_t)buffer & PAGE_MASK);
+	return (void *)((uintptr_t)buffer->data & PAGE_MASK);
 }
 
-static void *buffer_end_page(struct binder_buffer *buffer)
+static void *prev_buffer_end_page(struct binder_buffer *buffer)
 {
-	return (void *)(((uintptr_t)(buffer + 1) - 1) & PAGE_MASK);
+	return (void *)(((uintptr_t)(buffer->data) - 1) & PAGE_MASK);
 }
 
 static void binder_delete_free_buffer(struct binder_alloc *alloc,
 				      struct binder_buffer *buffer)
 {
 	struct binder_buffer *prev, *next = NULL;
-	int free_page_end = 1;
-	int free_page_start = 1;
-
+	bool to_free = true;
 	BUG_ON(alloc->buffers.next == &buffer->entry);
 	prev = binder_buffer_prev(buffer);
 	BUG_ON(!prev->free);
-	if (buffer_end_page(prev) == buffer_start_page(buffer)) {
-		free_page_start = 0;
-		if (buffer_end_page(prev) == buffer_end_page(buffer))
-			free_page_end = 0;
+	if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
+		to_free = false;
 		binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
-			     "%d: merge free, buffer %pK share page with %pK\n",
-			      alloc->pid, buffer, prev);
+				   "%d: merge free, buffer %pK share page with %pK\n",
+				   alloc->pid, buffer->data, prev->data);
 	}
 
 	if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 		next = binder_buffer_next(buffer);
-		if (buffer_start_page(next) == buffer_end_page(buffer)) {
-			free_page_end = 0;
-			if (buffer_start_page(next) ==
-			    buffer_start_page(buffer))
-				free_page_start = 0;
+		if (buffer_start_page(next) == buffer_start_page(buffer)) {
+			to_free = false;
 			binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
-				     "%d: merge free, buffer %pK share page with %pK\n",
-				      alloc->pid, buffer, prev);
+					   "%d: merge free, buffer %pK share page with %pK\n",
+					   alloc->pid,
+					   buffer->data,
+					   next->data);
 		}
 	}
-	list_del(&buffer->entry);
-	if (free_page_start || free_page_end) {
+
+	if (PAGE_ALIGNED(buffer->data)) {
+		binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
+				   "%d: merge free, buffer start %pK is page aligned\n",
+				   alloc->pid, buffer->data);
+		to_free = false;
+	}
+
+	if (to_free) {
 		binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
-			     "%d: merge free, buffer %pK do not share page%s%s with %pK or %pK\n",
-			     alloc->pid, buffer, free_page_start ? "" : " end",
-			     free_page_end ? "" : " start", prev, next);
-		binder_update_page_range(alloc, 0, free_page_start ?
-			buffer_start_page(buffer) : buffer_end_page(buffer),
-			(free_page_end ? buffer_end_page(buffer) :
-			buffer_start_page(buffer)) + PAGE_SIZE, NULL);
+				   "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
+				   alloc->pid, buffer->data,
+				   prev->data, next->data);
+		binder_update_page_range(alloc, 0, buffer_start_page(buffer),
+					 buffer_start_page(buffer) + PAGE_SIZE,
+					 NULL);
 	}
+	list_del(&buffer->entry);
+	kfree(buffer);
 }
 
 static void binder_free_buf_locked(struct binder_alloc *alloc,
@@ -533,8 +547,8 @@ static void binder_free_buf_locked(struct binder_alloc *alloc,
 	BUG_ON(buffer->free);
 	BUG_ON(size > buffer_size);
 	BUG_ON(buffer->transaction != NULL);
-	BUG_ON((void *)buffer < alloc->buffer);
-	BUG_ON((void *)buffer > alloc->buffer + alloc->buffer_size);
+	BUG_ON(buffer->data < alloc->buffer);
+	BUG_ON(buffer->data > alloc->buffer + alloc->buffer_size);
 
 	if (buffer->async_transaction) {
 		alloc->free_async_space += size + sizeof(struct binder_buffer);
@@ -646,13 +660,14 @@ int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 	}
 	alloc->buffer_size = vma->vm_end - vma->vm_start;
 
-	if (binder_update_page_range(alloc, 1, alloc->buffer,
-				     alloc->buffer + PAGE_SIZE, vma)) {
+	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
+	if (!buffer) {
 		ret = -ENOMEM;
-		failure_string = "alloc small buf";
-		goto err_alloc_small_buf_failed;
+		failure_string = "alloc buffer struct";
+		goto err_alloc_buf_struct_failed;
 	}
-	buffer = alloc->buffer;
+
+	buffer->data = alloc->buffer;
 	INIT_LIST_HEAD(&alloc->buffers);
 	list_add(&buffer->entry, &alloc->buffers);
 	buffer->free = 1;
@@ -664,7 +679,7 @@ int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 
 	return 0;
 
-err_alloc_small_buf_failed:
+err_alloc_buf_struct_failed:
 	kfree(alloc->pages);
 	alloc->pages = NULL;
 err_alloc_pages_failed:
@@ -684,14 +699,13 @@ void binder_alloc_deferred_release(struct binder_alloc *alloc)
 {
 	struct rb_node *n;
 	int buffers, page_count;
+	struct binder_buffer *buffer;
 
 	BUG_ON(alloc->vma);
 
 	buffers = 0;
 	mutex_lock(&alloc->mutex);
 	while ((n = rb_first(&alloc->allocated_buffers))) {
-		struct binder_buffer *buffer;
-
 		buffer = rb_entry(n, struct binder_buffer, rb_node);
 
 		/* Transaction should already have been freed */
@@ -701,6 +715,16 @@ void binder_alloc_deferred_release(struct binder_alloc *alloc)
 		buffers++;
 	}
 
+	while (!list_empty(&alloc->buffers)) {
+		buffer = list_first_entry(&alloc->buffers,
+					  struct binder_buffer, entry);
+		WARN_ON(!buffer->free);
+
+		list_del(&buffer->entry);
+		WARN_ON_ONCE(!list_empty(&alloc->buffers));
+		kfree(buffer);
+	}
+
 	page_count = 0;
 	if (alloc->pages) {
 		int i;
diff --git a/drivers/android/binder_alloc.h b/drivers/android/binder_alloc.h
index 4f02cc084c15..dd5649bf6469 100644
--- a/drivers/android/binder_alloc.h
+++ b/drivers/android/binder_alloc.h
@@ -57,7 +57,7 @@ struct binder_buffer {
 	size_t data_size;
 	size_t offsets_size;
 	size_t extra_buffers_size;
-	uint8_t data[0];
+	void *data;
 };
 
 /**
diff --git a/drivers/android/binder_alloc_selftest.c b/drivers/android/binder_alloc_selftest.c
index cc00ab6ee29d..0bf72079a9da 100644
--- a/drivers/android/binder_alloc_selftest.c
+++ b/drivers/android/binder_alloc_selftest.c
@@ -105,8 +105,9 @@ static bool check_buffer_pages_allocated(struct binder_alloc *alloc,
 	void *page_addr, *end;
 	int page_index;
 
-	end = (void *)PAGE_ALIGN((uintptr_t)buffer + size);
-	for (page_addr = buffer; page_addr < end; page_addr += PAGE_SIZE) {
+	end = (void *)PAGE_ALIGN((uintptr_t)buffer->data + size);
+	page_addr = buffer->data;
+	for (; page_addr < end; page_addr += PAGE_SIZE) {
 		page_index = (page_addr - alloc->buffer) / PAGE_SIZE;
 		if (!alloc->pages[page_index]) {
 			pr_err("incorrect alloc state at page index %d\n",
@@ -209,8 +210,7 @@ static void binder_selftest_alloc_size(struct binder_alloc *alloc,
 	 * Only BUFFER_NUM - 1 buffer sizes are adjustable since
 	 * we need one giant buffer before getting to the last page.
 	 */
-	back_sizes[0] += alloc->buffer_size - end_offset[BUFFER_NUM - 1]
-		- sizeof(struct binder_buffer) * BUFFER_NUM;
+	back_sizes[0] += alloc->buffer_size - end_offset[BUFFER_NUM - 1];
 	binder_selftest_free_seq(alloc, front_sizes, seq, 0);
 	binder_selftest_free_seq(alloc, back_sizes, seq, 0);
 }
@@ -228,8 +228,7 @@ static void binder_selftest_alloc_offset(struct binder_alloc *alloc,
 	prev = index == 0 ? 0 : end_offset[index - 1];
 	end = prev;
 
-	BUILD_BUG_ON((BUFFER_MIN_SIZE + sizeof(struct binder_buffer))
-		     * BUFFER_NUM >= PAGE_SIZE);
+	BUILD_BUG_ON(BUFFER_MIN_SIZE * BUFFER_NUM >= PAGE_SIZE);
 
 	for (align = SAME_PAGE_UNALIGNED; align < LOOP_END; align++) {
 		if (align % 2)