Merging upstream version 6.8.9.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

6 files changed, 486 insertions, 468 deletions

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 8460458ebe..d6f14c8e20 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -1708,8 +1708,10 @@ static size_t binder_get_object(struct binder_proc *proc,
 	size_t object_size = 0;
 
 	read_size = min_t(size_t, sizeof(*object), buffer->data_size - offset);
-	if (offset > buffer->data_size || read_size < sizeof(*hdr))
+	if (offset > buffer->data_size || read_size < sizeof(*hdr) ||
+	    !IS_ALIGNED(offset, sizeof(u32)))
 		return 0;
+
 	if (u) {
 		if (copy_from_user(object, u + offset, read_size))
 			return 0;
@@ -1931,7 +1933,7 @@ static void binder_deferred_fd_close(int fd)
 	if (!twcb)
 		return;
 	init_task_work(&twcb->twork, binder_do_fd_close);
-	twcb->file = close_fd_get_file(fd);
+	twcb->file = file_close_fd(fd);
 	if (twcb->file) {
 		// pin it until binder_do_fd_close(); see comments there
 		get_file(twcb->file);
@@ -2087,9 +2089,8 @@ static void binder_transaction_buffer_release(struct binder_proc *proc,
 			 * Convert the address to an offset relative to
 			 * the base of the transaction buffer.
 			 */
-			fda_offset =
-			    (parent->buffer - (uintptr_t)buffer->user_data) +
-			    fda->parent_offset;
+			fda_offset = parent->buffer - buffer->user_data +
+				fda->parent_offset;
 			for (fd_index = 0; fd_index < fda->num_fds;
 			     fd_index++) {
 				u32 fd;
@@ -2607,7 +2608,7 @@ static int binder_translate_fd_array(struct list_head *pf_head,
 	 * Convert the address to an offset relative to
 	 * the base of the transaction buffer.
 	 */
-	fda_offset = (parent->buffer - (uintptr_t)t->buffer->user_data) +
+	fda_offset = parent->buffer - t->buffer->user_data +
 		fda->parent_offset;
 	sender_ufda_base = (void __user *)(uintptr_t)sender_uparent->buffer +
 				fda->parent_offset;
@@ -2682,8 +2683,9 @@ static int binder_fixup_parent(struct list_head *pf_head,
 				  proc->pid, thread->pid);
 		return -EINVAL;
 	}
-	buffer_offset = bp->parent_offset +
-			(uintptr_t)parent->buffer - (uintptr_t)b->user_data;
+
+	buffer_offset = bp->parent_offset + parent->buffer - b->user_data;
+
 	return binder_add_fixup(pf_head, buffer_offset, bp->buffer, 0);
 }
 
@@ -3235,7 +3237,7 @@ static void binder_transaction(struct binder_proc *proc,
 
 	t->buffer = binder_alloc_new_buf(&target_proc->alloc, tr->data_size,
 		tr->offsets_size, extra_buffers_size,
-		!reply && (t->flags & TF_ONE_WAY), current->tgid);
+		!reply && (t->flags & TF_ONE_WAY));
 	if (IS_ERR(t->buffer)) {
 		char *s;
 
@@ -3260,7 +3262,7 @@ static void binder_transaction(struct binder_proc *proc,
 				    ALIGN(extra_buffers_size, sizeof(void *)) -
 				    ALIGN(secctx_sz, sizeof(u64));
 
-		t->security_ctx = (uintptr_t)t->buffer->user_data + buf_offset;
+		t->security_ctx = t->buffer->user_data + buf_offset;
 		err = binder_alloc_copy_to_buffer(&target_proc->alloc,
 						  t->buffer, buf_offset,
 						  secctx, secctx_sz);
@@ -3537,8 +3539,7 @@ static void binder_transaction(struct binder_proc *proc,
 				goto err_translate_failed;
 			}
 			/* Fixup buffer pointer to target proc address space */
-			bp->buffer = (uintptr_t)
-				t->buffer->user_data + sg_buf_offset;
+			bp->buffer = t->buffer->user_data + sg_buf_offset;
 			sg_buf_offset += ALIGN(bp->length, sizeof(u64));
 
 			num_valid = (buffer_offset - off_start_offset) /
@@ -4708,7 +4709,7 @@ retry:
 		}
 		trd->data_size = t->buffer->data_size;
 		trd->offsets_size = t->buffer->offsets_size;
-		trd->data.ptr.buffer = (uintptr_t)t->buffer->user_data;
+		trd->data.ptr.buffer = t->buffer->user_data;
 		trd->data.ptr.offsets = trd->data.ptr.buffer +
 					ALIGN(t->buffer->data_size,
 					    sizeof(void *));
@@ -5991,9 +5992,9 @@ static void print_binder_transaction_ilocked(struct seq_file *m,
 	}
 	if (buffer->target_node)
 		seq_printf(m, " node %d", buffer->target_node->debug_id);
-	seq_printf(m, " size %zd:%zd data %pK\n",
+	seq_printf(m, " size %zd:%zd offset %lx\n",
 		   buffer->data_size, buffer->offsets_size,
-		   buffer->user_data);
+		   proc->alloc.buffer - buffer->user_data);
 }
 
 static void print_binder_work_ilocked(struct seq_file *m,
diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index a56cbfd9ba..e0e4dc38b6 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -26,7 +26,7 @@
 #include "binder_alloc.h"
 #include "binder_trace.h"
 
-struct list_lru binder_alloc_lru;
+struct list_lru binder_freelist;
 
 static DEFINE_MUTEX(binder_alloc_mmap_lock);
 
@@ -125,23 +125,20 @@ static void binder_insert_allocated_buffer_locked(
 
 static struct binder_buffer *binder_alloc_prepare_to_free_locked(
 		struct binder_alloc *alloc,
-		uintptr_t user_ptr)
+		unsigned long user_ptr)
 {
 	struct rb_node *n = alloc->allocated_buffers.rb_node;
 	struct binder_buffer *buffer;
-	void __user *uptr;
-
-	uptr = (void __user *)user_ptr;
 
 	while (n) {
 		buffer = rb_entry(n, struct binder_buffer, rb_node);
 		BUG_ON(buffer->free);
 
-		if (uptr < buffer->user_data)
+		if (user_ptr < buffer->user_data) {
 			n = n->rb_left;
-		else if (uptr > buffer->user_data)
+		} else if (user_ptr > buffer->user_data) {
 			n = n->rb_right;
-		else {
+		} else {
 			/*
 			 * Guard against user threads attempting to
 			 * free the buffer when in use by kernel or
@@ -168,145 +165,168 @@ static struct binder_buffer *binder_alloc_prepare_to_free_locked(
  * Return:	Pointer to buffer or NULL
  */
 struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
-						   uintptr_t user_ptr)
+						   unsigned long user_ptr)
 {
 	struct binder_buffer *buffer;
 
-	mutex_lock(&alloc->mutex);
+	spin_lock(&alloc->lock);
 	buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
-	mutex_unlock(&alloc->mutex);
+	spin_unlock(&alloc->lock);
 	return buffer;
 }
 
-static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
-				    void __user *start, void __user *end)
+static inline void
+binder_set_installed_page(struct binder_lru_page *lru_page,
+			  struct page *page)
+{
+	/* Pairs with acquire in binder_get_installed_page() */
+	smp_store_release(&lru_page->page_ptr, page);
+}
+
+static inline struct page *
+binder_get_installed_page(struct binder_lru_page *lru_page)
+{
+	/* Pairs with release in binder_set_installed_page() */
+	return smp_load_acquire(&lru_page->page_ptr);
+}
+
+static void binder_lru_freelist_add(struct binder_alloc *alloc,
+				    unsigned long start, unsigned long end)
 {
-	void __user *page_addr;
-	unsigned long user_page_addr;
 	struct binder_lru_page *page;
-	struct vm_area_struct *vma = NULL;
-	struct mm_struct *mm = NULL;
-	bool need_mm = false;
+	unsigned long page_addr;
 
-	binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
-		     "%d: %s pages %pK-%pK\n", alloc->pid,
-		     allocate ? "allocate" : "free", start, end);
+	trace_binder_update_page_range(alloc, false, start, end);
 
-	if (end <= start)
-		return 0;
+	for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
+		size_t index;
+		int ret;
 
-	trace_binder_update_page_range(alloc, allocate, start, end);
+		index = (page_addr - alloc->buffer) / PAGE_SIZE;
+		page = &alloc->pages[index];
 
-	if (allocate == 0)
-		goto free_range;
+		if (!binder_get_installed_page(page))
+			continue;
 
-	for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
-		page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE];
-		if (!page->page_ptr) {
-			need_mm = true;
-			break;
-		}
+		trace_binder_free_lru_start(alloc, index);
+
+		ret = list_lru_add_obj(&binder_freelist, &page->lru);
+		WARN_ON(!ret);
+
+		trace_binder_free_lru_end(alloc, index);
 	}
+}
+
+static int binder_install_single_page(struct binder_alloc *alloc,
+				      struct binder_lru_page *lru_page,
+				      unsigned long addr)
+{
+	struct page *page;
+	int ret = 0;
 
-	if (need_mm && mmget_not_zero(alloc->mm))
-		mm = alloc->mm;
+	if (!mmget_not_zero(alloc->mm))
+		return -ESRCH;
 
-	if (mm) {
-		mmap_write_lock(mm);
-		vma = alloc->vma;
+	/*
+	 * Protected with mmap_sem in write mode as multiple tasks
+	 * might race to install the same page.
+	 */
+	mmap_write_lock(alloc->mm);
+	if (binder_get_installed_page(lru_page))
+		goto out;
+
+	if (!alloc->vma) {
+		pr_err("%d: %s failed, no vma\n", alloc->pid, __func__);
+		ret = -ESRCH;
+		goto out;
 	}
 
-	if (!vma && need_mm) {
-		binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
-				   "%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
-				   alloc->pid);
-		goto err_no_vma;
+	page = alloc_page(GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
+	if (!page) {
+		pr_err("%d: failed to allocate page\n", alloc->pid);
+		ret = -ENOMEM;
+		goto out;
 	}
 
-	for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
+	ret = vm_insert_page(alloc->vma, addr, page);
+	if (ret) {
+		pr_err("%d: %s failed to insert page at offset %lx with %d\n",
+		       alloc->pid, __func__, addr - alloc->buffer, ret);
+		__free_page(page);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/* Mark page installation complete and safe to use */
+	binder_set_installed_page(lru_page, page);
+out:
+	mmap_write_unlock(alloc->mm);
+	mmput_async(alloc->mm);
+	return ret;
+}
+
+static int binder_install_buffer_pages(struct binder_alloc *alloc,
+				       struct binder_buffer *buffer,
+				       size_t size)
+{
+	struct binder_lru_page *page;
+	unsigned long start, final;
+	unsigned long page_addr;
+
+	start = buffer->user_data & PAGE_MASK;
+	final = PAGE_ALIGN(buffer->user_data + size);
+
+	for (page_addr = start; page_addr < final; page_addr += PAGE_SIZE) {
+		unsigned long index;
 		int ret;
-		bool on_lru;
-		size_t index;
 
 		index = (page_addr - alloc->buffer) / PAGE_SIZE;
 		page = &alloc->pages[index];
 
-		if (page->page_ptr) {
-			trace_binder_alloc_lru_start(alloc, index);
-
-			on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
-			WARN_ON(!on_lru);
-
-			trace_binder_alloc_lru_end(alloc, index);
+		if (binder_get_installed_page(page))
 			continue;
-		}
-
-		if (WARN_ON(!vma))
-			goto err_page_ptr_cleared;
 
 		trace_binder_alloc_page_start(alloc, index);
-		page->page_ptr = alloc_page(GFP_KERNEL |
-					    __GFP_HIGHMEM |
-					    __GFP_ZERO);
-		if (!page->page_ptr) {
-			pr_err("%d: binder_alloc_buf failed for page at %pK\n",
-				alloc->pid, page_addr);
-			goto err_alloc_page_failed;
-		}
-		page->alloc = alloc;
-		INIT_LIST_HEAD(&page->lru);
-
-		user_page_addr = (uintptr_t)page_addr;
-		ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
-		if (ret) {
-			pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
-			       alloc->pid, user_page_addr);
-			goto err_vm_insert_page_failed;
-		}
 
-		if (index + 1 > alloc->pages_high)
-			alloc->pages_high = index + 1;
+		ret = binder_install_single_page(alloc, page, page_addr);
+		if (ret)
+			return ret;
 
 		trace_binder_alloc_page_end(alloc, index);
 	}
-	if (mm) {
-		mmap_write_unlock(mm);
-		mmput_async(mm);
-	}
+
 	return 0;
+}
 
-free_range:
-	for (page_addr = end - PAGE_SIZE; 1; page_addr -= PAGE_SIZE) {
-		bool ret;
-		size_t index;
+/* The range of pages should exclude those shared with other buffers */
+static void binder_lru_freelist_del(struct binder_alloc *alloc,
+				    unsigned long start, unsigned long end)
+{
+	struct binder_lru_page *page;
+	unsigned long page_addr;
+
+	trace_binder_update_page_range(alloc, true, start, end);
+
+	for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
+		unsigned long index;
+		bool on_lru;
 
 		index = (page_addr - alloc->buffer) / PAGE_SIZE;
 		page = &alloc->pages[index];
 
-		trace_binder_free_lru_start(alloc, index);
+		if (page->page_ptr) {
+			trace_binder_alloc_lru_start(alloc, index);
 
-		ret = list_lru_add(&binder_alloc_lru, &page->lru);
-		WARN_ON(!ret);
+			on_lru = list_lru_del_obj(&binder_freelist, &page->lru);
+			WARN_ON(!on_lru);
 
-		trace_binder_free_lru_end(alloc, index);
-		if (page_addr == start)
-			break;
-		continue;
-
-err_vm_insert_page_failed:
-		__free_page(page->page_ptr);
-		page->page_ptr = NULL;
-err_alloc_page_failed:
-err_page_ptr_cleared:
-		if (page_addr == start)
-			break;
-	}
-err_no_vma:
-	if (mm) {
-		mmap_write_unlock(mm);
-		mmput_async(mm);
+			trace_binder_alloc_lru_end(alloc, index);
+			continue;
+		}
+
+		if (index + 1 > alloc->pages_high)
+			alloc->pages_high = index + 1;
 	}
-	return vma ? -ENOMEM : -ESRCH;
 }
 
 static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
@@ -323,7 +343,44 @@ static inline struct vm_area_struct *binder_alloc_get_vma(
 	return smp_load_acquire(&alloc->vma);
 }
 
-static bool debug_low_async_space_locked(struct binder_alloc *alloc, int pid)
+static void debug_no_space_locked(struct binder_alloc *alloc)
+{
+	size_t largest_alloc_size = 0;
+	struct binder_buffer *buffer;
+	size_t allocated_buffers = 0;
+	size_t largest_free_size = 0;
+	size_t total_alloc_size = 0;
+	size_t total_free_size = 0;
+	size_t free_buffers = 0;
+	size_t buffer_size;
+	struct rb_node *n;
+
+	for (n = rb_first(&alloc->allocated_buffers); n; n = rb_next(n)) {
+		buffer = rb_entry(n, struct binder_buffer, rb_node);
+		buffer_size = binder_alloc_buffer_size(alloc, buffer);
+		allocated_buffers++;
+		total_alloc_size += buffer_size;
+		if (buffer_size > largest_alloc_size)
+			largest_alloc_size = buffer_size;
+	}
+
+	for (n = rb_first(&alloc->free_buffers); n; n = rb_next(n)) {
+		buffer = rb_entry(n, struct binder_buffer, rb_node);
+		buffer_size = binder_alloc_buffer_size(alloc, buffer);
+		free_buffers++;
+		total_free_size += buffer_size;
+		if (buffer_size > largest_free_size)
+			largest_free_size = buffer_size;
+	}
+
+	binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
+			   "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
+			   total_alloc_size, allocated_buffers,
+			   largest_alloc_size, total_free_size,
+			   free_buffers, largest_free_size);
+}
+
+static bool debug_low_async_space_locked(struct binder_alloc *alloc)
 {
 	/*
 	 * Find the amount and size of buffers allocated by the current caller;
@@ -332,10 +389,20 @@ static bool debug_low_async_space_locked(struct binder_alloc *alloc, int pid)
 	 * and at some point we'll catch them in the act. This is more efficient
 	 * than keeping a map per pid.
 	 */
-	struct rb_node *n;
 	struct binder_buffer *buffer;
 	size_t total_alloc_size = 0;
+	int pid = current->tgid;
 	size_t num_buffers = 0;
+	struct rb_node *n;
+
+	/*
+	 * Only start detecting spammers once we have less than 20% of async
+	 * space left (which is less than 10% of total buffer size).
+	 */
+	if (alloc->free_async_space >= alloc->buffer_size / 10) {
+		alloc->oneway_spam_detected = false;
+		return false;
+	}
 
 	for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 		 n = rb_next(n)) {
@@ -365,56 +432,26 @@ static bool debug_low_async_space_locked(struct binder_alloc *alloc, int pid)
 	return false;
 }
 
+/* Callers preallocate @new_buffer, it is freed by this function if unused */
 static struct binder_buffer *binder_alloc_new_buf_locked(
 				struct binder_alloc *alloc,
-				size_t data_size,
-				size_t offsets_size,
-				size_t extra_buffers_size,
-				int is_async,
-				int pid)
+				struct binder_buffer *new_buffer,
+				size_t size,
+				int is_async)
 {
 	struct rb_node *n = alloc->free_buffers.rb_node;
+	struct rb_node *best_fit = NULL;
 	struct binder_buffer *buffer;
+	unsigned long next_used_page;
+	unsigned long curr_last_page;
 	size_t buffer_size;
-	struct rb_node *best_fit = NULL;
-	void __user *has_page_addr;
-	void __user *end_page_addr;
-	size_t size, data_offsets_size;
-	int ret;
-
-	/* Check binder_alloc is fully initialized */
-	if (!binder_alloc_get_vma(alloc)) {
-		binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
-				   "%d: binder_alloc_buf, no vma\n",
-				   alloc->pid);
-		return ERR_PTR(-ESRCH);
-	}
-
-	data_offsets_size = ALIGN(data_size, sizeof(void *)) +
-		ALIGN(offsets_size, sizeof(void *));
-
-	if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
-		binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
-				"%d: got transaction with invalid size %zd-%zd\n",
-				alloc->pid, data_size, offsets_size);
-		return ERR_PTR(-EINVAL);
-	}
-	size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
-	if (size < data_offsets_size || size < extra_buffers_size) {
-		binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
-				"%d: got transaction with invalid extra_buffers_size %zd\n",
-				alloc->pid, extra_buffers_size);
-		return ERR_PTR(-EINVAL);
-	}
-
-	/* Pad 0-size buffers so they get assigned unique addresses */
-	size = max(size, sizeof(void *));
 
 	if (is_async && alloc->free_async_space < size) {
 		binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 			     "%d: binder_alloc_buf size %zd failed, no async space left\n",
 			      alloc->pid, size);
-		return ERR_PTR(-ENOSPC);
+		buffer = ERR_PTR(-ENOSPC);
+		goto out;
 	}
 
 	while (n) {
@@ -425,121 +462,92 @@ static struct binder_buffer *binder_alloc_new_buf_locked(
 		if (size < buffer_size) {
 			best_fit = n;
 			n = n->rb_left;
-		} else if (size > buffer_size)
+		} else if (size > buffer_size) {
 			n = n->rb_right;
-		else {
+		} else {
 			best_fit = n;
 			break;
 		}
 	}
-	if (best_fit == NULL) {
-		size_t allocated_buffers = 0;
-		size_t largest_alloc_size = 0;
-		size_t total_alloc_size = 0;
-		size_t free_buffers = 0;
-		size_t largest_free_size = 0;
-		size_t total_free_size = 0;
-
-		for (n = rb_first(&alloc->allocated_buffers); n != NULL;
-		     n = rb_next(n)) {
-			buffer = rb_entry(n, struct binder_buffer, rb_node);
-			buffer_size = binder_alloc_buffer_size(alloc, buffer);
-			allocated_buffers++;
-			total_alloc_size += buffer_size;
-			if (buffer_size > largest_alloc_size)
-				largest_alloc_size = buffer_size;
-		}
-		for (n = rb_first(&alloc->free_buffers); n != NULL;
-		     n = rb_next(n)) {
-			buffer = rb_entry(n, struct binder_buffer, rb_node);
-			buffer_size = binder_alloc_buffer_size(alloc, buffer);
-			free_buffers++;
-			total_free_size += buffer_size;
-			if (buffer_size > largest_free_size)
-				largest_free_size = buffer_size;
-		}
+
+	if (unlikely(!best_fit)) {
 		binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 				   "%d: binder_alloc_buf size %zd failed, no address space\n",
 				   alloc->pid, size);
-		binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
-				   "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
-				   total_alloc_size, allocated_buffers,
-				   largest_alloc_size, total_free_size,
-				   free_buffers, largest_free_size);
-		return ERR_PTR(-ENOSPC);
+		debug_no_space_locked(alloc);
+		buffer = ERR_PTR(-ENOSPC);
+		goto out;
 	}
-	if (n == NULL) {
+
+	if (buffer_size != size) {
+		/* Found an oversized buffer and needs to be split */
 		buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
 		buffer_size = binder_alloc_buffer_size(alloc, buffer);
+
+		WARN_ON(n || buffer_size == size);
+		new_buffer->user_data = buffer->user_data + size;
+		list_add(&new_buffer->entry, &buffer->entry);
+		new_buffer->free = 1;
+		binder_insert_free_buffer(alloc, new_buffer);
+		new_buffer = NULL;
 	}
 
 	binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 		     "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
 		      alloc->pid, size, buffer, buffer_size);
 
-	has_page_addr = (void __user *)
-		(((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK);
-	WARN_ON(n && buffer_size != size);
-	end_page_addr =
-		(void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
-	if (end_page_addr > has_page_addr)
-		end_page_addr = has_page_addr;
-	ret = binder_update_page_range(alloc, 1, (void __user *)
-		PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr);
-	if (ret)
-		return ERR_PTR(ret);
-
-	if (buffer_size != 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->user_data = (u8 __user *)buffer->user_data + size;
-		list_add(&new_buffer->entry, &buffer->entry);
-		new_buffer->free = 1;
-		binder_insert_free_buffer(alloc, new_buffer);
-	}
+	/*
+	 * Now we remove the pages from the freelist. A clever calculation
+	 * with buffer_size determines if the last page is shared with an
+	 * adjacent in-use buffer. In such case, the page has been already
+	 * removed from the freelist so we trim our range short.
+	 */
+	next_used_page = (buffer->user_data + buffer_size) & PAGE_MASK;
+	curr_last_page = PAGE_ALIGN(buffer->user_data + size);
+	binder_lru_freelist_del(alloc, PAGE_ALIGN(buffer->user_data),
+				min(next_used_page, curr_last_page));
 
-	rb_erase(best_fit, &alloc->free_buffers);
+	rb_erase(&buffer->rb_node, &alloc->free_buffers);
 	buffer->free = 0;
 	buffer->allow_user_free = 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);
-	buffer->data_size = data_size;
-	buffer->offsets_size = offsets_size;
 	buffer->async_transaction = is_async;
-	buffer->extra_buffers_size = extra_buffers_size;
-	buffer->pid = pid;
 	buffer->oneway_spam_suspect = false;
 	if (is_async) {
 		alloc->free_async_space -= size;
 		binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 			     "%d: binder_alloc_buf size %zd async free %zd\n",
 			      alloc->pid, size, alloc->free_async_space);
-		if (alloc->free_async_space < alloc->buffer_size / 10) {
-			/*
-			 * Start detecting spammers once we have less than 20%
-			 * of async space left (which is less than 10% of total
-			 * buffer size).
-			 */
-			buffer->oneway_spam_suspect = debug_low_async_space_locked(alloc, pid);
-		} else {
-			alloc->oneway_spam_detected = false;
-		}
+		if (debug_low_async_space_locked(alloc))
+			buffer->oneway_spam_suspect = true;
 	}
+
+out:
+	/* Discard possibly unused new_buffer */
+	kfree(new_buffer);
 	return buffer;
+}
 
-err_alloc_buf_struct_failed:
-	binder_update_page_range(alloc, 0, (void __user *)
-				 PAGE_ALIGN((uintptr_t)buffer->user_data),
-				 end_page_addr);
-	return ERR_PTR(-ENOMEM);
+/* Calculate the sanitized total size, returns 0 for invalid request */
+static inline size_t sanitized_size(size_t data_size,
+				    size_t offsets_size,
+				    size_t extra_buffers_size)
+{
+	size_t total, tmp;
+
+	/* Align to pointer size and check for overflows */
+	tmp = ALIGN(data_size, sizeof(void *)) +
+		ALIGN(offsets_size, sizeof(void *));
+	if (tmp < data_size || tmp < offsets_size)
+		return 0;
+	total = tmp + ALIGN(extra_buffers_size, sizeof(void *));
+	if (total < tmp || total < extra_buffers_size)
+		return 0;
+
+	/* Pad 0-sized buffers so they get a unique address */
+	total = max(total, sizeof(void *));
+
+	return total;
 }
 
 /**
@@ -549,7 +557,6 @@ err_alloc_buf_struct_failed:
  * @offsets_size:       user specified buffer offset
  * @extra_buffers_size: size of extra space for meta-data (eg, security context)
  * @is_async:           buffer for async transaction
- * @pid:				pid to attribute allocation to (used for debugging)
  *
  * Allocate a new buffer given the requested sizes. Returns
  * the kernel version of the buffer pointer. The size allocated
@@ -562,74 +569,89 @@ struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 					   size_t data_size,
 					   size_t offsets_size,
 					   size_t extra_buffers_size,
-					   int is_async,
-					   int pid)
+					   int is_async)
 {
-	struct binder_buffer *buffer;
+	struct binder_buffer *buffer, *next;
+	size_t size;
+	int ret;
+
+	/* Check binder_alloc is fully initialized */
+	if (!binder_alloc_get_vma(alloc)) {
+		binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
+				   "%d: binder_alloc_buf, no vma\n",
+				   alloc->pid);
+		return ERR_PTR(-ESRCH);
+	}
+
+	size = sanitized_size(data_size, offsets_size, extra_buffers_size);
+	if (unlikely(!size)) {
+		binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
+				   "%d: got transaction with invalid size %zd-%zd-%zd\n",
+				   alloc->pid, data_size, offsets_size,
+				   extra_buffers_size);
+		return ERR_PTR(-EINVAL);
+	}
+
+	/* Preallocate the next buffer */
+	next = kzalloc(sizeof(*next), GFP_KERNEL);
+	if (!next)
+		return ERR_PTR(-ENOMEM);
+
+	spin_lock(&alloc->lock);
+	buffer = binder_alloc_new_buf_locked(alloc, next, size, is_async);
+	if (IS_ERR(buffer)) {
+		spin_unlock(&alloc->lock);
+		goto out;
+	}
+
+	buffer->data_size = data_size;
+	buffer->offsets_size = offsets_size;
+	buffer->extra_buffers_size = extra_buffers_size;
+	buffer->pid = current->tgid;
+	spin_unlock(&alloc->lock);
 
-	mutex_lock(&alloc->mutex);
-	buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
-					     extra_buffers_size, is_async, pid);
-	mutex_unlock(&alloc->mutex);
+	ret = binder_install_buffer_pages(alloc, buffer, size);
+	if (ret) {
+		binder_alloc_free_buf(alloc, buffer);
+		buffer = ERR_PTR(ret);
+	}
+out:
 	return buffer;
 }
 
-static void __user *buffer_start_page(struct binder_buffer *buffer)
+static unsigned long buffer_start_page(struct binder_buffer *buffer)
 {
-	return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK);
+	return buffer->user_data & PAGE_MASK;
 }
 
-static void __user *prev_buffer_end_page(struct binder_buffer *buffer)
+static unsigned long prev_buffer_end_page(struct binder_buffer *buffer)
 {
-	return (void __user *)
-		(((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK);
+	return (buffer->user_data - 1) & PAGE_MASK;
 }
 
 static void binder_delete_free_buffer(struct binder_alloc *alloc,
 				      struct binder_buffer *buffer)
 {
-	struct binder_buffer *prev, *next = NULL;
-	bool to_free = true;
+	struct binder_buffer *prev, *next;
+
+	if (PAGE_ALIGNED(buffer->user_data))
+		goto skip_freelist;
 
 	BUG_ON(alloc->buffers.next == &buffer->entry);
 	prev = binder_buffer_prev(buffer);
 	BUG_ON(!prev->free);
-	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->user_data,
-				   prev->user_data);
-	}
+	if (prev_buffer_end_page(prev) == buffer_start_page(buffer))
+		goto skip_freelist;
 
 	if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 		next = binder_buffer_next(buffer);
-		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->user_data,
-					   next->user_data);
-		}
-	}
-
-	if (PAGE_ALIGNED(buffer->user_data)) {
-		binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
-				   "%d: merge free, buffer start %pK is page aligned\n",
-				   alloc->pid, buffer->user_data);
-		to_free = false;
+		if (buffer_start_page(next) == buffer_start_page(buffer))
+			goto skip_freelist;
 	}
 
-	if (to_free) {
-		binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
-				   "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
-				   alloc->pid, buffer->user_data,
-				   prev->user_data,
-				   next ? next->user_data : NULL);
-		binder_update_page_range(alloc, 0, buffer_start_page(buffer),
-					 buffer_start_page(buffer) + PAGE_SIZE);
-	}
+	binder_lru_freelist_add(alloc, buffer_start_page(buffer),
+				buffer_start_page(buffer) + PAGE_SIZE);
+skip_freelist:
 	list_del(&buffer->entry);
 	kfree(buffer);
 }
@@ -662,10 +684,8 @@ static void binder_free_buf_locked(struct binder_alloc *alloc,
 			      alloc->pid, size, alloc->free_async_space);
 	}
 
-	binder_update_page_range(alloc, 0,
-		(void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data),
-		(void __user *)(((uintptr_t)
-			  buffer->user_data + buffer_size) & PAGE_MASK));
+	binder_lru_freelist_add(alloc, PAGE_ALIGN(buffer->user_data),
+				(buffer->user_data + buffer_size) & PAGE_MASK);
 
 	rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
 	buffer->free = 1;
@@ -689,8 +709,68 @@ static void binder_free_buf_locked(struct binder_alloc *alloc,
 	binder_insert_free_buffer(alloc, buffer);
 }
 
+/**
+ * binder_alloc_get_page() - get kernel pointer for given buffer offset
+ * @alloc: binder_alloc for this proc
+ * @buffer: binder buffer to be accessed
+ * @buffer_offset: offset into @buffer data
+ * @pgoffp: address to copy final page offset to
+ *
+ * Lookup the struct page corresponding to the address
+ * at @buffer_offset into @buffer->user_data. If @pgoffp is not
+ * NULL, the byte-offset into the page is written there.
+ *
+ * The caller is responsible to ensure that the offset points
+ * to a valid address within the @buffer and that @buffer is
+ * not freeable by the user. Since it can't be freed, we are
+ * guaranteed that the corresponding elements of @alloc->pages[]
+ * cannot change.
+ *
+ * Return: struct page
+ */
+static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
+					  struct binder_buffer *buffer,
+					  binder_size_t buffer_offset,
+					  pgoff_t *pgoffp)
+{
+	binder_size_t buffer_space_offset = buffer_offset +
+		(buffer->user_data - alloc->buffer);
+	pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
+	size_t index = buffer_space_offset >> PAGE_SHIFT;
+	struct binder_lru_page *lru_page;
+
+	lru_page = &alloc->pages[index];
+	*pgoffp = pgoff;
+	return lru_page->page_ptr;
+}
+
+/**
+ * binder_alloc_clear_buf() - zero out buffer
+ * @alloc: binder_alloc for this proc
+ * @buffer: binder buffer to be cleared
+ *
+ * memset the given buffer to 0
+ */
 static void binder_alloc_clear_buf(struct binder_alloc *alloc,
-				   struct binder_buffer *buffer);
+				   struct binder_buffer *buffer)
+{
+	size_t bytes = binder_alloc_buffer_size(alloc, buffer);
+	binder_size_t buffer_offset = 0;
+
+	while (bytes) {
+		unsigned long size;
+		struct page *page;
+		pgoff_t pgoff;
+
+		page = binder_alloc_get_page(alloc, buffer,
+					     buffer_offset, &pgoff);
+		size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
+		memset_page(page, pgoff, 0, size);
+		bytes -= size;
+		buffer_offset += size;
+	}
+}
+
 /**
  * binder_alloc_free_buf() - free a binder buffer
  * @alloc:	binder_alloc for this proc
@@ -705,17 +785,17 @@ void binder_alloc_free_buf(struct binder_alloc *alloc,
 	 * We could eliminate the call to binder_alloc_clear_buf()
 	 * from binder_alloc_deferred_release() by moving this to
 	 * binder_free_buf_locked(). However, that could
-	 * increase contention for the alloc mutex if clear_on_free
-	 * is used frequently for large buffers. The mutex is not
+	 * increase contention for the alloc->lock if clear_on_free
+	 * is used frequently for large buffers. This lock is not
 	 * needed for correctness here.
 	 */
 	if (buffer->clear_on_free) {
 		binder_alloc_clear_buf(alloc, buffer);
 		buffer->clear_on_free = false;
 	}
-	mutex_lock(&alloc->mutex);
+	spin_lock(&alloc->lock);
 	binder_free_buf_locked(alloc, buffer);
-	mutex_unlock(&alloc->mutex);
+	spin_unlock(&alloc->lock);
 }
 
 /**
@@ -734,9 +814,9 @@ void binder_alloc_free_buf(struct binder_alloc *alloc,
 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 			      struct vm_area_struct *vma)
 {
-	int ret;
-	const char *failure_string;
 	struct binder_buffer *buffer;
+	const char *failure_string;
+	int ret, i;
 
 	if (unlikely(vma->vm_mm != alloc->mm)) {
 		ret = -EINVAL;
@@ -754,7 +834,7 @@ int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 				   SZ_4M);
 	mutex_unlock(&binder_alloc_mmap_lock);
 
-	alloc->buffer = (void __user *)vma->vm_start;
+	alloc->buffer = vma->vm_start;
 
 	alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
 			       sizeof(alloc->pages[0]),
@@ -765,6 +845,11 @@ int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 		goto err_alloc_pages_failed;
 	}
 
+	for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
+		alloc->pages[i].alloc = alloc;
+		INIT_LIST_HEAD(&alloc->pages[i].lru);
+	}
+
 	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 	if (!buffer) {
 		ret = -ENOMEM;
@@ -787,7 +872,7 @@ err_alloc_buf_struct_failed:
 	kfree(alloc->pages);
 	alloc->pages = NULL;
 err_alloc_pages_failed:
-	alloc->buffer = NULL;
+	alloc->buffer = 0;
 	mutex_lock(&binder_alloc_mmap_lock);
 	alloc->buffer_size = 0;
 err_already_mapped:
@@ -808,7 +893,7 @@ void binder_alloc_deferred_release(struct binder_alloc *alloc)
 	struct binder_buffer *buffer;
 
 	buffers = 0;
-	mutex_lock(&alloc->mutex);
+	spin_lock(&alloc->lock);
 	BUG_ON(alloc->vma);
 
 	while ((n = rb_first(&alloc->allocated_buffers))) {
@@ -840,25 +925,25 @@ void binder_alloc_deferred_release(struct binder_alloc *alloc)
 		int i;
 
 		for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
-			void __user *page_addr;
+			unsigned long page_addr;
 			bool on_lru;
 
 			if (!alloc->pages[i].page_ptr)
 				continue;
 
-			on_lru = list_lru_del(&binder_alloc_lru,
-					      &alloc->pages[i].lru);
+			on_lru = list_lru_del_obj(&binder_freelist,
+						  &alloc->pages[i].lru);
 			page_addr = alloc->buffer + i * PAGE_SIZE;
 			binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
-				     "%s: %d: page %d at %pK %s\n",
-				     __func__, alloc->pid, i, page_addr,
+				     "%s: %d: page %d %s\n",
+				     __func__, alloc->pid, i,
 				     on_lru ? "on lru" : "active");
 			__free_page(alloc->pages[i].page_ptr);
 			page_count++;
 		}
 		kfree(alloc->pages);
 	}
-	mutex_unlock(&alloc->mutex);
+	spin_unlock(&alloc->lock);
 	if (alloc->mm)
 		mmdrop(alloc->mm);
 
@@ -867,16 +952,6 @@ void binder_alloc_deferred_release(struct binder_alloc *alloc)
 		     __func__, alloc->pid, buffers, page_count);
 }
 
-static void print_binder_buffer(struct seq_file *m, const char *prefix,
-				struct binder_buffer *buffer)
-{
-	seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
-		   prefix, buffer->debug_id, buffer->user_data,
-		   buffer->data_size, buffer->offsets_size,
-		   buffer->extra_buffers_size,
-		   buffer->transaction ? "active" : "delivered");
-}
-
 /**
  * binder_alloc_print_allocated() - print buffer info
  * @m:     seq_file for output via seq_printf()
@@ -888,13 +963,20 @@ static void print_binder_buffer(struct seq_file *m, const char *prefix,
 void binder_alloc_print_allocated(struct seq_file *m,
 				  struct binder_alloc *alloc)
 {
+	struct binder_buffer *buffer;
 	struct rb_node *n;
 
-	mutex_lock(&alloc->mutex);
-	for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
-		print_binder_buffer(m, "  buffer",
-				    rb_entry(n, struct binder_buffer, rb_node));
-	mutex_unlock(&alloc->mutex);
+	spin_lock(&alloc->lock);
+	for (n = rb_first(&alloc->allocated_buffers); n; n = rb_next(n)) {
+		buffer = rb_entry(n, struct binder_buffer, rb_node);
+		seq_printf(m, "  buffer %d: %lx size %zd:%zd:%zd %s\n",
+			   buffer->debug_id,
+			   buffer->user_data - alloc->buffer,
+			   buffer->data_size, buffer->offsets_size,
+			   buffer->extra_buffers_size,
+			   buffer->transaction ? "active" : "delivered");
+	}
+	spin_unlock(&alloc->lock);
 }
 
 /**
@@ -911,7 +993,7 @@ void binder_alloc_print_pages(struct seq_file *m,
 	int lru = 0;
 	int free = 0;
 
-	mutex_lock(&alloc->mutex);
+	spin_lock(&alloc->lock);
 	/*
 	 * Make sure the binder_alloc is fully initialized, otherwise we might
 	 * read inconsistent state.
@@ -927,7 +1009,7 @@ void binder_alloc_print_pages(struct seq_file *m,
 				lru++;
 		}
 	}
-	mutex_unlock(&alloc->mutex);
+	spin_unlock(&alloc->lock);
 	seq_printf(m, "  pages: %d:%d:%d\n", active, lru, free);
 	seq_printf(m, "  pages high watermark: %zu\n", alloc->pages_high);
 }
@@ -943,10 +1025,10 @@ int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
 	struct rb_node *n;
 	int count = 0;
 
-	mutex_lock(&alloc->mutex);
+	spin_lock(&alloc->lock);
 	for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 		count++;
-	mutex_unlock(&alloc->mutex);
+	spin_unlock(&alloc->lock);
 	return count;
 }
 
@@ -979,35 +1061,39 @@ enum lru_status binder_alloc_free_page(struct list_head *item,
 				       void *cb_arg)
 	__must_hold(lock)
 {
-	struct mm_struct *mm = NULL;
-	struct binder_lru_page *page = container_of(item,
-						    struct binder_lru_page,
-						    lru);
-	struct binder_alloc *alloc;
-	uintptr_t page_addr;
-	size_t index;
+	struct binder_lru_page *page = container_of(item, typeof(*page), lru);
+	struct binder_alloc *alloc = page->alloc;
+	struct mm_struct *mm = alloc->mm;
 	struct vm_area_struct *vma;
+	struct page *page_to_free;
+	unsigned long page_addr;
+	size_t index;
 
-	alloc = page->alloc;
-	if (!mutex_trylock(&alloc->mutex))
-		goto err_get_alloc_mutex_failed;
-
+	if (!mmget_not_zero(mm))
+		goto err_mmget;
+	if (!mmap_read_trylock(mm))
+		goto err_mmap_read_lock_failed;
+	if (!spin_trylock(&alloc->lock))
+		goto err_get_alloc_lock_failed;
 	if (!page->page_ptr)
 		goto err_page_already_freed;
 
 	index = page - alloc->pages;
-	page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
+	page_addr = alloc->buffer + index * PAGE_SIZE;
 
-	mm = alloc->mm;
-	if (!mmget_not_zero(mm))
-		goto err_mmget;
-	if (!mmap_read_trylock(mm))
-		goto err_mmap_read_lock_failed;
 	vma = vma_lookup(mm, page_addr);
 	if (vma && vma != binder_alloc_get_vma(alloc))
 		goto err_invalid_vma;
 
+	trace_binder_unmap_kernel_start(alloc, index);
+
+	page_to_free = page->page_ptr;
+	page->page_ptr = NULL;
+
+	trace_binder_unmap_kernel_end(alloc, index);
+
 	list_lru_isolate(lru, item);
+	spin_unlock(&alloc->lock);
 	spin_unlock(lock);
 
 	if (vma) {
@@ -1017,41 +1103,35 @@ enum lru_status binder_alloc_free_page(struct list_head *item,
 
 		trace_binder_unmap_user_end(alloc, index);
 	}
+
 	mmap_read_unlock(mm);
 	mmput_async(mm);
-
-	trace_binder_unmap_kernel_start(alloc, index);
-
-	__free_page(page->page_ptr);
-	page->page_ptr = NULL;
-
-	trace_binder_unmap_kernel_end(alloc, index);
+	__free_page(page_to_free);
 
 	spin_lock(lock);
-	mutex_unlock(&alloc->mutex);
 	return LRU_REMOVED_RETRY;
 
 err_invalid_vma:
+err_page_already_freed:
+	spin_unlock(&alloc->lock);
+err_get_alloc_lock_failed:
 	mmap_read_unlock(mm);
 err_mmap_read_lock_failed:
 	mmput_async(mm);
 err_mmget:
-err_page_already_freed:
-	mutex_unlock(&alloc->mutex);
-err_get_alloc_mutex_failed:
 	return LRU_SKIP;
 }
 
 static unsigned long
 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 {
-	return list_lru_count(&binder_alloc_lru);
+	return list_lru_count(&binder_freelist);
 }
 
 static unsigned long
 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 {
-	return list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
+	return list_lru_walk(&binder_freelist, binder_alloc_free_page,
 			    NULL, sc->nr_to_scan);
 }
 
@@ -1069,7 +1149,7 @@ void binder_alloc_init(struct binder_alloc *alloc)
 	alloc->pid = current->group_leader->pid;
 	alloc->mm = current->mm;
 	mmgrab(alloc->mm);
-	mutex_init(&alloc->mutex);
+	spin_lock_init(&alloc->lock);
 	INIT_LIST_HEAD(&alloc->buffers);
 }
 
@@ -1077,13 +1157,13 @@ int binder_alloc_shrinker_init(void)
 {
 	int ret;
 
-	ret = list_lru_init(&binder_alloc_lru);
+	ret = list_lru_init(&binder_freelist);
 	if (ret)
 		return ret;
 
 	binder_shrinker = shrinker_alloc(0, "android-binder");
 	if (!binder_shrinker) {
-		list_lru_destroy(&binder_alloc_lru);
+		list_lru_destroy(&binder_freelist);
 		return -ENOMEM;
 	}
 
@@ -1098,7 +1178,7 @@ int binder_alloc_shrinker_init(void)
 void binder_alloc_shrinker_exit(void)
 {
 	shrinker_free(binder_shrinker);
-	list_lru_destroy(&binder_alloc_lru);
+	list_lru_destroy(&binder_freelist);
 }
 
 /**
@@ -1134,68 +1214,6 @@ static inline bool check_buffer(struct binder_alloc *alloc,
 }
 
 /**
- * binder_alloc_get_page() - get kernel pointer for given buffer offset
- * @alloc: binder_alloc for this proc
- * @buffer: binder buffer to be accessed
- * @buffer_offset: offset into @buffer data
- * @pgoffp: address to copy final page offset to
- *
- * Lookup the struct page corresponding to the address
- * at @buffer_offset into @buffer->user_data. If @pgoffp is not
- * NULL, the byte-offset into the page is written there.
- *
- * The caller is responsible to ensure that the offset points
- * to a valid address within the @buffer and that @buffer is
- * not freeable by the user. Since it can't be freed, we are
- * guaranteed that the corresponding elements of @alloc->pages[]
- * cannot change.
- *
- * Return: struct page
- */
-static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
-					  struct binder_buffer *buffer,
-					  binder_size_t buffer_offset,
-					  pgoff_t *pgoffp)
-{
-	binder_size_t buffer_space_offset = buffer_offset +
-		(buffer->user_data - alloc->buffer);
-	pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
-	size_t index = buffer_space_offset >> PAGE_SHIFT;
-	struct binder_lru_page *lru_page;
-
-	lru_page = &alloc->pages[index];
-	*pgoffp = pgoff;
-	return lru_page->page_ptr;
-}
-
-/**
- * binder_alloc_clear_buf() - zero out buffer
- * @alloc: binder_alloc for this proc
- * @buffer: binder buffer to be cleared
- *
- * memset the given buffer to 0
- */
-static void binder_alloc_clear_buf(struct binder_alloc *alloc,
-				   struct binder_buffer *buffer)
-{
-	size_t bytes = binder_alloc_buffer_size(alloc, buffer);
-	binder_size_t buffer_offset = 0;
-
-	while (bytes) {
-		unsigned long size;
-		struct page *page;
-		pgoff_t pgoff;
-
-		page = binder_alloc_get_page(alloc, buffer,
-					     buffer_offset, &pgoff);
-		size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
-		memset_page(page, pgoff, 0, size);
-		bytes -= size;
-		buffer_offset += size;
-	}
-}
-
-/**
  * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
  * @alloc: binder_alloc for this proc
  * @buffer: binder buffer to be accessed
@@ -1289,4 +1307,3 @@ int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
 	return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
 					   dest, bytes);
 }
-
diff --git a/drivers/android/binder_alloc.h b/drivers/android/binder_alloc.h
index dc1e2b01dd..7038723447 100644
--- a/drivers/android/binder_alloc.h
+++ b/drivers/android/binder_alloc.h
@@ -9,13 +9,13 @@
 #include <linux/rbtree.h>
 #include <linux/list.h>
 #include <linux/mm.h>
-#include <linux/rtmutex.h>
+#include <linux/spinlock.h>
 #include <linux/vmalloc.h>
 #include <linux/slab.h>
 #include <linux/list_lru.h>
 #include <uapi/linux/android/binder.h>
 
-extern struct list_lru binder_alloc_lru;
+extern struct list_lru binder_freelist;
 struct binder_transaction;
 
 /**
@@ -49,21 +49,19 @@ struct binder_buffer {
 	unsigned async_transaction:1;
 	unsigned oneway_spam_suspect:1;
 	unsigned debug_id:27;
-
 	struct binder_transaction *transaction;
-
 	struct binder_node *target_node;
 	size_t data_size;
 	size_t offsets_size;
 	size_t extra_buffers_size;
-	void __user *user_data;
-	int    pid;
+	unsigned long user_data;
+	int pid;
 };
 
 /**
  * struct binder_lru_page - page object used for binder shrinker
  * @page_ptr: pointer to physical page in mmap'd space
- * @lru:      entry in binder_alloc_lru
+ * @lru:      entry in binder_freelist
  * @alloc:    binder_alloc for a proc
  */
 struct binder_lru_page {
@@ -74,7 +72,7 @@ struct binder_lru_page {
 
 /**
  * struct binder_alloc - per-binder proc state for binder allocator
- * @mutex:              protects binder_alloc fields
+ * @lock:               protects binder_alloc fields
  * @vma:                vm_area_struct passed to mmap_handler
  *                      (invariant after mmap)
  * @mm:                 copy of task->mm (invariant after open)
@@ -98,10 +96,10 @@ struct binder_lru_page {
  * struct binder_buffer objects used to track the user buffers
  */
 struct binder_alloc {
-	struct mutex mutex;
+	spinlock_t lock;
 	struct vm_area_struct *vma;
 	struct mm_struct *mm;
-	void __user *buffer;
+	unsigned long buffer;
 	struct list_head buffers;
 	struct rb_root free_buffers;
 	struct rb_root allocated_buffers;
@@ -121,27 +119,26 @@ static inline void binder_selftest_alloc(struct binder_alloc *alloc) {}
 enum lru_status binder_alloc_free_page(struct list_head *item,
 				       struct list_lru_one *lru,
 				       spinlock_t *lock, void *cb_arg);
-extern struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
-						  size_t data_size,
-						  size_t offsets_size,
-						  size_t extra_buffers_size,
-						  int is_async,
-						  int pid);
-extern void binder_alloc_init(struct binder_alloc *alloc);
-extern int binder_alloc_shrinker_init(void);
-extern void binder_alloc_shrinker_exit(void);
-extern void binder_alloc_vma_close(struct binder_alloc *alloc);
-extern struct binder_buffer *
+struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
+					   size_t data_size,
+					   size_t offsets_size,
+					   size_t extra_buffers_size,
+					   int is_async);
+void binder_alloc_init(struct binder_alloc *alloc);
+int binder_alloc_shrinker_init(void);
+void binder_alloc_shrinker_exit(void);
+void binder_alloc_vma_close(struct binder_alloc *alloc);
+struct binder_buffer *
 binder_alloc_prepare_to_free(struct binder_alloc *alloc,
-			     uintptr_t user_ptr);
-extern void binder_alloc_free_buf(struct binder_alloc *alloc,
-				  struct binder_buffer *buffer);
-extern int binder_alloc_mmap_handler(struct binder_alloc *alloc,
-				     struct vm_area_struct *vma);
-extern void binder_alloc_deferred_release(struct binder_alloc *alloc);
-extern int binder_alloc_get_allocated_count(struct binder_alloc *alloc);
-extern void binder_alloc_print_allocated(struct seq_file *m,
-					 struct binder_alloc *alloc);
+			     unsigned long user_ptr);
+void binder_alloc_free_buf(struct binder_alloc *alloc,
+			   struct binder_buffer *buffer);
+int binder_alloc_mmap_handler(struct binder_alloc *alloc,
+			      struct vm_area_struct *vma);
+void binder_alloc_deferred_release(struct binder_alloc *alloc);
+int binder_alloc_get_allocated_count(struct binder_alloc *alloc);
+void binder_alloc_print_allocated(struct seq_file *m,
+				  struct binder_alloc *alloc);
 void binder_alloc_print_pages(struct seq_file *m,
 			      struct binder_alloc *alloc);
 
@@ -156,9 +153,9 @@ binder_alloc_get_free_async_space(struct binder_alloc *alloc)
 {
 	size_t free_async_space;
 
-	mutex_lock(&alloc->mutex);
+	spin_lock(&alloc->lock);
 	free_async_space = alloc->free_async_space;
-	mutex_unlock(&alloc->mutex);
+	spin_unlock(&alloc->lock);
 	return free_async_space;
 }
 
diff --git a/drivers/android/binder_alloc_selftest.c b/drivers/android/binder_alloc_selftest.c
index c2b323bc3b..81442fe20a 100644
--- a/drivers/android/binder_alloc_selftest.c
+++ b/drivers/android/binder_alloc_selftest.c
@@ -72,6 +72,10 @@ enum buf_end_align_type {
 	 * buf1 ]|[ buf2 | buf2 | buf2 ][ ...
 	 */
 	NEXT_NEXT_UNALIGNED,
+	/**
+	 * @LOOP_END: The number of enum values in &buf_end_align_type.
+	 * It is used for controlling loop termination.
+	 */
 	LOOP_END,
 };
 
@@ -93,11 +97,11 @@ static bool check_buffer_pages_allocated(struct binder_alloc *alloc,
 					 struct binder_buffer *buffer,
 					 size_t size)
 {
-	void __user *page_addr;
-	void __user *end;
+	unsigned long page_addr;
+	unsigned long end;
 	int page_index;
 
-	end = (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
+	end = PAGE_ALIGN(buffer->user_data + size);
 	page_addr = buffer->user_data;
 	for (; page_addr < end; page_addr += PAGE_SIZE) {
 		page_index = (page_addr - alloc->buffer) / PAGE_SIZE;
@@ -119,7 +123,7 @@ static void binder_selftest_alloc_buf(struct binder_alloc *alloc,
 	int i;
 
 	for (i = 0; i < BUFFER_NUM; i++) {
-		buffers[i] = binder_alloc_new_buf(alloc, sizes[i], 0, 0, 0, 0);
+		buffers[i] = binder_alloc_new_buf(alloc, sizes[i], 0, 0, 0);
 		if (IS_ERR(buffers[i]) ||
 		    !check_buffer_pages_allocated(alloc, buffers[i],
 						  sizes[i])) {
@@ -158,8 +162,8 @@ static void binder_selftest_free_page(struct binder_alloc *alloc)
 	int i;
 	unsigned long count;
 
-	while ((count = list_lru_count(&binder_alloc_lru))) {
-		list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
+	while ((count = list_lru_count(&binder_freelist))) {
+		list_lru_walk(&binder_freelist, binder_alloc_free_page,
 			      NULL, count);
 	}
 
@@ -183,7 +187,7 @@ static void binder_selftest_alloc_free(struct binder_alloc *alloc,
 
 	/* Allocate from lru. */
 	binder_selftest_alloc_buf(alloc, buffers, sizes, seq);
-	if (list_lru_count(&binder_alloc_lru))
+	if (list_lru_count(&binder_freelist))
 		pr_err("lru list should be empty but is not\n");
 
 	binder_selftest_free_buf(alloc, buffers, sizes, seq, end);
diff --git a/drivers/android/binder_trace.h b/drivers/android/binder_trace.h
index 8cc07e6a42..fe38c6fc65 100644
--- a/drivers/android/binder_trace.h
+++ b/drivers/android/binder_trace.h
@@ -317,7 +317,7 @@ DEFINE_EVENT(binder_buffer_class, binder_transaction_update_buffer_release,
 
 TRACE_EVENT(binder_update_page_range,
 	TP_PROTO(struct binder_alloc *alloc, bool allocate,
-		 void __user *start, void __user *end),
+		 unsigned long start, unsigned long end),
 	TP_ARGS(alloc, allocate, start, end),
 	TP_STRUCT__entry(
 		__field(int, proc)
diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
index 1224ab7aa0..3001d754ac 100644
--- a/drivers/android/binderfs.c
+++ b/drivers/android/binderfs.c
@@ -29,7 +29,6 @@
 #include <linux/uaccess.h>
 #include <linux/user_namespace.h>
 #include <linux/xarray.h>
-#include <uapi/asm-generic/errno-base.h>
 #include <uapi/linux/android/binder.h>
 #include <uapi/linux/android/binderfs.h>