binder: remove user_buffer_offset

Remove user_buffer_offset since there is no kernel
buffer pointer anymore.

Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 13 insertions, 65 deletions

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index db0c45bc9134..ddd692cbcd7a 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2380,7 +2380,6 @@ static void binder_transaction_buffer_release(struct binder_proc *proc,
                         struct binder_fd_array_object *fda;
                         struct binder_buffer_object *parent;
                         struct binder_object ptr_object;
-                        uintptr_t parent_buffer;
                         u32 *fd_array;
                         size_t fd_index;
                         binder_size_t fd_buf_size;
@@ -2405,14 +2404,6 @@ static void binder_transaction_buffer_release(struct binder_proc *proc,
                                        debug_id);
                                 continue;
                         }
-                        /*
-                         * Since the parent was already fixed up, convert it
-                         * back to kernel address space to access it
-                         */
-                        parent_buffer = parent->buffer -
-                                binder_alloc_get_user_buffer_offset(
-                                                &proc->alloc);
-
                         fd_buf_size = sizeof(u32) * fda->num_fds;
                         if (fda->num_fds >= SIZE_MAX / sizeof(u32)) {
                                 pr_err("transaction release %d invalid number of fds (%lld)\n",
@@ -2426,7 +2417,8 @@ static void binder_transaction_buffer_release(struct binder_proc *proc,
                                        debug_id, (u64)fda->num_fds);
                                 continue;
                         }
-                        fd_array = (u32 *)(parent_buffer + (uintptr_t)fda->parent_offset);
+                        fd_array = (u32 *)(uintptr_t)
+                                (parent->buffer + fda->parent_offset);
                         for (fd_index = 0; fd_index < fda->num_fds;
                              fd_index++) {
                                 u32 fd;
@@ -2646,7 +2638,6 @@ static int binder_translate_fd_array(struct binder_fd_array_object *fda,
                                      struct binder_transaction *in_reply_to)
 {
         binder_size_t fdi, fd_buf_size;
-        uintptr_t parent_buffer;
         u32 *fd_array;
         struct binder_proc *proc = thread->proc;
         struct binder_proc *target_proc = t->to_proc;
@@ -2664,13 +2655,7 @@ static int binder_translate_fd_array(struct binder_fd_array_object *fda,
                                   proc->pid, thread->pid, (u64)fda->num_fds);
                 return -EINVAL;
         }
-        /*
-         * Since the parent was already fixed up, convert it
-         * back to the kernel address space to access it
-         */
-        parent_buffer = parent->buffer -
-                binder_alloc_get_user_buffer_offset(&target_proc->alloc);
-        fd_array = (u32 *)(parent_buffer + (uintptr_t)fda->parent_offset);
+        fd_array = (u32 *)(uintptr_t)(parent->buffer + fda->parent_offset);
         if (!IS_ALIGNED((unsigned long)fd_array, sizeof(u32))) {
                 binder_user_error("%d:%d parent offset not aligned correctly.\n",
                                   proc->pid, thread->pid);
@@ -2703,7 +2688,6 @@ static int binder_fixup_parent(struct binder_transaction *t,
                                binder_size_t last_fixup_min_off)
 {
         struct binder_buffer_object *parent;
-        u8 *parent_buffer;
         struct binder_buffer *b = t->buffer;
         struct binder_proc *proc = thread->proc;
         struct binder_proc *target_proc = t->to_proc;
@@ -2739,11 +2723,8 @@ static int binder_fixup_parent(struct binder_transaction *t,
                                   proc->pid, thread->pid);
                 return -EINVAL;
         }
-        parent_buffer = (u8 *)((uintptr_t)parent->buffer -
-                        binder_alloc_get_user_buffer_offset(
-                                &target_proc->alloc));
         buffer_offset = bp->parent_offset +
-                        (uintptr_t)parent_buffer - (uintptr_t)b->data;
+                        (uintptr_t)parent->buffer - (uintptr_t)b->data;
         binder_alloc_copy_to_buffer(&target_proc->alloc, b, buffer_offset,
                                     &bp->buffer, sizeof(bp->buffer));
 
@@ -3159,10 +3140,8 @@ static void binder_transaction(struct binder_proc *proc,
                                     ALIGN(tr->offsets_size, sizeof(void *)) +
                                     ALIGN(extra_buffers_size, sizeof(void *)) -
                                     ALIGN(secctx_sz, sizeof(u64));
-                char *kptr = t->buffer->data + buf_offset;
 
-                t->security_ctx = (uintptr_t)kptr +
-                    binder_alloc_get_user_buffer_offset(&target_proc->alloc);
+                t->security_ctx = (uintptr_t)t->buffer->data + buf_offset;
                 binder_alloc_copy_to_buffer(&target_proc->alloc,
                                             t->buffer, buf_offset,
                                             secctx, secctx_sz);
@@ -3380,9 +3359,7 @@ static void binder_transaction(struct binder_proc *proc,
                                 goto err_copy_data_failed;
                         }
                         /* Fixup buffer pointer to target proc address space */
-                        bp->buffer = (uintptr_t)sg_bufp +
-                                binder_alloc_get_user_buffer_offset(
-                                                &target_proc->alloc);
+                        bp->buffer = (uintptr_t)sg_bufp;
                         sg_bufp += ALIGN(bp->length, sizeof(u64));
 
                         ret = binder_fixup_parent(t, thread, bp,
@@ -4474,9 +4451,7 @@ retry:
                 }
                 trd->data_size = t->buffer->data_size;
                 trd->offsets_size = t->buffer->offsets_size;
-                trd->data.ptr.buffer = (binder_uintptr_t)
-                        ((uintptr_t)t->buffer->data +
-                        binder_alloc_get_user_buffer_offset(&proc->alloc));
+                trd->data.ptr.buffer = (uintptr_t)t->buffer->data;
                 trd->data.ptr.offsets = trd->data.ptr.buffer +
                                         ALIGN(t->buffer->data_size,
                                             sizeof(void *));
diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index d4cbe4b3947a..0e7f0aa967c3 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -138,17 +138,17 @@ static struct binder_buffer *binder_alloc_prepare_to_free_locked(
 {
         struct rb_node *n = alloc->allocated_buffers.rb_node;
         struct binder_buffer *buffer;
-        void *kern_ptr;
+        void *uptr;
 
-        kern_ptr = (void *)(user_ptr - alloc->user_buffer_offset);
+        uptr = (void *)user_ptr;
 
         while (n) {
                 buffer = rb_entry(n, struct binder_buffer, rb_node);
                 BUG_ON(buffer->free);
 
-                if (kern_ptr < buffer->data)
+                if (uptr < buffer->data)
                         n = n->rb_left;
-                else if (kern_ptr > buffer->data)
+                else if (uptr > buffer->data)
                         n = n->rb_right;
                 else {
                         /*
@@ -265,8 +265,7 @@ static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
                 page->alloc = alloc;
                 INIT_LIST_HEAD(&page->lru);
 
-                user_page_addr =
-                        (uintptr_t)page_addr + alloc->user_buffer_offset;
+                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",
@@ -694,7 +693,6 @@ int binder_alloc_mmap_handler(struct binder_alloc *alloc,
         }
 
         alloc->buffer = (void *)vma->vm_start;
-        alloc->user_buffer_offset = 0;
         mutex_unlock(&binder_alloc_mmap_lock);
 
         alloc->pages = kcalloc((vma->vm_end - vma->vm_start) / PAGE_SIZE,
@@ -941,9 +939,7 @@ enum lru_status binder_alloc_free_page(struct list_head *item,
         if (vma) {
                 trace_binder_unmap_user_start(alloc, index);
 
-                zap_page_range(vma,
-                               page_addr + alloc->user_buffer_offset,
-                               PAGE_SIZE);
+                zap_page_range(vma, page_addr, PAGE_SIZE);
 
                 trace_binder_unmap_user_end(alloc, index);
 
diff --git a/drivers/android/binder_alloc.h b/drivers/android/binder_alloc.h
index 9d682b9d6c24..1026e9fb20db 100644
--- a/drivers/android/binder_alloc.h
+++ b/drivers/android/binder_alloc.h
@@ -82,7 +82,6 @@ struct binder_lru_page {
  *                      (invariant after init)
  * @vma_vm_mm:          copy of vma->vm_mm (invarient after mmap)
  * @buffer:             base of per-proc address space mapped via mmap
- * @user_buffer_offset: offset between user and kernel VAs for buffer
  * @buffers:            list of all buffers for this proc
  * @free_buffers:       rb tree of buffers available for allocation
  *                      sorted by size
@@ -104,7 +103,6 @@ struct binder_alloc {
         struct vm_area_struct *vma;
         struct mm_struct *vma_vm_mm;
         void *buffer;
-        ptrdiff_t user_buffer_offset;
         struct list_head buffers;
         struct rb_root free_buffers;
         struct rb_root allocated_buffers;
@@ -163,27 +161,6 @@ binder_alloc_get_free_async_space(struct binder_alloc *alloc)
         return free_async_space;
 }
 
-/**
- * binder_alloc_get_user_buffer_offset() - get offset between kernel/user addrs
- * @alloc:      binder_alloc for this proc
- *
- * Return:      the offset between kernel and user-space addresses to use for
- * virtual address conversion
- */
-static inline ptrdiff_t
-binder_alloc_get_user_buffer_offset(struct binder_alloc *alloc)
-{
-        /*
-         * user_buffer_offset is constant if vma is set and
-         * undefined if vma is not set. It is possible to
-         * get here with !alloc->vma if the target process
-         * is dying while a transaction is being initiated.
-         * Returning the old value is ok in this case and
-         * the transaction will fail.
-         */
-        return alloc->user_buffer_offset;
-}
-
 unsigned long
 binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
                                  struct binder_buffer *buffer,