binder: remove kernel vm_area for buffer space

Remove the kernel's vm_area and the code that maps
buffer pages into it.

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

1 files changed, 2 insertions, 38 deletions

diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index 2eebff4be83e..d4cbe4b3947a 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -265,16 +265,6 @@ static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
                 page->alloc = alloc;
                 INIT_LIST_HEAD(&page->lru);
 
-                ret = map_kernel_range_noflush((unsigned long)page_addr,
-                                               PAGE_SIZE, PAGE_KERNEL,
-                                               &page->page_ptr);
-                flush_cache_vmap((unsigned long)page_addr,
-                                (unsigned long)page_addr + PAGE_SIZE);
-                if (ret != 1) {
-                        pr_err("%d: binder_alloc_buf failed to map page at %pK in kernel\n",
-                               alloc->pid, page_addr);
-                        goto err_map_kernel_failed;
-                }
                 user_page_addr =
                         (uintptr_t)page_addr + alloc->user_buffer_offset;
                 ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
@@ -314,8 +304,6 @@ free_range:
                 continue;
 
 err_vm_insert_page_failed:
-                unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
-err_map_kernel_failed:
                 __free_page(page->page_ptr);
                 page->page_ptr = NULL;
 err_alloc_page_failed:
@@ -695,7 +683,6 @@ int binder_alloc_mmap_handler(struct binder_alloc *alloc,
                               struct vm_area_struct *vma)
 {
         int ret;
-        struct vm_struct *area;
         const char *failure_string;
         struct binder_buffer *buffer;
 
@@ -706,28 +693,10 @@ int binder_alloc_mmap_handler(struct binder_alloc *alloc,
                 goto err_already_mapped;
         }
 
-        area = get_vm_area(vma->vm_end - vma->vm_start, VM_ALLOC);
-        if (area == NULL) {
-                ret = -ENOMEM;
-                failure_string = "get_vm_area";
-                goto err_get_vm_area_failed;
-        }
-        alloc->buffer = area->addr;
-        alloc->user_buffer_offset =
-                vma->vm_start - (uintptr_t)alloc->buffer;
+        alloc->buffer = (void *)vma->vm_start;
+        alloc->user_buffer_offset = 0;
         mutex_unlock(&binder_alloc_mmap_lock);
 
-#ifdef CONFIG_CPU_CACHE_VIPT
-        if (cache_is_vipt_aliasing()) {
-                while (CACHE_COLOUR(
-                                (vma->vm_start ^ (uint32_t)alloc->buffer))) {
-                        pr_info("%s: %d %lx-%lx maps %pK bad alignment\n",
-                                __func__, alloc->pid, vma->vm_start,
-                                vma->vm_end, alloc->buffer);
-                        vma->vm_start += PAGE_SIZE;
-                }
-        }
-#endif
         alloc->pages = kcalloc((vma->vm_end - vma->vm_start) / PAGE_SIZE,
                                sizeof(alloc->pages[0]),
                                GFP_KERNEL);
@@ -760,9 +729,7 @@ err_alloc_buf_struct_failed:
         alloc->pages = NULL;
 err_alloc_pages_failed:
         mutex_lock(&binder_alloc_mmap_lock);
-        vfree(alloc->buffer);
         alloc->buffer = NULL;
-err_get_vm_area_failed:
 err_already_mapped:
         mutex_unlock(&binder_alloc_mmap_lock);
         binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
@@ -821,12 +788,10 @@ void binder_alloc_deferred_release(struct binder_alloc *alloc)
                                      "%s: %d: page %d at %pK %s\n",
                                      __func__, alloc->pid, i, page_addr,
                                      on_lru ? "on lru" : "active");
-                        unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
                         __free_page(alloc->pages[i].page_ptr);
                         page_count++;
                 }
                 kfree(alloc->pages);
-                vfree(alloc->buffer);
         }
         mutex_unlock(&alloc->mutex);
         if (alloc->vma_vm_mm)
@@ -988,7 +953,6 @@ enum lru_status binder_alloc_free_page(struct list_head *item,
 
         trace_binder_unmap_kernel_start(alloc, index);
 
-        unmap_kernel_range(page_addr, PAGE_SIZE);
         __free_page(page->page_ptr);
         page->page_ptr = NULL;