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Subject[PATCH v2 5/7] binder: remove kernel vm_area for buffer space
Date
Remove the kernel's vm_area and the code that maps
buffer pages into it.

Signed-off-by: Todd Kjos <tkjos@google.com>
---
drivers/android/binder_alloc.c | 40 ++--------------------------------
1 file 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 @@ static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
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 @@ int binder_alloc_mmap_handler(struct binder_alloc *alloc,
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;

--
2.20.1.495.gaa96b0ce6b-goog
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