4.15-stable review patch. If anyone has any objections, please let me know.
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From: Ganesh Mahendran opensource.ganesh@gmail.com
commit aac6830ec1cb681544212838911cdc57f2638216 upstream.
VM_IOREMAP is used to access hardware through a mechanism called I/O mapped memory. Android binder is a IPC machanism which will not access I/O memory.
And VM_IOREMAP has alignment requiement which may not needed in binder. __get_vm_area_node() { ... if (flags & VM_IOREMAP) align = 1ul << clamp_t(int, fls_long(size), PAGE_SHIFT, IOREMAP_MAX_ORDER); ... }
This patch will save some kernel vm area, especially for 32bit os.
In 32bit OS, kernel vm area is only 240MB. We may got below error when launching a app:
<3>[ 4482.440053] binder_alloc: binder_alloc_mmap_handler: 15728 8ce67000-8cf65000 get_vm_area failed -12 <3>[ 4483.218817] binder_alloc: binder_alloc_mmap_handler: 15745 8ce67000-8cf65000 get_vm_area failed -12
Signed-off-by: Ganesh Mahendran opensource.ganesh@gmail.com Acked-by: Martijn Coenen maco@android.com Acked-by: Todd Kjos tkjos@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/android/binder_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/android/binder_alloc.c +++ b/drivers/android/binder_alloc.c @@ -666,7 +666,7 @@ int binder_alloc_mmap_handler(struct bin goto err_already_mapped; }
- area = get_vm_area(vma->vm_end - vma->vm_start, VM_IOREMAP); + area = get_vm_area(vma->vm_end - vma->vm_start, VM_ALLOC); if (area == NULL) { ret = -ENOMEM; failure_string = "get_vm_area";