FROMLIST: android: binder: Drop lru lock in isolate callback

(from https://patchwork.kernel.org/patch/9945123/)

Drop the global lru lock in isolate callback
before calling zap_page_range which calls
cond_resched, and re-acquire the global lru
lock before returning. Also change return
code to LRU_REMOVED_RETRY.

Use mmput_async when fail to acquire mmap sem
in an atomic context.

Fix "BUG: sleeping function called from invalid context"
errors when CONFIG_DEBUG_ATOMIC_SLEEP is enabled.

Bug: 63926541
Change-Id: I45dbada421b715abed9a66d03d30ae2285671ca1
Fixes: f2517eb76f1f2 ("android: binder: Add global lru shrinker to binder")
Reported-by: Kyle Yan <kyan@codeaurora.org>
Acked-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Sherry Yang <sherryy@android.com>
This commit is contained in:
Sherry Yang 2017-09-08 02:09:26 -04:00
parent 9cfefbcfaa
commit 849c7764d8

View file

@ -913,6 +913,7 @@ enum lru_status binder_alloc_free_page(struct list_head *item,
struct binder_alloc *alloc;
uintptr_t page_addr;
size_t index;
struct vm_area_struct *vma;
alloc = page->alloc;
if (!mutex_trylock(&alloc->mutex))
@ -923,16 +924,22 @@ enum lru_status binder_alloc_free_page(struct list_head *item,
index = page - alloc->pages;
page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
if (alloc->vma) {
vma = alloc->vma;
if (vma) {
mm = get_task_mm(alloc->tsk);
if (!mm)
goto err_get_task_mm_failed;
if (!down_write_trylock(&mm->mmap_sem))
goto err_down_write_mmap_sem_failed;
}
list_lru_isolate(lru, item);
spin_unlock(lock);
if (vma) {
trace_binder_unmap_user_start(alloc, index);
zap_page_range(alloc->vma,
zap_page_range(vma,
page_addr +
alloc->user_buffer_offset,
PAGE_SIZE, NULL);
@ -951,13 +958,12 @@ enum lru_status binder_alloc_free_page(struct list_head *item,
trace_binder_unmap_kernel_end(alloc, index);
list_lru_isolate(lru, item);
spin_lock(lock);
mutex_unlock(&alloc->mutex);
return LRU_REMOVED;
return LRU_REMOVED_RETRY;
err_down_write_mmap_sem_failed:
mmput(mm);
mmput_async(mm);
err_get_task_mm_failed:
err_page_already_freed:
mutex_unlock(&alloc->mutex);