linux-kernel - [PATCH 56/64] drivers/android: use mm locking wrappers

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Date:   Mon,  5 Feb 2018 02:27:46 +0100
From:   Davidlohr Bueso <dbueso@...e.de>
To:     akpm@...ux-foundation.org, mingo@...nel.org
Cc:     peterz@...radead.org, ldufour@...ux.vnet.ibm.com, jack@...e.cz,
        mhocko@...nel.org, kirill.shutemov@...ux.intel.com,
        mawilcox@...rosoft.com, mgorman@...hsingularity.net,
        dave@...olabs.net, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, Davidlohr Bueso <dbueso@...e.de>
Subject: [PATCH 56/64] drivers/android: use mm locking wrappers

From: Davidlohr Bueso <dave@...olabs.net>

The binder_alloc_free_page() shrinker callback can call
zap_page_range(), which needs mmap_sem. Use mm locking
wrappers, no change in semantics.

Signed-off-by: Davidlohr Bueso <dbueso@...e.de>
---
 drivers/android/binder_alloc.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index 5a426c877dfb..191724983638 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -194,6 +194,7 @@ static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
 	struct vm_area_struct *vma = NULL;
 	struct mm_struct *mm = NULL;
 	bool need_mm = false;
+	DEFINE_RANGE_LOCK_FULL(mmrange);
 
 	binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 		     "%d: %s pages %pK-%pK\n", alloc->pid,
@@ -219,7 +220,7 @@ static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
 		mm = alloc->vma_vm_mm;
 
 	if (mm) {
-		down_write(&mm->mmap_sem);
+		mm_write_lock(mm, &mmrange);
 		vma = alloc->vma;
 	}
 
@@ -288,7 +289,7 @@ static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
 		/* vm_insert_page does not seem to increment the refcount */
 	}
 	if (mm) {
-		up_write(&mm->mmap_sem);
+		mm_write_unlock(mm, &mmrange);
 		mmput(mm);
 	}
 	return 0;
@@ -321,7 +322,7 @@ static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
 	}
 err_no_vma:
 	if (mm) {
-		up_write(&mm->mmap_sem);
+		mm_write_unlock(mm, &mmrange);
 		mmput(mm);
 	}
 	return vma ? -ENOMEM : -ESRCH;
@@ -914,6 +915,7 @@ enum lru_status binder_alloc_free_page(struct list_head *item,
 	uintptr_t page_addr;
 	size_t index;
 	struct vm_area_struct *vma;
+	DEFINE_RANGE_LOCK_FULL(mmrange);
 
 	alloc = page->alloc;
 	if (!mutex_trylock(&alloc->mutex))
@@ -929,7 +931,7 @@ enum lru_status binder_alloc_free_page(struct list_head *item,
 		if (!mmget_not_zero(alloc->vma_vm_mm))
 			goto err_mmget;
 		mm = alloc->vma_vm_mm;
-		if (!down_write_trylock(&mm->mmap_sem))
+		if (!mm_write_trylock(mm, &mmrange))
 			goto err_down_write_mmap_sem_failed;
 	}
 
@@ -945,7 +947,7 @@ enum lru_status binder_alloc_free_page(struct list_head *item,
 
 		trace_binder_unmap_user_end(alloc, index);
 
-		up_write(&mm->mmap_sem);
+		mm_write_unlock(mm, &mmrange);
 		mmput(mm);
 	}
 
-- 
2.13.6