mmap locking API: use coccinelle to convert mmap_sem rwsem call sites

This change converts the existing mmap_sem rwsem calls to use the new mmap
locking API instead.

The change is generated using coccinelle with the following rule:

// spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir .

@@
expression mm;
@@
(
-init_rwsem
+mmap_init_lock
|
-down_write
+mmap_write_lock
|
-down_write_killable
+mmap_write_lock_killable
|
-down_write_trylock
+mmap_write_trylock
|
-up_write
+mmap_write_unlock
|
-downgrade_write
+mmap_write_downgrade
|
-down_read
+mmap_read_lock
|
-down_read_killable
+mmap_read_lock_killable
|
-down_read_trylock
+mmap_read_trylock
|
-up_read
+mmap_read_unlock
)
-(&mm->mmap_sem)
+(mm)

Signed-off-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/ksm.c

@@ -542,11 +542,11 @@ static void break_cow(struct rmap_item *rmap_item)
 	 */
 	put_anon_vma(rmap_item->anon_vma);
 
-	down_read(&mm->mmap_sem);
+	mmap_read_lock(mm);
 	vma = find_mergeable_vma(mm, addr);
 	if (vma)
 		break_ksm(vma, addr);
-	up_read(&mm->mmap_sem);
+	mmap_read_unlock(mm);
 }
 
 static struct page *get_mergeable_page(struct rmap_item *rmap_item)
@@ -556,7 +556,7 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item)
 	struct vm_area_struct *vma;
 	struct page *page;
 
-	down_read(&mm->mmap_sem);
+	mmap_read_lock(mm);
 	vma = find_mergeable_vma(mm, addr);
 	if (!vma)
 		goto out;
@@ -572,7 +572,7 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item)
 out:
 		page = NULL;
 	}
-	up_read(&mm->mmap_sem);
+	mmap_read_unlock(mm);
 	return page;
 }
 
@@ -976,7 +976,7 @@ static int unmerge_and_remove_all_rmap_items(void)
 	for (mm_slot = ksm_scan.mm_slot;
 			mm_slot != &ksm_mm_head; mm_slot = ksm_scan.mm_slot) {
 		mm = mm_slot->mm;
-		down_read(&mm->mmap_sem);
+		mmap_read_lock(mm);
 		for (vma = mm->mmap; vma; vma = vma->vm_next) {
 			if (ksm_test_exit(mm))
 				break;
@@ -989,7 +989,7 @@ static int unmerge_and_remove_all_rmap_items(void)
 		}
 
 		remove_trailing_rmap_items(mm_slot, &mm_slot->rmap_list);
-		up_read(&mm->mmap_sem);
+		mmap_read_unlock(mm);
 
 		spin_lock(&ksm_mmlist_lock);
 		ksm_scan.mm_slot = list_entry(mm_slot->mm_list.next,
@@ -1012,7 +1012,7 @@ static int unmerge_and_remove_all_rmap_items(void)
 	return 0;
 
 error:
-	up_read(&mm->mmap_sem);
+	mmap_read_unlock(mm);
 	spin_lock(&ksm_mmlist_lock);
 	ksm_scan.mm_slot = &ksm_mm_head;
 	spin_unlock(&ksm_mmlist_lock);
@@ -1280,7 +1280,7 @@ static int try_to_merge_with_ksm_page(struct rmap_item *rmap_item,
 	struct vm_area_struct *vma;
 	int err = -EFAULT;
 
-	down_read(&mm->mmap_sem);
+	mmap_read_lock(mm);
 	vma = find_mergeable_vma(mm, rmap_item->address);
 	if (!vma)
 		goto out;
@@ -1296,7 +1296,7 @@ static int try_to_merge_with_ksm_page(struct rmap_item *rmap_item,
 	rmap_item->anon_vma = vma->anon_vma;
 	get_anon_vma(vma->anon_vma);
 out:
-	up_read(&mm->mmap_sem);
+	mmap_read_unlock(mm);
 	return err;
 }
 
@@ -2110,7 +2110,7 @@ static void cmp_and_merge_page(struct page *page, struct rmap_item *rmap_item)
 	if (ksm_use_zero_pages && (checksum == zero_checksum)) {
 		struct vm_area_struct *vma;
 
-		down_read(&mm->mmap_sem);
+		mmap_read_lock(mm);
 		vma = find_mergeable_vma(mm, rmap_item->address);
 		if (vma) {
 			err = try_to_merge_one_page(vma, page,
@@ -2122,7 +2122,7 @@ static void cmp_and_merge_page(struct page *page, struct rmap_item *rmap_item)
 			 */
 			err = 0;
 		}
-		up_read(&mm->mmap_sem);
+		mmap_read_unlock(mm);
 		/*
 		 * In case of failure, the page was not really empty, so we
 		 * need to continue. Otherwise we're done.
@@ -2285,7 +2285,7 @@ next_mm:
 	}
 
 	mm = slot->mm;
-	down_read(&mm->mmap_sem);
+	mmap_read_lock(mm);
 	if (ksm_test_exit(mm))
 		vma = NULL;
 	else
@@ -2319,7 +2319,7 @@ next_mm:
 					ksm_scan.address += PAGE_SIZE;
 				} else
 					put_page(*page);
-				up_read(&mm->mmap_sem);
+				mmap_read_unlock(mm);
 				return rmap_item;
 			}
 			put_page(*page);
@@ -2357,10 +2357,10 @@ next_mm:
 
 		free_mm_slot(slot);
 		clear_bit(MMF_VM_MERGEABLE, &mm->flags);
-		up_read(&mm->mmap_sem);
+		mmap_read_unlock(mm);
 		mmdrop(mm);
 	} else {
-		up_read(&mm->mmap_sem);
+		mmap_read_unlock(mm);
 		/*
 		 * up_read(&mm->mmap_sem) first because after
 		 * spin_unlock(&ksm_mmlist_lock) run, the "mm" may
@@ -2560,8 +2560,8 @@ void __ksm_exit(struct mm_struct *mm)
 		clear_bit(MMF_VM_MERGEABLE, &mm->flags);
 		mmdrop(mm);
 	} else if (mm_slot) {
-		down_write(&mm->mmap_sem);
-		up_write(&mm->mmap_sem);
+		mmap_write_lock(mm);
+		mmap_write_unlock(mm);
 	}
 }