mm: hugetlb_vmemmap: move mmap lock to vmemmap_remap_range()

All the users of vmemmap_remap_range() will hold the mmap lock and release
it once it returns, it is naturally to move the lock to
vmemmap_remap_range() to simplify the code and the users.

Link: https://lkml.kernel.org/r/20231205030853.3921-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index 2646a2798a0e5eaab093fa160f3558894f5506aa..da177e49d95648aaa73fb912a6797bd08dc96bf2 100644 (file)
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -163,8 +163,10 @@ static int vmemmap_remap_range(unsigned long start, unsigned long end,
 
        VM_BUG_ON(!PAGE_ALIGNED(start | end));
 
+       mmap_read_lock(&init_mm);
        ret = walk_page_range_novma(&init_mm, start, end, &vmemmap_remap_ops,
                                    NULL, walk);
+       mmap_read_unlock(&init_mm);
        if (ret)
                return ret;
 
@@ -282,7 +284,6 @@ static void vmemmap_restore_pte(pte_t *pte, unsigned long addr,
 static int vmemmap_remap_split(unsigned long start, unsigned long end,
                               unsigned long reuse)
 {
-       int ret;
        struct vmemmap_remap_walk walk = {
                .remap_pte      = NULL,
                .flags          = VMEMMAP_SPLIT_NO_TLB_FLUSH,
@@ -291,11 +292,7 @@ static int vmemmap_remap_split(unsigned long start, unsigned long end,
        /* See the comment in the vmemmap_remap_free(). */
        BUG_ON(start - reuse != PAGE_SIZE);
 
-       mmap_read_lock(&init_mm);
-       ret = vmemmap_remap_range(reuse, end, &walk);
-       mmap_read_unlock(&init_mm);
-
-       return ret;
+       return vmemmap_remap_range(reuse, end, &walk);
 }
 
 /**
@@ -358,7 +355,6 @@ static int vmemmap_remap_free(unsigned long start, unsigned long end,
         */
        BUG_ON(start - reuse != PAGE_SIZE);
 
-       mmap_read_lock(&init_mm);
        ret = vmemmap_remap_range(reuse, end, &walk);
        if (ret && walk.nr_walked) {
                end = reuse + walk.nr_walked * PAGE_SIZE;
@@ -377,7 +373,6 @@ static int vmemmap_remap_free(unsigned long start, unsigned long end,
 
                vmemmap_remap_range(reuse, end, &walk);
        }
-       mmap_read_unlock(&init_mm);
 
        return ret;
 }
@@ -434,11 +429,7 @@ static int vmemmap_remap_alloc(unsigned long start, unsigned long end,
        if (alloc_vmemmap_page_list(start, end, &vmemmap_pages))
                return -ENOMEM;
 
-       mmap_read_lock(&init_mm);
-       vmemmap_remap_range(reuse, end, &walk);
-       mmap_read_unlock(&init_mm);
-
-       return 0;
+       return vmemmap_remap_range(reuse, end, &walk);
 }
 
 DEFINE_STATIC_KEY_FALSE(hugetlb_optimize_vmemmap_key);