hugetlbfs: hugetlb_vmtruncate_list() needs to take a range to delete

fallocate hole punch will want to unmap a specific range of pages.
Modify the existing hugetlb_vmtruncate_list() routine to take a
start/end range.  If end is 0, this indicates all pages after start
should be unmapped.  This is the same as the existing truncate
functionality.  Modify existing callers to add 0 as end of range.

Since the routine will be used in hole punch as well as truncate
operations, it is more appropriately renamed to hugetlb_vmdelete_list().

Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 18 insertions, 7 deletions

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 973c24ce59ad..b1e197d38abb 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -349,11 +349,15 @@ static void hugetlbfs_evict_inode(struct inode *inode)
 }
 
 static inline void
-hugetlb_vmtruncate_list(struct rb_root *root, pgoff_t pgoff)
+hugetlb_vmdelete_list(struct rb_root *root, pgoff_t start, pgoff_t end)
 {
         struct vm_area_struct *vma;
 
-        vma_interval_tree_foreach(vma, root, pgoff, ULONG_MAX) {
+        /*
+         * end == 0 indicates that the entire range after
+         * start should be unmapped.
+         */
+        vma_interval_tree_foreach(vma, root, start, end ? end : ULONG_MAX) {
                 unsigned long v_offset;
 
                 /*
@@ -362,13 +366,20 @@ hugetlb_vmtruncate_list(struct rb_root *root, pgoff_t pgoff)
                  * which overlap the truncated area starting at pgoff,
                  * and no vma on a 32-bit arch can span beyond the 4GB.
                  */
-                if (vma->vm_pgoff < pgoff)
-                        v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
+                if (vma->vm_pgoff < start)
+                        v_offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
                 else
                         v_offset = 0;
 
-                unmap_hugepage_range(vma, vma->vm_start + v_offset,
-                                     vma->vm_end, NULL);
+                if (end) {
+                        end = ((end - start) << PAGE_SHIFT) +
+                               vma->vm_start + v_offset;
+                        if (end > vma->vm_end)
+                                end = vma->vm_end;
+                } else
+                        end = vma->vm_end;
+
+                unmap_hugepage_range(vma, vma->vm_start + v_offset, end, NULL);
         }
 }
 
@@ -384,7 +395,7 @@ static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
         i_size_write(inode, offset);
         i_mmap_lock_write(mapping);
         if (!RB_EMPTY_ROOT(&mapping->i_mmap))
-                hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
+                hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0);
         i_mmap_unlock_write(mapping);
         truncate_hugepages(inode, offset);
         return 0;