[PATCH 1/2] mm: Report success more often from filemap_map_folio_range()

["Matthew Wilcox (Oracle)" <willy@infradead.org>]

Even though we had successfully mapped the relevant page, we would
rarely return success from filemap_map_folio_range().  That leads to
falling back from the VMA lock path to the mmap_lock path, which is a
speed & scalability issue.  Found by inspection.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Fixes: 617c28ecab22 ("filemap: batch PTE mappings")
---
 mm/filemap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 582f5317ff71..580d0b2b1a7c 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3506,7 +3506,7 @@ static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf,
 		if (count) {
 			set_pte_range(vmf, folio, page, count, addr);
 			folio_ref_add(folio, count);
-			if (in_range(vmf->address, addr, count))
+			if (in_range(vmf->address, addr, count * PAGE_SIZE))
 				ret = VM_FAULT_NOPAGE;
 		}
 
@@ -3520,7 +3520,7 @@ static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf,
 	if (count) {
 		set_pte_range(vmf, folio, page, count, addr);
 		folio_ref_add(folio, count);
-		if (in_range(vmf->address, addr, count))
+		if (in_range(vmf->address, addr, count * PAGE_SIZE))
 			ret = VM_FAULT_NOPAGE;
 	}
 
-- 
2.40.1