mm: handle read faults under the VMA lock

Most file-backed faults are already handled through ->map_pages(), but if we need to do I/O we'll come this way. Since filemap_fault() is now safe to be called under the VMA lock, we can handle these faults under the VMA lock now. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Matthew Wilcox (Oracle) <[email protected]> Cc: Suren Baghdasaryan <[email protected]> Signed-off-by: Andrew Morton <[email protected]>
akiyks · Oct 6, 2023 · 78018dc · 78018dc
1 parent 4708d7c
commit 78018dc
Showing 1 changed file with 3 additions and 4 deletions.
diff --git a/mm/memory.c b/mm/memory.c
@@ -4620,10 +4620,9 @@ static vm_fault_t do_read_fault(struct vm_fault *vmf)
 			return ret;
 	}
 
-	if (vmf->flags & FAULT_FLAG_VMA_LOCK) {
-		vma_end_read(vmf->vma);
-		return VM_FAULT_RETRY;
-	}
+	ret = vmf_can_call_fault(vmf);
+	if (ret)
+		return ret;
 
 	ret = __do_fault(vmf);
 	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))