dax: Use radix tree entry lock to protect cow faults

[sfrench/cifs-2.6.git] / include / linux / mm.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index a55e5be0894f44d01145a0f3fc6d9c6b011e5754..0ef9dc720ec3b023f51cdc37060a48eb3e9ab1b1 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -299,6 +299,12 @@ struct vm_fault {
                                         * is set (which is also implied by
                                         * VM_FAULT_ERROR).
                                         */
+       void *entry;                    /* ->fault handler can alternatively
+                                        * return locked DAX entry. In that
+                                        * case handler should return
+                                        * VM_FAULT_DAX_LOCKED and fill in
+                                        * entry here.
+                                        */
        /* for ->map_pages() only */
        pgoff_t max_pgoff;              /* map pages for offset from pgoff till
                                         * max_pgoff inclusive */
@@ -1084,6 +1090,7 @@ static inline void clear_page_pfmemalloc(struct page *page)
 #define VM_FAULT_LOCKED        0x0200  /* ->fault locked the returned page */
 #define VM_FAULT_RETRY 0x0400  /* ->fault blocked, must retry */
 #define VM_FAULT_FALLBACK 0x0800       /* huge page fault failed, fall back to small */
+#define VM_FAULT_DAX_LOCKED 0x1000     /* ->fault has locked DAX entry */
 
 #define VM_FAULT_HWPOISON_LARGE_MASK 0xf000 /* encodes hpage index for large hwpoison */