.

bigfile/virtmem.c

@@ -41,6 +41,7 @@ static size_t   page_size(const Page *page);
 static void     page_drop_memory(Page *page);
 static void    *vma_page_addr(VMA *vma, Page *page);
 static pgoff_t  vma_addr_fpgoffset(VMA *vma, uintptr_t addr);
+static void     vma_mmap_page(VMA *vma, Page *page);
 static int      vma_page_ismapped(VMA *vma, Page *page);
 static void     vma_page_ensure_unmapped(VMA *vma, Page *page);
 static void     vma_page_ensure_notmappedrw(VMA *vma, Page *page);
@@ -270,11 +271,8 @@ int fileh_mmap(VMA *vma, BigFileH *fileh, pgoff_t pgoffset, pgoff_t pglen)
             if (!(pgoffset <= page->f_pgoffset && page->f_pgoffset < pgoffset + pglen))
                 continue; /* page is out of requested mmap coverage */
 
-            // XXX err
-            // XXX notify watcher that we mmaped RAM page in its range?
-            page_mmap(page, vma_page_addr(vma, page), PROT_READ | PROT_WRITE);
-            bitmap_set_bit(vma->page_ismappedv, page->f_pgoffset - vma->f_pgoffset);
-            page_incref(page);
+            // XXX notify watcher that we mmap RAM page in its range?
+            vma_mmap_page(vma, page);
         }
     }
 
@@ -818,6 +816,8 @@ VMFaultResult vma_on_pagefault(VMA *vma, uintptr_t addr, int write)
     // XXX overlay: assert !vma->page_ismappedv[blk]    XXX not ok? (retrying after virt unlock/lock)
     // XXX mmap page to all vma with .mmap_overlay=1 of this fileh.
 
+    vma_mmap_page(vma, page);
+#if 0
     if (!bitmap_test_bit(vma->page_ismappedv, page->f_pgoffset - vma->f_pgoffset)) {
         // XXX err
         page_mmap(page, vma_page_addr(vma, page), prot);
@@ -828,8 +828,10 @@ VMFaultResult vma_on_pagefault(VMA *vma, uintptr_t addr, int write)
         /* just changing protection bits should not fail, if parameters ok */
         xmprotect(vma_page_addr(vma, page), page_size(page), prot);
     }
+#endif
 
     // XXX also call page->markdirty() ?
+    // XXX move ^^^ before vma_mmap_page
     if (newstate == PAGE_DIRTY  &&  newstate != page->state) {
         /* it is not allowed to modify pages while writeout is in progress */
         BUG_ON(fileh->writeout_inprogress);
@@ -993,6 +995,34 @@ static pgoff_t vma_addr_fpgoffset(VMA *vma, uintptr_t addr)
 }
 
 
+/* vma_mmap_page mmaps page into vma.
+ *
+ * the page must belong to covered file.
+ * mmap protection is PROT_READ if page is PAGE_LOADED or PROT_READ|PROT_WRITE
+ * if page is PAGE_DIRTY.
+ *
+ * must be called under virtmem lock.
+ */
+static void vma_mmap_page(VMA *vma, Page *page) {
+    pgoff_t pgoff_invma;
+    int prot = (page->state == PAGE_DIRTY ? PROT_READ|PROT_WRITE : PROT_READ);
+
+    ASSERT(page->state == PAGE_LOADED || page->state == PAGE_DIRTY);
+    ASSERT(vma->f_pgoffset <= page->f_pgoffset &&
+                              page->f_pgoffset < vma_addr_fpgoffset(vma, vma->addr_stop));
+
+    pgoff_invma = page->f_pgoffset - vma->f_pgoffset;
+    if (!bitmap_test_bit(vma->page_ismappedv, pgoff_invma)) {
+        // XXX err
+        page_mmap(page, vma_page_addr(vma, page), prot);
+        bitmap_set_bit(vma->page_ismappedv, pgoff_invma);
+        page_incref(page);
+    }
+    else {
+        /* just changing protection bits should not fail, if parameters ok */
+        xmprotect(vma_page_addr(vma, page), page_size(page), prot);
+    }
+}
 
 /* is `page` mapped to `vma` */
 static int vma_page_ismapped(VMA *vma, Page *page)