1 files changed, 41 insertions, 18 deletions

diff --git a/kernel/vm/vmmap.c b/kernel/vm/vmmap.c
index fd99c55..8789371 100644
--- a/kernel/vm/vmmap.c
+++ b/kernel/vm/vmmap.c
@@ -172,21 +172,35 @@ ssize_t vmmap_find_range(vmmap_t *map, size_t npages, int dir)
     // case 1: dir is VMMAP_DIR_LOHI
     if (dir == VMMAP_DIR_LOHI)
     {
-        // iterate over the page numbers
+        // iterate over the page numbers, going from low to high
+        // determine the continguous range of free virtual pages 
+
+        int start, end = 0;
         size_t vfn = ADDR_TO_PN(USER_MEM_LOW);
-        while (vfn <= ADDR_TO_PN(USER_MEM_HIGH) - npages)
+        while (vfn <= ADDR_TO_PN(USER_MEM_HIGH))
         {
             // Lookup the vmarea for this page number
-            vmarea_t *vma = vmmap_lookup(map, vfn);
-
-            // if the vmarea is NULL, return the page number
+            vmarea_t *vma = vmmap_lookup(map, vfn++);
             if (vma == NULL)
             {
-                return vfn;
+                // if unmapped, document this
+                end = vfn;
+                if (start == 0)
+                {
+                    start = vfn;
+                }
+            }
+            else
+            {
+                // if mapped, start over
+                start, end = 0;
             }
 
-            // if the vmarea is not NULL, set the page number to the end of the vmarea
-            vfn = vma->vma_end;
+            // if the range exists, return the start
+            if (end == npages)
+            {
+                return start;
+            }
         }
     }
 
@@ -194,20 +208,28 @@ ssize_t vmmap_find_range(vmmap_t *map, size_t npages, int dir)
     else if (dir == VMMAP_DIR_HILO)
     {
         // iterate over the page numbers
-        size_t vfn = ADDR_TO_PN(USER_MEM_HIGH) - npages;
+        int contig = 0;
+        size_t vfn = ADDR_TO_PN(USER_MEM_HIGH);
         while (vfn >= ADDR_TO_PN(USER_MEM_LOW))
         {
             // Lookup the vmarea for this page number
-            vmarea_t *vma = vmmap_lookup(map, vfn);
-
-            // if the vmarea is NULL, return the page number
+            vmarea_t *vma = vmmap_lookup(map, --vfn);
             if (vma == NULL)
             {
-                return vfn;
+                // if unmapped, increment the contig
+                contig++;
+            }
+            else
+            {
+                // if mapped, reset the contig
+                contig = 0;
             }
 
-            // if the vmarea is not NULL, set the page number to the start of the vmarea
-            vfn = vma->vma_start - npages;
+            // if there are n contiguous pages, return the current vfn
+            if (contig == npages)
+            {
+                return vfn;
+            }
         }
     }
 
@@ -448,6 +470,7 @@ long vmmap_map(vmmap_t *map, vnode_t *file, size_t lopage, size_t npages,
         mobj_t *shadow_obj = shadow_create(new_vmarea->vma_obj);
         mobj_unlock(new_vmarea->vma_obj);
         mobj_unlock(shadow_obj); // unlock the shadow object before use
+        mobj_put(&new_vmarea->vma_obj); // put the original object
         if (shadow_obj == NULL)
         {
             vmarea_free(new_vmarea);
@@ -674,7 +697,7 @@ long vmmap_read(vmmap_t *map, const void *vaddr, void *buf, size_t count)
     size_t vfn = ADDR_TO_PN(vaddr);
     size_t end_vfn = ADDR_TO_PN(vaddr + count);
     size_t bytes_read = 0;
-    while (vfn < end_vfn)
+    while (vfn <= end_vfn)
     {
         // Lookup the vmarea for this page number
         vmarea_t *vma = vmmap_lookup(map, vfn);
@@ -697,7 +720,7 @@ long vmmap_read(vmmap_t *map, const void *vaddr, void *buf, size_t count)
         void *cursor = (void *)(bytes_read + vaddr);
         size_t bytes_this_iteration = MIN(PAGE_SIZE - PAGE_OFFSET(cursor), count - bytes_read);
         memcpy(
-            buf + bytes_read,
+            (void *) buf + bytes_read,
             (void *)pf->pf_addr + PAGE_OFFSET(cursor),
             bytes_this_iteration
         );
@@ -768,7 +791,7 @@ long vmmap_write(vmmap_t *map, void *vaddr, const void *buf, size_t count)
         size_t bytes_this_iteration = MIN(PAGE_SIZE - PAGE_OFFSET(cursor), count - bytes_written);
         memcpy(
             (void *)pf->pf_addr + PAGE_OFFSET(cursor),
-            buf + bytes_written,
+            (void *)buf + bytes_written,
             bytes_this_iteration
         );