kernel: physmem: Only set bits if memory is found

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 17 insertions, 20 deletions

diff --git a/sys/vm/vm_physmem.c b/sys/vm/vm_physmem.c
index 90d6cd1..ed9b5d2 100644
--- a/sys/vm/vm_physmem.c
+++ b/sys/vm/vm_physmem.c
@@ -141,38 +141,35 @@ uintptr_t
 vm_alloc_frame(size_t count)
 {
     size_t frames = 0;
-    ssize_t free_i = -1;
-    size_t start, end;
+    ssize_t idx = -1;
     uintptr_t ret = 0;
 
     spinlock_acquire(&lock);
     for (size_t i = 0; i < highest_frame_idx; ++i) {
-        if (testbit(bitmap, i)) {
-            /* Not free, try again... */
-            frames = 0;
-            free_i = -1;
+        if (!testbit(bitmap, i)) {
+            if (idx < 0)
+                idx = i;
+            if (++frames >= count)
+                break;
+
             continue;
         }
 
-        if (free_i < 0) {
-            free_i = i;
-        }
+        idx = -1;
+        frames = 0;
+    }
 
-        /* We have a free page */
-        if (++frames == count) {
-            ret = free_i * DEFAULT_PAGESIZE;
-            break;
-        }
+    if (idx < 0 || frames != count) {
+        ret = 0;
+        goto done;
     }
 
-    if (ret > 0) {
-        start = free_i;
-        end = free_i + count;
-        for (size_t i = start; i < end; ++i) {
-            setbit(bitmap, i);
-        }
+    for (size_t i = idx; i < idx + count; ++i) {
+        setbit(bitmap, i);
     }
 
+    ret = idx * DEFAULT_PAGESIZE;
+done:
     spinlock_release(&lock);
     return ret;
 }