full mmap implementation

1 files changed, 66 insertions, 25 deletions

diff --git a/vm/mmap.c b/vm/mmap.c
index 9e7ae47..55ee91b 100644
--- a/vm/mmap.c
+++ b/vm/mmap.c
@@ -1,4 +1,6 @@
 #include <string.h>
+#include "userprog/pagedir.h"
+#include "userprog/process.h"
 #include "filesys/file.h"
 #include "threads/thread.h"
 #include "threads/vaddr.h"
@@ -23,18 +25,20 @@ mmap_table_init (struct mmap_table *table)
   return true;
 }
 
-/* frees the content of mmap table */
+/* closes all mapped files and frees the content of the table */
 void
 mmap_table_free (struct mmap_table *table)
 {
-  //TODO
+  mapid_t id;
+  for (id = 0; id <= table->id_max; id++)
+    mmap_table_remove (table, id);
   palloc_free_page (table->ids);
 }
 
-/* inserts a new mmap entry in the mmap table
+/* inserts a new mmap entry in the mmap table.
    returns -1 if entry is invalid or already in the table */
 mapid_t
-mmap_table_insert (struct mmap_table *table, void *addr, struct file *file,
+mmap_table_insert (struct mmap_table *table, uint8_t *upage, struct file *file,
     off_t len)
 {
   off_t ofs = 0;
@@ -46,43 +50,49 @@ mmap_table_insert (struct mmap_table *table, void *addr, struct file *file,
   if (table->id_free >= table->id_cap)
     return -1;
 
+  /* create mmap table entry */
   mme = malloc (sizeof *mme);
   if (mme == NULL)
     return -1;
 
-  mapid = table->id_free++;
-  mme->addr  = addr;
+  mme->upage = upage;
   mme->file  = file;
-  table->ids[mapid] = mme;
+  mme->pages = 0;
 
   /* create needed pages in page table */
   while (len > 0)
     {
       page_read_bytes = (len < PGSIZE) ? len : PGSIZE;
-
       if (!page_table_insert_segment (&thread_current ()->page_table, file, ofs,
-            addr, page_read_bytes, true))
+            upage, page_read_bytes, true))
         return -1;
 
       /* Advance. */
-      len  -= PGSIZE;
-      ofs  += page_read_bytes;
-      addr += PGSIZE;
+      len   -= PGSIZE;
+      ofs   += page_read_bytes;
+      upage += PGSIZE;
+      mme->pages++;
     }
 
+  /* insert entry into our table */
+  mapid = table->id_free++;
+  table->ids[mapid] = mme;
+
   /* update index of free/max mapid index */
   if (mapid > table->id_max)
     table->id_max = mapid;
   while (table->ids[table->id_free] != NULL)
-  {
-    table->id_free++;
-    if (table->id_free >= table->id_cap)
-      break;
-  }
+    {
+      table->id_free++;
+      if (table->id_free >= table->id_cap)
+        break;
+    }
 
   return mapid;
 }
 
+/* get the mmap table entry associated with the given map id.
+   return NULL if no mapping is associated with the given id */
 static struct mmap_table_entry *
 mmap_table_get (struct mmap_table *table, mapid_t mapid)
 {
@@ -91,26 +101,57 @@ mmap_table_get (struct mmap_table *table, mapid_t mapid)
   return table->ids[mapid];
 }
 
+/* remove the entry associated with the given map id from the mmap table.
+   flushes all dirty/modified pages back to disk. return true if successful */
 bool
 mmap_table_remove (struct mmap_table *table, mapid_t mapid)
 {
+  struct page_table_entry *pte;
+  off_t ofs = 0;
+  struct thread *thread = thread_current ();
   struct mmap_table_entry *mme = mmap_table_get(table, mapid);
   if (mme == NULL)
     return false;
 
-  table->ids[mapid] = NULL;
+  /* fetch pages needed by mapped file and check whether the page is dirty */
+  while (mme->pages-- > 0)
+    {
+      pte = page_table_remove (&thread->page_table, mme->upage + ofs);
+      if (pte != NULL && pte->loaded &&
+          pagedir_is_dirty (thread->pagedir, pte->upage))
+        {
+          /* write modified page back to disk */
+          ASSERT (pte->segment.file == mme->file);
+          process_lock_filesys ();
+          file_seek (pte->segment.file, pte->segment.ofs);
+          file_write (pte->segment.file, pte->upage, pte->segment.read_bytes);
+          process_unlock_filesys ();
+        }
+
+      if (pte != NULL)
+        free (pte);
+
+      ofs += PGSIZE;
+    }
+
+  /* close the file */
+  process_lock_filesys ();
+  file_close (mme->file);
+  process_unlock_filesys ();
 
-  //TODO
+  /* remove mmap entry from mmap table */
+  free (mme);
+  table->ids[mapid] = NULL;
 
-  /* update index of free/max file descriptor index */
+  /* update index of free/max mapid index */
   if (mapid < table->id_free)
     table->id_free = mapid;
   while (table->ids[table->id_max] == NULL)
-  {
-    table->id_max--;
-    if (table->id_max < 0)
-      break;
-  }
+    {
+      table->id_max--;
+      if (table->id_max < 0)
+        break;
+    }
 
   return true;
 }