[nuttx] 04/06: fs/mmap: Add mappings to mm_map list if CONFIG_MM_MAP is defined

[xi...@apache.org]

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xiaoxiang pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/nuttx.git

commit dd97900221a84a2dc50ff229176fd14577ae9604
Author: Jukka Laitinen <ju...@ssrc.tii.ae>
AuthorDate: Fri Apr 8 11:31:24 2022 +0400

    fs/mmap: Add mappings to mm_map list if CONFIG_MM_MAP is defined
    
    Signed-off-by: Jukka Laitinen <ju...@ssrc.tii.ae>
---
 fs/mmap/fs_mmap.c   | 80 ++++++++++++++++++++++++++++++++++++++++++-----------
 fs/mmap/fs_munmap.c | 28 ++++++++++++++++++-
 2 files changed, 91 insertions(+), 17 deletions(-)

diff --git a/fs/mmap/fs_mmap.c b/fs/mmap/fs_mmap.c
index 36e710ad23..4f541fffe9 100644
--- a/fs/mmap/fs_mmap.c
+++ b/fs/mmap/fs_mmap.c
@@ -41,6 +41,46 @@
  * Private Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: unmap_anonymous
+ ****************************************************************************/
+
+static int unmap_anonymous(FAR struct task_group_s *group,
+                           FAR struct mm_map_entry_s *entry,
+                           FAR void *start,
+                           size_t length)
+{
+  int ret;
+
+  /* De-allocate memory.
+   * NB: This is incomplete anounymous mapping implementation
+   * see file_mmap_ below
+   */
+
+  if (start == entry->vaddr && length == entry->length)
+    {
+      /* entry->priv marks allocation from kernel heap */
+
+      if (entry->priv.i)
+        {
+          kmm_free(start);
+        }
+      else
+        {
+          kumm_free(start);
+        }
+
+      ret = mm_map_remove(group, &entry);
+    }
+  else
+    {
+      ret = -EINVAL;
+      ferr("ERROR: Unknown map type\n");
+    }
+
+  return ret;
+}
+
 /****************************************************************************
  * Name: file_mmap_
  ****************************************************************************/
@@ -51,6 +91,23 @@ static int file_mmap_(FAR struct file *filep, FAR void *start,
 {
   int ret;
 
+  /* Pass the information about the mapping in mm_map_entry_s structure.
+   * The driver may alter the structure, and if it supports unmap, it
+   * will also add it to the kernel maintained list of mappings.
+   */
+
+  struct mm_map_entry_s entry =
+    {
+     NULL,     /* sq_entry_t */
+     start,
+     length,
+     offset,
+     prot,
+     flags,
+     { NULL }, /* priv.p */
+     NULL      /* munmap */
+    };
+
   /* Since only a tiny subset of mmap() functionality, we have to verify many
    * things.
    */
@@ -120,6 +177,11 @@ static int file_mmap_(FAR struct file *filep, FAR void *start,
           return -ENOMEM;
         }
 
+      entry.vaddr = *mapped;
+      entry.munmap = unmap_anonymous;
+      entry.priv.i = kernel;
+      mm_map_add(&entry);
+
       return OK;
     }
 
@@ -140,24 +202,10 @@ static int file_mmap_(FAR struct file *filep, FAR void *start,
 
   if (filep->f_inode && filep->f_inode->u.i_ops->mmap != NULL)
     {
-      /* Pass the information about the mapping in mm_map_entry_s structure.
-       * The driver may alter the structure, and if it supports unmap, it
-       * will also add it to the kernel maintained list of mappings.
-       */
-
-      struct mm_map_entry_s map =
-        {
-         NULL, /* sq_entry_t */
-         start, length, offset,
-         prot, flags,
-         NULL, /* priv */
-         NULL  /* munmap */
-        };
-
-      ret = filep->f_inode->u.i_ops->mmap(filep, &map);
+      ret = filep->f_inode->u.i_ops->mmap(filep, &entry);
       if (ret == OK)
         {
-          *mapped = (void *)map.vaddr;
+          *mapped = (void *)entry.vaddr;
         }
     }
   else
diff --git a/fs/mmap/fs_munmap.c b/fs/mmap/fs_munmap.c
index 7b8e57d492..85ec132876 100644
--- a/fs/mmap/fs_munmap.c
+++ b/fs/mmap/fs_munmap.c
@@ -23,6 +23,7 @@
  ****************************************************************************/
 
 #include <nuttx/config.h>
+#include <nuttx/mm/map.h>
 
 #include <sys/types.h>
 #include <sys/mman.h>
@@ -158,7 +159,32 @@ errout_with_lock:
   nxmutex_unlock(&g_rammaps.lock);
   return ret;
 #else
-  return OK;
+
+  FAR struct tcb_s *tcb = nxsched_self();
+  FAR struct task_group_s *group = tcb->group;
+  FAR struct mm_map_entry_s *entry = NULL;
+  int ret = OK;
+
+  /* Iterate through all the mappings and call the underlying
+   * unmap for every mapping where "start" lies
+   * break loop on any errors.
+   *
+   * Get exclusive access to mm_map for this
+   */
+
+  ret = mm_map_lock();
+  if (ret == OK)
+    {
+      while (ret == OK && (entry = mm_map_find(start, length)))
+        {
+          DEBUGASSERT(entry->munmap);
+          ret = entry->munmap(group, entry, start, length);
+        }
+
+      mm_map_unlock();
+    }
+
+  return ret;
 #endif /* CONFIG_FS_RAMMAP */
 }