fs/mmap/msync:support msync.

Summary:
  1.Added msync callback in struct mm_map_entry_s
  2.Added msync API in fs_msync.c
  3.Added static msync_rammap for rammap.

Signed-off-by: chenrun1 <chenrun1@xiaomi.com>

fs/inode/fs_files.c

@@ -799,6 +799,33 @@ int fs_getfilep(int fd, FAR struct file **filep)
   return OK;
 }
 
+/****************************************************************************
+ * Name: fs_reffilep
+ *
+ * Description:
+ *   To specify filep increase the reference count.
+ *
+ * Input Parameters:
+ *   None.
+ *
+ * Returned Value:
+ *   None.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_FS_REFCOUNT
+void fs_reffilep(FAR struct file *filep)
+{
+  /* This interface is used to increase the reference count of filep */
+
+  irqstate_t flags;
+
+  DEBUGASSERT(filep);
+  flags = spin_lock_irqsave(NULL);
+  filep->f_refs++;
+  spin_unlock_irqrestore(NULL, flags);
+}
+
 /****************************************************************************
  * Name: fs_putfilep
  *
@@ -811,7 +838,6 @@ int fs_getfilep(int fd, FAR struct file **filep)
  *            file' instance.
  ****************************************************************************/
 
-#ifdef CONFIG_FS_REFCOUNT
 int fs_putfilep(FAR struct file *filep)
 {
   irqstate_t flags;

fs/mmap/CMakeLists.txt

@@ -18,7 +18,7 @@
 #
 # ##############################################################################
 
-set(SRCS fs_mmap.c fs_munmap.c fs_mmisc.c)
+set(SRCS fs_mmap.c fs_munmap.c fs_mmisc.c fs_msync.c)
 
 if(CONFIG_FS_RAMMAP)
   list(APPEND SRCS fs_rammap.c)

fs/mmap/Make.defs

@@ -18,7 +18,7 @@
 #
 ############################################################################
 
-CSRCS += fs_mmap.c fs_munmap.c fs_mmisc.c
+CSRCS += fs_mmap.c fs_munmap.c fs_mmisc.c fs_msync.c
 
 ifeq ($(CONFIG_FS_RAMMAP),y)
 CSRCS += fs_rammap.c

fs/mmap/fs_anonmap.c

@@ -44,7 +44,7 @@ static int unmap_anonymous(FAR struct task_group_s *group,
                            FAR void *start,
                            size_t length)
 {
-  FAR void *newaddr;
+  FAR void *newaddr = NULL;
   off_t offset;
   bool kernel = entry->priv.i;
   int ret = OK;

fs/mmap/fs_msync.c

@@ -0,0 +1,95 @@
+/****************************************************************************
+ * fs/mmap/fs_msync.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <sys/mman.h>
+#include <debug.h>
+#include <errno.h>
+
+#include <nuttx/fs/fs.h>
+#include <nuttx/sched.h>
+
+#include "inode/inode.h"
+#include "fs_rammap.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: msync
+ *
+ * Description:
+ *   Equivalent to the standard msync() function except that it accepts
+ *   a struct file instance instead of a memory address and it does not set
+ *   the errno variable.
+ *
+ * Input Parameters:
+ *   file   - A pointer to the struct file instance representing the
+ *            mappedfile
+ *   start  - The starting address of the memory region to be synchronized
+ *   length - The length of the memory region to be synchronized
+ *   flags  - Flags that determine the type of synchronization to be
+ *            performed
+ *
+ * Returned Value:
+ *   On success, returns 0 (OK); On failure, returns a negated errno value.
+ *
+ ****************************************************************************/
+
+int msync(FAR void *start, size_t length, int flags)
+{
+  FAR struct mm_map_entry_s *entry;
+  int ret;
+
+  ret = mm_map_lock();
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  entry = mm_map_find(get_current_mm(), start, length);
+  if (!entry)
+    {
+      ferr("ERROR: Region not found\n");
+      ret = -ENOMEM;
+      goto out;
+    }
+
+  if (entry->msync == NULL)
+    {
+      ret = OK;
+      goto out;
+    }
+
+  ret = entry->msync(entry, start, length, flags);
+out:
+  mm_map_unlock();
+  if (ret < 0)
+    {
+      set_errno(-ret);
+      ret = ERROR;
+    }
+
+  return ret;
+}

fs/mmap/fs_rammap.c

@@ -49,14 +49,84 @@
  * Private Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: msync_rammap
+ ****************************************************************************/
+
+static int msync_rammap(FAR struct mm_map_entry_s *entry, FAR void *start,
+                        size_t length, int flags)
+{
+  FAR struct file *filep = (FAR void *)((uintptr_t)entry->priv.p & ~1);
+  FAR uint8_t *wrbuffer = start;
+  ssize_t nwrite = 0;
+  off_t offset;
+  off_t fpos;
+  off_t opos;
+
+  offset = (uintptr_t)start - (uintptr_t)entry->vaddr;
+  if (length > entry->length - offset)
+    {
+      length = entry->length - offset;
+    }
+
+  opos = file_seek(filep, 0, SEEK_CUR);
+  if (opos < 0)
+    {
+      ferr("ERROR: Get current position failed\n");
+      return opos;
+    }
+
+  fpos = file_seek(filep, entry->offset + offset, SEEK_SET);
+  if (fpos < 0)
+    {
+      ferr("ERRORL Seek to position %"PRIdOFF" failed\n", fpos);
+      return fpos;
+    }
+
+  while (length > 0)
+    {
+      nwrite = file_write(filep, wrbuffer, length);
+      if (nwrite < 0)
+        {
+          /* Handle the special case where the write was interrupted by a
+           * signal.
+           */
+
+          if (nwrite != -EINTR)
+            {
+              /* All other write errors are bad. */
+
+              ferr("ERROR: Write failed: offset=%"PRIdOFF" nwrite=%zd\n",
+                   entry->offset, nwrite);
+              break;
+            }
+        }
+
+      /* Increment number of bytes written */
+
+      wrbuffer += nwrite;
+      length   -= nwrite;
+    }
+
+  /* Restore file pos */
+
+  file_seek(filep, opos, SEEK_SET);
+  return nwrite >= 0 ? 0 : nwrite;
+}
+
+/****************************************************************************
+ * Name: unmap_rammap
+ ****************************************************************************/
+
 static int unmap_rammap(FAR struct task_group_s *group,
                         FAR struct mm_map_entry_s *entry,
                         FAR void *start,
                         size_t length)
 {
+  FAR struct file *filep = (FAR void *)((uintptr_t)entry->priv.p & ~1);
+  enum mm_map_type_e type = (uintptr_t)entry->priv.p & 1;
   FAR void *newaddr = NULL;
   off_t offset;
-  enum mm_map_type_e type = entry->priv.i;
   int ret = OK;
 
   /* Get the offset from the beginning of the region and the actual number
@@ -94,6 +164,8 @@ static int unmap_rammap(FAR struct task_group_s *group,
           kumm_free(entry->vaddr);
         }
 
+      fs_putfilep(filep);
+
       /* Then remove the mapping from the list */
 
       ret = mm_map_remove(get_group_mm(group), entry);
@@ -248,8 +320,10 @@ int rammap(FAR struct file *filep, FAR struct mm_map_entry_s *entry,
   /* Add the buffer to the list of regions */
 
 out:
-  entry->priv.i = type;
+  fs_reffilep(filep);
+  entry->priv.p = (FAR void *)((uintptr_t)filep | type);
   entry->munmap = unmap_rammap;
+  entry->msync = msync_rammap;
 
   ret = mm_map_add(get_current_mm(), entry);
   if (ret < 0)

include/nuttx/fs/fs.h

@@ -1159,6 +1159,22 @@ int nx_open(FAR const char *path, int oflags, ...);
 
 int fs_getfilep(int fd, FAR struct file **filep);
 
+/****************************************************************************
+ * Name: fs_reffilep
+ *
+ * Description:
+ *   To specify filep increase the reference count.
+ *
+ * Input Parameters:
+ *   None.
+ *
+ * Returned Value:
+ *   None.
+ *
+ ****************************************************************************/
+
+void fs_reffilep(FAR struct file *filep);
+
 /****************************************************************************
  * Name: fs_putfilep
  *

include/nuttx/mm/map.h

@@ -56,11 +56,14 @@ struct mm_map_entry_s
     int i;
   } priv;
 
-  /* Drivers which register mappings may also implement the unmap function
-   * to undo anything done in mmap.
-   * Nb. Implementation must NOT use "this_task()->group" since it is not
-   * valid during process exit. The argument "group" will be NULL in this
-   * case.
+  int (*msync)(FAR struct mm_map_entry_s *entry, FAR void *start,
+               size_t length, int flags);
+
+  /* Drivers which register mappings may also
+   * implement the unmap function to undo anything done in mmap.
+   * Nb. Implementation must NOT use "this_task()->group" since
+   * this is not valid during process exit. The argument "group" will be
+   * NULL in this case.
    */
 
   int (*munmap)(FAR struct task_group_s *group,

include/sys/syscall_lookup.h

@@ -248,6 +248,7 @@ SYSCALL_LOOKUP(fchown,                     3)
 SYSCALL_LOOKUP(utimens,                    2)
 SYSCALL_LOOKUP(lutimens,                   2)
 SYSCALL_LOOKUP(futimens,                   2)
+SYSCALL_LOOKUP(msync,                      3)
 SYSCALL_LOOKUP(munmap,                     2)
 
 #if defined(CONFIG_PSEUDOFS_SOFTLINKS)

syscall/syscall.csv

@@ -77,6 +77,7 @@
 "mq_timedreceive","mqueue.h","!defined(CONFIG_DISABLE_MQUEUE)","ssize_t","mqd_t","FAR char *","size_t","FAR unsigned int *","FAR const struct timespec *"
 "mq_timedsend","mqueue.h","!defined(CONFIG_DISABLE_MQUEUE)","int","mqd_t","FAR const char *","size_t","unsigned int","FAR const struct timespec *"
 "mq_unlink","mqueue.h","!defined(CONFIG_DISABLE_MQUEUE)","int","FAR const char *"
+"msync","sys/mman.h","","int","FAR void *","size_t","int"
 "munmap","sys/mman.h","","int","FAR void *","size_t"
 "nanosleep","time.h","","int","FAR const struct timespec *","FAR struct timespec *"
 "nx_mkfifo","nuttx/fs/fs.h","defined(CONFIG_PIPES) && CONFIG_DEV_FIFO_SIZE > 0","int","FAR const char *","mode_t","size_t"