fs/vfs: Zero file struct field with memset

to avoid set fields to zero one by one

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

fs/mqueue/mq_open.c

@@ -253,10 +253,9 @@ static int file_mq_vopen(FAR struct file *mq, FAR const char *mq_name,
 
       /* Associate the inode with a file structure */
 
-      mq->f_oflags  = oflags;
-      mq->f_pos     = 0;
-      mq->f_inode   = inode;
-      mq->f_priv    = NULL;
+      memset(mq, 0, sizeof(*mq));
+      mq->f_oflags = oflags;
+      mq->f_inode  = inode;
 
       if (created)
         {
@@ -303,10 +302,9 @@ static int file_mq_vopen(FAR struct file *mq, FAR const char *mq_name,
 
       /* Associate the inode with a file structure */
 
-      mq->f_oflags  = oflags;
-      mq->f_pos     = 0;
-      mq->f_inode   = inode;
-      mq->f_priv    = NULL;
+      memset(mq, 0, sizeof(*mq));
+      mq->f_oflags = oflags;
+      mq->f_inode  = inode;
 
       INODE_SET_MQUEUE(inode);
       inode->u.i_ops    = &g_nxmq_fileops;

fs/nxffs/nxffs_write.c

@@ -607,8 +607,8 @@ ssize_t nxffs_write(FAR struct file *filep, FAR const char *buffer,
 
   /* Success.. return the number of bytes written */
 
-  ret           = total;
-  filep->f_pos  = wrfile->datlen;
+  ret          = total;
+  filep->f_pos = wrfile->datlen;
 
 errout_with_lock:
   nxmutex_unlock(&volume->lock);

fs/shm/shm_open.c

@@ -141,10 +141,9 @@ static int file_shm_open(FAR struct file *shm, FAR const char *name,
 
   /* Associate the inode with a file structure */
 
+  memset(shm, 0, sizeof(*shm));
   shm->f_oflags = oflags;
-  shm->f_pos = 0;
   shm->f_inode = inode;
-  shm->f_priv = NULL;
 
 errout_with_sem:
   inode_unlock();

fs/unionfs/fs_unionfs.c

@@ -869,7 +869,7 @@ static int unionfs_open(FAR struct file *filep, FAR const char *relpath,
   /* Allocate a container to hold the open file system information */
 
   uf = (FAR struct unionfs_file_s *)
-    kmm_malloc(sizeof(struct unionfs_file_s));
+    kmm_zalloc(sizeof(struct unionfs_file_s));
   if (uf == NULL)
     {
       ret = -ENOMEM;
@@ -883,9 +883,7 @@ static int unionfs_open(FAR struct file *filep, FAR const char *relpath,
               um->um_node->u.i_mops != NULL);
 
   uf->uf_file.f_oflags = filep->f_oflags;
-  uf->uf_file.f_pos    = 0;
   uf->uf_file.f_inode  = um->um_node;
-  uf->uf_file.f_priv   = NULL;
 
   ret = unionfs_tryopen(&uf->uf_file, relpath, um->um_prefix, oflags, mode);
   if (ret >= 0)
@@ -901,9 +899,7 @@ static int unionfs_open(FAR struct file *filep, FAR const char *relpath,
       um  = &ui->ui_fs[1];
 
       uf->uf_file.f_oflags = filep->f_oflags;
-      uf->uf_file.f_pos    = 0;
       uf->uf_file.f_inode  = um->um_node;
-      uf->uf_file.f_priv   = NULL;
 
       ret = unionfs_tryopen(&uf->uf_file, relpath, um->um_prefix, oflags,
                             mode);

fs/vfs/fs_close.c

@@ -80,10 +80,7 @@ int file_close(FAR struct file *filep)
 
       /* Reset the user file struct instance so that it cannot be reused. */
 
-      filep->f_oflags = 0;
-      filep->f_pos    = 0;
-      filep->f_inode  = NULL;
-      filep->f_priv   = NULL;
+      memset(filep, 0, sizeof(*filep));
     }
 
   return ret;

fs/vfs/fs_dir.c

@@ -607,8 +607,8 @@ int dir_allocate(FAR struct file *filep, FAR const char *relpath)
       return ret;
     }
 
-  filep->f_inode  = &g_dir_inode;
-  filep->f_priv   = dir;
+  filep->f_inode = &g_dir_inode;
+  filep->f_priv  = dir;
   inode_addref(&g_dir_inode);
   return ret;
 }

fs/vfs/fs_dup2.c

@@ -79,10 +79,10 @@ int file_dup2(FAR struct file *filep1, FAR struct file *filep2)
 
   /* Then clone the file structure */
 
+  memset(&temp, 0, sizeof(temp));
   temp.f_oflags = filep1->f_oflags;
   temp.f_pos    = filep1->f_pos;
   temp.f_inode  = inode;
-  temp.f_priv   = NULL;
 
   /* Call the open method on the file, driver, mountpoint so that it
    * can maintain the correct open counts.

fs/vfs/fs_open.c

@@ -156,10 +156,9 @@ static int file_vopen(FAR struct file *filep, FAR const char *path,
 
   /* Associate the inode with a file structure */
 
+  memset(filep, 0, sizeof(*filep));
   filep->f_oflags = oflags;
-  filep->f_pos    = 0;
   filep->f_inode  = inode;
-  filep->f_priv   = NULL;
 
   /* Perform the driver open operation.  NOTE that the open method may be
    * called many times.  The driver/mountpoint logic should handle this