lsfd: (refactor) call ioctl(TUNGETDEVNETNS) from target_fd related methods

In the original code, the attach_xinfo method of the cdev_tun_ops
struct called the ioctl. The attach_xinfo method retrieved the fd
passing to the ioctl by calling call_with_foreign_fd utility function.

In the last commit, we added the target_fd related methods in
cdev_tun_ops struct. The caller side of the target_fd related methods
calls call_with_foreign_fd.

We can reduce the code calling call_with_foreign_fd by moving the code
calling ioctl from the attach_xinfo method to the target_fd related
methods.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>

diff --git a/lsfd-cmd/cdev.c b/lsfd-cmd/cdev.c
index 4c996100bb6f548e7f49bd9346d830a959a7e4a3..b9252e3bcfb5a7664c0531ce1a59762f8200a6ea 100644 (file)
--- a/lsfd-cmd/cdev.c
+++ b/lsfd-cmd/cdev.c
@@ -470,39 +470,42 @@ static int cdev_tun_handle_fdinfo(struct cdev *cdev, const char *key, const char
 }
 
 #ifdef TUNGETDEVNETNS
-static int cdev_tun_get_devnetns(int tfd, void *data)
+static bool cdev_tun_needs_target_fd(struct cdev *cdev)
 {
-       struct tundata *tundata = data;
-       int nsfd = ioctl(tfd, TUNGETDEVNETNS);
+       struct tundata *tundata = cdev->cdev_data;
+
+       return (tundata->iff != NULL);
+}
+#else
+static bool cdev_tun_needs_target_fd(struct cdev *cdev __attribute__((__unused__)))
+{
+       return false;
+}
+#endif /* TUNGETDEVNETNS */
+
+#ifdef TUNGETDEVNETNS
+static void cdev_tun_inspect_target_fd(struct cdev *cdev, int fd)
+{
+       struct tundata *tundata = cdev->cdev_data;
+
+       int nsfd = ioctl(fd, TUNGETDEVNETNS);
        struct stat sb;
 
        if (nsfd < 0)
-               return -1;
+               return;
 
        if (fstat(nsfd, &sb) == 0)
                tundata->devnetns = sb.st_ino;
 
        close(nsfd);
-
-       return 0;
 }
-#endif
-
-static void cdev_tun_attach_xinfo(struct cdev *cdev)
+#else
+static void cdev_tun_inspect_target_fd(struct cdev *cdev __attribute__((__unused__)),
+                                      int fd __attribute__((__unused__)))
 {
-       struct tundata *tundata = cdev->cdev_data;
-
-       if (tundata->iff == NULL)
-               return;
-
-#ifdef TUNGETDEVNETNS
-       {
-               struct file *file = &cdev->file;
-               call_with_foreign_fd(file->proc->pid, file->association,
-                                    cdev_tun_get_devnetns, tundata);
-       }
-#endif
+       /* Do nothing */
 }
+#endif /* TUNGETDEVNETNS */
 
 static struct cdev_ops cdev_tun_ops = {
        .parent = &cdev_misc_ops,
@@ -511,7 +514,8 @@ static struct cdev_ops cdev_tun_ops = {
        .get_name = cdev_tun_get_name,
        .fill_column = cdev_tun_fill_column,
        .handle_fdinfo = cdev_tun_handle_fdinfo,
-       .attach_xinfo = cdev_tun_attach_xinfo,
+       .needs_target_fd = cdev_tun_needs_target_fd,
+       .inspect_target_fd = cdev_tun_inspect_target_fd,
 };
 
 /*