Re: [PATCH RFC 1/5] vringfd syscall

On Saturday 05 April 2008, Rusty Russell wrote:
+asmlinkage long sys_vringfd(void __user *addr,
+                           unsigned num_descs,
+                           u16 __user *last_used)
+{
+       int fd, err;
+       struct file *filp;
+       struct vring_info *vr;
+
+       /* Must be a power of two, and representable by u16 */
+       if (!num_descs || (num_descs & (num_descs-1)) || num_descs > 65536) {
+               err = -EINVAL;
+               goto out;
+       }
+
+       fd = get_unused_fd();
+       if (fd < 0) {
+               err = fd;
+               goto out;
+       }
+
+       filp = alloc_file(vring_mnt, dget(vring_mnt->mnt_root), FMODE_WRITE,
+                         &vring_fops);
+       if (!filp) {
+               err = -ENFILE;
+               goto put_fd;
+       }

This looks like a candidate for anon_inode_getfd(), which would let you
get rid of the code for registering your own file system.

Arnd <><

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