Merge tag 'block-2023-01-06' of git://git.kernel.dk/linux

Pull block fixes from Jens Axboe:
 "The big change here is obviously the revert of the pktcdvd driver
  removal. Outside of that, just minor tweaks. In detail:

   - Re-instate the pktcdvd driver, which necessitates adding back
     bio_copy_data_iter() and the fops->devnode() hook for now (me)

   - Fix for splitting of a bio marked as NOWAIT, causing either nowait
     reads or writes to error with EAGAIN even if parts of the IO
     completed (me)

   - Fix for ublk, punting management commands to io-wq as they can all
     easily block for extended periods of time (Ming)

   - Removal of SRCU dependency for the block layer (Paul)"

* tag 'block-2023-01-06' of git://git.kernel.dk/linux:
  block: Remove "select SRCU"
  Revert "pktcdvd: remove driver."
  Revert "block: remove devnode callback from struct block_device_operations"
  Revert "block: bio_copy_data_iter"
  ublk: honor IO_URING_F_NONBLOCK for handling control command
  block: don't allow splitting of a REQ_NOWAIT bio
  block: handle bio_split_to_limits() NULL return

block/genhd.c

@@ -1201,10 +1201,21 @@ struct class block_class = {
 	.dev_uevent	= block_uevent,
 };
 
+static char *block_devnode(struct device *dev, umode_t *mode,
+			   kuid_t *uid, kgid_t *gid)
+{
+	struct gendisk *disk = dev_to_disk(dev);
+
+	if (disk->fops->devnode)
+		return disk->fops->devnode(disk, mode);
+	return NULL;
+}
+
 const struct device_type disk_type = {
 	.name		= "disk",
 	.groups		= disk_attr_groups,
 	.release	= disk_release,
+	.devnode	= block_devnode,
 };
 
 #ifdef CONFIG_PROC_FS