no_llseek had been defined to NULL two years ago, in commit 868941b14441
("fs: remove no_llseek")

To quote that commit,

  At -rc1 we'll need do a mechanical removal of no_llseek -

  git grep -l -w no_llseek | grep -v porting.rst | while read i; do
	sed -i '/\<no_llseek\>/d' $i
  done

  would do it.

Unfortunately, that hadn't been done.  Linus, could you do that now, so
that we could finally put that thing to rest? All instances are of the
form
	.llseek = no_llseek,
so it's obviously safe.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This corresponds to the NT syscall NtReleaseSemaphore().

This increases the semaphore's internal counter by the given value, and returns
the previous value. If the counter would overflow the defined maximum, the
function instead fails and returns -EOVERFLOW.

Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com>
Link: https://lore.kernel.org/r/20240329000621.148791-4-zfigura@codeweavers.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This corresponds to the NT syscall NtCreateSemaphore().

Semaphores are one of three types of object to be implemented in this driver,
the others being mutexes and events.

An NT semaphore contains a 32-bit counter, and is signaled and can be acquired
when the counter is nonzero. The counter has a maximum value which is specified
at creation time. The initial value of the semaphore is also specified at
creation time. There are no restrictions on the maximum and initial value.

Each object is exposed as an file, to which any number of fds may be opened.
When all fds are closed, the object is deleted.

Objects hold a pointer to the ntsync_device that created them. The device's
reference count is driven by struct file.

Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com>
Link: https://lore.kernel.org/r/20240329000621.148791-3-zfigura@codeweavers.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ntsync uses a misc device as the simplest and least intrusive uAPI interface.

Each file description on the device represents an isolated NT instance, intended
to correspond to a single NT virtual machine.

Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com>
Link: https://lore.kernel.org/r/20240329000621.148791-2-zfigura@codeweavers.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>