From: Manfred Spraul <manfred@colorfullife.com>

SysV sem operations that involve multiple semaphores can fail in the
middle, and then sempid (pid of the last successful operation) must be
restored.  This happens with "sempid >>= 16" - broken due to the 32-bit pid
values.  The attached patch fixes that by reordering the updates of the
semaphore fields.

Additionally, the patch fixes the corruption of the sempid value that occurs
if a wait-for-zero operation fails.

The patch is more than two years old, and was in -dj and -ak kernels.