cxl: Fix struct pid leak when attaching a process through user API

[Michael Ellerman]

On Tue, 2015-03-11 at 12:13:52 UTC, Frederic Barrat wrote:
> When the cxl driver creates a context, it stores the pid of the
> calling task, and mistakenly increments the reference count of the
> struct pid twice, once through get_task_pid(), once through
> get_pid(). The reference count is only decremented once on detach. As
> a result, a struct pid is leaked and it reduces the number of
> processes that can run simultaneously by one.
> The fix is to simply remove the call to get_pid().
> 
> There is a separate patch for the kernel API, since it goes to
> different kernel versions.
> 
> Signed-off-by: Frederic Barrat <fbarrat at linux.vnet.ibm.com>
> Cc: <stable at vger.kernel.org> # 3.18+
> Acked-by: Ian Munsie <imunsie at au1.ibm.com>
> Reviewed-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>

This no longer applies, since we merged 7b8ad495d592 ("cxl: Fix DSI misses when
the context owning task exits").

Please resend if it's still applicable.

cheers