selftests: futex: Add sys_futex_waitv() test

Create a new file to test the waitv mechanism. Test both private and
shared futexes. Wake the last futex in the array, and check if the
return value from futex_waitv() is the right index.

Signed-off-by: André Almeida <andrealmeid@collabora.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210923171111.300673-20-andrealmeid@collabora.com

selftests: futex: Add futex compare requeue test

Add testing for futex_cmp_requeue(). The first test just requeues from one
waiter to another one, and wakes it. The second performs both wake and
requeue, and checks the return values to see if the operation woke/requeued
the expected number of waiters.

Signed-off-by: André Almeida <andrealmeid@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lore.kernel.org/r/20210531165036.41468-3-andrealmeid@collabora.com

selftests: futex: Add futex wait test

There are three different strategies to uniquely identify a futex in the
kernel:

- Private futexes: uses the pointer to mm_struct and the page address

- Shared futexes: checks if the page containing the address is a PageAnon:
- If it is, uses the same data as a private futexes
- If it isn't, uses an inode sequence number from struct inode and
the page's index

Create a selftest to check those three paths and basic wait/wake
mechanism.

Signed-off-by: André Almeida <andrealmeid@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lore.kernel.org/r/20210531165036.41468-2-andrealmeid@collabora.com

.gitignore: add SPDX License Identifier

Add SPDX License Identifier to all .gitignore files.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

selftests/futex: Add .gitignore

Add the futex/functional targets to .gitignore.

Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: linux-api@vger.kernel.org
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>