Fix: uprobes: make uprobe_register() return struct uprobe * (v6.12)

Fix: uprobes: make uprobe_register() return struct uprobe * (v6.12)

See upstream commits :

  commit 3c83a9ad0295eb63bdeb81d821b8c3b9417fbcac
  Author: Oleg Nesterov <oleg@redhat.com>
  Date:   Thu Aug 1 15:27:34 2024 +0200

    uprobes: make uprobe_register() return struct uprobe *

    This way uprobe_unregister() and uprobe_apply() can use "struct uprobe *"
    rather than inode + offset. This simplifies the code and allows to avoid
    the unnecessary find_uprobe() + put_uprobe() in these functions.

    TODO: uprobe_unregister() still needs get_uprobe/put_uprobe to ensure that
    this uprobe can't be freed before up_write(&uprobe->register_rwsem).

  commit 04b01625da130c7521b768996cd5e48052198b97
  Author: Peter Zijlstra <peterz@infradead.org>
  Date:   Tue Sep 3 10:46:00 2024 -0700

    perf/uprobe: split uprobe_unregister()

    With uprobe_unregister() having grown a synchronize_srcu(), it becomes
    fairly slow to call. Esp. since both users of this API call it in a
    loop.

    Peel off the sync_srcu() and do it once, after the loop.

    We also need to add uprobe_unregister_sync() into uprobe_register()'s
    error handling path, as we need to be careful about returning to the
    caller before we have a guarantee that partially attached consumer won't
    be called anymore. This is an unlikely slow path and this should be
    totally fine to be slow in the case of a failed attach.

  commit e04332ebc8ac128fa551e83f1161ab1c094d13a9
  Author: Oleg Nesterov <oleg@redhat.com>
  Date:   Thu Aug 1 15:27:28 2024 +0200

    uprobes: kill uprobe_register_refctr()

    It doesn't make any sense to have 2 versions of _register(). Note that
    trace_uprobe_enable(), the only user of uprobe_register(), doesn't need
    to check tu->ref_ctr_offset to decide which one should be used, it could
    safely pass ref_ctr_offset == 0 to uprobe_register_refctr().

    Add this argument to uprobe_register(), update the callers, and kill
    uprobe_register_refctr().

Change-Id: I8d1f9a5db1f19c2bc2029709ae36f82e86f6fe58
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>