24 May, 2012
1 commit
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Provide a simple mechanism that allows running code in the (nonatomic)
context of the arbitrary task.The caller does task_work_add(task, task_work) and this task executes
task_work->func() either from do_notify_resume() or from do_exit(). The
callback can rely on PF_EXITING to detect the latter case."struct task_work" can be embedded in another struct, still it has "void
*data" to handle the most common/simple case.This allows us to kill the ->replacement_session_keyring hack, and
potentially this can have more users.Performance-wise, this adds 2 "unlikely(!hlist_empty())" checks into
tracehook_notify_resume() and do_exit(). But at the same time we can
remove the "replacement_session_keyring != NULL" checks from
arch/*/signal.c and exit_creds().Note: task_work_add/task_work_run abuses ->pi_lock. This is only because
this lock is already used by lookup_pi_state() to synchronize with
do_exit() setting PF_EXITING. Fortunately the scope of this lock in
task_work.c is really tiny, and the code is unlikely anyway.Signed-off-by: Oleg Nesterov
Acked-by: David Howells
Cc: Thomas Gleixner
Cc: Richard Kuo
Cc: Linus Torvalds
Cc: Alexander Gordeev
Cc: Chris Zankel
Cc: David Smith
Cc: "Frank Ch. Eigler"
Cc: Geert Uytterhoeven
Cc: Larry Woodman
Cc: Peter Zijlstra
Cc: Tejun Heo
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Al Viro
