kernel/include/linux/task_work.h, branch linux-3.6.y

merge task_work and rcu_head, get rid of separate allocation for keyring case

2012-07-22T19:57:56Z

task_work and rcu_head are identical now; merge them (calling the result struct callback_head, rcu_head #define'd to it), kill separate allocation in security/keys since we can just use cred->rcu now. Signed-off-by: Al Viro

trim task_work: get rid of hlist

2012-07-22T19:57:55Z

layout based on Oleg's suggestion; single-linked list, task->task_works points to the last element, forward pointer from said last element points to head. I'd still prefer much more regular scheme with two pointers in task_work, but... Signed-off-by: Al Viro

trimming task_work: kill ->data

2012-07-22T19:57:54Z

get rid of the only user of ->data; this is _not_ the final variant - in the end we'll have task_work and rcu_head identical and just use cred->rcu, at which point the separate allocation will be gone completely. Signed-off-by: Al Viro

task_work_add: generic process-context callbacks

2012-05-24T02:09:21Z

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