Skip to content

L
linux-davinci
Switch branch/tag
  1. 23 Sep, 2009 2 commits
    • Paul E. McKenney's avatar
      rcu: Clean up code based on review feedback from Josh Triplett, part 2 · 1eba8f84
      Paul E. McKenney authored 
      These issues identified during an old-fashioned face-to-face code
review extending over many hours.

o	Add comments for tricky parts of code, and correct comments
	that have passed their sell-by date.

o	Get rid of the vestiges of rcu_init_sched(), which is no
	longer needed now that PREEMPT_RCU is gone.

o	Move the #include of rcutree_plugin.h to the end of
	rcutree.c, which means that, rather than having a random
	collection of forward declarations, the new set of forward
	declarations document the set of plugins.  The new home for
	this #include also allows __rcu_init_preempt() to move into
	rcutree_plugin.h.

o	Fix rcu_preempt_check_callbacks() to be static.
Suggested-by: default avatarJosh Triplett <josh@joshtriplett.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <12537246443924-git-send-email->
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Peter Zijlstra <peterz@infradead.org>
      1eba8f84
    • Paul E. McKenney's avatar
      rcu: Clean up code based on review feedback from Josh Triplett · fc2219d4
      Paul E. McKenney authored 
      These issues identified during an old-fashioned face-to-face code
review extended over many hours.

o	Bury various forms of the "rsp->completed == rsp->gpnum"
	comparison into an rcu_gp_in_progress() function, which has
	the beneficial side-effect of forcing consistent use of
	ACCESS_ONCE().

o	Replace hand-coded arithmetic with DIV_ROUND_UP().

o	Bury several "!list_empty(&rnp->blocked_tasks[rnp->gpnum & 0x01])"
	instances into an rcu_preempted_readers() function, as this
	expression indicates that there are no readers blocked
	within RCU read-side critical sections blocking the current
	grace period.  (Though there might well be similar readers
	blocking the next grace period.)

o	Remove a dangling rcu_restart_cpu() declaration that has
	been dangling for almost 20 minor releases of the kernel.
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <12537246442687-git-send-email->
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      fc2219d4
  3. 22 Sep, 2009 5 commits
    • Darren Hart's avatar
      futex: Fix wakeup race by setting TASK_INTERRUPTIBLE before queue_me() · 0729e196
      Darren Hart authored 
      PI futexes do not use the same plist_node_empty() test for wakeup.
It was possible for the waiter (in futex_wait_requeue_pi()) to set
TASK_INTERRUPTIBLE after the waker assigned the rtmutex to the
waiter. The waiter would then note the plist was not empty and call
schedule(). The task would not be found by any subsequeuent futex
wakeups, resulting in a userspace hang.

By moving the setting of TASK_INTERRUPTIBLE to before the call to
queue_me(), the race with the waker is eliminated. Since we no
longer call get_user() from within queue_me(), there is no need to
delay the setting of TASK_INTERRUPTIBLE until after the call to
queue_me().

The FUTEX_LOCK_PI operation is not affected as futex_lock_pi()
relies entirely on the rtmutex code to handle schedule() and
wakeup.  The requeue PI code is affected because the waiter starts
as a non-PI waiter and is woken on a PI futex.

Remove the crusty old comment about holding spinlocks() across
get_user() as we no longer do that. Correct the locking statement
with a description of why the test is performed.
Signed-off-by: default avatarDarren Hart <dvhltc@us.ibm.com>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Dinakar Guniguntala <dino@in.ibm.com>
Cc: John Stultz <johnstul@us.ibm.com>
LKML-Reference: <20090922053038.8717.97838.stgit@Aeon>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      0729e196
    • Darren Hart's avatar
      futex: Correct futex_q woken state commentary · d8d88fbb
      Darren Hart authored 
      Use kernel-doc format to describe struct futex_q.

Correct the wakeup definition to eliminate the statement about
waking the waiter between the plist_del() and the q->lock_ptr = 0.

Note in the comment that PI futexes have a different definition of
the woken state.
Signed-off-by: default avatarDarren Hart <dvhltc@us.ibm.com>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Dinakar Guniguntala <dino@in.ibm.com>
Cc: John Stultz <johnstul@us.ibm.com>
LKML-Reference: <20090922053029.8717.62798.stgit@Aeon>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      d8d88fbb
    • Darren Hart's avatar
      futex: Make function kernel-doc commentary consistent · d96ee56c
      Darren Hart authored 
      Make the existing function kernel-doc consistent throughout
futex.c, following Documentation/kernel-doc-nano-howto.txt as
closely as possible.

When unsure, at least be consistent within futex.c.
Signed-off-by: default avatarDarren Hart <dvhltc@us.ibm.com>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Dinakar Guniguntala <dino@in.ibm.com>
Cc: John Stultz <johnstul@us.ibm.com>
LKML-Reference: <20090922053022.8717.13339.stgit@Aeon>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      d96ee56c
    • Darren Hart's avatar
      futex: Correct queue_me and unqueue_me commentary · d40d65c8
      Darren Hart authored 
      The queue_me/unqueue_me commentary is oddly placed and out of date.
Clean it up and correct the inaccurate bits.
Signed-off-by: default avatarDarren Hart <dvhltc@us.ibm.com>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Dinakar Guniguntala <dino@in.ibm.com>
Cc: John Stultz <johnstul@us.ibm.com>
LKML-Reference: <20090922053015.8717.71713.stgit@Aeon>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      d40d65c8
    • Darren Hart's avatar
      futex: Correct futex_wait_requeue_pi() commentary · 56ec1607
      Darren Hart authored 
      Correct various typos and formatting inconsistencies in the
commentary of futex_wait_requeue_pi().
Signed-off-by: default avatarDarren Hart <dvhltc@us.ibm.com>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Dinakar Guniguntala <dino@in.ibm.com>
Cc: John Stultz <johnstul@us.ibm.com>
LKML-Reference: <20090922052958.8717.21932.stgit@Aeon>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      56ec1607
  5. 21 Sep, 2009 23 commits
  7. 20 Sep, 2009 10 commits