90 lines
2.4 KiB
Diff
90 lines
2.4 KiB
Diff
From 739544c0eab09ad0faf0f47b7bd099e078a80a2e Mon Sep 17 00:00:00 2001
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From: Ingo Molnar <mingo@elte.hu>
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Date: Fri, 3 Jul 2009 08:30:12 -0500
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Subject: [103/256] ipc: Make the ipc code -rt aware
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RT serializes the code with the (rt)spinlock but keeps preemption
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enabled. Some parts of the code need to be atomic nevertheless.
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Protect it with preempt_disable/enable_rt pairts.
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Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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ipc/mqueue.c | 5 +++++
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ipc/msg.c | 16 ++++++++++++++++
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2 files changed, 21 insertions(+)
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diff --git a/ipc/mqueue.c b/ipc/mqueue.c
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index 28bd64d..dd9e66a 100644
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--- a/ipc/mqueue.c
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+++ b/ipc/mqueue.c
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@@ -813,12 +813,17 @@ static inline void pipelined_send(struct mqueue_inode_info *info,
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struct msg_msg *message,
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struct ext_wait_queue *receiver)
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{
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+ /*
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+ * Keep them in one critical section for PREEMPT_RT:
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+ */
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+ preempt_disable_rt();
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receiver->msg = message;
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list_del(&receiver->list);
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receiver->state = STATE_PENDING;
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wake_up_process(receiver->task);
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smp_wmb();
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receiver->state = STATE_READY;
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+ preempt_enable_rt();
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}
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/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
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diff --git a/ipc/msg.c b/ipc/msg.c
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index 7385de2..06642ac 100644
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--- a/ipc/msg.c
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+++ b/ipc/msg.c
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@@ -259,12 +259,20 @@ static void expunge_all(struct msg_queue *msq, int res)
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while (tmp != &msq->q_receivers) {
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struct msg_receiver *msr;
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+ /*
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+ * Make sure that the wakeup doesnt preempt
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+ * this CPU prematurely. (on PREEMPT_RT)
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+ */
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+ preempt_disable_rt();
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+
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msr = list_entry(tmp, struct msg_receiver, r_list);
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tmp = tmp->next;
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msr->r_msg = NULL;
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wake_up_process(msr->r_tsk);
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smp_mb();
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msr->r_msg = ERR_PTR(res);
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+
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+ preempt_enable_rt();
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}
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}
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@@ -611,6 +619,12 @@ static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg)
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!security_msg_queue_msgrcv(msq, msg, msr->r_tsk,
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msr->r_msgtype, msr->r_mode)) {
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+ /*
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+ * Make sure that the wakeup doesnt preempt
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+ * this CPU prematurely. (on PREEMPT_RT)
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+ */
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+ preempt_disable_rt();
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+
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list_del(&msr->r_list);
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if (msr->r_maxsize < msg->m_ts) {
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msr->r_msg = NULL;
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@@ -624,9 +638,11 @@ static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg)
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wake_up_process(msr->r_tsk);
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smp_mb();
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msr->r_msg = msg;
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+ preempt_enable_rt();
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return 1;
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}
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+ preempt_enable_rt();
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}
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}
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return 0;
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