From: Peter Zijlstra <peterz@infradead•org>
To: Sabrina Dubroca <sd@queasysnail•net>
Cc: Thomas Gleixner <tglx@linutronix•de>,
David Miller <davem@davemloft•net>,
netdev@vger•kernel.org
Subject: Re: [RFC PATCH net-next 00/11] net: remove disable_irq() from ->ndo_poll_controller
Date: Thu, 5 Feb 2015 14:06:23 +0100 [thread overview]
Message-ID: <20150205130623.GH5029@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20150205002059.GA28282@kria>
On Thu, Feb 05, 2015 at 01:20:59AM +0100, Sabrina Dubroca wrote:
> Thomas, ping?
>
> thread is over there if you need it:
> https://marc.info/?l=linux-netdev&m=141833435000554&w=2
It appears to me you have addressed most his issues and since it appears
to me the existing synchronze_hardirq() seems to be mostly what we need
I'll propose (and merge) the below and will take flames from tglx when
he returns :-)
---
Subject: genirq: Provide disable_hardirq()
For things like netpoll there is a need to disable an interrupt from
atomic context. Currently netpoll uses disable_irq() which will
sleep-wait on threaded handlers and thus forced_irqthreads breaks
things.
Provide disable_hardirq(), which uses synchronize_hardirq() to only wait
for active hardirq handlers; also change synchronize_hardirq() to
return the status of threaded handlers.
This will allow one to try-disable an interrupt from atomic context, or
in case of request_threaded_irq() to only wait for the hardirq part.
Suggested-by: Sabrina Dubroca <sd@queasysnail•net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead•org>
---
include/linux/hardirq.h | 2 +-
include/linux/interrupt.h | 1 +
kernel/irq/manage.c | 36 ++++++++++++++++++++++++++++++++++--
3 files changed, 36 insertions(+), 3 deletions(-)
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index cba442ec3c66..f4af03404b97 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -9,7 +9,7 @@
extern void synchronize_irq(unsigned int irq);
-extern void synchronize_hardirq(unsigned int irq);
+extern bool synchronize_hardirq(unsigned int irq);
#if defined(CONFIG_TINY_RCU)
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index d9b05b5bf8c7..3bb01b9a379c 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -184,6 +184,7 @@ extern void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id);
#endif
extern void disable_irq_nosync(unsigned int irq);
+extern bool disable_hardirq(unsigned int irq);
extern void disable_irq(unsigned int irq);
extern void disable_percpu_irq(unsigned int irq);
extern void enable_irq(unsigned int irq);
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index f038e586a4b9..1309cccd714f 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -68,14 +68,20 @@ static void __synchronize_hardirq(struct irq_desc *desc)
* Do not use this for shutdown scenarios where you must be sure
* that all parts (hardirq and threaded handler) have completed.
*
+ * Returns: false if a theaded handler is active.
+ *
* This function may be called - with care - from IRQ context.
*/
-void synchronize_hardirq(unsigned int irq)
+bool synchronize_hardirq(unsigned int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
- if (desc)
+ if (desc) {
__synchronize_hardirq(desc);
+ return !atomic_read(&desc->threads_active);
+ }
+
+ return true;
}
EXPORT_SYMBOL(synchronize_hardirq);
@@ -439,6 +445,32 @@ void disable_irq(unsigned int irq)
}
EXPORT_SYMBOL(disable_irq);
+/**
+ * disable_hardirq - disables an irq and waits for hardirq completion
+ * @irq: Interrupt to disable
+ *
+ * Disable the selected interrupt line. Enables and Disables are
+ * nested.
+ * This function waits for any pending hard IRQ handlers for this
+ * interrupt to complete before returning. If you use this function while
+ * holding a resource the hard IRQ handler may need you will deadlock.
+ *
+ * When used to optimistically disable an interrupt from atomic context
+ * the return value must be checked.
+ *
+ * Returns: false if a theaded handler is active.
+ *
+ * This function may be called - with care - from IRQ context.
+ */
+bool disable_hardirq(unsigned int irq)
+{
+ if (!__disable_irq_nosync(irq))
+ return synchronize_hardirq(irq);
+
+ return false;
+}
+EXPORT_SYMBOL(disable_hardirq);
+
void __enable_irq(struct irq_desc *desc, unsigned int irq)
{
switch (desc->depth) {
next prev parent reply other threads:[~2015-02-05 13:06 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-09 14:37 [RFC PATCH net-next 00/11] net: remove disable_irq() from ->ndo_poll_controller Sabrina Dubroca
2014-12-09 14:37 ` [RFC PATCH net-next 01/11] netpoll: introduce netpoll_irq_lock to protect netpoll controller against interrupts Sabrina Dubroca
2014-12-09 14:37 ` [RFC PATCH net-next 02/11] e1000: remove disable_irq from netpoll controller, use netpoll_irq_lock Sabrina Dubroca
2014-12-09 14:37 ` [RFC PATCH net-next 03/11] 8139cp/too: remove disable_irq from netpoll controller Sabrina Dubroca
2014-12-09 14:37 ` [RFC PATCH net-next 04/11] atl1c: remove disable_irq from netpoll controller, use netpoll_irq_lock Sabrina Dubroca
[not found] ` <CAMXMK6t5NfPQFBxK1Qny45LCS6rwX4Ys1n4C7fsTPHXu=x_vuQ@mail.gmail.com>
2014-12-09 17:23 ` Sabrina Dubroca
2014-12-09 21:17 ` Chris Snook
2014-12-09 14:37 ` [RFC PATCH net-next 05/11] bnx2: " Sabrina Dubroca
2014-12-09 14:37 ` [RFC PATCH net-next 06/11] s2io: " Sabrina Dubroca
2014-12-09 14:37 ` [RFC PATCH net-next 07/11] pasemi: " Sabrina Dubroca
2014-12-09 14:37 ` [RFC PATCH net-next 08/11] ll_temac: " Sabrina Dubroca
2014-12-09 14:37 ` [RFC PATCH net-next 09/11] xilinx/axienet: " Sabrina Dubroca
2014-12-09 14:37 ` [RFC PATCH net-next 10/11] gianfar: " Sabrina Dubroca
2014-12-09 14:37 ` [RFC PATCH net-next 11/11] net: fec: " Sabrina Dubroca
2014-12-10 2:44 ` [RFC PATCH net-next 00/11] net: remove disable_irq() from ->ndo_poll_controller David Miller
2014-12-11 21:45 ` Sabrina Dubroca
2014-12-12 2:14 ` David Miller
2014-12-12 22:01 ` Thomas Gleixner
2015-01-05 14:31 ` Sabrina Dubroca
2015-02-05 0:20 ` Sabrina Dubroca
2015-02-05 13:06 ` Peter Zijlstra [this message]
2015-02-05 15:33 ` Sabrina Dubroca
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