From: "tip-bot2 for Barry Song" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Barry Song <song.bao.hua@hisilicon.com>,
Thomas Gleixner <tglx@linutronix.de>,
dmitry.torokhov@gmail.com, x86@kernel.org,
linux-kernel@vger.kernel.org, maz@kernel.org
Subject: [tip: irq/core] genirq: Add IRQF_NO_AUTOEN for request_irq/nmi()
Date: Thu, 04 Mar 2021 10:53:53 -0000 [thread overview]
Message-ID: <161485523394.398.10007682711343433706.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20210302224916.13980-2-song.bao.hua@hisilicon.com>
The following commit has been merged into the irq/core branch of tip:
Commit-ID: e749df1bbd23f4472082210650514548d8a39e9b
Gitweb: https://git.kernel.org/tip/e749df1bbd23f4472082210650514548d8a39e9b
Author: Barry Song <song.bao.hua@hisilicon.com>
AuthorDate: Wed, 03 Mar 2021 11:49:15 +13:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 04 Mar 2021 11:47:52 +01:00
genirq: Add IRQF_NO_AUTOEN for request_irq/nmi()
Many drivers don't want interrupts enabled automatically via request_irq().
So they are handling this issue by either way of the below two:
(1)
irq_set_status_flags(irq, IRQ_NOAUTOEN);
request_irq(dev, irq...);
(2)
request_irq(dev, irq...);
disable_irq(irq);
The code in the second way is silly and unsafe. In the small time gap
between request_irq() and disable_irq(), interrupts can still come.
The code in the first way is safe though it's subobtimal.
Add a new IRQF_NO_AUTOEN flag which can be handed in by drivers to
request_irq() and request_nmi(). It prevents the automatic enabling of the
requested interrupt/nmi in the same safe way as #1 above. With that the
various usage sites of #1 and #2 above can be simplified and corrected.
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: dmitry.torokhov@gmail.com
Link: https://lore.kernel.org/r/20210302224916.13980-2-song.bao.hua@hisilicon.com
---
include/linux/interrupt.h | 4 ++++
kernel/irq/manage.c | 11 +++++++++--
2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 967e257..76f1161 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -61,6 +61,9 @@
* interrupt handler after suspending interrupts. For system
* wakeup devices users need to implement wakeup detection in
* their interrupt handlers.
+ * IRQF_NO_AUTOEN - Don't enable IRQ or NMI automatically when users request it.
+ * Users will enable it explicitly by enable_irq() or enable_nmi()
+ * later.
*/
#define IRQF_SHARED 0x00000080
#define IRQF_PROBE_SHARED 0x00000100
@@ -74,6 +77,7 @@
#define IRQF_NO_THREAD 0x00010000
#define IRQF_EARLY_RESUME 0x00020000
#define IRQF_COND_SUSPEND 0x00040000
+#define IRQF_NO_AUTOEN 0x00080000
#define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD)
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index dec3f73..97c231a 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1693,7 +1693,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
}
- if (irq_settings_can_autoenable(desc)) {
+ if (!(new->flags & IRQF_NO_AUTOEN) &&
+ irq_settings_can_autoenable(desc)) {
irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
} else {
/*
@@ -2086,10 +2087,15 @@ int request_threaded_irq(unsigned int irq, irq_handler_t handler,
* which interrupt is which (messes up the interrupt freeing
* logic etc).
*
+ * Also shared interrupts do not go well with disabling auto enable.
+ * The sharing interrupt might request it while it's still disabled
+ * and then wait for interrupts forever.
+ *
* Also IRQF_COND_SUSPEND only makes sense for shared interrupts and
* it cannot be set along with IRQF_NO_SUSPEND.
*/
if (((irqflags & IRQF_SHARED) && !dev_id) ||
+ ((irqflags & IRQF_SHARED) && (irqflags & IRQF_NO_AUTOEN)) ||
(!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) ||
((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND)))
return -EINVAL;
@@ -2245,7 +2251,8 @@ int request_nmi(unsigned int irq, irq_handler_t handler,
desc = irq_to_desc(irq);
- if (!desc || irq_settings_can_autoenable(desc) ||
+ if (!desc || (irq_settings_can_autoenable(desc) &&
+ !(irqflags & IRQF_NO_AUTOEN)) ||
!irq_settings_can_request(desc) ||
WARN_ON(irq_settings_is_per_cpu_devid(desc)) ||
!irq_supports_nmi(desc))
next prev parent reply other threads:[~2021-03-04 10:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-02 22:49 [PATCH v5 0/2] add IRQF_NO_AUTOEN for request_irq Barry Song
2021-03-02 22:49 ` [PATCH v5 1/2] genirq: " Barry Song
2021-03-04 10:53 ` tip-bot2 for Barry Song [this message]
2021-03-04 10:57 ` [tip: irq/core] genirq: Add IRQF_NO_AUTOEN for request_irq/nmi() Thomas Gleixner
2021-03-04 18:50 ` Thomas Gleixner
2021-03-23 22:44 ` Dmitry Torokhov
2021-03-25 6:59 ` Thomas Gleixner
2021-03-25 22:32 ` Dmitry Torokhov
2021-03-06 11:54 ` tip-bot2 for Barry Song
2021-03-02 22:49 ` [PATCH v5 2/2] Input: move to use request_irq by IRQF_NO_AUTOEN flag Barry Song
2021-03-25 22:31 ` Dmitry Torokhov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=161485523394.398.10007682711343433706.tip-bot2@tip-bot2 \
--to=tip-bot2@linutronix.de \
--cc=dmitry.torokhov@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tip-commits@vger.kernel.org \
--cc=maz@kernel.org \
--cc=song.bao.hua@hisilicon.com \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).