From: Lukas Wunner <lukas@wunner.de>
To: Jakub Kicinski <kuba@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Marc Zyngier <maz@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Paolo Abeni <pabeni@redhat.com>,
netdev@vger.kernel.org, linux-usb@vger.kernel.org,
Steve Glendinning <steve.glendinning@shawell.net>,
UNGLinuxDriver@microchip.com, Oliver Neukum <oneukum@suse.com>,
Andre Edich <andre.edich@microchip.com>,
Oleksij Rempel <linux@rempel-privat.de>,
Martyn Welch <martyn.welch@collabora.com>,
Gabriel Hojda <ghojda@yo2urs.ro>,
Christoph Fritz <chf.fritz@googlemail.com>,
Lino Sanfilippo <LinoSanfilippo@gmx.de>,
Philipp Rosenberger <p.rosenberger@kunbus.com>,
Heiner Kallweit <hkallweit1@gmail.com>,
Andrew Lunn <andrew@lunn.ch>,
Russell King <linux@armlinux.org.uk>,
Ferry Toth <fntoth@gmail.com>
Subject: Re: [PATCH net-next v2 5/7] usbnet: smsc95xx: Forward PHY interrupts to PHY driver to avoid polling
Date: Thu, 5 May 2022 20:53:28 +0200 [thread overview]
Message-ID: <20220505185328.GA14123@wunner.de> (raw)
In-Reply-To: <20220505113207.487861b2@kernel.org>
On Thu, May 05, 2022 at 11:32:07AM -0700, Jakub Kicinski wrote:
> On Tue, 3 May 2022 15:15:05 +0200 Lukas Wunner wrote:
> > @@ -608,11 +618,20 @@ static void smsc95xx_status(struct usbnet *dev, struct urb *urb)
> > intdata = get_unaligned_le32(urb->transfer_buffer);
> > netif_dbg(dev, link, dev->net, "intdata: 0x%08X\n", intdata);
> >
> > + /* USB interrupts are received in softirq (tasklet) context.
> > + * Switch to hardirq context to make genirq code happy.
> > + */
> > + local_irq_save(flags);
> > + __irq_enter_raw();
> > +
> > if (intdata & INT_ENP_PHY_INT_)
> > - ;
> > + generic_handle_domain_irq(pdata->irqdomain, PHY_HWIRQ);
> > else
> > netdev_warn(dev->net, "unexpected interrupt, intdata=0x%08X\n",
> > intdata);
> > +
> > + __irq_exit_raw();
> > + local_irq_restore(flags);
>
> IRQ maintainers could you cast your eyes over this?
>
> Full patch:
>
> https://lore.kernel.org/all/c6b7f4e4a17913d2f2bc4fe722df0804c2d6fea7.1651574194.git.lukas@wunner.de/
This is basically identical to what drivers/net/usb/lan78xx.c does
in lan78xx_status(), except I'm passing the hw irq instead of the
linux irq to genirq code, thereby avoiding the overhead of a
radix_tree_lookup().
generic_handle_domain_irq() warns unconditionally on !in_irq(),
unlike handle_irq_desc(), which constrains the warning to
handle_enforce_irqctx() (i.e. x86 APIC, arm GIC/GICv3).
Perhaps that's an oversight in generic_handle_domain_irq(),
unless __irq_resolve_mapping() becomes unsafe outside in_irq()
for some reason...
In any case the unconditional in_irq() necessitates __irq_enter_raw()
here.
And there's no _safe variant() of generic_handle_domain_irq()
(unlike generic_handle_irq_safe() which was recently added by
509853f9e1e7), hence the necessity of an explicit local_irq_save().
Thanks,
Lukas
next prev parent reply other threads:[~2022-05-05 18:53 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-03 13:15 [PATCH net-next v2 0/7] Polling be gone on LAN95xx Lukas Wunner
2022-05-03 13:15 ` [PATCH net-next v2 1/7] usbnet: Run unregister_netdev() before unbind() again Lukas Wunner
2022-05-03 13:15 ` [PATCH net-next v2 2/7] usbnet: smsc95xx: Don't clear read-only PHY interrupt Lukas Wunner
2022-05-03 22:20 ` Andrew Lunn
2022-05-03 13:15 ` [PATCH net-next v2 3/7] usbnet: smsc95xx: Don't reset PHY behind PHY driver's back Lukas Wunner
2022-05-03 22:21 ` Andrew Lunn
2022-05-03 13:15 ` [PATCH net-next v2 4/7] usbnet: smsc95xx: Avoid link settings race on interrupt reception Lukas Wunner
2022-05-03 22:23 ` Andrew Lunn
2022-05-03 13:15 ` [PATCH net-next v2 5/7] usbnet: smsc95xx: Forward PHY interrupts to PHY driver to avoid polling Lukas Wunner
2022-05-05 18:32 ` Jakub Kicinski
2022-05-05 18:53 ` Lukas Wunner [this message]
2022-05-06 10:58 ` Marc Zyngier
2022-05-06 20:16 ` Lukas Wunner
2022-05-09 8:47 ` Marc Zyngier
2022-05-10 8:18 ` Lukas Wunner
2022-05-11 9:26 ` Lukas Wunner
2022-05-11 16:15 ` Jakub Kicinski
2022-05-03 13:15 ` [PATCH net-next v2 6/7] net: phy: smsc: Cache interrupt mask Lukas Wunner
2022-05-03 22:26 ` Andrew Lunn
2022-05-03 13:15 ` [PATCH net-next v2 7/7] net: phy: smsc: Cope with hot-removal in interrupt handler Lukas Wunner
2022-05-03 22:26 ` Andrew Lunn
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=20220505185328.GA14123@wunner.de \
--to=lukas@wunner.de \
--cc=LinoSanfilippo@gmx.de \
--cc=UNGLinuxDriver@microchip.com \
--cc=andre.edich@microchip.com \
--cc=andrew@lunn.ch \
--cc=chf.fritz@googlemail.com \
--cc=davem@davemloft.net \
--cc=fntoth@gmail.com \
--cc=ghojda@yo2urs.ro \
--cc=hkallweit1@gmail.com \
--cc=kuba@kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=linux@rempel-privat.de \
--cc=martyn.welch@collabora.com \
--cc=maz@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=oneukum@suse.com \
--cc=p.rosenberger@kunbus.com \
--cc=pabeni@redhat.com \
--cc=steve.glendinning@shawell.net \
--cc=tglx@linutronix.de \
/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).