Aw: Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses.

From	"Lino Sanfilippo" <LinoSanfilippo@gmx.de>
Newsgroups	linux.kernel
Subject	Aw: Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses.
Date	2016-12-02 15:10 +0100
Message-ID	<sJWHg-4R5-27@gated-at.bofh.it> (permalink)
References	(1 earlier) <sGY2X-lZ-25@gated-at.bofh.it> <sH4UG-57A-27@gated-at.bofh.it> <sH9KF-8i4-1@gated-at.bofh.it> <sJWHg-4R5-29@gated-at.bofh.it> <sJRHz-1oa-1@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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Hi,


> 
> There's nothing that protect stmmac_poll() from running concurently
> with stmmac_dma_interrupt(), right?
> 

could it be that there is also another issue concerned locking?:
The tx completion handler takes the xmit_lock in case that the
netif_queue is stopped. This is AFAICS unnecessary, since both
xmit and completion handler are already synchronized by the private
tx lock. But it is IMHO also dangerous:

In the xmit handler we have the locking order
1. xmit_lock
2. private tx lock

while in the completion handler its the reverse:

1. private tx lock
2. xmit lock.

Do I miss something?


Regards,
Lino

Thread

Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Giuseppe CAVALLARO <peppe.cavallaro@st.com> - 2016-12-02 09:30 +0100
  Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Pavel Machek <pavel@ucw.cz> - 2016-12-02 09:50 +0100
    Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Giuseppe CAVALLARO <peppe.cavallaro@st.com> - 2016-12-02 10:50 +0100
      Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Pavel Machek <pavel@ucw.cz> - 2016-12-02 13:40 +0100
        Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Giuseppe CAVALLARO <peppe.cavallaro@st.com> - 2016-12-02 15:00 +0100
          Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Alexandre Torgue <alexandre.torgue@st.com> - 2016-12-02 15:30 +0100
            Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Giuseppe CAVALLARO <peppe.cavallaro@st.com> - 2016-12-02 17:10 +0100
              Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Pavel Machek <pavel@ucw.cz> - 2016-12-05 13:40 +0100
          Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Pavel Machek <pavel@ucw.cz> - 2016-12-05 13:10 +0100
      Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Pavel Machek <pavel@ucw.cz> - 2016-12-05 11:40 +0100
        Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. "Lino Sanfilippo" <LinoSanfilippo@gmx.de> - 2016-12-05 12:50 +0100
          Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Pavel Machek <pavel@ucw.cz> - 2016-12-05 23:20 +0100
            Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Lino Sanfilippo <LinoSanfilippo@gmx.de> - 2016-12-05 23:40 +0100
              Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Pavel Machek <pavel@ucw.cz> - 2016-12-05 23:50 +0100
                Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Lino Sanfilippo <LinoSanfilippo@gmx.de> - 2016-12-06 00:00 +0100
                Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Lino Sanfilippo <LinoSanfilippo@gmx.de> - 2016-12-06 00:20 +0100
    Aw: Re: stmmac ethernet in kernel 4.9-rc6: coalescing related  pauses. "Lino Sanfilippo" <LinoSanfilippo@gmx.de> - 2016-12-02 15:10 +0100
      [RFC] Re: Re: stmmac ethernet in kernel 4.9-rc6: coalescing related  pauses. Pavel Machek <pavel@ucw.cz> - 2016-12-07 13:40 +0100
        Re: [RFC] Re: Re: stmmac ethernet in kernel 4.9-rc6: coalescing  related pauses. Lino Sanfilippo <lsanfil@marvell.com> - 2016-12-07 14:20 +0100
  Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Giuseppe CAVALLARO <peppe.cavallaro@st.com> - 2016-12-02 09:50 +0100
  Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses. Pavel Machek <pavel@ucw.cz> - 2016-12-05 13:00 +0100

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