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From: Francois Romieu <romieu@fr.zoreil.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: Lino Sanfilippo <LinoSanfilippo@gmx.de>,
	bh74.an@samsung.com, ks.giri@samsung.com,
	vipul.pandya@samsung.com, peppe.cavallaro@st.com,
	alexandre.torgue@st.com, davem@davemloft.net,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH 1/2] net: ethernet: sxgbe: remove private tx queue lock
Date: Sun, 18 Dec 2016 01:15:07 +0100	[thread overview]
Message-ID: <20161218001507.GA5343@electric-eye.fr.zoreil.com> (raw)
In-Reply-To: <20161217173150.GA20231@amd>

Pavel Machek <pavel@ucw.cz> :
[...]
> Won't this up/down the interface, in a way userspace can observe?

It won't up/down the interface as it doesn't exactly mimic what the
network code does (there's more than rtnl_lock).

For the same reason it's broken if it races with the transmit path: it
can release driver resources while the transmit path uses these.

Btw the points below may not matter/hurt much for a proof a concept
but they would need to be addressed as well:
1) unchecked (and avoidable) extra error paths due to stmmac_release()
2) racy cancel_work_sync. Low probability as it is, an irq + error could
   take place right after cancel_work_sync

Lino, have you considered via-rhine.c since its "move work from irq to
workqueue context" changes that started in
7ab87ff4c770eed71e3777936299292739fcd0fe [*] ?

It's a shameless plug - originated in r8169.c - but it should be rather
close to what the sxgbe and friends require. Thought / opinion ?

[*] Including fixes/changes in:
- 3a5a883a8a663b930908cae4abe5ec913b9b2fd2
- e1efa87241272104d6a12c8b9fcdc4f62634d447
- 810f19bcb862f8889b27e0c9d9eceac9593925dd
- e45af497950a89459a0c4b13ffd91e1729fffef4
- a926592f5e4e900f3fa903298c4619a131e60963
- 559bcac35facfed49ab4f408e162971612dcfdf3

-- 
Ueimor

  reply	other threads:[~2016-12-18  0:15 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-07 20:05 Remove private locks to avoid possible deadlock Lino Sanfilippo
2016-12-07 20:05 ` [PATCH 1/2] net: ethernet: sxgbe: remove private tx queue lock Lino Sanfilippo
2016-12-07 23:15   ` Francois Romieu
2016-12-08 20:32     ` Lino Sanfilippo
2016-12-08 21:54       ` Pavel Machek
2016-12-08 22:12         ` Lino Sanfilippo
2016-12-08 22:18           ` Pavel Machek
2016-12-08 22:45             ` Lino Sanfilippo
2016-12-08 23:19       ` Francois Romieu
2016-12-09 11:21         ` Pavel Machek
2016-12-10  2:25           ` Lino Sanfilippo
2016-12-11 20:11             ` Pavel Machek
2016-12-15 19:27               ` Lino Sanfilippo
2016-12-15 21:03                 ` Pavel Machek
2016-12-15 21:32                   ` Lino Sanfilippo
2016-12-15 22:33                     ` Lino Sanfilippo
2016-12-17 17:31                       ` Pavel Machek
2016-12-18  0:15                         ` Francois Romieu [this message]
2016-12-18 16:15                           ` Lino Sanfilippo
2016-12-18 17:23                             ` Pavel Machek
2016-12-18 18:30                             ` Pavel Machek
2016-12-19 22:49                               ` Lino Sanfilippo
2016-12-18 20:16                             ` Pavel Machek
2016-12-19 10:02                           ` Pavel Machek
2016-12-20  0:05                             ` Francois Romieu
2016-12-07 20:05 ` [PATCH 2/2] net: ethernet: stmmac: " Lino Sanfilippo
2016-12-07 20:55   ` Pavel Machek
2016-12-07 20:59   ` Pavel Machek
2016-12-07 21:37   ` Pavel Machek
2016-12-07 21:43     ` Lino Sanfilippo
2016-12-07 22:34       ` Lino Sanfilippo
2016-12-07 23:21         ` Pavel Machek
2016-12-07 23:41     ` David Miller
2016-12-08 14:08       ` Pavel Machek
2016-12-08 15:26         ` David Miller
2016-12-08 15:46           ` Pavel Machek

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