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Message-Id: <cover.1578257976.git.mkubecek@suse.cz>
Date: Sun, 5 Jan 2020 22:16:56 +0100 (CET)
From: Michal Kubecek <mkubecek@...e.cz>
To: "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org
Cc: Maya Erez <merez@...eaurora.org>,
Kalle Valo <kvalo@...eaurora.org>,
linux-wireless@...r.kernel.org, wil6210@....qualcomm.com,
Francois Romieu <romieu@...zoreil.com>,
linux-kernel@...r.kernel.org, Andrew Lunn <andrew@...n.ch>,
Florian Fainelli <f.fainelli@...il.com>
Subject: [PATCH net-next 0/3] ethtool: allow nesting of begin() and complete()
callbacks
The ethtool ioctl interface used to guarantee that ethtool_ops callbacks
were always called in a block between calls to ->begin() and ->complete()
(if these are defined) and that this whole block was executed with RTNL
lock held:
rtnl_lock();
ops->begin();
/* other ethtool_ops calls */
ops->complete();
rtnl_unlock();
This prevented any nesting or crossing of the begin-complete blocks.
However, this is no longer guaranteed even for ioctl interface as at least
ethtool_phys_id() releases RTNL lock while waiting for a timer. With the
introduction of netlink ethtool interface, the begin-complete pairs are
naturally nested e.g. when a request triggers a netlink notification.
Fortunately, only minority of networking drivers implements begin() and
complete() callbacks and most of those that do, fall into three groups:
- wrappers for pm_runtime_get_sync() and pm_runtime_put()
- wrappers for clk_prepare_enable() and clk_disable_unprepare()
- begin() checks netif_running() (fails if false), no complete()
First two have their own refcounting, third is safe w.r.t. nesting of the
blocks.
Only three in-tree networking drivers need an update to deal with nesting
of begin() and complete() calls: via-velocity and epic100 perform resume
and suspend on their own and wil6210 completely serializes the calls using
its own mutex (which would lead to a deadlock if a request request
triggered a netlink notification). The series addresses these problems.
Michal Kubecek (3):
wil6210: get rid of begin() and complete() ethtool_ops
via-velocity: allow nesting of ethtool_ops begin() and complete()
epic100: allow nesting of ethtool_ops begin() and complete()
drivers/net/ethernet/smsc/epic100.c | 7 +++-
drivers/net/ethernet/via/via-velocity.c | 14 +++++--
drivers/net/ethernet/via/via-velocity.h | 1 +
drivers/net/wireless/ath/wil6210/ethtool.c | 43 ++++++++--------------
4 files changed, 32 insertions(+), 33 deletions(-)
--
2.24.1
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