Merge branch 'devlink-locking'

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Jakub Kicinski says:

====================
improve ethtool/rtnl vs devlink locking

During ethtool netlink development we decided to move some of
the commmands to devlink. Since we don't want drivers to implement
both devlink and ethtool version of the commands ethtool ioctl
falls back to calling devlink. Unfortunately devlink locks must
be taken before rtnl_lock. This results in a questionable
dev_hold() / rtnl_unlock() / devlink / rtnl_lock() / dev_put()
pattern.

This method "works" but it working depends on drivers in question
not doing much in ethtool_ops->begin / complete, and on the netdev
not having needs_free_netdev set.

Since commit 437ebfd90a ("devlink: Count struct devlink consumers")
we can hold a reference on a devlink instance and prevent it from
going away (sort of like netdev with dev_hold()). We can use this
to create a more natural reference nesting where we get a ref on
the devlink instance and make the devlink call entirely outside
of the rtnl_lock section.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

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This commit is contained in:

David S. Miller 2021-11-01 13:26:07 +00:00

parent c6e03dbe0c 1af0a0948e

commit 1adc58ea23

4 changed files with 136 additions and 87 deletions

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20

include/net/devlink.h

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2

net/core/dev_ioctl.c

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53

net/core/devlink.c

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148

net/ethtool/ioctl.c

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