From: David S. Miller Date: Wed, 3 Jan 2018 16:00:24 +0000 (-0500) Subject: Merge branch 'net-Resolve-races-in-phy-accessors' X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=318ff60eb4640817606cc2ea8d857b2d7de2455c;p=openwrt%2Fstaging%2Fblogic.git Merge branch 'net-Resolve-races-in-phy-accessors' Russell King says: ==================== Resolve races in phy accessors This series resolves races with various accesses to PHY registers. The first five patches are necessary before we add phylink support to mvneta, the remaining three are merely cleanups for unobserved races, and hence are less critical. There are two possible classes of races that can occur: where we write to a page register that changes the meaning of a group of other registers, and where we read-modify-write a register. Resolve these races by performing the accesses under the mdio bus lock, ensuring that no other user can access the bus while the series of atomic operations are being performed. These patches have been posted before, and have been modified along the lines of previous feedback: - The third patch was originally reviewed by Florian, but as I've added __phy_modify() to it, I've removed that attributation. - Included generic page-based accessors as suggested last time around. - Since we have the unlocked __phy_modify() in this patch series, it is sensible to include the changes for this to marvell.c - these accessors have to change anyway to avoid deadlocks on the mdio bus lock. I haven't been able to test the at803x.c changes yet beyond compile testing - although I do have systems with an ar8035 PHY. However, they should be straight forward to review. This is targetted for net-next because the races have not been found in existing drivers, but have been observed with phylink integrated into mvneta - that's not to say that the races do not exist today, they are just unobserved (probably through lack of rigorous enough testing.) The race provoking condition is detailed in patch 5. ==================== Signed-off-by: David S. Miller --- 318ff60eb4640817606cc2ea8d857b2d7de2455c