sata_promise: fix hardreset lockdep error
authorMikael Pettersson <mikpe@it.uu.se>
Sun, 16 Sep 2012 18:53:43 +0000 (20:53 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 17 Jan 2013 16:43:54 +0000 (08:43 -0800)
commit1bf35799a1d4fa0db11cdfa0da020fabde140982
treea2a2213c3b41c7b4ca0e18bd652e5cbfa500e110
parent78c9672f78f8bdf6321f6bead28c7dbd251ddd24
sata_promise: fix hardreset lockdep error

commit 3100d49d3cd236443faae9d81137c81b22d36003 upstream.

sata_promise's pdc_hard_reset_port() needs to serialize because it
flips a port-specific bit in controller register that's shared by
all ports. The code takes the ata host lock for this, but that's
broken because an interrupt may arrive on our irq during the hard
reset sequence, and that too will take the ata host lock. With
lockdep enabled a big nasty warning is seen.

Fixed by adding private state to the ata host structure, containing
a second lock used only for serializing the hard reset sequences.
This eliminated the lockdep warnings both on my test rig and on
the original reporter's machine.

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Tested-by: Adko Branil <adkobranil@yahoo.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/ata/sata_promise.c