sata_promise: fix hardreset lockdep error
authorMikael Pettersson <mikpe@it.uu.se>
Sun, 16 Sep 2012 18:53:43 +0000 (20:53 +0200)
committerJeff Garzik <jgarzik@redhat.com>
Wed, 28 Nov 2012 17:37:56 +0000 (12:37 -0500)
commit3100d49d3cd236443faae9d81137c81b22d36003
tree7fb4455806be0ac8dad86e26adc0efe82967f874
parent2844a48706e54ddda4a04269dba4250b42f449de
sata_promise: fix hardreset lockdep error

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>
Cc: stable@vger.kernel.org
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
drivers/ata/sata_promise.c