From 0b7e7c53307de217cfc7eeb036c9b8b013d67fcc Mon Sep 17 00:00:00 2001 From: Andrew Vasquez Date: Fri, 8 Feb 2013 01:57:42 -0500 Subject: [PATCH] [SCSI] qla2xxx: Correct race in loop_state assignment during reset handling. There's a subtle race in the loop/bus-reset handling whereby a VHA's loop-state can get incorrectly set to 'down' after the loop-reset and firmware's completion of link re-negotiation. The original code incorrectly assumes that firmware AENs would arrive only after mailbox-command execution to initiate the link-flap. Here's a good case with the old code (AENs arrive after mailbox-command completion): qla2xxx [0000:03:00.1]-8012:91: BUS RESET ISSUED nexus=91:0:4. qla2xxx [0000:03:00.1]-287d:91: FCPort state transitioned from ONLINE to LOST - portid=010100. qla2xxx [0000:03:00.1]-580e:91: Asynchronous P2P MODE received. qla2xxx [0000:03:00.1]-287d:91: FCPort state transitioned from ONLINE to LOST - portid=010400. qla2xxx [0000:03:00.1]-802b:91: BUS RESET SUCCEEDED nexus=91:0:4. qla2xxx [0000:03:00.1]-480b:91: Reset marker scheduled. qla2xxx [0000:03:00.1]-5812:91: Port database changed ffff 0006 0000. qla2xxx [0000:03:00.1]-505f:91: Link is operational (4 Gbps). qla2xxx [0000:03:00.1]-480c:91: Reset marker end. qla2xxx [0000:03:00.1]-480f:91: Loop resync scheduled. qla2xxx [0000:03:00.1]-8837:91: F/W Ready - OK. qla2xxx [0000:03:00.1]-883a:91: fw_state=3 (7, 0, 0, 0) curr time=170b8f315. qla2xxx [0000:03:00.1]-280e:91: HBA in F P2P topology. qla2xxx [0000:03:00.1]-2812:91: qla2x00_configure_hba success qla2xxx [0000:03:00.1]-2814:91: Configure loop -- dpc flags = 0x5260. notice how the 'Port database changed' (8014) arrived after the bus-reset handler completed 'BUS RESET SUCCEEDED'. Now, here's a failing case with the old code (AENs arrive before mailbox-command completion): qla2xxx [0000:03:00.1]-8012:91: BUS RESET ISSUED nexus=91:0:0. qla2xxx [0000:03:00.1]-580e:91: Asynchronous P2P MODE received. qla2xxx [0000:03:00.1]-287d:91: FCPort state transitioned from ONLINE to LOST - portid=010100. qla2xxx [0000:03:00.1]-287d:91: FCPort state transitioned from ONLINE to LOST - portid=010400. qla2xxx [0000:03:00.1]-4800:91: DPC handler sleeping. qla2xxx [0000:03:00.1]-5812:91: Port database changed ffff 0006 0000. qla2xxx [0000:03:00.1]-505f:91: Link is operational (4 Gbps). qla2xxx [0000:03:00.1]-802b:91: BUS RESET SUCCEEDED nexus=91:0:0. qla2xxx [0000:03:00.1]-480b:91: Reset marker scheduled. qla2xxx [0000:03:00.1]-480c:91: Reset marker end. qla2xxx [0000:03:00.1]-480f:91: Loop resync scheduled. qla2xxx [0000:03:00.1]-8837:91: F/W Ready - OK. qla2xxx [0000:03:00.1]-883a:91: fw_state=3 (7, 0, 0, 0) curr time=170be9eb2. qla2xxx [0000:03:00.1]-280e:91: HBA in F P2P topology. qla2xxx [0000:03:00.1]-2812:91: qla2x00_configure_hba success qla2xxx [0000:03:00.1]-2814:91: Configure loop -- dpc flags = 0x5260. qla2xxx [0000:03:00.1]-281e:91: Needs RSCN update and loop transition. qla2xxx [0000:03:00.1]-286a:91: qla2x00_configure_loop *** FAILED ***. qla2xxx [0000:03:00.1]-4810:91: Loop resync end. qla2xxx [0000:03:00.1]-4800:91: DPC handler sleeping. This race would ultimately lead to devices go unexpectedly offline until another link-flap or chip-reset would cause driver re-discovery to take place. Signed-off-by: Andrew Vasquez Signed-off-by: Saurav Kashyap Signed-off-by: James Bottomley --- drivers/scsi/qla2xxx/qla_os.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c index 2d2afdb..0612d25 100644 --- a/drivers/scsi/qla2xxx/qla_os.c +++ b/drivers/scsi/qla2xxx/qla_os.c @@ -1305,14 +1305,14 @@ qla2x00_loop_reset(scsi_qla_host_t *vha) } if (ha->flags.enable_lip_full_login && !IS_CNA_CAPABLE(ha)) { + atomic_set(&vha->loop_state, LOOP_DOWN); + atomic_set(&vha->loop_down_timer, LOOP_DOWN_TIME); + qla2x00_mark_all_devices_lost(vha, 0); ret = qla2x00_full_login_lip(vha); if (ret != QLA_SUCCESS) { ql_dbg(ql_dbg_taskm, vha, 0x802d, "full_login_lip=%d.\n", ret); } - atomic_set(&vha->loop_state, LOOP_DOWN); - atomic_set(&vha->loop_down_timer, LOOP_DOWN_TIME); - qla2x00_mark_all_devices_lost(vha, 0); } if (ha->flags.enable_lip_reset) { -- 2.7.4