[PATCH 0/2] qla2xxx: fix errors in PCI device remove with ongoing I/O

[Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>]

This patchset addresses a couple of errors that might happen during
PCI device remove (e.g., PCI hotplug, PowerVM DLPAR), which prevent
the successful removal and re-addition of the adapter to the system,
and cause an oops and/or invalid DMA access (triggers an EEH event).

It allowed several cycles of PCI device add/remove with ongoing I/O,
to complete successfully without triggering oopses or EEH events.

Verified on v4.9-rc3.

Test-case:
---
    # lspci
    <...>
    001d:70:00.0 Fibre Channel: QLogic Corp. ISP2532-based ...
    001d:70:00.1 Fibre Channel: QLogic Corp. ISP2532-based ...
    <...>

    # for sd in $(find /sys/bus/pci/devices/001d:70:00.*/ \
                       -name 'sd*' -printf "%f\n"); do \
        dd if=/dev/$sd of=/dev/null iflag=nocache & done

    # echo 1 | tee /sys/bus/pci/devices/001d:70:00.*/remove
    (this either works or not)

    # echo 1 > /sys/bus/pci/rescan

Before:
---
    <...>
    EEH: Frozen PHB#1d-PE#700000 detected
    qla2xxx [001d:70:00.1]-8042:2: PCI/Register disconnect, exiting.
    <...>
    EEH: Detected PCI bus error on PHB#29-PE#700000
    <...>
    (and/or)
    Unable to handle kernel paging request for data at address 0x00000138
    <...>
    NIP [d000000004700a40] qla2xxx_queuecommand+0x80/0x3f0 [qla2xxx]
    LR [d000000004700a10] qla2xxx_queuecommand+0x50/0x3f0 [qla2xxx]

    (command does not return; adapter cannot be re-added)

After:
---
    <...>
    qla2xxx [001d:70:00.0]-801c:1: Abort command issued nexus=1:0:0 --  1 2003.
    <...>
    qla2xxx [001d:70:00.1]-801c:2: Abort command issued nexus=2:3:0 --  1 2003.
    <...>

    (command does return; adapter can be re-added correctly)


Mauricio Faria de Oliveira (2):
  qla2xxx: do not queue commands when unloading
  qla2xxx: fix invalid DMA access after command aborts in PCI device
    remove

 drivers/scsi/qla2xxx/qla_os.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

-- 
1.8.3.1