From: Andrew Vasquez <andrew.vasquez@qlogic.com>
Date: Mon, 29 Sep 2008 15:15:04 +0000 (+0000)
Subject: SCSI: qla2xxx: Defer enablement of RISC interrupts until ISP initialization completes.
X-Git-Tag: v2.6.26.6~60
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=61c8bd1d3a9e7e57843d98d9b133fec77ecf4e1b;p=karo-tx-linux.git

SCSI: qla2xxx: Defer enablement of RISC interrupts until ISP initialization completes.

commit 048feec5548c0582ee96148c61b87cccbcb5f9be upstream

Josip Rodin noted
(http://article.gmane.org/gmane.linux.ports.sparc/10152) the
driver oopsing during registration of an rport to the
FC-transport layer with a backtrace indicating a dereferencing of
an shost->shost_data equal to NULL.  David Miller identified a
small window in driver logic where this could happen:

    > Look at how the driver registers the IRQ handler before the host has
    > been registered with the SCSI layer.
    >
    > That leads to a window of time where the shost hasn't been setup
    > fully, yet ISRs can come in and trigger DPC thread events, such as
    > loop resyncs, which expect the transport area to be setup.
    >
    > But it won't be setup, because scsi_add_host() hasn't finished yet.
    >
    > Note that in Josip's crash log, we don't even see the
    >
    >         qla_printk(KERN_INFO, ha, "\n"
    >             " QLogic Fibre Channel HBA Driver: %s\n"
    >             "  QLogic %s - %s\n"
    >             "  ISP%04X: %s @ %s hdma%c, host#=%ld, fw=%s\n",
    >  ...
    >
    > message yet.
    >
    > Which means that the crash occurs between qla2x00_request_irqs()
    > and printing that message.

Close this window by enabling RISC interrupts after the host has
been registered with the SCSI midlayer.

Reported-by: Josip Rodin <joy@entuzijast.net>
Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
index ec63b79f900a..d191cecd417f 100644
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -1838,7 +1838,6 @@ clear_risc_ints:
 		WRT_REG_WORD(&reg->isp.hccr, HCCR_CLR_HOST_INT);
 	}
 	spin_unlock_irq(&ha->hardware_lock);
-	ha->isp_ops->enable_intrs(ha);
 
 fail:
 	return ret;
diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index 047ee644aa91..4c6b90222b70 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -1740,6 +1740,8 @@ qla2x00_probe_one(struct pci_dev *pdev, const struct pci_device_id *id)
 	if (ret)
 		goto probe_failed;
 
+	ha->isp_ops->enable_intrs(ha);
+
 	scsi_scan_host(host);
 
 	qla2x00_alloc_sysfs_attr(ha);