alistair23-linux/drivers/scsi/dmx3191d.c
Finn Thain 0a4e361254 ncr5380: Fix soft lockups
Because of the rudimentary design of the chip, it is necessary to poll the
SCSI bus signals during PIO and this tends to hog the CPU. The driver will
accept new commands while others execute, and this causes a soft lockup
because the workqueue item will not terminate until the issue queue is
emptied.

When exercising dmx3191d using sequential IO from dd, the driver is sent
512 KiB WRITE commands and 128 KiB READs. For a PIO transfer, the rate is
is only about 300 KiB/s, so these are long-running commands. And although
PDMA may run at several MiB/s, interrupts are disabled for the duration
of the transfer.

Fix the unresponsiveness and soft lockup issues by calling cond_resched()
after each command is completed and by limiting max_sectors for drivers
that don't implement real DMA.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Ondrej Zary <linux@rainbow-software.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2016-01-06 21:43:09 -05:00

166 lines
4.2 KiB
C

/*
dmx3191d.c - driver for the Domex DMX3191D SCSI card.
Copyright (C) 2000 by Massimo Piccioni <dafastidio@libero.it>
Portions Copyright (C) 2004 by Christoph Hellwig <hch@lst.de>
Based on the generic NCR5380 driver by Drew Eckhardt et al.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/interrupt.h>
#include <asm/io.h>
#include <scsi/scsi_host.h>
/*
* Definitions for the generic 5380 driver.
*/
#define DONT_USE_INTR
#define NCR5380_read(reg) inb(instance->io_port + reg)
#define NCR5380_write(reg, value) outb(value, instance->io_port + reg)
#define NCR5380_implementation_fields /* none */
#include "NCR5380.h"
#include "NCR5380.c"
#define DMX3191D_DRIVER_NAME "dmx3191d"
#define DMX3191D_REGION_LEN 8
static struct scsi_host_template dmx3191d_driver_template = {
.module = THIS_MODULE,
.proc_name = DMX3191D_DRIVER_NAME,
.name = "Domex DMX3191D",
.info = NCR5380_info,
.queuecommand = NCR5380_queue_command,
.eh_abort_handler = NCR5380_abort,
.eh_bus_reset_handler = NCR5380_bus_reset,
.can_queue = 32,
.this_id = 7,
.sg_tablesize = SG_ALL,
.cmd_per_lun = 2,
.use_clustering = DISABLE_CLUSTERING,
.cmd_size = NCR5380_CMD_SIZE,
.max_sectors = 128,
};
static int dmx3191d_probe_one(struct pci_dev *pdev,
const struct pci_device_id *id)
{
struct Scsi_Host *shost;
unsigned long io;
int error = -ENODEV;
if (pci_enable_device(pdev))
goto out;
io = pci_resource_start(pdev, 0);
if (!request_region(io, DMX3191D_REGION_LEN, DMX3191D_DRIVER_NAME)) {
printk(KERN_ERR "dmx3191: region 0x%lx-0x%lx already reserved\n",
io, io + DMX3191D_REGION_LEN);
goto out_disable_device;
}
shost = scsi_host_alloc(&dmx3191d_driver_template,
sizeof(struct NCR5380_hostdata));
if (!shost)
goto out_release_region;
shost->io_port = io;
/* This card does not seem to raise an interrupt on pdev->irq.
* Steam-powered SCSI controllers run without an IRQ anyway.
*/
shost->irq = NO_IRQ;
error = NCR5380_init(shost, FLAG_NO_PSEUDO_DMA);
if (error)
goto out_host_put;
NCR5380_maybe_reset_bus(shost);
pci_set_drvdata(pdev, shost);
error = scsi_add_host(shost, &pdev->dev);
if (error)
goto out_exit;
scsi_scan_host(shost);
return 0;
out_exit:
NCR5380_exit(shost);
out_host_put:
scsi_host_put(shost);
out_release_region:
release_region(io, DMX3191D_REGION_LEN);
out_disable_device:
pci_disable_device(pdev);
out:
return error;
}
static void dmx3191d_remove_one(struct pci_dev *pdev)
{
struct Scsi_Host *shost = pci_get_drvdata(pdev);
unsigned long io = shost->io_port;
scsi_remove_host(shost);
NCR5380_exit(shost);
scsi_host_put(shost);
release_region(io, DMX3191D_REGION_LEN);
pci_disable_device(pdev);
}
static struct pci_device_id dmx3191d_pci_tbl[] = {
{PCI_VENDOR_ID_DOMEX, PCI_DEVICE_ID_DOMEX_DMX3191D,
PCI_ANY_ID, PCI_ANY_ID, 0, 0, 4},
{ }
};
MODULE_DEVICE_TABLE(pci, dmx3191d_pci_tbl);
static struct pci_driver dmx3191d_pci_driver = {
.name = DMX3191D_DRIVER_NAME,
.id_table = dmx3191d_pci_tbl,
.probe = dmx3191d_probe_one,
.remove = dmx3191d_remove_one,
};
static int __init dmx3191d_init(void)
{
return pci_register_driver(&dmx3191d_pci_driver);
}
static void __exit dmx3191d_exit(void)
{
pci_unregister_driver(&dmx3191d_pci_driver);
}
module_init(dmx3191d_init);
module_exit(dmx3191d_exit);
MODULE_AUTHOR("Massimo Piccioni <dafastidio@libero.it>");
MODULE_DESCRIPTION("Domex DMX3191D SCSI driver");
MODULE_LICENSE("GPL");