• F
    ncr5380: Fix soft lockups · 0a4e3612
    Finn Thain 提交于
    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: NFinn Thain <fthain@telegraphics.com.au>
    Reviewed-by: NHannes Reinecke <hare@suse.com>
    Tested-by: NOndrej Zary <linux@rainbow-software.org>
    Tested-by: NMichael Schmitz <schmitzmic@gmail.com>
    Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
    0a4e3612
dmx3191d.c 4.2 KB
/*
    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");
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