Attachment 155210 Details for Bug 195685 – Simpler patch against 2.6.22-rc1 (does not have retries or anything)

[patch] Simpler patch against 2.6.22-rc1 (does not have retries or anything)

dm-hp-sw-v0.974.patch (text/plain), 7.60 KB, created by Dave Wysochanski on 2007-05-22 22:45:32 UTC

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Creator: Dave Wysochanski

Created: 2007-05-22 22:45:32 UTC

Size: 7.60 KB

patch

obsolete

>Index: linux-2.6.22-rc1/drivers/md/Makefile
>===================================================================
>--- linux-2.6.22-rc1.orig/drivers/md/Makefile
>+++ linux-2.6.22-rc1/drivers/md/Makefile
>@@ -34,6 +34,7 @@ obj-$(CONFIG_DM_CRYPT)		+= dm-crypt.o
> obj-$(CONFIG_DM_DELAY)		+= dm-delay.o
> obj-$(CONFIG_DM_MULTIPATH)	+= dm-multipath.o dm-round-robin.o
> obj-$(CONFIG_DM_MULTIPATH_EMC)	+= dm-emc.o
>+obj-$(CONFIG_DM_MULTIPATH_HP)	+= dm-hp-sw.o
> obj-$(CONFIG_DM_SNAPSHOT)	+= dm-snapshot.o
> obj-$(CONFIG_DM_MIRROR)		+= dm-mirror.o
> obj-$(CONFIG_DM_ZERO)		+= dm-zero.o
>Index: linux-2.6.22-rc1/drivers/md/dm-hp-sw.c
>===================================================================
>--- /dev/null
>+++ linux-2.6.22-rc1/drivers/md/dm-hp-sw.c
>@@ -0,0 +1,230 @@
>+/*
>+ * Copyright (C) 2005 Mike Christie, All rights reserved.
>+ * Copyright (C) 2007 Red Hat, Inc. All rights reserved.
>+ * Authors: Mike Christie
>+ *          Dave Wysochanski
>+ *
>+ * This file is released under the GPL.
>+ *
>+ * Basic support for HP StorageWorks and FSC FibreCat Asymmetric (Active/Passive)
>+ * storage arrays. These storage arrays have controller-based failover, not
>+ * LUN-based failover.  This module is written for LUN-based failover.
>+ * LUN-based failover is the design of dm-mp.
>+ */
>+#include <scsi/scsi.h>
>+#include <scsi/scsi_cmnd.h>
>+#include <scsi/scsi_dbg.h>
>+#include <scsi/scsi_device.h>
>+#include <scsi/scsi_host.h>
>+#include <scsi/scsi_transport_fc.h>
>+#include <linux/list.h>
>+#include <linux/types.h>
>+
>+#include "dm.h"
>+#include "dm-hw-handler.h"
>+
>+#define DM_MSG_PREFIX "multipath hp"
>+
>+/*
>+ * A path activation command may take a longer time to complete.
>+ * The time depends on the I/O load, the number of LUNs, etc.
>+ * Set a miniumum of 30 seconds to allow path activation command
>+ * completion.
>+ */
>+#define MIN_CMD_TIMEOUT 30
>+static int hp_sw_cmd_timeout=MIN_CMD_TIMEOUT;
>+module_param_named(cmd_timeout, hp_sw_cmd_timeout, int, S_IRUGO|S_IWUSR);
>+MODULE_PARM_DESC(cmd_timeout,
>+		 "Time (in seconds) to wait for path activation "
>+		 "command completion.  Set to a higher value when "
>+		 "there are many LUNs or the I/O load is high. ");
>+/*
>+ * Data specific to the HP hardware handler and path activation completion
>+ */
>+struct hp_sw_context {
>+	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
>+};
>+
>+
>+/**
>+ * hp_sw_end_io - Completion handler for HP path activation.
>+ * @req: failover request
>+ * @error: scsi-ml error
>+ *
>+ *  Check sense data, free request structure, and notify dm that
>+ *  pg initialization has completed.
>+ *
>+ * Context: scsi-ml softirq
>+ * TODO: add comment about locking.
>+ */
>+static void hp_sw_end_io(struct request *req, int error)
>+{
>+	struct dm_path *path = req->end_io_data;
>+	unsigned err_flags;
>+
>+	/* TODO: difference between 'error' arg and req->errors */
>+	if (error == 0) {
>+		err_flags = 0;
>+		/* XXX - Remove this log message? */
>+		DMINFO("hp_sw: START_STOP on %s completed successfully",
>+		       path->dev->name);
>+	}
>+	else {
>+		/* FIXME: Error might be retryable */
>+		/* XXX - Remove this log message? */
>+		DMINFO("hp_sw: START_STOP on %s completed with error=0x%x",
>+		       path->dev->name, error);
>+		DMINFO("hp_sw: %s pg_init fail", path->dev->name);
>+		err_flags = MP_FAIL_PATH;
>+	}
>+
>+	req->end_io_data = NULL;
>+	__blk_put_request(req->q, req);
>+	dm_pg_init_complete(path, err_flags);
>+}
>+
>+/**
>+ * hp_sw_get_request - Allocate an HP specific path activation request
>+ * @path: path on which request will be sent (needed for request queue)
>+ *
>+ * The START command is used for path activation request.
>+ * These arrays are controller-based failover, not LUN based.
>+ * One START command issued to a single path will fail over all
>+ * LUNs for the same controller.
>+ */
>+static struct request *hp_sw_get_request(struct dm_path *path)
>+{
>+	struct request *req=NULL;
>+	struct block_device *bdev = path->dev->bdev;
>+	struct request_queue *q = bdev_get_queue(bdev);
>+	struct hp_sw_context *h = path->hwhcontext;
>+
>+	req = blk_get_request(q, WRITE, GFP_ATOMIC);
>+	if (req == NULL)
>+		goto exit;
>+
>+	req->timeout = hp_sw_cmd_timeout*HZ;
>+
>+	req->errors = 0;
>+	req->cmd_type = REQ_TYPE_BLOCK_PC;
>+	req->cmd_flags |= REQ_FAILFAST | REQ_NOMERGE;
>+	req->end_io = hp_sw_end_io;
>+	req->end_io_data = path;
>+	req->sense = h->sense;
>+	memset(req->sense, 0, SCSI_SENSE_BUFFERSIZE);
>+
>+	memset(&req->cmd, 0, BLK_MAX_CDB);
>+	req->cmd[0] = START_STOP;
>+	req->cmd[4] = 1;
>+	req->cmd_len = COMMAND_SIZE(req->cmd[0]);
>+exit:
>+	return req;
>+}
>+
>+/**
>+ * hp_sw_pg_init - HP path activation implementation.
>+ * @hwh: hardware handler specific data
>+ * @bypassed:
>+ * @path: path to send initialization command
>+ *
>+ * For now, we blindly initialize the path and rely on the upper layers to
>+ * know whether the path is good or not (don't check the state before
>+ * sending the activation request - just send it and do a best-effort).
>+ * This should work fine for simple failover.  Worst case, we are sending
>+ * an extra START cmd on an already active path, but this should complete
>+ * quickly and not affect the HP.
>+ * One possible optimization would include some mechanism to detect an
>+ * already in flight START command on the same controller and avoid sending
>+ * another START in that case.
>+ *
>+ * Context: kmpathd (see process_queued_ios() in dm-mpath.c)
>+ */
>+static void hp_sw_pg_init(struct hw_handler *hwh, unsigned bypassed,
>+			  struct dm_path *path)
>+{
>+	struct request *req;
>+	struct hp_sw_context *h;
>+	unsigned err_flags;
>+
>+	path->hwhcontext = hwh->context;
>+	h = (struct hp_sw_context *) hwh->context;
>+
>+	req = hp_sw_get_request(path);
>+	if (!req) {
>+		/* XXX - Remove this log message? */
>+		DMERR("hp_sw: could not allocate request for START_STOP");
>+		goto fail;
>+	}
>+
>+	/* XXX - Remove this log message? */
>+	DMINFO("hp_sw: queueing START_STOP command on %s",
>+	       path->dev->name);
>+
>+	elv_add_request(req->q, req, ELEVATOR_INSERT_FRONT, 1);
>+	return;
>+
>+ fail:
>+	err_flags = MP_FAIL_PATH;
>+	dm_pg_init_complete(path, err_flags);
>+}
>+
>+static int hp_sw_create(struct hw_handler *hwh, unsigned argc, char **argv)
>+{
>+	struct hp_sw_context *h;
>+
>+	h = kmalloc(sizeof(*h), GFP_KERNEL);
>+	if (!h)
>+		return -ENOMEM;
>+	hwh->context = h;
>+	return 0;
>+}
>+
>+static void hp_sw_destroy(struct hw_handler *hwh)
>+{
>+	struct hp_sw_context *h = hwh->context;
>+
>+	kfree(h);
>+	hwh->context = NULL;
>+}
>+
>+static struct hw_handler_type hp_sw_hwh = {
>+	.name = "hp_sw",
>+	.module = THIS_MODULE,
>+	.create = hp_sw_create,
>+	.destroy = hp_sw_destroy,
>+	.pg_init = hp_sw_pg_init,
>+};
>+
>+static int __init hp_sw_init(void)
>+{
>+	int r;
>+
>+	if (hp_sw_cmd_timeout < MIN_CMD_TIMEOUT)
>+		hp_sw_cmd_timeout = MIN_CMD_TIMEOUT;
>+
>+	r = dm_register_hw_handler(&hp_sw_hwh);
>+	if (r < 0)
>+		DMERR("hp_sw: register failed %d", r);
>+
>+	DMINFO("hp_sw version 0.977 loaded");
>+
>+	return r;
>+}
>+
>+static void __exit hp_sw_exit(void)
>+{
>+	int r;
>+
>+	/* FIXME: what about outstanding pg_inits? */
>+
>+	r = dm_unregister_hw_handler(&hp_sw_hwh);
>+	if (r < 0)
>+		DMERR("hp_sw: unregister failed %d", r);
>+}
>+
>+module_init(hp_sw_init);
>+module_exit(hp_sw_exit);
>+
>+MODULE_DESCRIPTION("HP StorageWorks and FSC FibreCat (A/P) support for dm-multipath");
>+MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>");
>+MODULE_LICENSE("GPL");
>Index: linux-2.6.22-rc1/drivers/md/Kconfig
>===================================================================
>--- linux-2.6.22-rc1.orig/drivers/md/Kconfig
>+++ linux-2.6.22-rc1/drivers/md/Kconfig
>@@ -271,6 +271,12 @@ config DM_DELAY
> 
> 	If unsure, say N.
> 
>+config DM_MULTIPATH_HP
>+        tristate "HP MSA multipath support (EXPERIMENTAL)"
>+        depends on DM_MULTIPATH && BLK_DEV_DM && EXPERIMENTAL
>+        ---help---
>+          Multipath support for HP MSA (Active/Passive) series hardware.
>+
> endmenu
> 
> endif

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Attachments on bug 195685: 131053 | 131073 | 131074 | 132388 | 140056 | 140721 | 140741 | 142204 | 142207 | 148162 | 148204 | 155210 | 292333 | 292553