[PATCH] s390 (2/4): common i/o layer.

From: Martin Schwidefsky
Date: Wed Jun 02 2004 - 06:02:30 EST

[PATCH] s390: common i/o layer.

From: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>

Common i/o layer changes:
- qdio: Lose the adapter lock for thin interrupts to improve performance
and do unregister of the adapter interrupt handler with rcu.
- ccwgroup: Fix error handling when creating a ccwgroup device.
- Convert the slow crw kernel thread to a single threaded workqueue.
- Use the slow crw workqueue to unregister a subchannel after it was
found not operational to serialize it with other possible unregister/
register events coming in via machine checks.
- Trigger a rescan of the css via the slow path if a missing channel path
is found in __recover_lost_chpids.
- Use saner default levels for the debug feature, add some debugging code.
- Remove request_irq and free_irq stubs.
- Remove bogus inlines.

diffstat:
drivers/s390/cio/airq.c | 38 +++++----------------
drivers/s390/cio/ccwgroup.c | 24 ++++++++-----
drivers/s390/cio/chsc.c | 39 +++++++++++----------
drivers/s390/cio/cio.c | 8 ++--
drivers/s390/cio/css.c | 75 +++++++++++++++++++++---------------------
drivers/s390/cio/css.h | 4 +-
drivers/s390/cio/device.c | 15 +++++---
drivers/s390/cio/device_fsm.c | 14 -------
drivers/s390/cio/requestirq.c | 17 ---------
drivers/s390/s390mach.c | 25 ++------------
10 files changed, 109 insertions(+), 150 deletions(-)

diff -urN linux-2.6/drivers/s390/cio/airq.c linux-2.6-s390/drivers/s390/cio/airq.c
--- linux-2.6/drivers/s390/cio/airq.c Mon May 10 04:33:10 2004
+++ linux-2.6-s390/drivers/s390/cio/airq.c Wed Jun 2 11:29:35 2004
@@ -2,7 +2,7 @@
* drivers/s390/cio/airq.c
* S/390 common I/O routines -- support for adapter interruptions
*
- * $Revision: 1.11 $
+ * $Revision: 1.12 $
*
* Copyright (C) 1999-2002 IBM Deutschland Entwicklung GmbH,
* IBM Corporation
@@ -14,11 +14,11 @@
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
+#include <linux/rcupdate.h>

#include "cio_debug.h"
#include "airq.h"

-static spinlock_t adapter_lock = SPIN_LOCK_UNLOCKED;
static adapter_int_handler_t adapter_handler;

/*
@@ -40,23 +40,17 @@

CIO_TRACE_EVENT (4, "rgaint");

- spin_lock (&adapter_lock);
-
if (handler == NULL)
ret = -EINVAL;
- else if (adapter_handler)
- ret = -EBUSY;
- else {
- adapter_handler = handler;
- ret = 0;
- }
-
- spin_unlock (&adapter_lock);
+ else
+ ret = (cmpxchg(&adapter_handler, NULL, handler) ? -EBUSY : 0);
+ if (!ret)
+ synchronize_kernel();

sprintf (dbf_txt, "ret:%d", ret);
CIO_TRACE_EVENT (4, dbf_txt);

- return (ret);
+ return ret;
}

int
@@ -67,38 +61,26 @@

CIO_TRACE_EVENT (4, "urgaint");

- spin_lock (&adapter_lock);
-
if (handler == NULL)
ret = -EINVAL;
- else if (handler != adapter_handler)
- ret = -EINVAL;
else {
adapter_handler = NULL;
+ synchronize_kernel();
ret = 0;
}
-
- spin_unlock (&adapter_lock);
-
sprintf (dbf_txt, "ret:%d", ret);
CIO_TRACE_EVENT (4, dbf_txt);

- return (ret);
+ return ret;
}

void
do_adapter_IO (void)
{
- CIO_TRACE_EVENT (4, "doaio");
-
- spin_lock (&adapter_lock);
+ CIO_TRACE_EVENT (6, "doaio");

if (adapter_handler)
(*adapter_handler) ();
-
- spin_unlock (&adapter_lock);
-
- return;
}

EXPORT_SYMBOL (s390_register_adapter_interrupt);
diff -urN linux-2.6/drivers/s390/cio/ccwgroup.c linux-2.6-s390/drivers/s390/cio/ccwgroup.c
--- linux-2.6/drivers/s390/cio/ccwgroup.c Mon May 10 04:32:38 2004
+++ linux-2.6-s390/drivers/s390/cio/ccwgroup.c Wed Jun 2 11:29:35 2004
@@ -1,7 +1,7 @@
/*
* drivers/s390/cio/ccwgroup.c
* bus driver for ccwgroup
- * $Revision: 1.27 $
+ * $Revision: 1.28 $
*
* Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
* IBM Corporation
@@ -179,12 +179,12 @@
|| gdev->cdev[i]->id.driver_info !=
gdev->cdev[0]->id.driver_info) {
rc = -EINVAL;
- goto error;
+ goto free_dev;
}
/* Don't allow a device to belong to more than one group. */
if (gdev->cdev[i]->dev.driver_data) {
rc = -EINVAL;
- goto error;
+ goto free_dev;
}
}
for (i = 0; i < argc; i++)
@@ -207,8 +207,8 @@
rc = device_register(&gdev->dev);

if (rc)
- goto error;
-
+ goto free_dev;
+ get_device(&gdev->dev);
rc = device_create_file(&gdev->dev, &dev_attr_ungroup);

if (rc) {
@@ -217,20 +217,28 @@
}

rc = __ccwgroup_create_symlinks(gdev);
- if (!rc)
+ if (!rc) {
+ put_device(&gdev->dev);
return 0;
-
+ }
device_remove_file(&gdev->dev, &dev_attr_ungroup);
device_unregister(&gdev->dev);
error:
for (i = 0; i < argc; i++)
if (gdev->cdev[i]) {
put_device(&gdev->cdev[i]->dev);
+ gdev->cdev[i]->dev.driver_data = NULL;
+ }
+ put_device(&gdev->dev);
+ return rc;
+free_dev:
+ for (i = 0; i < argc; i++)
+ if (gdev->cdev[i]) {
+ put_device(&gdev->cdev[i]->dev);
if (del_drvdata)
gdev->cdev[i]->dev.driver_data = NULL;
}
kfree(gdev);
-
return rc;
}

diff -urN linux-2.6/drivers/s390/cio/chsc.c linux-2.6-s390/drivers/s390/cio/chsc.c
--- linux-2.6/drivers/s390/cio/chsc.c Mon May 10 04:32:38 2004
+++ linux-2.6-s390/drivers/s390/cio/chsc.c Wed Jun 2 11:29:35 2004
@@ -1,7 +1,7 @@
/*
* drivers/s390/cio/chsc.c
* S/390 common I/O routines -- channel subsystem call
- * $Revision: 1.110 $
+ * $Revision: 1.111 $
*
* Copyright (C) 1999-2002 IBM Deutschland Entwicklung GmbH,
* IBM Corporation
@@ -62,11 +62,11 @@
int state;

state = get_chp_status(chp);
- if (state < 0)
- new_channel_path(chp);
- else
+ if (state < 0) {
+ need_rescan = 1;
+ queue_work(slow_path_wq, &slow_path_work);
+ } else
WARN_ON(!state);
- /* FIXME: should notify other subchannels here */
}

/* FIXME: this is _always_ called for every subchannel. shouldn't we
@@ -285,8 +285,10 @@
out_unreg:
spin_unlock(&sch->lock);
sch->lpm = 0;
- /* We can't block here. */
- device_call_nopath_notify(sch);
+ if (css_enqueue_subchannel_slow(sch->irq)) {
+ css_clear_subchannel_slow_list();
+ need_rescan = 1;
+ }
return 0;
}

@@ -303,6 +305,9 @@

bus_for_each_dev(&css_bus_type, NULL, &chpid,
s390_subchannel_remove_chpid);
+
+ if (need_rescan || css_slow_subchannels_exist())
+ queue_work(slow_path_wq, &slow_path_work);
}

static int
@@ -737,10 +742,12 @@
* can successfully terminate, even using the
* just varied off path. Then kill it.
*/
- if (!__check_for_io_and_kill(sch, chp) && !sch->lpm)
- /* Get over with it now. */
- device_call_nopath_notify(sch);
- else if (sch->driver && sch->driver->verify)
+ if (!__check_for_io_and_kill(sch, chp) && !sch->lpm) {
+ if (css_enqueue_subchannel_slow(sch->irq)) {
+ css_clear_subchannel_slow_list();
+ need_rescan = 1;
+ }
+ } else if (sch->driver && sch->driver->verify)
sch->driver->verify(&sch->dev);
}
break;
@@ -773,11 +780,6 @@
return 0;
}

-extern void css_trigger_slow_path(void);
-typedef void (*workfunc)(void *);
-static DECLARE_WORK(varyonoff_work, (workfunc)css_trigger_slow_path,
- NULL);
-
/*
* Function: s390_vary_chpid
* Varies the specified chpid online or offline
@@ -813,7 +815,7 @@
s390_subchannel_vary_chpid_on :
s390_subchannel_vary_chpid_off);
if (!on)
- return 0;
+ goto out;
/* Scan for new devices on varied on path. */
for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
struct schib schib;
@@ -835,8 +837,9 @@
need_rescan = 1;
}
}
+out:
if (need_rescan || css_slow_subchannels_exist())
- schedule_work(&varyonoff_work);
+ queue_work(slow_path_wq, &slow_path_work);
return 0;
}

diff -urN linux-2.6/drivers/s390/cio/cio.c linux-2.6-s390/drivers/s390/cio/cio.c
--- linux-2.6/drivers/s390/cio/cio.c Mon May 10 04:33:21 2004
+++ linux-2.6-s390/drivers/s390/cio/cio.c Wed Jun 2 11:29:35 2004
@@ -1,7 +1,7 @@
/*
* drivers/s390/cio/cio.c
* S/390 common I/O routines -- low level i/o calls
- * $Revision: 1.121 $
+ * $Revision: 1.123 $
*
* Copyright (C) 1999-2002 IBM Deutschland Entwicklung GmbH,
* IBM Corporation
@@ -67,17 +67,17 @@
if (!cio_debug_msg_id)
goto out_unregister;
debug_register_view (cio_debug_msg_id, &debug_sprintf_view);
- debug_set_level (cio_debug_msg_id, 6);
+ debug_set_level (cio_debug_msg_id, 2);
cio_debug_trace_id = debug_register ("cio_trace", 4, 4, 8);
if (!cio_debug_trace_id)
goto out_unregister;
debug_register_view (cio_debug_trace_id, &debug_hex_ascii_view);
- debug_set_level (cio_debug_trace_id, 6);
+ debug_set_level (cio_debug_trace_id, 2);
cio_debug_crw_id = debug_register ("cio_crw", 2, 4, 16*sizeof (long));
if (!cio_debug_crw_id)
goto out_unregister;
debug_register_view (cio_debug_crw_id, &debug_sprintf_view);
- debug_set_level (cio_debug_crw_id, 6);
+ debug_set_level (cio_debug_crw_id, 2);
pr_debug("debugging initialized\n");
return 0;

diff -urN linux-2.6/drivers/s390/cio/css.c linux-2.6-s390/drivers/s390/cio/css.c
--- linux-2.6/drivers/s390/cio/css.c Wed Jun 2 11:29:04 2004
+++ linux-2.6-s390/drivers/s390/cio/css.c Wed Jun 2 11:29:35 2004
@@ -1,7 +1,7 @@
/*
* drivers/s390/cio/css.c
* driver for channel subsystem
- * $Revision: 1.74 $
+ * $Revision: 1.77 $
*
* Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
* IBM Corporation
@@ -166,10 +166,12 @@
if (sch && sch->schib.pmcw.dnv &&
(schib.pmcw.dev != sch->schib.pmcw.dev))
return CIO_REVALIDATE;
+ if (sch && !sch->lpm)
+ return CIO_NO_PATH;
return CIO_OPER;
}

-static inline int
+static int
css_evaluate_subchannel(int irq, int slow)
{
int event, ret, disc;
@@ -188,7 +190,11 @@
return -EAGAIN; /* Will be done on the slow path. */
}
event = css_get_subchannel_status(sch, irq);
+ CIO_MSG_EVENT(4, "Evaluating schid %04x, event %d, %s, %s path.\n",
+ irq, event, sch?(disc?"disconnected":"normal"):"unknown",
+ slow?"slow":"fast");
switch (event) {
+ case CIO_NO_PATH:
case CIO_GONE:
if (!sch) {
/* Never used this subchannel. Ignore. */
@@ -196,7 +202,8 @@
break;
}
if (sch->driver && sch->driver->notify &&
- sch->driver->notify(&sch->dev, CIO_GONE)) {
+ sch->driver->notify(&sch->dev, event)) {
+ cio_disable_subchannel(sch);
device_set_disconnected(sch);
ret = 0;
break;
@@ -205,6 +212,7 @@
* Unregister subchannel.
* The device will be killed automatically.
*/
+ cio_disable_subchannel(sch);
device_unregister(&sch->dev);
/* Reset intparm to zeroes. */
sch->schib.pmcw.intparm = 0;
@@ -266,23 +274,44 @@
}
}

-static void
-css_evaluate_slow_subchannel(unsigned long schid)
-{
- css_evaluate_subchannel(schid, 1);
-}
+struct slow_subchannel {
+ struct list_head slow_list;
+ unsigned long schid;
+};

-void
+static LIST_HEAD(slow_subchannels_head);
+static spinlock_t slow_subchannel_lock = SPIN_LOCK_UNLOCKED;
+
+static void
css_trigger_slow_path(void)
{
+ CIO_TRACE_EVENT(4, "slowpath");
+
if (need_rescan) {
need_rescan = 0;
css_rescan_devices();
return;
}
- css_walk_subchannel_slow_list(css_evaluate_slow_subchannel);
+
+ spin_lock_irq(&slow_subchannel_lock);
+ while (!list_empty(&slow_subchannels_head)) {
+ struct slow_subchannel *slow_sch =
+ list_entry(slow_subchannels_head.next,
+ struct slow_subchannel, slow_list);
+
+ list_del_init(slow_subchannels_head.next);
+ spin_unlock_irq(&slow_subchannel_lock);
+ css_evaluate_subchannel(slow_sch->schid, 1);
+ spin_lock_irq(&slow_subchannel_lock);
+ kfree(slow_sch);
+ }
+ spin_unlock_irq(&slow_subchannel_lock);
}

+typedef void (*workfunc)(void *);
+DECLARE_WORK(slow_path_work, (workfunc)css_trigger_slow_path, NULL);
+struct workqueue_struct *slow_path_wq;
+
/*
* Rescan for new devices. FIXME: This is slow.
* This function is called when we have lost CRWs due to overflows and we have
@@ -443,14 +472,6 @@
device_unregister(dev);
}

-struct slow_subchannel {
- struct list_head slow_list;
- unsigned long schid;
-};
-
-static LIST_HEAD(slow_subchannels_head);
-static spinlock_t slow_subchannel_lock = SPIN_LOCK_UNLOCKED;
-
int
css_enqueue_subchannel_slow(unsigned long schid)
{
@@ -484,25 +505,7 @@
spin_unlock_irqrestore(&slow_subchannel_lock, flags);
}

-void
-css_walk_subchannel_slow_list(void (*fn)(unsigned long))
-{
- unsigned long flags;

- spin_lock_irqsave(&slow_subchannel_lock, flags);
- while (!list_empty(&slow_subchannels_head)) {
- struct slow_subchannel *slow_sch =
- list_entry(slow_subchannels_head.next,
- struct slow_subchannel, slow_list);
-
- list_del_init(slow_subchannels_head.next);
- spin_unlock_irqrestore(&slow_subchannel_lock, flags);
- fn(slow_sch->schid);
- spin_lock_irqsave(&slow_subchannel_lock, flags);
- kfree(slow_sch);
- }
- spin_unlock_irqrestore(&slow_subchannel_lock, flags);
-}

int
css_slow_subchannels_exist(void)
diff -urN linux-2.6/drivers/s390/cio/css.h linux-2.6-s390/drivers/s390/cio/css.h
--- linux-2.6/drivers/s390/cio/css.h Mon May 10 04:33:22 2004
+++ linux-2.6-s390/drivers/s390/cio/css.h Wed Jun 2 11:29:35 2004
@@ -136,7 +136,6 @@

/* Helper functions for vary on/off. */
void device_set_waiting(struct subchannel *);
-void device_call_nopath_notify(struct subchannel *);

/* Helper functions to build lists for the slow path. */
int css_enqueue_subchannel_slow(unsigned long schid);
@@ -144,4 +143,7 @@
void css_clear_subchannel_slow_list(void);
int css_slow_subchannels_exist(void);
extern int need_rescan;
+
+extern struct workqueue_struct *slow_path_wq;
+extern struct work_struct slow_path_work;
#endif
diff -urN linux-2.6/drivers/s390/cio/device.c linux-2.6-s390/drivers/s390/cio/device.c
--- linux-2.6/drivers/s390/cio/device.c Wed Jun 2 11:29:04 2004
+++ linux-2.6-s390/drivers/s390/cio/device.c Wed Jun 2 11:29:35 2004
@@ -1,7 +1,7 @@
/*
* drivers/s390/cio/device.c
* bus driver for ccw devices
- * $Revision: 1.117 $
+ * $Revision: 1.119 $
*
* Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
* IBM Corporation
@@ -159,6 +159,11 @@
ret = -ENOMEM; /* FIXME: better errno ? */
goto out_err;
}
+ slow_path_wq = create_singlethread_workqueue("kslowcrw");
+ if (!slow_path_wq) {
+ ret = -ENOMEM; /* FIXME: better errno ? */
+ goto out_err;
+ }
if ((ret = bus_register (&ccw_bus_type)))
goto out_err;

@@ -174,6 +179,8 @@
destroy_workqueue(ccw_device_work);
if (ccw_device_notify_work)
destroy_workqueue(ccw_device_notify_work);
+ if (slow_path_wq)
+ destroy_workqueue(slow_path_wq);
return ret;
}

@@ -646,9 +653,7 @@
struct subchannel *sch;

sch = to_subchannel(cdev->dev.parent);
- /* Check if device is registered. */
- if (!list_empty(&sch->dev.node))
- device_unregister(&sch->dev);
+ device_unregister(&sch->dev);
/* Reset intparm to zeroes. */
sch->schib.pmcw.intparm = 0;
cio_modify(sch);
@@ -677,7 +682,7 @@
sch = to_subchannel(cdev->dev.parent);
INIT_WORK(&cdev->private->kick_work,
ccw_device_call_sch_unregister, (void *) cdev);
- queue_work(ccw_device_work, &cdev->private->kick_work);
+ queue_work(slow_path_wq, &cdev->private->kick_work);
break;
case DEV_STATE_BOXED:
/* Device did not respond in time. */
diff -urN linux-2.6/drivers/s390/cio/device_fsm.c linux-2.6-s390/drivers/s390/cio/device_fsm.c
--- linux-2.6/drivers/s390/cio/device_fsm.c Wed Jun 2 11:29:04 2004
+++ linux-2.6-s390/drivers/s390/cio/device_fsm.c Wed Jun 2 11:29:35 2004
@@ -459,20 +459,6 @@
}

void
-device_call_nopath_notify(struct subchannel *sch)
-{
- struct ccw_device *cdev;
-
- if (!sch->dev.driver_data)
- return;
- cdev = sch->dev.driver_data;
- PREPARE_WORK(&cdev->private->kick_work,
- ccw_device_nopath_notify, (void *)cdev);
- queue_work(ccw_device_notify_work, &cdev->private->kick_work);
-}
-
-
-void
ccw_device_verify_done(struct ccw_device *cdev, int err)
{
cdev->private->flags.doverify = 0;
diff -urN linux-2.6/drivers/s390/cio/requestirq.c linux-2.6-s390/drivers/s390/cio/requestirq.c
--- linux-2.6/drivers/s390/cio/requestirq.c Mon May 10 04:32:54 2004
+++ linux-2.6-s390/drivers/s390/cio/requestirq.c Wed Jun 2 11:29:35 2004
@@ -1,7 +1,7 @@
/*
* drivers/s390/cio/requestirq.c
* S/390 common I/O routines -- enabling and disabling of devices
- * $Revision: 1.45 $
+ * $Revision: 1.46 $
*
* Copyright (C) 1999-2002 IBM Deutschland Entwicklung GmbH,
* IBM Corporation
@@ -18,21 +18,6 @@

#include "css.h"

-/* for compatiblity only... */
-int
-request_irq (unsigned int irq,
- void (*handler) (int, void *, struct pt_regs *),
- unsigned long irqflags, const char *devname, void *dev_id)
-{
- return -EINVAL;
-}
-
-/* for compatiblity only... */
-void
-free_irq (unsigned int irq, void *dev_id)
-{
-}
-
struct pgid global_pgid;
EXPORT_SYMBOL_GPL(global_pgid);

diff -urN linux-2.6/drivers/s390/s390mach.c linux-2.6-s390/drivers/s390/s390mach.c
--- linux-2.6/drivers/s390/s390mach.c Mon May 10 04:33:21 2004
+++ linux-2.6-s390/drivers/s390/s390mach.c Wed Jun 2 11:29:35 2004
@@ -12,6 +12,7 @@
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/errno.h>
+#include <linux/workqueue.h>

#include <asm/lowcore.h>

@@ -21,13 +22,14 @@
// #define DBG(args,...) do {} while (0);

static struct semaphore m_sem;
-static struct semaphore s_sem;

extern int css_process_crw(int);
extern int chsc_process_crw(void);
extern int chp_process_crw(int, int);
extern void css_reiterate_subchannels(void);
-extern void css_trigger_slow_path(void);
+
+extern struct workqueue_struct *slow_path_wq;
+extern struct work_struct slow_path_work;

static void
s390_handle_damage(char *msg)
@@ -39,21 +41,6 @@
disabled_wait((unsigned long) __builtin_return_address(0));
}

-static int
-s390_mchk_slow_path(void *param)
-{
- struct semaphore *sem;
-
- sem = (struct semaphore *)param;
- /* Set a nice name. */
- daemonize("kslowcrw");
-repeat:
- down_interruptible(sem);
- css_trigger_slow_path();
- goto repeat;
- return 0;
-}
-
/*
* Retrieve CRWs and call function to handle event.
*
@@ -130,7 +117,7 @@
}
}
if (slow)
- up(&s_sem);
+ queue_work(slow_path_wq, &slow_path_work);
goto repeat;
return 0;
}
@@ -202,7 +189,6 @@
machine_check_init(void)
{
init_MUTEX_LOCKED(&m_sem);
- init_MUTEX_LOCKED( &s_sem );
ctl_clear_bit(14, 25); /* disable damage MCH */
ctl_set_bit(14, 26); /* enable degradation MCH */
ctl_set_bit(14, 27); /* enable system recovery MCH */
@@ -226,7 +212,6 @@
machine_check_crw_init (void)
{
kernel_thread(s390_collect_crw_info, &m_sem, CLONE_FS|CLONE_FILES);
- kernel_thread(s390_mchk_slow_path, &s_sem, CLONE_FS|CLONE_FILES);
ctl_set_bit(14, 28); /* enable channel report MCH */
return 0;
}
-
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