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Message-ID: <47B324E7.9040502@panasas.com>
Date: Wed, 13 Feb 2008 19:12:07 +0200
From: Boaz Harrosh <bharrosh@...asas.com>
To: James Bottomley <James.Bottomley@...senPartnership.com>
CC: Sven Köhler <skoehler@....de>,
Christoph Hellwig <hch@...radead.org>,
Jeff Garzik <jeff@...zik.org>,
linux-scsi <linux-scsi@...r.kernel.org>,
linux-kernel@...r.kernel.org, Joerg Dorchain <joerg@...chain.net>,
Jon Chelton <jchelton@...global.com>,
Stefan Priebe - allied internet ag
<s.priebe@...ied-internet.ag>
Subject: Re: [BUGFIX 2/2] gdth: bugfix for the Timer at exit crash
On Wed, Feb 13 2008 at 19:03 +0200, James Bottomley <James.Bottomley@...senPartnership.com> wrote:
> On Wed, 2008-02-13 at 18:50 +0200, Boaz Harrosh wrote:
>> On Wed, Feb 13 2008 at 18:45 +0200, James Bottomley <James.Bottomley@...senPartnership.com> wrote:
>>> On Wed, 2008-02-13 at 18:33 +0200, Boaz Harrosh wrote:
>>>> On Wed, Feb 13 2008 at 17:54 +0200, Boaz Harrosh <bharrosh@...asas.com> wrote:
>>>>> On Wed, Feb 13 2008 at 17:44 +0200, James Bottomley <James.Bottomley@...senPartnership.com> wrote:
>>>>>> On Tue, 2008-02-12 at 19:40 +0200, Boaz Harrosh wrote:
>>>>>>> - gdth_flush(ha);
>>>>>>> -
>>>>>> This piece doesn't look right. gdth_flush() forces the internal cache
>>>>>> to disk backing. If you remove it, you're taking the chance that the
>>>>>> machine will be powered off without a writeback which can cause data
>>>>>> corruption.
>>>>>>
>>>>>> James
>>>>>>
>>>>> Yes.
>>>>> I have more problems reported, with exit, and am just sending one more patch that puts
>>>>> this back in. Which was tested.
>>>>>
>>>>> So I will resend this one plus one new one.
>>>>>
>>>>> Boaz
>>>>>
>>>> The gdth driver would do a register_reboot_notifier(&gdth_notifier);
>>>> to a gdth_halt() function, which would then redo half of what gdth_exit
>>>> does, and wrongly so, and crash.
>>>>
>>>> Are we guaranteed in todays kernel that modules .exit function be called
>>>> on an halt or reboot? If so then there is no need for duplications and
>>>> the gdth_halt() should go.
>>> No. The __exit section is actually discardable if you promise never to
>>> remove the module.
>>>
>> I don't understand please explain.
>> What does a driver need to do if it needs a consistent shutdown retine?
>> module or built in? unload or shutdown?
>
> It needs to register a reboot notifier, which gdth does.
>
> However, the notifier is only called on reboot, so it also needs to
> clean up correctly on module exit as well.
>
> The alternative for GDTH would be to process the SCSI SYNCHRONIZE CACHE
> command. That's done by a shutdown notifier from sd, so the correct
> thing would always get done; however it does mean the driver has to be
> in a condition to process the last sync cache command.
>
> For the quick fix, just keep the current infrastructure and put back the
> gdth_flush() command where it can be effective.
>
> James
>
>
Totally untested.
---
From: Boaz Harrosh <bharrosh@...asas.com>
Subject: [PATCH] gdth: bugfix for the at-exit problems
gdth_exit would first remove all cards then stop the timer
and would not sync with the timer function. This caused a crash
in gdth_timer() when module was unloaded.
So del_timer_sync the timer before we delete the cards.
also the reboot notifier function would crash. So unify
the exit and halt functions with a gdth_shutdown() that's
called by both.
Signed-off-by: Boaz Harrosh <bharrosh@...asas.com>
---
drivers/scsi/gdth.c | 99 ++++++++++++++++++++------------------------------
1 files changed, 40 insertions(+), 59 deletions(-)
diff --git a/drivers/scsi/gdth.c b/drivers/scsi/gdth.c
index 8eb78be..7bb9b45 100644
--- a/drivers/scsi/gdth.c
+++ b/drivers/scsi/gdth.c
@@ -183,7 +183,6 @@ static int gdth_ioctl(struct inode *inode, struct file *filep,
unsigned int cmd, unsigned long arg);
static void gdth_flush(gdth_ha_str *ha);
-static int gdth_halt(struct notifier_block *nb, ulong event, void *buf);
static int gdth_queuecommand(Scsi_Cmnd *scp,void (*done)(Scsi_Cmnd *));
static int __gdth_queuecommand(gdth_ha_str *ha, struct scsi_cmnd *scp,
struct gdth_cmndinfo *cmndinfo);
@@ -418,12 +417,6 @@ static inline void gdth_set_sglist(struct scsi_cmnd *cmd,
#include "gdth_proc.h"
#include "gdth_proc.c"
-/* notifier block to get a notify on system shutdown/halt/reboot */
-static struct notifier_block gdth_notifier = {
- gdth_halt, NULL, 0
-};
-static int notifier_disabled = 0;
-
static gdth_ha_str *gdth_find_ha(int hanum)
{
gdth_ha_str *ha;
@@ -3793,6 +3786,8 @@ static void gdth_timeout(ulong data)
gdth_ha_str *ha;
ulong flags;
+ BUG_ON(list_empty(&gdth_instances));
+
ha = list_first_entry(&gdth_instances, gdth_ha_str, list);
spin_lock_irqsave(&ha->smp_lock, flags);
@@ -4668,45 +4663,6 @@ static void gdth_flush(gdth_ha_str *ha)
}
}
-/* shutdown routine */
-static int gdth_halt(struct notifier_block *nb, ulong event, void *buf)
-{
- gdth_ha_str *ha;
-#ifndef __alpha__
- gdth_cmd_str gdtcmd;
- char cmnd[MAX_COMMAND_SIZE];
-#endif
-
- if (notifier_disabled)
- return NOTIFY_OK;
-
- TRACE2(("gdth_halt() event %d\n",(int)event));
- if (event != SYS_RESTART && event != SYS_HALT && event != SYS_POWER_OFF)
- return NOTIFY_DONE;
-
- notifier_disabled = 1;
- printk("GDT-HA: Flushing all host drives .. ");
- list_for_each_entry(ha, &gdth_instances, list) {
- gdth_flush(ha);
-
-#ifndef __alpha__
- /* controller reset */
- memset(cmnd, 0xff, MAX_COMMAND_SIZE);
- gdtcmd.BoardNode = LOCALBOARD;
- gdtcmd.Service = CACHESERVICE;
- gdtcmd.OpCode = GDT_RESET;
- TRACE2(("gdth_halt(): reset controller %d\n", ha->hanum));
- gdth_execute(ha->shost, &gdtcmd, cmnd, 10, NULL);
-#endif
- }
- printk("Done.\n");
-
-#ifdef GDTH_STATISTICS
- del_timer(&gdth_timer);
-#endif
- return NOTIFY_OK;
-}
-
/* configure lun */
static int gdth_slave_configure(struct scsi_device *sdev)
{
@@ -5141,13 +5097,13 @@ static void gdth_remove_one(gdth_ha_str *ha)
scsi_remove_host(shp);
+ gdth_flush(ha);
+
if (ha->sdev) {
scsi_free_host_dev(ha->sdev);
ha->sdev = NULL;
}
- gdth_flush(ha);
-
if (shp->irq)
free_irq(shp->irq,ha);
@@ -5173,6 +5129,40 @@ static void gdth_remove_one(gdth_ha_str *ha)
scsi_host_put(shp);
}
+static void gdth_shutdown(void);
+static int gdth_halt(struct notifier_block *nb, ulong event, void *buf)
+{
+ TRACE2(("gdth_halt() event %d\n",(int)event));
+ if (event != SYS_RESTART && event != SYS_HALT && event != SYS_POWER_OFF)
+ return NOTIFY_DONE;
+
+ gdth_shutdown();
+ return NOTIFY_OK;
+}
+
+static struct notifier_block gdth_notifier = {
+ gdth_halt, NULL, 0
+};
+
+bool gdth_shutdown_done;
+static void gdth_shutdown()
+{
+ gdth_ha_str *ha;
+ if (gdth_shutdown_done)
+ return;
+
+ gdth_shutdown_done = true;
+ unregister_chrdev(major,"gdth");
+ unregister_reboot_notifier(&gdth_notifier);
+
+#ifdef GDTH_STATISTICS
+ del_timer_sync(&gdth_timer);
+#endif
+
+ list_for_each_entry(ha, &gdth_instances, list)
+ gdth_remove_one(ha);
+}
+
static int __init gdth_init(void)
{
if (disable) {
@@ -5185,6 +5175,7 @@ static int __init gdth_init(void)
GDTH_VERSION_STR);
/* initializations */
+ gdth_shutdown_done = false;
gdth_polling = TRUE;
gdth_clear_events();
@@ -5235,7 +5226,6 @@ static int __init gdth_init(void)
add_timer(&gdth_timer);
#endif
major = register_chrdev(0,"gdth", &gdth_fops);
- notifier_disabled = 0;
register_reboot_notifier(&gdth_notifier);
gdth_polling = FALSE;
return 0;
@@ -5243,16 +5233,7 @@ static int __init gdth_init(void)
static void __exit gdth_exit(void)
{
- gdth_ha_str *ha;
-
- list_for_each_entry(ha, &gdth_instances, list)
- gdth_remove_one(ha);
-
-#ifdef GDTH_STATISTICS
- del_timer(&gdth_timer);
-#endif
- unregister_chrdev(major,"gdth");
- unregister_reboot_notifier(&gdth_notifier);
+ gdth_shutdown();
}
module_init(gdth_init);
--
1.5.3.3
--
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