On Sun, Feb 17 2008 at 19:24 +0200, James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote:
> On Sun, 2008-02-17 at 18:46 +0200, Boaz Harrosh wrote:
>> On Thu, Feb 14 2008 at 20:47 +0200, Boaz Harrosh <bharrosh@xxxxxxxxxxx> wrote:
>>> Submitted are a new set of patches, that fix lots of problems
>>> with the gdth driver.
>>>
>>> It fixes the following problems:
>>> - scan for drives on hosts. (Already in mainline)
>>> - truly fixes the exit/reboot problems but does call flush() before
>>> reboot.
>>> - fix crash when accessing array with icpcon management application.
>>> - fix crash when doing $ cat /proc/sys/gdth/0.
>>> This one still has the below WARN_ON in messages (see <gdth_info> below)
>>> So there is one more thing hiding in there.
>>> - use pci_get_device
>>> One of the testers requested if we can also put the move to pci_get_device
>>> patch with removal of dependency on PCI_LEGACY, to the stable release.
>>>
>>> The patches are for and based on Linux-2.6.24. here is the list of patches:
>>> [PATCH 1/5] gdth: update deprecated pci_find_device
>>> [PATCH 2/5] gdth: scan for scsi devices
>>> [PATCH 3/5] gdth: bugfix for the at-exit problems
>>> [PATCH 4/5] gdth: fix to internal commands execution
>>> [PATCH 5/5] gdth: remove gdth cooked up command accessors
>>>
>>> Please all test and report your findings.
>>>
>>> Thanks in advance
>>> Boaz
>>>
>>> ---
>>> <gdth_info>
>>> WARNING: at arch/x86/kernel/pci-dma_32.c:66 dma_free_coherent()
>>> Pid: 5501, comm: cat Not tainted 2.6.24 #43
>>> [<c0107137>] dma_free_coherent+0x93/0x95
>>> [<c025ef73>] gdth_ioctl_free+0x4c/0x69
>>> [<c0264a36>] gdth_proc_info+0x165f/0x182c
>>> [<c0111f7a>] update_curr+0xeb/0xf2
>>> [<c01132aa>] task_rq_lock+0x29/0x50
>>> [<c0113706>] try_to_wake_up+0x42/0x342
>>> [<c0113706>] try_to_wake_up+0x42/0x342
>>> [<c0111a9f>] __wake_up_common+0x46/0x6d
>>> [<c0113569>] __wake_up+0x32/0x42
>>> [<c022dad9>] n_tty_receive_buf+0x2e8/0xe97
>>> [<c022dad9>] n_tty_receive_buf+0x2e8/0xe97
>>> [<c0111f0a>] update_curr+0x7b/0xf2
>>> [<c0112625>] enqueue_task_fair+0x27/0x30
>>> [<c0111783>] enqueue_task+0xa/0x14
>>> [<c025e351>] proc_scsi_read+0x29/0x3d
>>> [<c025e328>] proc_scsi_read+0x0/0x3d
>>> [<c0189704>] proc_file_read+0x1c6/0x279
>>> [<c018953e>] proc_file_read+0x0/0x279
>>> [<c0185eca>] proc_reg_read+0x53/0x71
>>> [<c0185e77>] proc_reg_read+0x0/0x71
>>> [<c0159968>] vfs_read+0x85/0x11b
>>> [<c0159d9d>] sys_read+0x41/0x6a
>>> [<c0102822>] sysenter_past_esp+0x5f/0x85
>>> </gdth_info>
>>> -
>> James hi.
>>
>> All my testers have reported back that with these 5 patches applied they can
>> now run with a 2.6.24 kernel the same way they ran before. However there is
>> that reported issue, with the dma_free_coherent WARN_ON (above). The code was
>> like that from day one and it is a very old issue, however it is a regression
>> because 2.6.24 introduced that new WARN_ON.
>> (infamous commit aa24886e379d2b641c5117e178b15ce1d5d366ba)
>> >From posts on lkml and even recent one in linux-scsi about the arcmsr driver
>> it looks that all a driver can do is work around it with different kernel mechanisms
>> and driver rewrites. I'm afraid I need your help here. I'm not sure I understand
>> why does the gdth driver uses the pci_{alloc,free}_consistent() API's, and what
>> is needed to replace it. Could you please have a look in gdth_proc.c and also in
>> gdth.c for all the places that call gdth_ioctl_alloc/gdth_ioctl_free, and advise
>> what can I do in it's place. Please bear in mind that we need it for 2.6.24, as
>> a bugfix.
>>
>> Apart from the above issue, please accept patches 3,4,5 above they have now
>> been tested and are reported to bring broken system back to production.
>> (Given that you approve off course). And mark them for inclusion to the
>> 2.6.24 stable releases. (Or is there some thing that I should do)
>>
>> ---
>> Meanwhile on x86 systems I understand the WARN_ON is cosmetic, and does not
>> pose any harm. Some people have reported stability with temporarily disabling
>> it. For testers that want to try, here it is below. At your own risk.
>
> Isn't this the correct fix? pscratch is a permanent address (it's
> allocated at boot time and never changes). All you need the smp lock
> for is mediating the scratch in use flag.
>
> James
>
> diff --git a/drivers/scsi/gdth_proc.c b/drivers/scsi/gdth_proc.c
> index de57734..ce0228e 100644
> --- a/drivers/scsi/gdth_proc.c
> +++ b/drivers/scsi/gdth_proc.c
> @@ -694,15 +694,13 @@ static void gdth_ioctl_free(gdth_ha_str *ha, int size, char *buf, ulong64 paddr)
> {
> ulong flags;
>
> - spin_lock_irqsave(&ha->smp_lock, flags);
> -
> if (buf == ha->pscratch) {
> + spin_lock_irqsave(&ha->smp_lock, flags);
> ha->scratch_busy = FALSE;
> + spin_unlock_irqrestore(&ha->smp_lock, flags);
> } else {
> pci_free_consistent(ha->pdev, size, buf, paddr);
> }
> -
> - spin_unlock_irqrestore(&ha->smp_lock, flags);
> }
>
> #ifdef GDTH_IOCTL_PROC
>
>
> -
James
You are bung on the money. It was tested and it works. So simple, I was
thinking it was accessed by DMA and freed at interrupt. But no, just a
simple lock like this.
So that's it then, all reported problems with gdth are now resolved. Please
Submit above together with the other patches.
Do I need to do anything else to get it into 2.6.24.x stable releases?
Thanks for everything
Boaz
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