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Re: [PATCH v2 1/5] usb: xhci: Disable slot even virt-dev is null

Started byMathias Nyman <mathias.nyman@linux.intel.com>
First post2017-08-09 10:00 +0200
Last post2017-08-11 03:20 +0200
Articles 4 — 2 participants

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  Re: [PATCH v2 1/5] usb: xhci: Disable slot even virt-dev is null Mathias Nyman <mathias.nyman@linux.intel.com> - 2017-08-09 10:00 +0200
    Re: [PATCH v2 1/5] usb: xhci: Disable slot even virt-dev is null Lu Baolu <baolu.lu@linux.intel.com> - 2017-08-10 02:40 +0200
      Re: [PATCH v2 1/5] usb: xhci: Disable slot even virt-dev is null Mathias Nyman <mathias.nyman@linux.intel.com> - 2017-08-10 12:00 +0200
        Re: [PATCH v2 1/5] usb: xhci: Disable slot even virt-dev is null Lu Baolu <baolu.lu@linux.intel.com> - 2017-08-11 03:20 +0200

#1707113 — Re: [PATCH v2 1/5] usb: xhci: Disable slot even virt-dev is null

FromMathias Nyman <mathias.nyman@linux.intel.com>
Date2017-08-09 10:00 +0200
SubjectRe: [PATCH v2 1/5] usb: xhci: Disable slot even virt-dev is null
Message-ID<ucu4h-44e-1@gated-at.bofh.it>
On 27.07.2017 05:21, Lu Baolu wrote:
> xhci_disable_slot() is a helper for disabling a slot when a device
> goes away or recovers from error situations. Currently, it checks
> the corespoding virt-dev pointer and returns directly (w/o issuing
> disable slot command) if it's null.
>
> This is unnecessary and will cause problems in case where virt-dev
> allocation fails and xhci_disable_slot() is called to roll back the
> hardware state. Refer to the implementation of xhci_alloc_dev().
>

True, checking for xhci->devs[slot_id] doesn't work if xhci_alloc_dev()
failed xhci_alloc_virt_device() and calls xhci_disable_slot,

but the virt dev check is needed for test mode, which will just try
to disable all slots from 1 to HCS_MAX_SLOTS:

  xhci_enter_test_mode(..)
        /* Disable all Device Slots */
	for (i = 1; i <= HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
                 retval = xhci_disable_slot(xhci, NULL, i);



> This patch removes lines to check virt-dev in xhci_disable_slot().
>
> Fixes: f9e609b82479 ("usb: xhci: Add helper function xhci_disable_slot().")
> Cc: Guoqing Zhang <guoqing.zhang@intel.com>
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> ---
>   drivers/usb/host/xhci.c | 4 ----
>   1 file changed, 4 deletions(-)
>
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index b2ff1ff..e69073f 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -3567,11 +3567,7 @@ int xhci_disable_slot(struct xhci_hcd *xhci, struct xhci_command *command,
>   	unsigned long flags;
>   	u32 state;
>   	int ret = 0;
> -	struct xhci_virt_device *virt_dev;
>
> -	virt_dev = xhci->devs[slot_id];
> -	if (!virt_dev)
> -		return -EINVAL;
>   	if (!command)
>   		command = xhci_alloc_command(xhci, false, false, GFP_KERNEL);
>   	if (!command)
>

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#1708101

FromLu Baolu <baolu.lu@linux.intel.com>
Date2017-08-10 02:40 +0200
Message-ID<ucJG1-6yK-11@gated-at.bofh.it>
In reply to#1707113
Hi,

On 08/09/2017 03:58 PM, Mathias Nyman wrote:
> On 27.07.2017 05:21, Lu Baolu wrote:
>> xhci_disable_slot() is a helper for disabling a slot when a device
>> goes away or recovers from error situations. Currently, it checks
>> the corespoding virt-dev pointer and returns directly (w/o issuing
>> disable slot command) if it's null.
>>
>> This is unnecessary and will cause problems in case where virt-dev
>> allocation fails and xhci_disable_slot() is called to roll back the
>> hardware state. Refer to the implementation of xhci_alloc_dev().
>>
>
> True, checking for xhci->devs[slot_id] doesn't work if xhci_alloc_dev()
> failed xhci_alloc_virt_device() and calls xhci_disable_slot,
>
> but the virt dev check is needed for test mode, which will just try
> to disable all slots from 1 to HCS_MAX_SLOTS:
>
>  xhci_enter_test_mode(..)
>        /* Disable all Device Slots */
>     for (i = 1; i <= HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
>                 retval = xhci_disable_slot(xhci, NULL, i);
>
>

So, how about checking virt dev before this invoking?

@@ -612,10 +612,12 @@ static int xhci_enter_test_mode(struct xhci_hcd *xhci,
        xhci_dbg(xhci, "Disable all slots\n");
        spin_unlock_irqrestore(&xhci->lock, *flags);
        for (i = 1; i <= HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
-               retval = xhci_disable_slot(xhci, NULL, i);
-               if (retval)
-                       xhci_err(xhci, "Failed to disable slot %d, %d. Enter test mode anyway\n",
-                                i, retval);
+               if (xhci->devs[i]) {
+                       retval = xhci_disable_slot(xhci, NULL, i);
+                       if (retval)
+                               xhci_err(xhci, "Failed to disable slot %d, %d. Enter test mode anyway\n",
+                                        i, retval);
+               }
        }
        spin_lock_irqsave(&xhci->lock, *flags);
        /* Put all ports to the Disable state by clear PP */

Best regards,
Lu Baolu

>
>> This patch removes lines to check virt-dev in xhci_disable_slot().
>>
>> Fixes: f9e609b82479 ("usb: xhci: Add helper function xhci_disable_slot().")
>> Cc: Guoqing Zhang <guoqing.zhang@intel.com>
>> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>> ---
>>   drivers/usb/host/xhci.c | 4 ----
>>   1 file changed, 4 deletions(-)
>>
>> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
>> index b2ff1ff..e69073f 100644
>> --- a/drivers/usb/host/xhci.c
>> +++ b/drivers/usb/host/xhci.c
>> @@ -3567,11 +3567,7 @@ int xhci_disable_slot(struct xhci_hcd *xhci, struct xhci_command *command,
>>       unsigned long flags;
>>       u32 state;
>>       int ret = 0;
>> -    struct xhci_virt_device *virt_dev;
>>
>> -    virt_dev = xhci->devs[slot_id];
>> -    if (!virt_dev)
>> -        return -EINVAL;
>>       if (!command)
>>           command = xhci_alloc_command(xhci, false, false, GFP_KERNEL);
>>       if (!command)
>>
>
> -- 
> To unsubscribe from this list: send the line "unsubscribe linux-usb" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

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#1708384

FromMathias Nyman <mathias.nyman@linux.intel.com>
Date2017-08-10 12:00 +0200
Message-ID<ucSpY-3Sk-5@gated-at.bofh.it>
In reply to#1708101
On 10.08.2017 03:35, Lu Baolu wrote:
> Hi,
>
> On 08/09/2017 03:58 PM, Mathias Nyman wrote:
>> On 27.07.2017 05:21, Lu Baolu wrote:
>>> xhci_disable_slot() is a helper for disabling a slot when a device
>>> goes away or recovers from error situations. Currently, it checks
>>> the corespoding virt-dev pointer and returns directly (w/o issuing
>>> disable slot command) if it's null.
>>>
>>> This is unnecessary and will cause problems in case where virt-dev
>>> allocation fails and xhci_disable_slot() is called to roll back the
>>> hardware state. Refer to the implementation of xhci_alloc_dev().
>>>
>>
>> True, checking for xhci->devs[slot_id] doesn't work if xhci_alloc_dev()
>> failed xhci_alloc_virt_device() and calls xhci_disable_slot,
>>
>> but the virt dev check is needed for test mode, which will just try
>> to disable all slots from 1 to HCS_MAX_SLOTS:
>>
>>   xhci_enter_test_mode(..)
>>         /* Disable all Device Slots */
>>      for (i = 1; i <= HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
>>                  retval = xhci_disable_slot(xhci, NULL, i);
>>
>>
>
> So, how about checking virt dev before this invoking?
>
> @@ -612,10 +612,12 @@ static int xhci_enter_test_mode(struct xhci_hcd *xhci,
>          xhci_dbg(xhci, "Disable all slots\n");
>          spin_unlock_irqrestore(&xhci->lock, *flags);
>          for (i = 1; i <= HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
> -               retval = xhci_disable_slot(xhci, NULL, i);
> -               if (retval)
> -                       xhci_err(xhci, "Failed to disable slot %d, %d. Enter test mode anyway\n",
> -                                i, retval);
> +               if (xhci->devs[i]) {
> +                       retval = xhci_disable_slot(xhci, NULL, i);
> +                       if (retval)
> +                               xhci_err(xhci, "Failed to disable slot %d, %d. Enter test mode anyway\n",
> +                                        i, retval);
> +               }


Yes, something like this will work

Thanks
Mathias

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#1709155

FromLu Baolu <baolu.lu@linux.intel.com>
Date2017-08-11 03:20 +0200
Message-ID<ud6Mh-5kY-9@gated-at.bofh.it>
In reply to#1708384
Hi,

On 08/10/2017 06:00 PM, Mathias Nyman wrote:
> On 10.08.2017 03:35, Lu Baolu wrote:
>> Hi,
>>
>> On 08/09/2017 03:58 PM, Mathias Nyman wrote:
>>> On 27.07.2017 05:21, Lu Baolu wrote:
>>>> xhci_disable_slot() is a helper for disabling a slot when a device
>>>> goes away or recovers from error situations. Currently, it checks
>>>> the corespoding virt-dev pointer and returns directly (w/o issuing
>>>> disable slot command) if it's null.
>>>>
>>>> This is unnecessary and will cause problems in case where virt-dev
>>>> allocation fails and xhci_disable_slot() is called to roll back the
>>>> hardware state. Refer to the implementation of xhci_alloc_dev().
>>>>
>>>
>>> True, checking for xhci->devs[slot_id] doesn't work if xhci_alloc_dev()
>>> failed xhci_alloc_virt_device() and calls xhci_disable_slot,
>>>
>>> but the virt dev check is needed for test mode, which will just try
>>> to disable all slots from 1 to HCS_MAX_SLOTS:
>>>
>>>   xhci_enter_test_mode(..)
>>>         /* Disable all Device Slots */
>>>      for (i = 1; i <= HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
>>>                  retval = xhci_disable_slot(xhci, NULL, i);
>>>
>>>
>>
>> So, how about checking virt dev before this invoking?
>>
>> @@ -612,10 +612,12 @@ static int xhci_enter_test_mode(struct xhci_hcd *xhci,
>>          xhci_dbg(xhci, "Disable all slots\n");
>>          spin_unlock_irqrestore(&xhci->lock, *flags);
>>          for (i = 1; i <= HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
>> -               retval = xhci_disable_slot(xhci, NULL, i);
>> -               if (retval)
>> -                       xhci_err(xhci, "Failed to disable slot %d, %d. Enter test mode anyway\n",
>> -                                i, retval);
>> +               if (xhci->devs[i]) {
>> +                       retval = xhci_disable_slot(xhci, NULL, i);
>> +                       if (retval)
>> +                               xhci_err(xhci, "Failed to disable slot %d, %d. Enter test mode anyway\n",
>> +                                        i, retval);
>> +               }
>
>
> Yes, something like this will work
>

Okay, I will submit a v3 to include this change.

Best regards,
Lu Baolu

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