Patchwork libata: remove dead code from libata-acpi.c

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Submitter Aaron Lu
Date June 20, 2013, 2:26 a.m.
Message ID <51C26861.9050106@intel.com>
Download mbox | patch
Permalink /patch/252703/
State Not Applicable
Delegated to: David Miller
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Comments

Aaron Lu - June 20, 2013, 2:26 a.m.
On 06/18/2013 05:16 PM, Aaron Lu wrote:
> On 06/18/2013 02:01 AM, Tejun Heo wrote:
>> On Mon, Jun 17, 2013 at 09:50:20AM +0800, Aaron Lu wrote:
>>> On 06/15/2013 11:02 AM, Liu Jiang wrote:
>>>> From: Liu Jiang <liu97@gmail.com>
>>>>
>>>> Commit 30dcf76acc69 "libata: migrate ACPI code over to new bindings"
>>>> removed ACPI dock notification related code, but there's some dead
>>>> code left, so clean up it.
>>>
>>> I never noticed this, but it looks to be the case...
>>>
>>> I'm not sure the dock notification code is removed intentionally or
>>> mistakenly though, if it is a mistake, then instead of removing the left
>>> code here, we probably should add the dock notification code back.
>>>
>>> But I have no test system or any knowledge about how ata dock works, so
>>> I may be wrong :-)
>>
>> Looks like a regression to me.  We're probably locking up on some
>> older laptops which connects optical drives with hotpluggable PATA.
>> Matthew, can you please fix it?
> 
> A user just reported a bug for this:
> https://bugzilla.kernel.org/show_bug.cgi?id=59871
> 
> And bisected to commit 30dcf76acc69. I proposed a fix patch there, let's
> see what the user's test result.

Patch below.

If it is true that the ATA dock is only for PATA devices, then I can
simply the code a little bit in that I can do the notification registration
in ATA port's binding time for both ATA port ACPI handle and ACPI handle
of ATA devices belonging to this port, since we will always create SCSI
host devices along with its corresponding ATA port, the binding for ATA
port will always occur no matter if there is devices attached or not.

Hi Dirk,
I made a small change in the following patch than the last one I posted
in bugzilla that you tested OK to mimic the original behavior in pre-3.6
kernels to install notification handler for ATA devices even when the ATA
port's handle is NULL, this can only happen in SATA case, so if the
above question is true, then this change will not be necessary.


Subject: [PATCH] libata-acpi: add back ACPI based hotplug functionality

Commit 30dcf76acc mistakenly dropped the code to register hotplug
notificaion handler for ATA port/devices, causing regression for people
using ATA bay, as bug #59871 shows.

Fix this by adding back the hotplug notification handler registration
code. Since this code has to be run once and notification needs to be
installed on every ATA port/devices handle no matter if there is actual
device attached, we can't do this in binding time for ATA device ACPI
handle, as the binding only occurs when a SCSI device is created, i.e.
there is device attached. So introduced the ata_acpi_hotplug_init
function to loop scan all ATA ACPI handles and if it is available,
install the notification handler for it during ATA init time.

With the ATA ACPI handle binding to SCSI device tree, it is possible now
that when the SCSI hotplug work removes the SCSI device, the ACPI unbind
function will find that the corresponding ACPI device has already been
deleted by dock driver, causing a scaring message like:
[  128.263966] scsi 4:0:0:0: Oops, 'acpi_handle' corrupt
Fix this by waiting for SCSI hotplug task finish in our notificaion
handler, so that the removal of ACPI device done in ACPI unbind function
triggered by the removal of SCSI device is run earlier when ACPI device
is still available.

References: https://bugzilla.kernel.org/show_bug.cgi?id=59871
Reported-and-bisected-by: Dirk Griesbach <spamthis@freenet.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
---
 drivers/ata/libata-acpi.c | 34 +++++++++++++++++++++++++++++++++-
 drivers/ata/libata-core.c |  2 ++
 drivers/ata/libata.h      |  2 ++
 3 files changed, 37 insertions(+), 1 deletion(-)
Sergei Shtylyov - June 20, 2013, 11:02 a.m.
Hello.

On 20-06-2013 6:26, Aaron Lu wrote:

>>>>> From: Liu Jiang <liu97@gmail.com>
>>>>>
>>>>> Commit 30dcf76acc69 "libata: migrate ACPI code over to new bindings"
>>>>> removed ACPI dock notification related code, but there's some dead
>>>>> code left, so clean up it.

[...]

> Subject: [PATCH] libata-acpi: add back ACPI based hotplug functionality

> Commit 30dcf76acc mistakenly dropped the code to register hotplug

    Please specify the summary line for this commit, the same as was 
done by Liu above (may use parens instead of quotes).

> notificaion handler for ATA port/devices, causing regression for people
> using ATA bay, as bug #59871 shows.

> Fix this by adding back the hotplug notification handler registration
> code. Since this code has to be run once and notification needs to be
> installed on every ATA port/devices handle no matter if there is actual
> device attached, we can't do this in binding time for ATA device ACPI
> handle, as the binding only occurs when a SCSI device is created, i.e.
> there is device attached. So introduced the ata_acpi_hotplug_init
> function to loop scan all ATA ACPI handles and if it is available,
> install the notification handler for it during ATA init time.

> With the ATA ACPI handle binding to SCSI device tree, it is possible now
> that when the SCSI hotplug work removes the SCSI device, the ACPI unbind
> function will find that the corresponding ACPI device has already been
> deleted by dock driver, causing a scaring message like:
> [  128.263966] scsi 4:0:0:0: Oops, 'acpi_handle' corrupt
> Fix this by waiting for SCSI hotplug task finish in our notificaion
> handler, so that the removal of ACPI device done in ACPI unbind function
> triggered by the removal of SCSI device is run earlier when ACPI device
> is still available.

> References: https://bugzilla.kernel.org/show_bug.cgi?id=59871
> Reported-and-bisected-by: Dirk Griesbach <spamthis@freenet.de>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Aaron Lu <aaron.lu@intel.com>
> ---
>   drivers/ata/libata-acpi.c | 34 +++++++++++++++++++++++++++++++++-
>   drivers/ata/libata-core.c |  2 ++
>   drivers/ata/libata.h      |  2 ++
>   3 files changed, 37 insertions(+), 1 deletion(-)

> diff --git a/drivers/ata/libata-acpi.c b/drivers/ata/libata-acpi.c
> index 87f2f39..0ad54bb 100644
> --- a/drivers/ata/libata-acpi.c
> +++ b/drivers/ata/libata-acpi.c
[...]
> @@ -214,6 +216,36 @@ static const struct acpi_dock_ops ata_acpi_ap_dock_ops = {
>   	.uevent = ata_acpi_ap_uevent,
>   };
>
> +void ata_acpi_hotplug_init(struct ata_host *host)
> +{
> +	int i;
> +
> +	for (i = 0; i < host->n_ports; i++) {
> +		struct ata_port *ap = host->ports[i];
> +		acpi_handle handle;
> +		struct ata_device *dev;
> +
> +		if (!ap)
> +			continue;
> +
> +		handle = ata_ap_acpi_handle(ap);
> +		if (handle) {
> +			/* we might be on a docking station */
> +			register_hotplug_dock_device(handle,
> +					&ata_acpi_ap_dock_ops, ap);

    Please indent this line under the next character after ( above.

> +		}
> +
> +		ata_for_each_dev(dev, &ap->link, ALL) {
> +			handle = ata_dev_acpi_handle(dev);
> +			if (handle) {
> +				/* we might be on a docking station */
> +				register_hotplug_dock_device(handle,
> +						&ata_acpi_dev_dock_ops, dev);

    Same comment.

WBR, Sergei

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Aaron Lu - June 21, 2013, 12:55 a.m.
On 06/20/2013 07:02 PM, Sergei Shtylyov wrote:
> Hello.

Hi,

Thanks for your comments.

> 
> On 20-06-2013 6:26, Aaron Lu wrote:
>>
>> +void ata_acpi_hotplug_init(struct ata_host *host)
>> +{
>> +	int i;
>> +
>> +	for (i = 0; i < host->n_ports; i++) {
>> +		struct ata_port *ap = host->ports[i];
>> +		acpi_handle handle;
>> +		struct ata_device *dev;
>> +
>> +		if (!ap)
>> +			continue;
>> +
>> +		handle = ata_ap_acpi_handle(ap);
>> +		if (handle) {
>> +			/* we might be on a docking station */
>> +			register_hotplug_dock_device(handle,
>> +					&ata_acpi_ap_dock_ops, ap);
> 
>     Please indent this line under the next character after ( above.

Is there a link about this rule? I might have missed something about
coding style.

Thanks,
Aaron

> 
>> +		}
>> +
>> +		ata_for_each_dev(dev, &ap->link, ALL) {
>> +			handle = ata_dev_acpi_handle(dev);
>> +			if (handle) {
>> +				/* we might be on a docking station */
>> +				register_hotplug_dock_device(handle,
>> +						&ata_acpi_dev_dock_ops, dev);
> 
>     Same comment.
> 
> WBR, Sergei
> 
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Tejun Heo - June 21, 2013, 6:29 a.m.
Hello,

On Fri, Jun 21, 2013 at 08:55:37AM +0800, Aaron Lu wrote:
> >     Please indent this line under the next character after ( above.
> 
> Is there a link about this rule? I might have missed something about
> coding style.

I don't think there's an explicit rule about that and I don't follow
it religiously but I think it does make things easier on the eyes and
emacs does that by default so I just got used to it.  It's a very
minor thing but FWIW I prefer things that way.

Thanks.
Aaron Lu - June 21, 2013, 6:48 a.m.
On 06/21/2013 02:29 PM, Tejun Heo wrote:
> Hello,
> 
> On Fri, Jun 21, 2013 at 08:55:37AM +0800, Aaron Lu wrote:
>>>     Please indent this line under the next character after ( above.
>>
>> Is there a link about this rule? I might have missed something about
>> coding style.
> 
> I don't think there's an explicit rule about that and I don't follow
> it religiously but I think it does make things easier on the eyes and
> emacs does that by default so I just got used to it.  It's a very
> minor thing but FWIW I prefer things that way.

OK, will refresh the patch and send out again.

Thanks,
Aaron
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Sergei Shtylyov - June 21, 2013, 11:35 a.m.
Hello.

On 21-06-2013 4:55, Aaron Lu wrote:

>>> +void ata_acpi_hotplug_init(struct ata_host *host)
>>> +{
>>> +	int i;
>>> +
>>> +	for (i = 0; i < host->n_ports; i++) {
>>> +		struct ata_port *ap = host->ports[i];
>>> +		acpi_handle handle;
>>> +		struct ata_device *dev;
>>> +
>>> +		if (!ap)
>>> +			continue;
>>> +
>>> +		handle = ata_ap_acpi_handle(ap);
>>> +		if (handle) {
>>> +			/* we might be on a docking station */
>>> +			register_hotplug_dock_device(handle,
>>> +					&ata_acpi_ap_dock_ops, ap);

>>      Please indent this line under the next character after ( above.

> Is there a link about this rule? I might have missed something about
> coding style.

    Don't think so. This is a rule in some subsystems like networking, 
and it's also the way Emacs does such things. So, in principle, you can 
ignore my comment (although libata seems to also use this style).

WBR, Sergei

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James Bottomley - June 21, 2013, 3:25 p.m.
On Fri, 2013-06-21 at 08:55 +0800, Aaron Lu wrote:
> On 06/20/2013 07:02 PM, Sergei Shtylyov wrote:
> > Hello.
> 
> Hi,
> 
> Thanks for your comments.
> 
> > 
> > On 20-06-2013 6:26, Aaron Lu wrote:
> >>
> >> +void ata_acpi_hotplug_init(struct ata_host *host)
> >> +{
> >> +	int i;
> >> +
> >> +	for (i = 0; i < host->n_ports; i++) {
> >> +		struct ata_port *ap = host->ports[i];
> >> +		acpi_handle handle;
> >> +		struct ata_device *dev;
> >> +
> >> +		if (!ap)
> >> +			continue;
> >> +
> >> +		handle = ata_ap_acpi_handle(ap);
> >> +		if (handle) {
> >> +			/* we might be on a docking station */
> >> +			register_hotplug_dock_device(handle,
> >> +					&ata_acpi_ap_dock_ops, ap);
> > 
> >     Please indent this line under the next character after ( above.
> 
> Is there a link about this rule? I might have missed something about
> coding style.

The rule is follow the coding style in the file, unless there's
something really wrong with it (which there might be in the case of
really old drivers).  The reason is that a mixture of coding styles
makes the file much harder to read than a single consistent style.

In this case, if you look at libata-acpi.c you see all continuation
lines of function calls are aligned with open braces.

James


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Aaron Lu - June 26, 2013, 2:01 a.m.
On 06/21/2013 11:25 PM, James Bottomley wrote:
> On Fri, 2013-06-21 at 08:55 +0800, Aaron Lu wrote:
>> On 06/20/2013 07:02 PM, Sergei Shtylyov wrote:
>>> Hello.
>>
>> Hi,
>>
>> Thanks for your comments.
>>
>>>
>>> On 20-06-2013 6:26, Aaron Lu wrote:
>>>>
>>>> +void ata_acpi_hotplug_init(struct ata_host *host)
>>>> +{
>>>> +	int i;
>>>> +
>>>> +	for (i = 0; i < host->n_ports; i++) {
>>>> +		struct ata_port *ap = host->ports[i];
>>>> +		acpi_handle handle;
>>>> +		struct ata_device *dev;
>>>> +
>>>> +		if (!ap)
>>>> +			continue;
>>>> +
>>>> +		handle = ata_ap_acpi_handle(ap);
>>>> +		if (handle) {
>>>> +			/* we might be on a docking station */
>>>> +			register_hotplug_dock_device(handle,
>>>> +					&ata_acpi_ap_dock_ops, ap);
>>>
>>>     Please indent this line under the next character after ( above.
>>
>> Is there a link about this rule? I might have missed something about
>> coding style.
> 
> The rule is follow the coding style in the file, unless there's
> something really wrong with it (which there might be in the case of
> really old drivers).  The reason is that a mixture of coding styles
> makes the file much harder to read than a single consistent style.

Oh right, that's the rule I missed. Thanks for letting me know.

> 
> In this case, if you look at libata-acpi.c you see all continuation
> lines of function calls are aligned with open braces.

Indeed.

-Aaron
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Aaron Lu - June 26, 2013, 6:27 a.m.
On 06/21/2013 07:35 PM, Sergei Shtylyov wrote:
> Hello.
> 
> On 21-06-2013 4:55, Aaron Lu wrote:
> 
>>>> +void ata_acpi_hotplug_init(struct ata_host *host)
>>>> +{
>>>> +	int i;
>>>> +
>>>> +	for (i = 0; i < host->n_ports; i++) {
>>>> +		struct ata_port *ap = host->ports[i];
>>>> +		acpi_handle handle;
>>>> +		struct ata_device *dev;
>>>> +
>>>> +		if (!ap)
>>>> +			continue;
>>>> +
>>>> +		handle = ata_ap_acpi_handle(ap);
>>>> +		if (handle) {
>>>> +			/* we might be on a docking station */
>>>> +			register_hotplug_dock_device(handle,
>>>> +					&ata_acpi_ap_dock_ops, ap);
> 
>>>      Please indent this line under the next character after ( above.
> 
>> Is there a link about this rule? I might have missed something about
>> coding style.
> 
>     Don't think so. This is a rule in some subsystems like networking, 
> and it's also the way Emacs does such things. So, in principle, you can 
> ignore my comment (although libata seems to also use this style).

FYI, the updated patch has been sent by Rafael for me:
http://marc.info/?l=linux-acpi&m=137207724507019&w=2
with your suggestion taken.

Thanks,
Aaron
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Patch

diff --git a/drivers/ata/libata-acpi.c b/drivers/ata/libata-acpi.c
index 87f2f39..0ad54bb 100644
--- a/drivers/ata/libata-acpi.c
+++ b/drivers/ata/libata-acpi.c
@@ -156,8 +156,10 @@  static void ata_acpi_handle_hotplug(struct ata_port *ap, struct ata_device *dev,
 
 	spin_unlock_irqrestore(ap->lock, flags);
 
-	if (wait)
+	if (wait) {
 		ata_port_wait_eh(ap);
+		flush_work(&ap->hotplug_task.work);
+	}
 }
 
 static void ata_acpi_dev_notify_dock(acpi_handle handle, u32 event, void *data)
@@ -214,6 +216,36 @@  static const struct acpi_dock_ops ata_acpi_ap_dock_ops = {
 	.uevent = ata_acpi_ap_uevent,
 };
 
+void ata_acpi_hotplug_init(struct ata_host *host)
+{
+	int i;
+
+	for (i = 0; i < host->n_ports; i++) {
+		struct ata_port *ap = host->ports[i];
+		acpi_handle handle;
+		struct ata_device *dev;
+
+		if (!ap)
+			continue;
+
+		handle = ata_ap_acpi_handle(ap);
+		if (handle) {
+			/* we might be on a docking station */
+			register_hotplug_dock_device(handle,
+					&ata_acpi_ap_dock_ops, ap);
+		}
+
+		ata_for_each_dev(dev, &ap->link, ALL) {
+			handle = ata_dev_acpi_handle(dev);
+			if (handle) {
+				/* we might be on a docking station */
+				register_hotplug_dock_device(handle,
+						&ata_acpi_dev_dock_ops, dev);
+			}
+		}
+	}
+}
+
 /**
  * ata_acpi_dissociate - dissociate ATA host from ACPI objects
  * @host: target ATA host
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index f218427..adf002a 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -6148,6 +6148,8 @@  int ata_host_register(struct ata_host *host, struct scsi_host_template *sht)
 	if (rc)
 		goto err_tadd;
 
+	ata_acpi_hotplug_init(host);
+
 	/* set cable, sata_spd_limit and report */
 	for (i = 0; i < host->n_ports; i++) {
 		struct ata_port *ap = host->ports[i];
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index c949dd3..577d902b 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -122,6 +122,7 @@  extern int ata_acpi_register(void);
 extern void ata_acpi_unregister(void);
 extern void ata_acpi_bind(struct ata_device *dev);
 extern void ata_acpi_unbind(struct ata_device *dev);
+extern void ata_acpi_hotplug_init(struct ata_host *host);
 #else
 static inline void ata_acpi_dissociate(struct ata_host *host) { }
 static inline int ata_acpi_on_suspend(struct ata_port *ap) { return 0; }
@@ -134,6 +135,7 @@  static inline int ata_acpi_register(void) { return 0; }
 static inline void ata_acpi_unregister(void) { }
 static inline void ata_acpi_bind(struct ata_device *dev) { }
 static inline void ata_acpi_unbind(struct ata_device *dev) { }
+static inline void ata_acpi_hotplug_init(struct ata_host *host) {}
 #endif
 
 /* libata-scsi.c */