[PATCH] pcmcia: add error handling for pcmcia_enable_device

[PATCH] pcmcia: add error handling for pcmcia_enable_device

[Zhouyang Jia]

When pcmcia_enable_device fails, the lack of error-handling code may
cause unexpected results.

This patch adds error-handling code after calling pcmcia_enable_device.

Signed-off-by: Zhouyang Jia <jiazhouyang09@gmail.com>
---
 drivers/scsi/pcmcia/qlogic_stub.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/pcmcia/qlogic_stub.c b/drivers/scsi/pcmcia/qlogic_stub.c
index 0556054..9287d52 100644
--- a/drivers/scsi/pcmcia/qlogic_stub.c
+++ b/drivers/scsi/pcmcia/qlogic_stub.c
@@ -254,8 +254,14 @@ static void qlogic_release(struct pcmcia_device *link)
 static int qlogic_resume(struct pcmcia_device *link)
 {
 	scsi_info_t *info = link->priv;
+	int ret;
+
+	ret = pcmcia_enable_device(link);
+	if (ret) {
+		pcmcia_disable_device(link);
+		return -ENODEV;
+	}
 
-	pcmcia_enable_device(link);
 	if ((info->manf_id == MANFID_MACNICA) ||
 	    (info->manf_id == MANFID_PIONEER) ||
 	    (info->manf_id == 0x0098)) {
-- 
2.7.4

Re: [PATCH] pcmcia: add error handling for pcmcia_enable_device

[Johannes Thumshirn]

On Mon, Jun 11, 2018 at 01:15:50PM +0800, Zhouyang Jia wrote:
> When pcmcia_enable_device fails, the lack of error-handling code may
> cause unexpected results.
> 
> This patch adds error-handling code after calling pcmcia_enable_device.
> 
> Signed-off-by: Zhouyang Jia <jiazhouyang09@gmail.com>
> ---
>  drivers/scsi/pcmcia/qlogic_stub.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/pcmcia/qlogic_stub.c b/drivers/scsi/pcmcia/qlogic_stub.c
> index 0556054..9287d52 100644
> --- a/drivers/scsi/pcmcia/qlogic_stub.c
> +++ b/drivers/scsi/pcmcia/qlogic_stub.c
> @@ -254,8 +254,14 @@ static void qlogic_release(struct pcmcia_device *link)
>  static int qlogic_resume(struct pcmcia_device *link)
>  {
>  	scsi_info_t *info = link->priv;
> +	int ret;
> +
> +	ret = pcmcia_enable_device(link);
> +	if (ret) {
> +		pcmcia_disable_device(link);
> +		return -ENODEV;
> +	}

pcmcia_enable_device() can fail for three reasons:
1) the socket is not present
2) the configuration is locked
3) setting the socket's power control fails

In all three cases I think it's actually an error to call
pcmcia_disable_device().

Imagine the following scenario:
pcmcia_enable_device() failed because the device configuration is
locked by another driver, then you call pcmcia_disable_device() which
calls pcmcia_release_configuration(). pcmcia_release_configuration()
checks if the device is locked, decrements the lock counter, clears
the CONFIG_LOCKED bit in the PCMCIA config and sets the voltage to 0
without the first driver every noticing it.

Byte,
	Johannes
-- 
Johannes Thumshirn                                          Storage
jthumshirn@suse.de                                +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850

[PATCH v2] pcmcia: add error handling for pcmcia_enable_device

[Zhouyang Jia]

When pcmcia_enable_device fails, the lack of error-handling code may
cause unexpected results.

This patch adds error-handling code after calling pcmcia_enable_device.

Signed-off-by: Zhouyang Jia <jiazhouyang09@gmail.com>
---
v1->v2:
- Remove pcmcia_disable_device.
---
 drivers/scsi/pcmcia/qlogic_stub.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/pcmcia/qlogic_stub.c b/drivers/scsi/pcmcia/qlogic_stub.c
index 0556054..eb2c8bf 100644
--- a/drivers/scsi/pcmcia/qlogic_stub.c
+++ b/drivers/scsi/pcmcia/qlogic_stub.c
@@ -254,8 +254,12 @@ static void qlogic_release(struct pcmcia_device *link)
 static int qlogic_resume(struct pcmcia_device *link)
 {
 	scsi_info_t *info = link->priv;
+	int ret;
+
+	ret = pcmcia_enable_device(link);
+	if (ret)
+		return -ENODEV;
 
-	pcmcia_enable_device(link);
 	if ((info->manf_id == MANFID_MACNICA) ||
 	    (info->manf_id == MANFID_PIONEER) ||
 	    (info->manf_id == 0x0098)) {
-- 
2.7.4

Re: [PATCH v2] pcmcia: add error handling for pcmcia_enable_device

[Andy Shevchenko]

On Thu, Jun 14, 2018 at 12:23 PM, Zhouyang Jia <jiazhouyang09@gmail.com> wrote:
> When pcmcia_enable_device fails, the lack of error-handling code may
> cause unexpected results.

What results?
You need to elaborate this.,

> This patch adds error-handling code after calling pcmcia_enable_device.

> +       int ret;
> +
> +       ret = pcmcia_enable_device(link);
> +       if (ret)
> +               return -ENODEV;

And why not to return ret?

-- 
With Best Regards,
Andy Shevchenko

[PATCH v3] pcmcia: add error handling for pcmcia_enable_device

[Zhouyang Jia]

When pcmcia_enable_device fails, the lack of error-handling code may
cause unexpected results.

This patch adds error-handling code after calling pcmcia_enable_device.

Signed-off-by: Zhouyang Jia <jiazhouyang09@gmail.com>
---
v1->v2:
- Remove pcmcia_disable_device.
v2->v3:
- Change the return value.
---
 drivers/scsi/pcmcia/qlogic_stub.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/pcmcia/qlogic_stub.c b/drivers/scsi/pcmcia/qlogic_stub.c
index 0556054..9d5751a 100644
--- a/drivers/scsi/pcmcia/qlogic_stub.c
+++ b/drivers/scsi/pcmcia/qlogic_stub.c
@@ -254,8 +254,12 @@ static void qlogic_release(struct pcmcia_device *link)
 static int qlogic_resume(struct pcmcia_device *link)
 {
 	scsi_info_t *info = link->priv;
+	int ret;
+
+	ret = pcmcia_enable_device(link);
+	if (ret)
+		return ret;
 
-	pcmcia_enable_device(link);
 	if ((info->manf_id == MANFID_MACNICA) ||
 	    (info->manf_id == MANFID_PIONEER) ||
 	    (info->manf_id == 0x0098)) {
-- 
2.7.4