* Re: [patch] usb: gadget: f_midi: unlock on error
2016-04-02 4:51 [patch] usb: gadget: f_midi: unlock on error Dan Carpenter
@ 2016-04-04 9:43 ` Felipe Ferreri Tonello
2016-04-04 12:11 ` Michal Nazarewicz
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Felipe Ferreri Tonello @ 2016-04-04 9:43 UTC (permalink / raw)
To: kernel-janitors
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Hi Dan,
On 02/04/16 05:51, Dan Carpenter wrote:
> We added some new locking here, but missed an error path where we need
> to unlock.
>
> Fixes: 9acdf4df2fc4 ('usb: gadget: f_midi: added spinlock on transmit function')
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Felipe F. Tonello <eu@felipetonello.com>
>
> diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
> index 56e2dde..2c0616c 100644
> --- a/drivers/usb/gadget/function/f_midi.c
> +++ b/drivers/usb/gadget/function/f_midi.c
> @@ -609,8 +609,10 @@ static void f_midi_transmit(struct f_midi *midi)
>
> do {
> ret = f_midi_do_transmit(midi, ep);
> - if (ret < 0)
> + if (ret < 0) {
> + spin_unlock_irqrestore(&midi->transmit_lock, flags);
> goto drop_out;
> + }
> } while (ret);
>
> spin_unlock_irqrestore(&midi->transmit_lock, flags);
>
--
Felipe
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [patch] usb: gadget: f_midi: unlock on error
2016-04-02 4:51 [patch] usb: gadget: f_midi: unlock on error Dan Carpenter
2016-04-04 9:43 ` Felipe Ferreri Tonello
@ 2016-04-04 12:11 ` Michal Nazarewicz
2016-04-04 12:18 ` Felipe Balbi
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Michal Nazarewicz @ 2016-04-04 12:11 UTC (permalink / raw)
To: kernel-janitors
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
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On Sat, Apr 02 2016, Dan Carpenter wrote:
> We added some new locking here, but missed an error path where we need
> to unlock.
>
> Fixes: 9acdf4df2fc4 ('usb: gadget: f_midi: added spinlock on transmit function')
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
But perhaps this would be cleaner:
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index 56e2dde..c04436f 100644
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -606,19 +606,14 @@ static void f_midi_transmit(struct f_midi *midi)
goto drop_out;
spin_lock_irqsave(&midi->transmit_lock, flags);
-
- do {
- ret = f_midi_do_transmit(midi, ep);
- if (ret < 0)
- goto drop_out;
- } while (ret);
-
+ while ((ret = f_midi_do_transmit(midi, ep)) > 0) {
+ /* nop */
+ }
spin_unlock_irqrestore(&midi->transmit_lock, flags);
- return;
-
+ if (ret < 0)
drop_out:
- f_midi_drop_out_substreams(midi);
+ f_midi_drop_out_substreams(midi);
}
static void f_midi_in_tasklet(unsigned long data)
Or maybe even this which gets away with gotos all together:
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index 56e2dde..91cae60 100644
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -598,27 +598,20 @@ done:
static void f_midi_transmit(struct f_midi *midi)
{
struct usb_ep *ep = midi->in_ep;
- int ret;
unsigned long flags;
+ int ret = -1;
/* We only care about USB requests if IN endpoint is enabled */
- if (!ep || !ep->enabled)
- goto drop_out;
-
- spin_lock_irqsave(&midi->transmit_lock, flags);
-
- do {
- ret = f_midi_do_transmit(midi, ep);
- if (ret < 0)
- goto drop_out;
- } while (ret);
-
- spin_unlock_irqrestore(&midi->transmit_lock, flags);
-
- return;
+ if (ep && ep->enabled) {
+ spin_lock_irqsave(&midi->transmit_lock, flags);
+ while ((ret = f_midi_do_transmit(midi, ep)) > 0) {
+ /* nop */
+ }
+ spin_unlock_irqrestore(&midi->transmit_lock, flags);
+ }
-drop_out:
- f_midi_drop_out_substreams(midi);
+ if (ret < 0)
+ f_midi_drop_out_substreams(midi);
}
static void f_midi_in_tasklet(unsigned long data)
> diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
> index 56e2dde..2c0616c 100644
> --- a/drivers/usb/gadget/function/f_midi.c
> +++ b/drivers/usb/gadget/function/f_midi.c
> @@ -609,8 +609,10 @@ static void f_midi_transmit(struct f_midi *midi)
>
> do {
> ret = f_midi_do_transmit(midi, ep);
> - if (ret < 0)
> + if (ret < 0) {
> + spin_unlock_irqrestore(&midi->transmit_lock, flags);
> goto drop_out;
> + }
> } while (ret);
>
> spin_unlock_irqrestore(&midi->transmit_lock, flags);
--
Best regards
ミハウ “𝓶𝓲𝓷𝓪86” ナザレヴイツ
«If at first you don’t succeed, give up skydiving»
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^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [patch] usb: gadget: f_midi: unlock on error
2016-04-02 4:51 [patch] usb: gadget: f_midi: unlock on error Dan Carpenter
2016-04-04 9:43 ` Felipe Ferreri Tonello
2016-04-04 12:11 ` Michal Nazarewicz
@ 2016-04-04 12:18 ` Felipe Balbi
2016-04-04 13:22 ` Felipe Ferreri Tonello
2016-04-04 19:25 ` Michal Nazarewicz
4 siblings, 0 replies; 6+ messages in thread
From: Felipe Balbi @ 2016-04-04 12:18 UTC (permalink / raw)
To: kernel-janitors
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Michal Nazarewicz <mina86@mina86.com> writes:
> On Sat, Apr 02 2016, Dan Carpenter wrote:
>> We added some new locking here, but missed an error path where we need
>> to unlock.
>>
>> Fixes: 9acdf4df2fc4 ('usb: gadget: f_midi: added spinlock on transmit function')
>> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>>
>
> Acked-by: Michal Nazarewicz <mina86@mina86.com>
>
> But perhaps this would be cleaner:
both options below are not real fixes and, as such, as not subject to
the -rc cycle.
thanks
--
balbi
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [patch] usb: gadget: f_midi: unlock on error
2016-04-02 4:51 [patch] usb: gadget: f_midi: unlock on error Dan Carpenter
` (2 preceding siblings ...)
2016-04-04 12:18 ` Felipe Balbi
@ 2016-04-04 13:22 ` Felipe Ferreri Tonello
2016-04-04 19:25 ` Michal Nazarewicz
4 siblings, 0 replies; 6+ messages in thread
From: Felipe Ferreri Tonello @ 2016-04-04 13:22 UTC (permalink / raw)
To: kernel-janitors
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Hi Michal,
On 04/04/16 13:11, Michal Nazarewicz wrote:
> On Sat, Apr 02 2016, Dan Carpenter wrote:
>> We added some new locking here, but missed an error path where we need
>> to unlock.
>>
>> Fixes: 9acdf4df2fc4 ('usb: gadget: f_midi: added spinlock on transmit function')
>> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>>
>
> Acked-by: Michal Nazarewicz <mina86@mina86.com>
>
> But perhaps this would be cleaner:
>
> diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
> index 56e2dde..c04436f 100644
> --- a/drivers/usb/gadget/function/f_midi.c
> +++ b/drivers/usb/gadget/function/f_midi.c
> @@ -606,19 +606,14 @@ static void f_midi_transmit(struct f_midi *midi)
> goto drop_out;
>
> spin_lock_irqsave(&midi->transmit_lock, flags);
> -
> - do {
> - ret = f_midi_do_transmit(midi, ep);
> - if (ret < 0)
> - goto drop_out;
> - } while (ret);
> -
> + while ((ret = f_midi_do_transmit(midi, ep)) > 0) {
> + /* nop */
> + }
> spin_unlock_irqrestore(&midi->transmit_lock, flags);
>
> - return;
> -
> + if (ret < 0)
> drop_out:
> - f_midi_drop_out_substreams(midi);
> + f_midi_drop_out_substreams(midi);
> }
>
> static void f_midi_in_tasklet(unsigned long data)
>
> Or maybe even this which gets away with gotos all together:
>
> diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
> index 56e2dde..91cae60 100644
> --- a/drivers/usb/gadget/function/f_midi.c
> +++ b/drivers/usb/gadget/function/f_midi.c
> @@ -598,27 +598,20 @@ done:
> static void f_midi_transmit(struct f_midi *midi)
> {
> struct usb_ep *ep = midi->in_ep;
> - int ret;
> unsigned long flags;
> + int ret = -1;
>
> /* We only care about USB requests if IN endpoint is enabled */
> - if (!ep || !ep->enabled)
> - goto drop_out;
> -
> - spin_lock_irqsave(&midi->transmit_lock, flags);
> -
> - do {
> - ret = f_midi_do_transmit(midi, ep);
> - if (ret < 0)
> - goto drop_out;
> - } while (ret);
> -
> - spin_unlock_irqrestore(&midi->transmit_lock, flags);
> -
> - return;
> + if (ep && ep->enabled) {
> + spin_lock_irqsave(&midi->transmit_lock, flags);
> + while ((ret = f_midi_do_transmit(midi, ep)) > 0) {
> + /* nop */
> + }
> + spin_unlock_irqrestore(&midi->transmit_lock, flags);
> + }
>
> -drop_out:
> - f_midi_drop_out_substreams(midi);
> + if (ret < 0)
> + f_midi_drop_out_substreams(midi);
> }
>
> static void f_midi_in_tasklet(unsigned long data)
I am fine with these options, probably the second, but I don't think
they are any clearer than before, so I don't see any real benefits with
the changes.
In fact, I think f_midi_do_transmit should be documented, since there
are 3 possible return condition:
<0 breaks the loop and drop out substreams
0 breaks the loop
>0 continues the loop
>
>
>
>> diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
>> index 56e2dde..2c0616c 100644
>> --- a/drivers/usb/gadget/function/f_midi.c
>> +++ b/drivers/usb/gadget/function/f_midi.c
>> @@ -609,8 +609,10 @@ static void f_midi_transmit(struct f_midi *midi)
>>
>> do {
>> ret = f_midi_do_transmit(midi, ep);
>> - if (ret < 0)
>> + if (ret < 0) {
>> + spin_unlock_irqrestore(&midi->transmit_lock, flags);
>> goto drop_out;
>> + }
>> } while (ret);
>>
>> spin_unlock_irqrestore(&midi->transmit_lock, flags);
>
--
Felipe
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [patch] usb: gadget: f_midi: unlock on error
2016-04-02 4:51 [patch] usb: gadget: f_midi: unlock on error Dan Carpenter
` (3 preceding siblings ...)
2016-04-04 13:22 ` Felipe Ferreri Tonello
@ 2016-04-04 19:25 ` Michal Nazarewicz
4 siblings, 0 replies; 6+ messages in thread
From: Michal Nazarewicz @ 2016-04-04 19:25 UTC (permalink / raw)
To: kernel-janitors
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="windows-1254", Size: 2469 bytes --]
> On 04/04/16 13:11, Michal Nazarewicz wrote:
>> Or maybe even this which gets away with gotos all together:
>>
>> diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
>> index 56e2dde..91cae60 100644
>> --- a/drivers/usb/gadget/function/f_midi.c
>> +++ b/drivers/usb/gadget/function/f_midi.c
>> @@ -598,27 +598,20 @@ done:
>> static void f_midi_transmit(struct f_midi *midi)
>> {
>> struct usb_ep *ep = midi->in_ep;
>> - int ret;
>> unsigned long flags;
>> + int ret = -1;
>>
>> /* We only care about USB requests if IN endpoint is enabled */
>> - if (!ep || !ep->enabled)
>> - goto drop_out;
>> -
>> - spin_lock_irqsave(&midi->transmit_lock, flags);
>> -
>> - do {
>> - ret = f_midi_do_transmit(midi, ep);
>> - if (ret < 0)
>> - goto drop_out;
>> - } while (ret);
>> -
>> - spin_unlock_irqrestore(&midi->transmit_lock, flags);
>> -
>> - return;
>> + if (ep && ep->enabled) {
>> + spin_lock_irqsave(&midi->transmit_lock, flags);
>> + while ((ret = f_midi_do_transmit(midi, ep)) > 0) {
>> + /* nop */
>> + }
>> + spin_unlock_irqrestore(&midi->transmit_lock, flags);
>> + }
>>
>> -drop_out:
>> - f_midi_drop_out_substreams(midi);
>> + if (ret < 0)
>> + f_midi_drop_out_substreams(midi);
>> }
>>
>> static void f_midi_in_tasklet(unsigned long data)
On Mon, Apr 04 2016, Felipe Ferreri Tonello wrote:
> I am fine with these options, probably the second, but I don't think
> they are any clearer than before, so I don't see any real benefits with
> the changes.
The spin_lock_irqsave is paired with exactly one spin_unlock_irqrestore
which is cleaner in my book. I don’t have strong feelings about this
though.
> In fact, I think f_midi_do_transmit should be documented, since there
> are 3 possible return condition:
> <0 breaks the loop and drop out substreams
> 0 breaks the loop
> >0 continues the loop
That’s of course separate issue.
--
Best regards
ミハウ “𝓶𝓲𝓷𝓪86” ナザレヴイツ
«If at first you don’t succeed, give up skydiving»
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^ permalink raw reply [flat|nested] 6+ messages in thread