* [PATCH] ALSA: firewire-lib: Fix 'amdtp_domain_start()' when no AMDTP_OUT_STREAM stream is found
@ 2021-06-24 18:49 Christophe JAILLET
2021-06-24 21:05 ` Takashi Sakamoto
2021-06-25 7:38 ` Takashi Iwai
0 siblings, 2 replies; 4+ messages in thread
From: Christophe JAILLET @ 2021-06-24 18:49 UTC (permalink / raw)
To: clemens, o-takashi, perex, tiwai
Cc: alsa-devel, linux-kernel, kernel-janitors, Christophe JAILLET
The intent here is to return an error code if we don't find what we are
looking for in the 'list_for_each_entry()' loop.
's' is not NULL if the list is empty or if we scan the complete list.
Introduce a new 'found' variable to handle such cases.
Fixes: 60dd49298ec5 ("ALSA: firewire-lib: handle several AMDTP streams in callback handler of IRQ target")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
We could test with" if (list_entry_is_head(s, &d->streams, list))"
instead, but I find it much less readable.
---
sound/firewire/amdtp-stream.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c
index aad9778d1c4d..9be2260e4ca2 100644
--- a/sound/firewire/amdtp-stream.c
+++ b/sound/firewire/amdtp-stream.c
@@ -1943,6 +1943,7 @@ int amdtp_domain_start(struct amdtp_domain *d, unsigned int tx_init_skip_cycles,
unsigned int events_per_period = d->events_per_period;
unsigned int queue_size;
struct amdtp_stream *s;
+ bool found = false;
int err;
if (replay_seq) {
@@ -1955,10 +1956,12 @@ int amdtp_domain_start(struct amdtp_domain *d, unsigned int tx_init_skip_cycles,
// Select an IT context as IRQ target.
list_for_each_entry(s, &d->streams, list) {
- if (s->direction == AMDTP_OUT_STREAM)
+ if (s->direction == AMDTP_OUT_STREAM) {
+ found = true;
break;
+ }
}
- if (!s)
+ if (!found)
return -ENXIO;
d->irq_target = s;
--
2.30.2
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] ALSA: firewire-lib: Fix 'amdtp_domain_start()' when no AMDTP_OUT_STREAM stream is found
2021-06-24 18:49 [PATCH] ALSA: firewire-lib: Fix 'amdtp_domain_start()' when no AMDTP_OUT_STREAM stream is found Christophe JAILLET
@ 2021-06-24 21:05 ` Takashi Sakamoto
2021-06-25 9:05 ` Dan Carpenter
2021-06-25 7:38 ` Takashi Iwai
1 sibling, 1 reply; 4+ messages in thread
From: Takashi Sakamoto @ 2021-06-24 21:05 UTC (permalink / raw)
To: Christophe JAILLET
Cc: clemens, perex, tiwai, alsa-devel, linux-kernel, kernel-janitors
Hi,
On Thu, Jun 24, 2021 at 08:49:36PM +0200, Christophe JAILLET wrote:
> The intent here is to return an error code if we don't find what we are
> looking for in the 'list_for_each_entry()' loop.
>
> 's' is not NULL if the list is empty or if we scan the complete list.
> Introduce a new 'found' variable to handle such cases.
>
> Fixes: 60dd49298ec5 ("ALSA: firewire-lib: handle several AMDTP streams in callback handler of IRQ target")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
> We could test with" if (list_entry_is_head(s, &d->streams, list))"
> instead, but I find it much less readable.
> ---
> sound/firewire/amdtp-stream.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c
> index aad9778d1c4d..9be2260e4ca2 100644
> --- a/sound/firewire/amdtp-stream.c
> +++ b/sound/firewire/amdtp-stream.c
> @@ -1943,6 +1943,7 @@ int amdtp_domain_start(struct amdtp_domain *d, unsigned int tx_init_skip_cycles,
> unsigned int events_per_period = d->events_per_period;
> unsigned int queue_size;
> struct amdtp_stream *s;
> + bool found = false;
> int err;
>
> if (replay_seq) {
> @@ -1955,10 +1956,12 @@ int amdtp_domain_start(struct amdtp_domain *d, unsigned int tx_init_skip_cycles,
>
> // Select an IT context as IRQ target.
> list_for_each_entry(s, &d->streams, list) {
> - if (s->direction == AMDTP_OUT_STREAM)
> + if (s->direction == AMDTP_OUT_STREAM) {
> + found = true;
> break;
> + }
> }
> - if (!s)
> + if (!found)
> return -ENXIO;
> d->irq_target = s;
>
> --
> 2.30.2
Indeed. Nice to catch it. The bug affects Linux kernel v5.5 or later.
Acked-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
In kernel v5.10 or later, we can use 'list_entry_is_head()' macro added
by a commit e130816164e2 ("include/linux/list.h: add a macro to test if
entry is pointing to the head"). However the development of ALSA firewire
stack is out-of-tree repository for my convenience to backport it to kernel
v4.17 or later (I need testers...), so I prefer your change.
Thanks
Takashi Sakamoto
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] ALSA: firewire-lib: Fix 'amdtp_domain_start()' when no AMDTP_OUT_STREAM stream is found
2021-06-24 21:05 ` Takashi Sakamoto
@ 2021-06-25 9:05 ` Dan Carpenter
0 siblings, 0 replies; 4+ messages in thread
From: Dan Carpenter @ 2021-06-25 9:05 UTC (permalink / raw)
To: Christophe JAILLET, clemens, perex, tiwai, alsa-devel,
linux-kernel, kernel-janitors
On Fri, Jun 25, 2021 at 06:05:50AM +0900, Takashi Sakamoto wrote:
>
> In kernel v5.10 or later, we can use 'list_entry_is_head()' macro added
> by a commit e130816164e2 ("include/linux/list.h: add a macro to test if
> entry is pointing to the head").
Someone needs to backport that all the way back...
regards,
dan carpenter
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] ALSA: firewire-lib: Fix 'amdtp_domain_start()' when no AMDTP_OUT_STREAM stream is found
2021-06-24 18:49 [PATCH] ALSA: firewire-lib: Fix 'amdtp_domain_start()' when no AMDTP_OUT_STREAM stream is found Christophe JAILLET
2021-06-24 21:05 ` Takashi Sakamoto
@ 2021-06-25 7:38 ` Takashi Iwai
1 sibling, 0 replies; 4+ messages in thread
From: Takashi Iwai @ 2021-06-25 7:38 UTC (permalink / raw)
To: Christophe JAILLET
Cc: clemens, o-takashi, perex, tiwai, alsa-devel, linux-kernel,
kernel-janitors
On Thu, 24 Jun 2021 20:49:36 +0200,
Christophe JAILLET wrote:
>
> The intent here is to return an error code if we don't find what we are
> looking for in the 'list_for_each_entry()' loop.
>
> 's' is not NULL if the list is empty or if we scan the complete list.
> Introduce a new 'found' variable to handle such cases.
>
> Fixes: 60dd49298ec5 ("ALSA: firewire-lib: handle several AMDTP streams in callback handler of IRQ target")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Applied now. Thanks.
Takashi
> ---
> We could test with" if (list_entry_is_head(s, &d->streams, list))"
> instead, but I find it much less readable.
> ---
> sound/firewire/amdtp-stream.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c
> index aad9778d1c4d..9be2260e4ca2 100644
> --- a/sound/firewire/amdtp-stream.c
> +++ b/sound/firewire/amdtp-stream.c
> @@ -1943,6 +1943,7 @@ int amdtp_domain_start(struct amdtp_domain *d, unsigned int tx_init_skip_cycles,
> unsigned int events_per_period = d->events_per_period;
> unsigned int queue_size;
> struct amdtp_stream *s;
> + bool found = false;
> int err;
>
> if (replay_seq) {
> @@ -1955,10 +1956,12 @@ int amdtp_domain_start(struct amdtp_domain *d, unsigned int tx_init_skip_cycles,
>
> // Select an IT context as IRQ target.
> list_for_each_entry(s, &d->streams, list) {
> - if (s->direction == AMDTP_OUT_STREAM)
> + if (s->direction == AMDTP_OUT_STREAM) {
> + found = true;
> break;
> + }
> }
> - if (!s)
> + if (!found)
> return -ENXIO;
> d->irq_target = s;
>
> --
> 2.30.2
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2021-06-24 18:49 [PATCH] ALSA: firewire-lib: Fix 'amdtp_domain_start()' when no AMDTP_OUT_STREAM stream is found Christophe JAILLET
2021-06-24 21:05 ` Takashi Sakamoto
2021-06-25 9:05 ` Dan Carpenter
2021-06-25 7:38 ` Takashi Iwai
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