[PATCH] ALSA: firewire-lib: Fix 'amdtp_domain_start()' when no AMDTP_OUT_STREAM stream is found

From: Christophe JAILLET
Date: Thu Jun 24 2021 - 14:50:05 EST


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@xxxxxxxxxx>
---
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