[alsa-devel] [PATCH 0/3] ALSA: BeBoB: Fine-tuning for six function implementations
From: Markus Elfring elfring@users.sourceforge.net Date: Wed, 6 Sep 2017 12:16:54 +0200
Three update suggestions were taken into account from static source code analysis.
Markus Elfring (3): Use common error handling code in snd_bebob_stream_start_duplex() Adjust six checks for null pointers Improve a size determination in parse_stream_formation()
sound/firewire/bebob/bebob_stream.c | 35 +++++++++++++++++------------------ 1 file changed, 17 insertions(+), 18 deletions(-)
From: Markus Elfring elfring@users.sourceforge.net Date: Wed, 6 Sep 2017 11:40:53 +0200
Add jump targets so that a bit of exception handling can be better reused at the end of this function.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring elfring@users.sourceforge.net --- sound/firewire/bebob/bebob_stream.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-)
diff --git a/sound/firewire/bebob/bebob_stream.c b/sound/firewire/bebob/bebob_stream.c index 4d3034a68bdf..bc9e42b6368e 100644 --- a/sound/firewire/bebob/bebob_stream.c +++ b/sound/firewire/bebob/bebob_stream.c @@ -629,8 +629,7 @@ int snd_bebob_stream_start_duplex(struct snd_bebob *bebob, unsigned int rate) if (err < 0) { dev_err(&bebob->unit->device, "fail to run AMDTP master stream:%d\n", err); - break_both_connections(bebob); - goto end; + goto break_connections; }
/* @@ -644,19 +643,15 @@ int snd_bebob_stream_start_duplex(struct snd_bebob *bebob, unsigned int rate) dev_err(&bebob->unit->device, "fail to ensure sampling rate: %d\n", err); - amdtp_stream_stop(&bebob->rx_stream); - break_both_connections(bebob); - goto end; + goto stop_rx_stream; } }
/* wait first callback */ if (!amdtp_stream_wait_callback(&bebob->rx_stream, CALLBACK_TIMEOUT)) { - amdtp_stream_stop(&bebob->rx_stream); - break_both_connections(bebob); err = -ETIMEDOUT; - goto end; + goto stop_rx_stream; } }
@@ -666,9 +661,7 @@ int snd_bebob_stream_start_duplex(struct snd_bebob *bebob, unsigned int rate) if (err < 0) { dev_err(&bebob->unit->device, "fail to run AMDTP slave stream:%d\n", err); - amdtp_stream_stop(&bebob->rx_stream); - break_both_connections(bebob); - goto end; + goto stop_rx_stream; }
/* wait first callback */ @@ -682,6 +675,12 @@ int snd_bebob_stream_start_duplex(struct snd_bebob *bebob, unsigned int rate) } end: return err; + +stop_rx_stream: + amdtp_stream_stop(&bebob->rx_stream); +break_connections: + break_both_connections(bebob); + return err; }
void snd_bebob_stream_stop_duplex(struct snd_bebob *bebob)
Hi,
On Sep 6 2017 19:22, SF Markus Elfring wrote:
From: Markus Elfring elfring@users.sourceforge.net Date: Wed, 6 Sep 2017 11:40:53 +0200
Add jump targets so that a bit of exception handling can be better reused at the end of this function.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring elfring@users.sourceforge.net
sound/firewire/bebob/bebob_stream.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-)
diff --git a/sound/firewire/bebob/bebob_stream.c b/sound/firewire/bebob/bebob_stream.c index 4d3034a68bdf..bc9e42b6368e 100644 --- a/sound/firewire/bebob/bebob_stream.c +++ b/sound/firewire/bebob/bebob_stream.c ... @@ -666,9 +661,7 @@ int snd_bebob_stream_start_duplex(struct snd_bebob *bebob, unsigned int rate) if (err < 0) { dev_err(&bebob->unit->device, "fail to run AMDTP slave stream:%d\n", err);
amdtp_stream_stop(&bebob->rx_stream);break_both_connections(bebob);goto end;
goto stop_rx_stream;}
/* wait first callback */
After the above code block, we have below code block.
658 /* start slave if needed */ 659 if (!amdtp_stream_running(&bebob->tx_stream)) { 660 err = start_stream(bebob, &bebob->tx_stream, rate); 661 if (err < 0) { 662 dev_err(&bebob->unit->device, 663 "fail to run AMDTP slave stream:%d\n", err); 664 goto stop_rx_stream; 665 } 666 667 /* wait first callback */ 668 if (!amdtp_stream_wait_callback(&bebob->tx_stream, 669 CALLBACK_TIMEOUT)) { 670 amdtp_stream_stop(&bebob->tx_stream); 671 amdtp_stream_stop(&bebob->rx_stream); 672 break_both_connections(bebob); 673 err = -ETIMEDOUT; 674 } 675 }
I think it better to apply your solution too in the above to keep code consistency.
@@ -682,6 +675,12 @@ int snd_bebob_stream_start_duplex(struct snd_bebob *bebob, unsigned int rate) } end: return err;
+stop_rx_stream:
- amdtp_stream_stop(&bebob->rx_stream);
+break_connections:
break_both_connections(bebob);
return err; }
void snd_bebob_stream_stop_duplex(struct snd_bebob *bebob)
For the other patches, I can find no merit to apply except for reduction of the number of characters included in the file.
Thanks
Takashi Sakamoto
668 if (!amdtp_stream_wait_callback(&bebob->tx_stream, 669 CALLBACK_TIMEOUT)) { 670 amdtp_stream_stop(&bebob->tx_stream); 671 amdtp_stream_stop(&bebob->rx_stream); 672 break_both_connections(bebob); 673 err = -ETIMEDOUT; 674 } 675 }
I think it better to apply your solution too in the above to keep code consistency.
How do you think about to adjust this function implementation after the other two update steps from the patch series would be integrated?
For the other patches, I can find no merit to apply except for reduction of the number of characters included in the file.
Would you like to refer to any specific update suggestions for further clarification?
Regards, Markus
Hi,
On Sep 24 2017 16:06, SF Markus Elfring wrote:
668 if (!amdtp_stream_wait_callback(&bebob->tx_stream, 669 CALLBACK_TIMEOUT)) { 670 amdtp_stream_stop(&bebob->tx_stream); 671 amdtp_stream_stop(&bebob->rx_stream); 672 break_both_connections(bebob); 673 err = -ETIMEDOUT; 674 } 675 }
I think it better to apply your solution too in the above to keep code consistency.
How do you think about to adjust this function implementation after the other two update steps from the patch series would be integrated?
For the other patches, I can find no merit to apply except for reduction of the number of characters included in the file.
Would you like to refer to any specific update suggestions for further clarification?
I had already read your patch comments and understand your intention somehow, because it's a part of task for daily reviewing. Then, I did comment.
At development for Linux kernel, there're some important points for developers to notice. In our case, we should care of _practicality_. Roughly speaking, our work for kernel should add advantages for kernel/application runtime or assists the other developers' work. In this point, some patches are welcome and the others are not. I'll show you two examples.
In this subsystem, I have reviewed patches from Julia Lawall. The most of her or his patches attempt to add 'const' qualifier for read-only symbols. As a result, the symbols place to '.rodata' section of ELF binary. This section has a hint for loaders to put these symbols to segments with read-only attributes. This has an advantage for compilation time and runtime. Recent compilers can detect codes to change content of the symbols with 'const' qualifier. Even if the codes were exposed from developers understanding or compilers' check, segmentation would occur in runtime at early stage of development or early days after releasing kernel. This is very helpful for developers to find unexpected changes for contents of the symbol.
I also subscribe a mailing list of Linux Driver Project[1], which is for various drivers. Sometimes posted patches are rejected by maintainers. Such patches typically include minor code change without actual advantages for runtime or developers. For instance, patches for '80 characters per line' are often posted and rejected. If this kind of patchset were added to change history of kernel, tons of unpractical logs are accumulated for development. This make it worse for developers to maintain the kernel.
By the way, ALSA BeBoB driver is just for ASIC and firmwares which ArchWave AG (formerly BridgeCo. AG.) had produced for devices with IEC 61883-1/6 packet streaming on IEEE 1394 bus and Time Sensitive Network (TSN). As long as I know, the last product with this solution was shipped at 2010. Thus the driver is under maintenance. I have some tasks for this driver as well as drivers in ALSA firewire stack, however basically this driver is under maintenance and might not get further integration. I think that code cleanup for the driver don't help the other developers. It's better to apply such cleanup to more long-live codes such as core functionality of ALSA. (But pay enough attention to practicality of the changes when you start this kind of work.)
In this point of view, whether your patchset is worth to be applied or not, Please keep enough time to think about.
[1] http://driverdev.linuxdriverproject.org/mailman/listinfo
Thanks
Takashi Sakamoto
As long as I know, the last product with this solution was shipped at 2010. Thus the driver is under maintenance.
Thanks for your information.
I have some tasks for this driver as well as drivers in ALSA firewire stack, however basically this driver is under maintenance and might not get further integration.
Good to know in principle …
I think that code cleanup for the driver don't help the other developers.
I thought in an other direction if other contributors would like to care for longer term support.
It's better to apply such cleanup to more long-live codes such as core functionality of ALSA.
I am trying another general transformation pattern out.
In this point of view, whether your patchset is worth to be applied or not, Please keep enough time to think about.
Automatic source code analysis can find various update candidates. I am just unsure if a bit more software development attention is still appropriate at some places.
Do you find any of the affected software modules so outdated so that they should not be touched any more?
Regards, Markus
On Sep 27 2017 15:38, SF Markus Elfring wrote:
As long as I know, the last product with this solution was shipped at 2010. Thus the driver is under maintenance.
Thanks for your information.
I have some tasks for this driver as well as drivers in ALSA firewire stack, however basically this driver is under maintenance and might not get further integration.
Good to know in principle …
I think that code cleanup for the driver don't help the other developers.
I thought in an other direction if other contributors would like to care for longer term support.
It's better to apply such cleanup to more long-live codes such as core functionality of ALSA.
I am trying another general transformation pattern out.
In this point of view, whether your patchset is worth to be applied or not, Please keep enough time to think about.
Automatic source code analysis can find various update candidates. I am just unsure if a bit more software development attention is still appropriate at some places.
Do you find any of the affected software modules so outdated so that they should not be touched any more?
Please don't ignore the practicality I've explained, and don't accumulate your questions without it.
Regards
Takashi Sakamoto
From: Markus Elfring elfring@users.sourceforge.net Date: Wed, 6 Sep 2017 11:48:44 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
The script “checkpatch.pl” pointed information out like the following.
Comparison to NULL could be written …
Thus fix the affected source code places.
Signed-off-by: Markus Elfring elfring@users.sourceforge.net --- sound/firewire/bebob/bebob_stream.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/sound/firewire/bebob/bebob_stream.c b/sound/firewire/bebob/bebob_stream.c index bc9e42b6368e..211ff43207d6 100644 --- a/sound/firewire/bebob/bebob_stream.c +++ b/sound/firewire/bebob/bebob_stream.c @@ -268,7 +268,7 @@ map_data_channels(struct snd_bebob *bebob, struct amdtp_stream *s) * use the maximum length of FCP. */ buf = kzalloc(256, GFP_KERNEL); - if (buf == NULL) + if (!buf) return -ENOMEM;
if (s == &bebob->tx_stream) @@ -472,7 +472,7 @@ break_both_connections(struct snd_bebob *bebob) bebob->connected = false;
/* These models seems to be in transition state for a longer time. */ - if (bebob->maudio_special_quirk != NULL) + if (bebob->maudio_special_quirk) msleep(200); }
@@ -496,7 +496,7 @@ start_stream(struct snd_bebob *bebob, struct amdtp_stream *stream, conn = &bebob->out_conn;
/* channel mapping */ - if (bebob->maudio_special_quirk == NULL) { + if (!bebob->maudio_special_quirk) { err = map_data_channels(bebob, stream); if (err < 0) goto end; @@ -611,7 +611,7 @@ int snd_bebob_stream_start_duplex(struct snd_bebob *bebob, unsigned int rate) * * For firmware customized by M-Audio, refer to next NOTE. */ - if (bebob->maudio_special_quirk == NULL) { + if (!bebob->maudio_special_quirk) { err = rate_spec->set(bebob, rate); if (err < 0) { dev_err(&bebob->unit->device, @@ -637,7 +637,7 @@ int snd_bebob_stream_start_duplex(struct snd_bebob *bebob, unsigned int rate) * The firmware customized by M-Audio uses these commands to * start transmitting stream. This is not usual way. */ - if (bebob->maudio_special_quirk != NULL) { + if (bebob->maudio_special_quirk) { err = rate_spec->set(bebob, rate); if (err < 0) { dev_err(&bebob->unit->device, @@ -794,7 +794,7 @@ fill_stream_formations(struct snd_bebob *bebob, enum avc_bridgeco_plug_dir dir, int err;
buf = kmalloc(FORMAT_MAXIMUM_LENGTH, GFP_KERNEL); - if (buf == NULL) + if (!buf) return -ENOMEM;
if (dir == AVC_BRIDGECO_PLUG_DIR_IN)
From: Markus Elfring elfring@users.sourceforge.net Date: Wed, 6 Sep 2017 11:55:45 +0200
Replace the specification of a data structure by a pointer dereference as the parameter for the operator "sizeof" to make the corresponding size determination a bit safer according to the Linux coding style convention.
Signed-off-by: Markus Elfring elfring@users.sourceforge.net --- sound/firewire/bebob/bebob_stream.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/firewire/bebob/bebob_stream.c b/sound/firewire/bebob/bebob_stream.c index 211ff43207d6..a26863b82330 100644 --- a/sound/firewire/bebob/bebob_stream.c +++ b/sound/firewire/bebob/bebob_stream.c @@ -736,7 +736,7 @@ parse_stream_formation(u8 *buf, unsigned int len, return -ENOSYS;
/* Avoid double count by different entries for the same rate. */ - memset(&formation[i], 0, sizeof(struct snd_bebob_stream_formation)); + memset(&formation[i], 0, sizeof(*formation));
for (e = 0; e < buf[4]; e++) { channels = buf[5 + e * 2];
participants (2)
-
SF Markus Elfring -
Takashi Sakamoto