* [Qemu-devel] [PATCH] virtio-bus: avoid breaking build when open DEBUG switch
@ 2014-11-13 2:39 ` arei.gonglei
0 siblings, 0 replies; 10+ messages in thread
From: arei.gonglei @ 2014-11-13 2:39 UTC (permalink / raw)
To: qemu-devel; +Cc: qemu-trivial, Gonglei, peter.huangpeng, mst
From: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
---
hw/virtio/virtio-bus.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c
index eb77019..dfd2d8c 100644
--- a/hw/virtio/virtio-bus.c
+++ b/hw/virtio/virtio-bus.c
@@ -58,7 +58,7 @@ void virtio_bus_reset(VirtioBusState *bus)
{
VirtIODevice *vdev = virtio_bus_get_device(bus);
- DPRINTF("%s: reset device.\n", qbus->name);
+ DPRINTF("%s: reset device.\n", BUS(bus)->name);
if (vdev != NULL) {
virtio_reset(vdev);
}
--
1.7.12.4
^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [Qemu-trivial] [Qemu-devel] [PATCH] virtio-bus: avoid breaking build when open DEBUG switch
2014-11-13 2:39 ` [Qemu-devel] " arei.gonglei
@ 2014-11-13 11:23 ` Stefan Hajnoczi
-1 siblings, 0 replies; 10+ messages in thread
From: Stefan Hajnoczi @ 2014-11-13 11:23 UTC (permalink / raw)
To: arei.gonglei; +Cc: qemu-trivial, mst, qemu-devel, peter.huangpeng
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On Thu, Nov 13, 2014 at 10:39:32AM +0800, arei.gonglei@huawei.com wrote:
> From: Gonglei <arei.gonglei@huawei.com>
>
> Signed-off-by: Gonglei <arei.gonglei@huawei.com>
> ---
> hw/virtio/virtio-bus.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Qemu-devel] [PATCH] virtio-bus: avoid breaking build when open DEBUG switch
@ 2014-11-13 11:23 ` Stefan Hajnoczi
0 siblings, 0 replies; 10+ messages in thread
From: Stefan Hajnoczi @ 2014-11-13 11:23 UTC (permalink / raw)
To: arei.gonglei; +Cc: qemu-trivial, mst, qemu-devel, peter.huangpeng
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On Thu, Nov 13, 2014 at 10:39:32AM +0800, arei.gonglei@huawei.com wrote:
> From: Gonglei <arei.gonglei@huawei.com>
>
> Signed-off-by: Gonglei <arei.gonglei@huawei.com>
> ---
> hw/virtio/virtio-bus.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Qemu-trivial] [Qemu-devel] [PATCH] virtio-bus: avoid breaking build when open DEBUG switch
2014-11-13 2:39 ` [Qemu-devel] " arei.gonglei
@ 2014-11-13 11:27 ` Stefan Hajnoczi
-1 siblings, 0 replies; 10+ messages in thread
From: Stefan Hajnoczi @ 2014-11-13 11:27 UTC (permalink / raw)
To: arei.gonglei; +Cc: qemu-trivial, mst, qemu-devel, peter.huangpeng
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On Thu, Nov 13, 2014 at 10:39:32AM +0800, arei.gonglei@huawei.com wrote:
> From: Gonglei <arei.gonglei@huawei.com>
>
> Signed-off-by: Gonglei <arei.gonglei@huawei.com>
> ---
> hw/virtio/virtio-bus.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c
> index eb77019..dfd2d8c 100644
> --- a/hw/virtio/virtio-bus.c
> +++ b/hw/virtio/virtio-bus.c
> @@ -58,7 +58,7 @@ void virtio_bus_reset(VirtioBusState *bus)
> {
> VirtIODevice *vdev = virtio_bus_get_device(bus);
>
> - DPRINTF("%s: reset device.\n", qbus->name);
> + DPRINTF("%s: reset device.\n", BUS(bus)->name);
In general the problem with existing DPRINTF() macros is that they use
#ifdef. This leads to bitrot, such as this instance.
A better approach is:
#define DEBUG_FOO 0
#define DPRINTF(...) \
do { \
if (DEBUG_FOO) { \
fprintf(stderr, ...); \
} \
} while (0)
Now the compiler always checks the DPRINTF() code.
Trace events can be a good solution too. If you like stderr output,
build QEMU with ./configure --enable-trace-backend=stderr and all
trace_*() calls are turned into fprintf(stderr).
The cool thing about trace events is that they are available in
production too.
Stefan
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^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [Qemu-devel] [PATCH] virtio-bus: avoid breaking build when open DEBUG switch
@ 2014-11-13 11:27 ` Stefan Hajnoczi
0 siblings, 0 replies; 10+ messages in thread
From: Stefan Hajnoczi @ 2014-11-13 11:27 UTC (permalink / raw)
To: arei.gonglei; +Cc: qemu-trivial, mst, qemu-devel, peter.huangpeng
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On Thu, Nov 13, 2014 at 10:39:32AM +0800, arei.gonglei@huawei.com wrote:
> From: Gonglei <arei.gonglei@huawei.com>
>
> Signed-off-by: Gonglei <arei.gonglei@huawei.com>
> ---
> hw/virtio/virtio-bus.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c
> index eb77019..dfd2d8c 100644
> --- a/hw/virtio/virtio-bus.c
> +++ b/hw/virtio/virtio-bus.c
> @@ -58,7 +58,7 @@ void virtio_bus_reset(VirtioBusState *bus)
> {
> VirtIODevice *vdev = virtio_bus_get_device(bus);
>
> - DPRINTF("%s: reset device.\n", qbus->name);
> + DPRINTF("%s: reset device.\n", BUS(bus)->name);
In general the problem with existing DPRINTF() macros is that they use
#ifdef. This leads to bitrot, such as this instance.
A better approach is:
#define DEBUG_FOO 0
#define DPRINTF(...) \
do { \
if (DEBUG_FOO) { \
fprintf(stderr, ...); \
} \
} while (0)
Now the compiler always checks the DPRINTF() code.
Trace events can be a good solution too. If you like stderr output,
build QEMU with ./configure --enable-trace-backend=stderr and all
trace_*() calls are turned into fprintf(stderr).
The cool thing about trace events is that they are available in
production too.
Stefan
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^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [Qemu-trivial] [Qemu-devel] [PATCH] virtio-bus: avoid breaking build when open DEBUG switch
2014-11-13 11:27 ` Stefan Hajnoczi
@ 2014-11-13 11:49 ` Gonglei
-1 siblings, 0 replies; 10+ messages in thread
From: Gonglei @ 2014-11-13 11:49 UTC (permalink / raw)
To: Stefan Hajnoczi
Cc: qemu-trivial@nongnu.org, mst@redhat.com, qemu-devel@nongnu.org,
Huangpeng (Peter)
On 2014/11/13 19:27, Stefan Hajnoczi wrote:
> On Thu, Nov 13, 2014 at 10:39:32AM +0800, arei.gonglei@huawei.com wrote:
>> From: Gonglei <arei.gonglei@huawei.com>
>>
>> Signed-off-by: Gonglei <arei.gonglei@huawei.com>
>> ---
>> hw/virtio/virtio-bus.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c
>> index eb77019..dfd2d8c 100644
>> --- a/hw/virtio/virtio-bus.c
>> +++ b/hw/virtio/virtio-bus.c
>> @@ -58,7 +58,7 @@ void virtio_bus_reset(VirtioBusState *bus)
>> {
>> VirtIODevice *vdev = virtio_bus_get_device(bus);
>>
>> - DPRINTF("%s: reset device.\n", qbus->name);
>> + DPRINTF("%s: reset device.\n", BUS(bus)->name);
>
> In general the problem with existing DPRINTF() macros is that they use
> #ifdef. This leads to bitrot, such as this instance.
>
Yes.
> A better approach is:
>
> #define DEBUG_FOO 0
> #define DPRINTF(...) \
> do { \
> if (DEBUG_FOO) { \
> fprintf(stderr, ...); \
> } \
> } while (0)
>
> Now the compiler always checks the DPRINTF() code.
>
> Trace events can be a good solution too. If you like stderr output,
> build QEMU with ./configure --enable-trace-backend=stderr and all
> trace_*() calls are turned into fprintf(stderr).
>
> The cool thing about trace events is that they are available in
> production too.
>
Hum, trace events is great! :)
Best regards,
-Gonglei
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [Qemu-devel] [PATCH] virtio-bus: avoid breaking build when open DEBUG switch
@ 2014-11-13 11:49 ` Gonglei
0 siblings, 0 replies; 10+ messages in thread
From: Gonglei @ 2014-11-13 11:49 UTC (permalink / raw)
To: Stefan Hajnoczi
Cc: qemu-trivial@nongnu.org, mst@redhat.com, qemu-devel@nongnu.org,
Huangpeng (Peter)
On 2014/11/13 19:27, Stefan Hajnoczi wrote:
> On Thu, Nov 13, 2014 at 10:39:32AM +0800, arei.gonglei@huawei.com wrote:
>> From: Gonglei <arei.gonglei@huawei.com>
>>
>> Signed-off-by: Gonglei <arei.gonglei@huawei.com>
>> ---
>> hw/virtio/virtio-bus.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c
>> index eb77019..dfd2d8c 100644
>> --- a/hw/virtio/virtio-bus.c
>> +++ b/hw/virtio/virtio-bus.c
>> @@ -58,7 +58,7 @@ void virtio_bus_reset(VirtioBusState *bus)
>> {
>> VirtIODevice *vdev = virtio_bus_get_device(bus);
>>
>> - DPRINTF("%s: reset device.\n", qbus->name);
>> + DPRINTF("%s: reset device.\n", BUS(bus)->name);
>
> In general the problem with existing DPRINTF() macros is that they use
> #ifdef. This leads to bitrot, such as this instance.
>
Yes.
> A better approach is:
>
> #define DEBUG_FOO 0
> #define DPRINTF(...) \
> do { \
> if (DEBUG_FOO) { \
> fprintf(stderr, ...); \
> } \
> } while (0)
>
> Now the compiler always checks the DPRINTF() code.
>
> Trace events can be a good solution too. If you like stderr output,
> build QEMU with ./configure --enable-trace-backend=stderr and all
> trace_*() calls are turned into fprintf(stderr).
>
> The cool thing about trace events is that they are available in
> production too.
>
Hum, trace events is great! :)
Best regards,
-Gonglei
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Qemu-trivial] [PATCH] virtio-bus: avoid breaking build when open DEBUG switch
2014-11-13 2:39 ` [Qemu-devel] " arei.gonglei
@ 2014-12-10 8:20 ` Michael Tokarev
-1 siblings, 0 replies; 10+ messages in thread
From: Michael Tokarev @ 2014-12-10 8:20 UTC (permalink / raw)
To: arei.gonglei, qemu-devel; +Cc: qemu-trivial, peter.huangpeng, mst
Applied to -trivial as is, for now, since
the fixes are necessary anyway. Good suggestion
by Stefan, to turn it into constant-depending
always-compilable code stands, but it is not
a show-stopper for the actual fix.
Thanks,
/mnt
^ permalink raw reply [flat|nested] 10+ messages in thread