* [Qemu-devel] [PATCH] block: Remove unused assignment (fixes warning from clang)
@ 2013-09-28 9:55 Stefan Weil
2013-09-29 19:44 ` [Qemu-devel] [Qemu-trivial] " Michael Tokarev
0 siblings, 1 reply; 5+ messages in thread
From: Stefan Weil @ 2013-09-28 9:55 UTC (permalink / raw)
To: qemu-devel; +Cc: qemu-trivial, Kevin Wolf, Stefan Hajnoczi, Stefan Weil
blockdev.c:1929:13: warning: Value stored to 'ret' is never read
ret = 0;
^ ~
Signed-off-by: Stefan Weil <sw@weilnetz.de>
---
blockdev.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/blockdev.c b/blockdev.c
index 8aa66a9..8c83f6f 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1926,7 +1926,6 @@ void qmp_drive_mirror(const char *device, const char *target,
} else {
switch (mode) {
case NEW_IMAGE_MODE_EXISTING:
- ret = 0;
break;
case NEW_IMAGE_MODE_ABSOLUTE_PATHS:
/* create new image with backing file */
--
1.7.10.4
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [Qemu-devel] [Qemu-trivial] [PATCH] block: Remove unused assignment (fixes warning from clang)
2013-09-28 9:55 [Qemu-devel] [PATCH] block: Remove unused assignment (fixes warning from clang) Stefan Weil
@ 2013-09-29 19:44 ` Michael Tokarev
2013-09-29 20:15 ` Stefan Weil
0 siblings, 1 reply; 5+ messages in thread
From: Michael Tokarev @ 2013-09-29 19:44 UTC (permalink / raw)
To: Stefan Weil; +Cc: qemu-trivial, Kevin Wolf, qemu-devel, Stefan Hajnoczi
28.09.2013 13:55, Stefan Weil wrote:
> blockdev.c:1929:13: warning: Value stored to 'ret' is never read
> ret = 0;
> ^ ~
Applied to the trivial patches queue.
> Signed-off-by: Stefan Weil <sw@weilnetz.de>
> ---
> blockdev.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/blockdev.c b/blockdev.c
> index 8aa66a9..8c83f6f 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -1926,7 +1926,6 @@ void qmp_drive_mirror(const char *device, const char *target,
> } else {
> switch (mode) {
> case NEW_IMAGE_MODE_EXISTING:
> - ret = 0;
> break;
While this one is obviously unused assignment,
there's on more usage of `ret' variable in this
function, -- it is to store the return value
from bdrv_open():
ret = bdrv_open(target_bs, target, NULL, flags | BDRV_O_NO_BACKING, drv,
&local_err);
if (ret < 0) {...
What's the rule about converting that into if() ?
Thanks,
/mjt
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [Qemu-devel] [Qemu-trivial] [PATCH] block: Remove unused assignment (fixes warning from clang)
2013-09-29 19:44 ` [Qemu-devel] [Qemu-trivial] " Michael Tokarev
@ 2013-09-29 20:15 ` Stefan Weil
2013-09-30 7:57 ` Kevin Wolf
2013-09-30 9:16 ` Stefan Hajnoczi
0 siblings, 2 replies; 5+ messages in thread
From: Stefan Weil @ 2013-09-29 20:15 UTC (permalink / raw)
To: Michael Tokarev; +Cc: qemu-trivial, Kevin Wolf, qemu-devel, Stefan Hajnoczi
Am 29.09.2013 21:44, schrieb Michael Tokarev:
> 28.09.2013 13:55, Stefan Weil wrote:
[...]
>> diff --git a/blockdev.c b/blockdev.c
>> index 8aa66a9..8c83f6f 100644
>> --- a/blockdev.c
>> +++ b/blockdev.c
>> @@ -1926,7 +1926,6 @@ void qmp_drive_mirror(const char *device, const
>> char *target,
>> } else {
>> switch (mode) {
>> case NEW_IMAGE_MODE_EXISTING:
>> - ret = 0;
>> break;
>
> While this one is obviously unused assignment,
> there's on more usage of `ret' variable in this
> function, -- it is to store the return value
> from bdrv_open():
>
> ret = bdrv_open(target_bs, target, NULL, flags |
> BDRV_O_NO_BACKING, drv,
> &local_err);
> if (ret < 0) {...
>
> What's the rule about converting that into if() ?
>
> Thanks,
>
> /mjt
Is there a rule for cases like that? This pattern is very common in QEMU
code
(several occurrences in blockdev.c). Should we eliminate the 'ret' variable?
I don't think it's worth the effort.
Stefan
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [Qemu-devel] [Qemu-trivial] [PATCH] block: Remove unused assignment (fixes warning from clang)
2013-09-29 20:15 ` Stefan Weil
@ 2013-09-30 7:57 ` Kevin Wolf
2013-09-30 9:16 ` Stefan Hajnoczi
1 sibling, 0 replies; 5+ messages in thread
From: Kevin Wolf @ 2013-09-30 7:57 UTC (permalink / raw)
To: Stefan Weil; +Cc: qemu-trivial, Michael Tokarev, qemu-devel, Stefan Hajnoczi
Am 29.09.2013 um 22:15 hat Stefan Weil geschrieben:
> Am 29.09.2013 21:44, schrieb Michael Tokarev:
> > 28.09.2013 13:55, Stefan Weil wrote:
> [...]
> >> diff --git a/blockdev.c b/blockdev.c
> >> index 8aa66a9..8c83f6f 100644
> >> --- a/blockdev.c
> >> +++ b/blockdev.c
> >> @@ -1926,7 +1926,6 @@ void qmp_drive_mirror(const char *device, const
> >> char *target,
> >> } else {
> >> switch (mode) {
> >> case NEW_IMAGE_MODE_EXISTING:
> >> - ret = 0;
> >> break;
> >
> > While this one is obviously unused assignment,
> > there's on more usage of `ret' variable in this
> > function, -- it is to store the return value
> > from bdrv_open():
> >
> > ret = bdrv_open(target_bs, target, NULL, flags |
> > BDRV_O_NO_BACKING, drv,
> > &local_err);
> > if (ret < 0) {...
> >
> > What's the rule about converting that into if() ?
> >
> > Thanks,
> >
> > /mjt
>
> Is there a rule for cases like that? This pattern is very common in QEMU
> code
> (several occurrences in blockdev.c). Should we eliminate the 'ret' variable?
> I don't think it's worth the effort.
And actually I think removing it would make the code worse (less
readable).
Kevin
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [Qemu-devel] [Qemu-trivial] [PATCH] block: Remove unused assignment (fixes warning from clang)
2013-09-29 20:15 ` Stefan Weil
2013-09-30 7:57 ` Kevin Wolf
@ 2013-09-30 9:16 ` Stefan Hajnoczi
1 sibling, 0 replies; 5+ messages in thread
From: Stefan Hajnoczi @ 2013-09-30 9:16 UTC (permalink / raw)
To: Stefan Weil; +Cc: qemu-trivial, Kevin Wolf, Michael Tokarev, qemu-devel
On Sun, Sep 29, 2013 at 10:15:10PM +0200, Stefan Weil wrote:
> Am 29.09.2013 21:44, schrieb Michael Tokarev:
> > 28.09.2013 13:55, Stefan Weil wrote:
> [...]
> >> diff --git a/blockdev.c b/blockdev.c
> >> index 8aa66a9..8c83f6f 100644
> >> --- a/blockdev.c
> >> +++ b/blockdev.c
> >> @@ -1926,7 +1926,6 @@ void qmp_drive_mirror(const char *device, const
> >> char *target,
> >> } else {
> >> switch (mode) {
> >> case NEW_IMAGE_MODE_EXISTING:
> >> - ret = 0;
> >> break;
> >
> > While this one is obviously unused assignment,
> > there's on more usage of `ret' variable in this
> > function, -- it is to store the return value
> > from bdrv_open():
> >
> > ret = bdrv_open(target_bs, target, NULL, flags |
> > BDRV_O_NO_BACKING, drv,
> > &local_err);
> > if (ret < 0) {...
> >
> > What's the rule about converting that into if() ?
> >
> > Thanks,
> >
> > /mjt
>
> Is there a rule for cases like that? This pattern is very common in QEMU
> code
> (several occurrences in blockdev.c). Should we eliminate the 'ret' variable?
> I don't think it's worth the effort.
Me neither. There is a minor style difference between putting
everything into the if statement and using a variable to split up a
potentially complicated if statement.
Both approaches are usually okay.
Stefan
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2013-09-30 9:16 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2013-09-28 9:55 [Qemu-devel] [PATCH] block: Remove unused assignment (fixes warning from clang) Stefan Weil
2013-09-29 19:44 ` [Qemu-devel] [Qemu-trivial] " Michael Tokarev
2013-09-29 20:15 ` Stefan Weil
2013-09-30 7:57 ` Kevin Wolf
2013-09-30 9:16 ` Stefan Hajnoczi
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