* [PATCH] xen-blkback: prefer xenbus_write() over xenbus_printf() where possible
@ 2016-07-07 8:06 Jan Beulich
2016-07-07 9:42 ` Roger Pau Monne
` (3 more replies)
0 siblings, 4 replies; 7+ messages in thread
From: Jan Beulich @ 2016-07-07 8:06 UTC (permalink / raw)
To: Roger Pau Monne, Konrad Rzeszutek Wilk; +Cc: xen-devel, linux-kernel
... as being the simpler variant.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
drivers/block/xen-blkback/xenbus.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- 4.7-rc6-prefer-xenbus_write.orig/drivers/block/xen-blkback/xenbus.c
+++ 4.7-rc6-prefer-xenbus_write/drivers/block/xen-blkback/xenbus.c
@@ -617,9 +617,9 @@ static int xen_blkbk_probe(struct xenbus
goto fail;
}
- err = xenbus_printf(XBT_NIL, dev->nodename,
- "feature-max-indirect-segments", "%u",
- MAX_INDIRECT_SEGMENTS);
+ err = xenbus_write(XBT_NIL, dev->nodename,
+ "feature-max-indirect-segments",
+ __stringify(MAX_INDIRECT_SEGMENTS));
if (err)
dev_warn(&dev->dev,
"writing %s/feature-max-indirect-segments (%d)",
@@ -850,7 +850,7 @@ again:
xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support);
- err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", 1);
+ err = xenbus_write(xbt, dev->nodename, "feature-persistent", "1");
if (err) {
xenbus_dev_fatal(dev, err, "writing %s/feature-persistent",
dev->nodename);
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] xen-blkback: prefer xenbus_write() over xenbus_printf() where possible
2016-07-07 8:06 [PATCH] xen-blkback: prefer xenbus_write() over xenbus_printf() where possible Jan Beulich
2016-07-07 9:42 ` Roger Pau Monne
@ 2016-07-07 9:42 ` Roger Pau Monne
2016-07-07 10:26 ` [Xen-devel] " David Vrabel
2016-07-07 10:26 ` David Vrabel
3 siblings, 0 replies; 7+ messages in thread
From: Roger Pau Monne @ 2016-07-07 9:42 UTC (permalink / raw)
To: Jan Beulich; +Cc: Konrad Rzeszutek Wilk, xen-devel, linux-kernel
On Thu, Jul 07, 2016 at 02:06:12AM -0600, Jan Beulich wrote:
> ... as being the simpler variant.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] xen-blkback: prefer xenbus_write() over xenbus_printf() where possible
2016-07-07 8:06 [PATCH] xen-blkback: prefer xenbus_write() over xenbus_printf() where possible Jan Beulich
@ 2016-07-07 9:42 ` Roger Pau Monne
2016-07-07 9:42 ` Roger Pau Monne
` (2 subsequent siblings)
3 siblings, 0 replies; 7+ messages in thread
From: Roger Pau Monne @ 2016-07-07 9:42 UTC (permalink / raw)
To: Jan Beulich; +Cc: xen-devel, linux-kernel
On Thu, Jul 07, 2016 at 02:06:12AM -0600, Jan Beulich wrote:
> ... as being the simpler variant.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Xen-devel] [PATCH] xen-blkback: prefer xenbus_write() over xenbus_printf() where possible
2016-07-07 8:06 [PATCH] xen-blkback: prefer xenbus_write() over xenbus_printf() where possible Jan Beulich
2016-07-07 9:42 ` Roger Pau Monne
2016-07-07 9:42 ` Roger Pau Monne
@ 2016-07-07 10:26 ` David Vrabel
2016-07-07 10:43 ` David Vrabel
2016-07-07 10:43 ` David Vrabel
2016-07-07 10:26 ` David Vrabel
3 siblings, 2 replies; 7+ messages in thread
From: David Vrabel @ 2016-07-07 10:26 UTC (permalink / raw)
To: Jan Beulich, Roger Pau Monne, Konrad Rzeszutek Wilk
Cc: xen-devel, linux-kernel
On 07/07/16 09:06, Jan Beulich wrote:
> ... as being the simpler variant.
[...]
> --- 4.7-rc6-prefer-xenbus_write.orig/drivers/block/xen-blkback/xenbus.c
> +++ 4.7-rc6-prefer-xenbus_write/drivers/block/xen-blkback/xenbus.c
> @@ -617,9 +617,9 @@ static int xen_blkbk_probe(struct xenbus
> goto fail;
> }
>
> - err = xenbus_printf(XBT_NIL, dev->nodename,
> - "feature-max-indirect-segments", "%u",
> - MAX_INDIRECT_SEGMENTS);
> + err = xenbus_write(XBT_NIL, dev->nodename,
> + "feature-max-indirect-segments",
> + __stringify(MAX_INDIRECT_SEGMENTS));
Yuk :(
Now someone has to check both __stringify() and MAX_INDIRECT_SEGMENTS to
work out what this actually looks like.
David
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] xen-blkback: prefer xenbus_write() over xenbus_printf() where possible
2016-07-07 8:06 [PATCH] xen-blkback: prefer xenbus_write() over xenbus_printf() where possible Jan Beulich
` (2 preceding siblings ...)
2016-07-07 10:26 ` [Xen-devel] " David Vrabel
@ 2016-07-07 10:26 ` David Vrabel
3 siblings, 0 replies; 7+ messages in thread
From: David Vrabel @ 2016-07-07 10:26 UTC (permalink / raw)
To: Jan Beulich, Roger Pau Monne, Konrad Rzeszutek Wilk
Cc: xen-devel, linux-kernel
On 07/07/16 09:06, Jan Beulich wrote:
> ... as being the simpler variant.
[...]
> --- 4.7-rc6-prefer-xenbus_write.orig/drivers/block/xen-blkback/xenbus.c
> +++ 4.7-rc6-prefer-xenbus_write/drivers/block/xen-blkback/xenbus.c
> @@ -617,9 +617,9 @@ static int xen_blkbk_probe(struct xenbus
> goto fail;
> }
>
> - err = xenbus_printf(XBT_NIL, dev->nodename,
> - "feature-max-indirect-segments", "%u",
> - MAX_INDIRECT_SEGMENTS);
> + err = xenbus_write(XBT_NIL, dev->nodename,
> + "feature-max-indirect-segments",
> + __stringify(MAX_INDIRECT_SEGMENTS));
Yuk :(
Now someone has to check both __stringify() and MAX_INDIRECT_SEGMENTS to
work out what this actually looks like.
David
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Xen-devel] [PATCH] xen-blkback: prefer xenbus_write() over xenbus_printf() where possible
2016-07-07 10:26 ` [Xen-devel] " David Vrabel
@ 2016-07-07 10:43 ` David Vrabel
2016-07-07 10:43 ` David Vrabel
1 sibling, 0 replies; 7+ messages in thread
From: David Vrabel @ 2016-07-07 10:43 UTC (permalink / raw)
To: David Vrabel, Jan Beulich, Roger Pau Monne, Konrad Rzeszutek Wilk
Cc: xen-devel, linux-kernel
On 07/07/16 11:26, David Vrabel wrote:
> On 07/07/16 09:06, Jan Beulich wrote:
>> ... as being the simpler variant.
> [...]
>> --- 4.7-rc6-prefer-xenbus_write.orig/drivers/block/xen-blkback/xenbus.c
>> +++ 4.7-rc6-prefer-xenbus_write/drivers/block/xen-blkback/xenbus.c
>> @@ -617,9 +617,9 @@ static int xen_blkbk_probe(struct xenbus
>> goto fail;
>> }
>>
>> - err = xenbus_printf(XBT_NIL, dev->nodename,
>> - "feature-max-indirect-segments", "%u",
>> - MAX_INDIRECT_SEGMENTS);
>> + err = xenbus_write(XBT_NIL, dev->nodename,
>> + "feature-max-indirect-segments",
>> + __stringify(MAX_INDIRECT_SEGMENTS));
>
> Yuk :(
>
> Now someone has to check both __stringify() and MAX_INDIRECT_SEGMENTS to
> work out what this actually looks like.
In particular, if we ended up with
#define MAX_INDIRECT_SEGMENTS 512u
or similar then the code is now wrong.
David
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] xen-blkback: prefer xenbus_write() over xenbus_printf() where possible
2016-07-07 10:26 ` [Xen-devel] " David Vrabel
2016-07-07 10:43 ` David Vrabel
@ 2016-07-07 10:43 ` David Vrabel
1 sibling, 0 replies; 7+ messages in thread
From: David Vrabel @ 2016-07-07 10:43 UTC (permalink / raw)
To: David Vrabel, Jan Beulich, Roger Pau Monne, Konrad Rzeszutek Wilk
Cc: xen-devel, linux-kernel
On 07/07/16 11:26, David Vrabel wrote:
> On 07/07/16 09:06, Jan Beulich wrote:
>> ... as being the simpler variant.
> [...]
>> --- 4.7-rc6-prefer-xenbus_write.orig/drivers/block/xen-blkback/xenbus.c
>> +++ 4.7-rc6-prefer-xenbus_write/drivers/block/xen-blkback/xenbus.c
>> @@ -617,9 +617,9 @@ static int xen_blkbk_probe(struct xenbus
>> goto fail;
>> }
>>
>> - err = xenbus_printf(XBT_NIL, dev->nodename,
>> - "feature-max-indirect-segments", "%u",
>> - MAX_INDIRECT_SEGMENTS);
>> + err = xenbus_write(XBT_NIL, dev->nodename,
>> + "feature-max-indirect-segments",
>> + __stringify(MAX_INDIRECT_SEGMENTS));
>
> Yuk :(
>
> Now someone has to check both __stringify() and MAX_INDIRECT_SEGMENTS to
> work out what this actually looks like.
In particular, if we ended up with
#define MAX_INDIRECT_SEGMENTS 512u
or similar then the code is now wrong.
David
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2016-07-07 10:43 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2016-07-07 8:06 [PATCH] xen-blkback: prefer xenbus_write() over xenbus_printf() where possible Jan Beulich
2016-07-07 9:42 ` Roger Pau Monne
2016-07-07 9:42 ` Roger Pau Monne
2016-07-07 10:26 ` [Xen-devel] " David Vrabel
2016-07-07 10:43 ` David Vrabel
2016-07-07 10:43 ` David Vrabel
2016-07-07 10:26 ` David Vrabel
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