Re: [dpdk-dev] [EXT] Re: [v5] telemetry: fix json output buffer size

[Gowrishankar Muthukrishnan <gmuthukrishn@marvell.com>]

> -----Original Message-----
> From: Thomas Monjalon <thomas@monjalon.net>
> Sent: Thursday, October 7, 2021 12:52 PM
> To: Gowrishankar Muthukrishnan <gmuthukrishn@marvell.com>
> Cc: dev@dpdk.org; bruce.richardson@intel.com; ciara.power@intel.com; Jerin
> Jacob Kollanukkaran <jerinj@marvell.com>
> Subject: Re: [EXT] Re: [dpdk-dev] [v5] telemetry: fix json output buffer size
> 
> 07/10/2021 06:58, Gowrishankar Muthukrishnan:
> > From: Thomas Monjalon <thomas@monjalon.net>
> > > 29/09/2021 06:18, Gowrishankar Muthukrishnan:
> > > > Fix json output buffer size for an actual data length.
> > > >
> > > > Fixes: 52af6ccb2b39 ("telemetry: add utility functions for
> > > > creating
> > > > JSON")
> > >
> > > Please could you give a bit more explanations?
> > > What was not working and why?
> >
> > Without this patch, our driver end point (crypto/cnxk) could not
> > successfully deliver the requested info due to its larger amount than the fixed
> buffer length of 1024 bytes as handled by __json_snprintf.
> > I think it is genuine bug too which we caught up here.
> 
> So the commit log should say the JSON message was limited to 1024, and now
> you allow any specified length.
> 

Ack. I'll send new version with this correction.

Thanks,
Gowrishankar
> > > [...]
> > > > - * This function is not for use for values larger than 1k.
> > > > + * This function is not for use for values larger than given buffer length.
> > > >   */
> > > >  __rte_format_printf(3, 4)
> > > >  static inline int
> > > >  __json_snprintf(char *buf, const int len, const char *format, ...)  {
> > > > -	char tmp[1024];
> > > > +	char tmp[len];
> > > >  	va_list ap;
> > > >  	int ret;
> 
>