Re: [dpdk-dev] [PATCH 1/1 v2] eal: Fix misleading error messages, errno can't be trusted.

[Jean Tourrilhes <jt@labs.hpe.com>]

On Mon, Oct 03, 2016 at 02:25:40PM +0100, Sergio Gonzalez Monroy wrote:
> Hi Jean,
> 
> There are some format issues with the patch:
> 
> You can run scripts/check-git-log.sh to check them:
> Wrong headline format:
>         eal: Fix misleading error messages, errno can't be trusted.
> Wrong headline uppercase:
>         eal: Fix misleading error messages, errno can't be trusted.
> Missing 'Fixes' tag:
>         eal: Fix misleading error messages, errno can't be trusted.
> 
> The script's output highlights the different issues.

	SOrry about that, I casually read the page on
http://dpdk.org/dev, but obviously I need to look at it again.

> On 21/09/2016 22:10, Jean Tourrilhes wrote:
> >@@ -263,9 +264,16 @@ rte_eal_config_reattach(void)
> >  	mem_config = (struct rte_mem_config *) mmap(rte_mem_cfg_addr,
> >  			sizeof(*mem_config), PROT_READ | PROT_WRITE, MAP_SHARED,
> >  			mem_cfg_fd, 0);
> >+	if (mem_config == MAP_FAILED || mem_config != rte_mem_cfg_addr) {
> >+		if (mem_config != MAP_FAILED)
> >+			/* errno is stale, don't use */
> >+			rte_panic("Cannot mmap memory for rte_config at [%p], got [%p] - please use '--base-virtaddr' option\n",
> >+				  rte_mem_cfg_addr, mem_config);
> >+		else
> >+			rte_panic("Cannot mmap memory for rte_config! error %i (%s)\n",
> >+				  errno, strerror(errno));
> >+	}
> >  	close(mem_cfg_fd);
> >-	if (mem_config == MAP_FAILED || mem_config != rte_mem_cfg_addr)
> >-		rte_panic("Cannot mmap memory for rte_config\n");
> 
> NIT but any reason you moved the check before closing the file descriptor?
> (not that it matters with current code as we panic anyway)

	"close()" may change "errno" according to its man page.

> Thanks,
> Sergio

	Thanks for the review !

	Jean