From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Monjalon <thomas.monjalon@6wind.com>
Subject: Re: [PATCH v2] eal: fix check number of bytes from read
	function
Date: Fri, 22 Jul 2016 17:24:51 +0200
Message-ID: <2746518.l5JpmnHLoW@xps13>
References: <1469024689-1076-1-git-send-email-michalx.k.jastrzebski@intel.com>
 <1469198030-8664-1-git-send-email-michalx.k.jastrzebski@intel.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7Bit
Cc: bruce.richardson@intel.com, dev@dpdk.org, michalx.kobylinski@intel.com,
 sergio.gonzalez.monroy@intel.com, david.marchand@6wind.com
To: Michal Jastrzebski <michalx.k.jastrzebski@intel.com>
Return-path: <dev-bounces@dpdk.org>
Received: from mail-wm0-f51.google.com (mail-wm0-f51.google.com [74.125.82.51])
 by dpdk.org (Postfix) with ESMTP id 924762BE2
 for <dev@dpdk.org>; Fri, 22 Jul 2016 17:24:53 +0200 (CEST)
Received: by mail-wm0-f51.google.com with SMTP id o80so71403805wme.1
 for <dev@dpdk.org>; Fri, 22 Jul 2016 08:24:53 -0700 (PDT)
In-Reply-To: <1469198030-8664-1-git-send-email-michalx.k.jastrzebski@intel.com>
List-Id: patches and discussions about DPDK <dev.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

2016-07-22 16:33, Michal Jastrzebski:
> v2:
> -moved close(fd) just after read.
> -when read() from fd we expect 8 bytes, so PFN_MASK_SIZE macro 
> was introduced instead sizeof(uint64_t).
> -removed errno print when read returns less than 8 bytes

Looks better.
Note: this changelog should be below --- to avoid appearing in
the commit.

> In rte_mem_virt2phy: Value returned from a function and indicating the
> number of bytes was ignored. This could cause a wrong pfn (page frame
> number) mask read from pagemap file.
> When read returns less than the number of sizeof(uint64_t) bytes,
> function rte_mem_virt2phy returns error.

Better title to explain the issue:
mem: fix check of physical address retrieval

> +#define PFN_MASK_SIZE	8
> +
>  #ifdef RTE_LIBRTE_XEN_DOM0
>  int rte_xen_dom0_supported(void)
>  {
> @@ -158,7 +160,7 @@ rte_mem_lock_page(const void *virt)
>  phys_addr_t
>  rte_mem_virt2phy(const void *virtaddr)
>  {
> -	int fd;
> +	int fd, retval;
>  	uint64_t page, physaddr;
>  	unsigned long virt_pfn;
>  	int page_size;
> @@ -209,10 +211,19 @@ rte_mem_virt2phy(const void *virtaddr)
>  		close(fd);
>  		return RTE_BAD_PHYS_ADDR;
>  	}
> -	if (read(fd, &page, sizeof(uint64_t)) < 0) {
> +
> +	retval = read(fd, &page, sizeof(uint64_t));

We could use PFN_MASK_SIZE here

> +	close(fd);
> +	if (retval < 0) {
>  		RTE_LOG(ERR, EAL, "%s(): cannot read /proc/self/pagemap: %s\n",
>  				__func__, strerror(errno));
> -		close(fd);
> +

useless whitespace

> +		return RTE_BAD_PHYS_ADDR;
> +	} else if (retval != PFN_MASK_SIZE) {
> +		RTE_LOG(ERR, EAL, "%s(): read %d bytes from /proc/self/pagemap "
> +				"but expected %d:\n",
> +				__func__, retval, PFN_MASK_SIZE);
> +

useless whitespace

>  		return RTE_BAD_PHYS_ADDR;
>  	}
>  
> @@ -222,7 +233,7 @@ rte_mem_virt2phy(const void *virtaddr)
>  	 */
>  	physaddr = ((page & 0x7fffffffffffffULL) * page_size)
>  		+ ((unsigned long)virtaddr % page_size);
> -	close(fd);
> +
>  	return physaddr;
>  }

If you and Sergio agree, I can make the minor changes before applying.