Re: [dpdk-dev] [PATCH v2] eal: fix check number of bytes from read function

[Thomas Monjalon <thomas.monjalon@6wind.com>]

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.