On 2/1/2017 12:57 PM, Adrien Mazarguil wrote:

On Wed, Feb 01, 2017 at 11:13:59AM +0000, Ferruh Yigit wrote:

quoted

On 2/1/2017 9:07 AM, Adrien Mazarguil wrote:

quoted

On Wed, Feb 01, 2017 at 06:53:55AM +0000, Shahaf Shuler wrote:

quoted

: Tuesday, January 31, 2017 6:17 PM, Ferruh Yigit:

quoted

On 1/31/2017 11:45 AM, Shahaf Shuler wrote:

quoted

Trying to query the link status through new kernel ioctl API
ETHTOOL_GLINKSETTINGS was always failing due to kernel bug.
The bug was fixed on version 4.9
this patch uses the legacy ioctl API for lower kernels.

Fixes: 188408719888 ("net/mlx5: fix support for newer link speeds")
CC: stable@dpdk.org

Signed-off-by: Shahaf Shuler <redacted>
---

<...>

quoted

@@ -707,7 +708,7 @@ struct priv *
 static int
 mlx5_link_update_unlocked_gs(struct rte_eth_dev *dev, int

wait_to_complete)  { -#ifdef ETHTOOL_GLINKSETTINGS
+#if KERNEL_VERSION(4, 9, 0) <= LINUX_VERSION_CODE

Mostly it is not good idea to do kernel version check in the .c file.

It is possible to move this comparison to the .h file, and set a feature
macro based on comparison result, like HAVE_ETHTOOL_GLINKSETTINGS,
and
use this macro in the .c file.

This makes .c code easier to understand. And the abstraction in the
header file lets you update the comparison in the future without
changing the code itself.

But it is your call, do you prefer to continue with this one?

This is a good suggestion. 
Adrien, Nélio what do you think?

Let's include this patch as-is. Doing so in a header file such as mlx5.h
would require including linux/version.h from that file and cause the entire
PMD to be even more OS-dependent.

We'll move this check elsewhere in the future if we need several such
workarounds, thanks.

OK.

One more thing, comment log says:
"The bug was fixed on version 4.9"

And code does:
"+#if KERNEL_VERSION(4, 9, 0) <= LINUX_VERSION_CODE"

If the bug is fixed in 4.9, should check be "<" instead of "<="

I'll concede the argument order used in this condition is somewhat unusual
but it actually ends up being the same as:

 #if LINUX_VERSION_CODE > KERNEL_VERSION(4, 9, 0)

I don't think they are same, unless I am missing something obvious.

"+#if KERNEL_VERSION(4, 9, 0) <= LINUX_VERSION_CODE"
vs
"#if LINUX_VERSION_CODE > KERNEL_VERSION(4, 9, 0)"

Even if you change the argument order, one covers 4.9 release other not.

Which is the correct intent. I guess you can update this line for clarity if
you think it's necessary.

If the intention is as following, I can fix it while applying:
#if KERNEL_VERSION(4, 9, 0) < LINUX_VERSION_CODE

quoted

quoted

quoted

quoted

quoted

 	struct priv *priv = mlx5_get_priv(dev);
 	struct ethtool_link_settings edata = {
 		.cmd = ETHTOOL_GLINKSETTINGS,

<...>