Re: [libvirt] [PATCH] util: Fix configure.ac check for DEVLINK_CMD_ESWITCH_GET

On Tue, 2017-09-19 at 07:27 -0400, John Ferlan wrote: >> First of all, you're removing a number of checks >> on unrelated symbols >> that are still used in the code, and if any of those is not present >> then we shouldn't compile the relevant bits at all. > > I checked - up through 4.8 "most" are available. At 4.8 the *ESWITCH* > ones were added. Checking for a minimum version for a symbol is > something we do in other code under the assumption that any symbol that > is in a counted enum/list for a command or structure before it is > available. Otherwise, we'd have more symbol and field checking all over > the place. Okay, I see what you were aiminig for now, and I don't disagree with it; however, the rationale was not explained clearly in the original commit message.

>> Second, we're using >> DEVLINK_CMD_ESWITCH_GET in the code, but as you >> explain that version is only available in newer kernels. >> >> I think the approach need to be more nuanced: >> >> - use >> DEVLINK_CMD_ESWITCH_GET or DEVLINK_CMD_ESWITCH_MODE_GET, >> depending on which on is available, with the former one being the >> preferred option; > > That's another option to what I posted a few moments ago to use: > > # ifndef... Sure, that would work too, and look a little bit better than what I proposed.