On Wed, Dec 23, 2015 at 11:03 AM, Or Gerlitz <ogerlitz@xxxxxxxxxxxx> wrote: > On 12/22/2015 11:37 PM, Or Gerlitz wrote: >> >> On Tue, Dec 15, 2015 at 8:30 PM, Matan Barak<matanb@xxxxxxxxxxxx> wrote: >>> >>> >Pass hca_core_clock_offset to user-space is mandatory in order to >>> >let the user-space read the free-running clock register from the >>> >right offset in the memory mapped page. >>> >Passing this value is done by changing the vendor's command >>> >and response of init_ucontext to be in extensible form. >> >> Is "old" (unpatched) libmlx5 still operational over "new" (patched) >> mlx5 IB driver? > > > and same question for the other way around as well > new kernel, old lib - response length is initialized to min(offsetof(typeof(resp), response_length) + sizeof(resp.response_length), udata->outlen); I this case, we initialize it to udata->outlen, so the user-space gets exactly the same information as before. new lib, old kernel - the response is cleared before it is sent to the kernel. The command size has stayed the same. So - (reqlen == sizeof(struct mlx5_ib_alloc_ucontext_req_v2)) still holds true. Since the kernel isn't familiar with the new response fields, it doesn't copy them. Hence the response's comp_mask is still zero and libmlx5 knows that hca_core_clock isn't supported. Matan > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
