On Fri, Jul 12, 2019 at 3:05 PM Bernard Metzler <BMT@xxxxxxxxxxxxxx> wrote: > > We share CQ (completion queue) notification flags between application > (which may be user land) and producer (kernel QP's (queue pairs)). > Those flags can be written by both application and QP's. The application > writes those flags to let the driver know if it shall inform about new > work completions. It can write those flags at any time. > Only a kernel producer reads those flags to decide if > the CQ notification handler shall be kicked, if a new CQ element gets > added to the CQ. When kicking the completion handler, the driver resets the > notification flag, which must get re-armed by the application. > > We use READ_ONCE() and WRITE_ONCE(), since the flags are potentially > shared (mmap'd) between user and kernel land. > > siw_req_notify_cq() is being called only by kernel consumers to change > (write) the CQ notification state. We use smp_store_mb() to make sure > the new value becomes visible to all kernel producers (QP's) asap. > > > From cfb861a09dcfb24a98ba0f1e26bdaa1529d1b006 Mon Sep 17 00:00:00 2001 > From: Bernard Metzler <bmt@xxxxxxxxxxxxxx> > Date: Fri, 12 Jul 2019 13:19:27 +0200 > Subject: [PATCH] Make shared CQ notification flags 32bit to respect 32bit > architectures > > Signed-off-by: Bernard Metzler <bmt@xxxxxxxxxxxxxx> This fixes the build for me, thanks! Tested-by: Arnd Bergmann <arnd@xxxxxxxx>
