Re: [PATCH net-next v5 3/3] tsnep: Add TSN endpoint Ethernet MAC driver

On Mon, Nov 15, 2021 at 11:21 PM Heiner Kallweit [off-list ref] wrote:

On 15.11.2021 21:50, Gerhard Engleder wrote:

quoted

+     /* entry->properties shall be valid before write pointer is
+      * incrememted
+      */
+     wmb();

A lighter variant like smp_wmb() is not sufficient here?

This is some leftover from lockless descriptor ring processing, which has
been replaced by a spinlock. I will remove it.

quoted

+             dma_rmb();
+

Memory barriers should always have a comment explaining why
they are needed. I think checkpatch would complain here.

I don't see any checkpatch warning, but you are right. I will document
all DMA memory barriers.

Gerhard