On Mon, Oct 02, 2017 at 10:37:11AM -0400, Rob Clark wrote: > Fixes intermittent corruption of cmdstream dump. > > Signed-off-by: Rob Clark <robdclark@xxxxxxxxx> Rule of memory barriers: They always need to come in pairs, and you should put a comment to each one explaining where the other side is. I.e. for all the store_release ones you add here you need to put a few read_acquire ones somewhere else, and then explain how they link. One side only doesn't really work with barriers - except when you're lucky and on x86 :-) -Daniel > --- > drivers/gpu/drm/msm/msm_rd.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/msm/msm_rd.c b/drivers/gpu/drm/msm/msm_rd.c > index 5c087a4228ff..918c65e19964 100644 > --- a/drivers/gpu/drm/msm/msm_rd.c > +++ b/drivers/gpu/drm/msm/msm_rd.c > @@ -120,7 +120,7 @@ static void rd_write(struct msm_rd_state *rd, const void *buf, int sz) > n = min(sz, circ_space_to_end(&rd->fifo)); > memcpy(fptr, ptr, n); > > - fifo->head = (fifo->head + n) & (BUF_SZ - 1); > + smp_store_release(&fifo->head, (fifo->head + n) & (BUF_SZ - 1)); > sz -= n; > ptr += n; > > @@ -157,7 +157,7 @@ static ssize_t rd_read(struct file *file, char __user *buf, > goto out; > } > > - fifo->tail = (fifo->tail + n) & (BUF_SZ - 1); > + smp_store_release(&fifo->tail, (fifo->tail + n) & (BUF_SZ - 1)); > *ppos += n; > > wake_up_all(&rd->fifo_event); > -- > 2.13.5 > > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
