mhi: core: add memory barrier after ring operations (1edf9d02) · Commits · e / devices / android_kernel_xiaomi_markw

There are instances when MHI channel context read pointer can be accessed simultaneously by different CPU cores. To make sure read pointer updates visible to all cores, add a memory barrier after completion of MHI ring operation. CRs-Fixed: 966338 Change-Id: Ifc8c4cd7595fed9049009c42420a665fb170079f Signed-off-by:

Sujeev Dias <sdias@codeaurora.org>

drivers/platform/msm/mhi/mhi_ring_ops.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -48,6 +48,9 @@ static int add_element(struct mhi_ring ring, void *rp,
		assigned_addr = (char )ring->wp;
		wp = (void )(((d_wp + 1) % ring_size) * ring->el_size +
		(uintptr_t)ring->base);

		/* force update visible to other cores */
		smp_wmb();
		return 0;
		}

		@@ -101,6 +104,9 @@ int delete_element(struct mhi_ring ring, void *rp,

		rp = (void )(((d_rp + 1) % ring_size) * ring->el_size +
		(uintptr_t)ring->base);

		/* force update visible to other cores */
		smp_wmb();
		return 0;
		}