[PATCH V3 net-next 10/14] net/ena: use READ_ONCE to access completion descriptors
From: Netanel Belgazal <hidden>
Date: 2017-01-26 22:18:55
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Subsystem:
amazon ethernet drivers, networking drivers, the rest · Maintainers:
Arthur Kiyanovski, David Arinzon, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Completion descriptors are accessed from the driver and from the device. To avoid reading the old value, use READ_ONCE macro. Signed-off-by: Netanel Belgazal <redacted> --- drivers/net/ethernet/amazon/ena/ena_com.h | 1 + drivers/net/ethernet/amazon/ena/ena_eth_com.c | 8 ++++---- 2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/amazon/ena/ena_com.h b/drivers/net/ethernet/amazon/ena/ena_com.h
index 509d7b8..c9b33ee 100644
--- a/drivers/net/ethernet/amazon/ena/ena_com.h
+++ b/drivers/net/ethernet/amazon/ena/ena_com.h@@ -33,6 +33,7 @@ #ifndef ENA_COM #define ENA_COM +#include <linux/compiler.h> #include <linux/delay.h> #include <linux/dma-mapping.h> #include <linux/gfp.h>
diff --git a/drivers/net/ethernet/amazon/ena/ena_eth_com.c b/drivers/net/ethernet/amazon/ena/ena_eth_com.c
index 539c536..f999305 100644
--- a/drivers/net/ethernet/amazon/ena/ena_eth_com.c
+++ b/drivers/net/ethernet/amazon/ena/ena_eth_com.c@@ -45,7 +45,7 @@ static inline struct ena_eth_io_rx_cdesc_base *ena_com_get_next_rx_cdesc( cdesc = (struct ena_eth_io_rx_cdesc_base *)(io_cq->cdesc_addr.virt_addr + (head_masked * io_cq->cdesc_entry_size_in_bytes)); - desc_phase = (cdesc->status & ENA_ETH_IO_RX_CDESC_BASE_PHASE_MASK) >> + desc_phase = (READ_ONCE(cdesc->status) & ENA_ETH_IO_RX_CDESC_BASE_PHASE_MASK) >> ENA_ETH_IO_RX_CDESC_BASE_PHASE_SHIFT; if (desc_phase != expected_phase)
@@ -141,7 +141,7 @@ static inline u16 ena_com_cdesc_rx_pkt_get(struct ena_com_io_cq *io_cq, ena_com_cq_inc_head(io_cq); count++; - last = (cdesc->status & ENA_ETH_IO_RX_CDESC_BASE_LAST_MASK) >> + last = (READ_ONCE(cdesc->status) & ENA_ETH_IO_RX_CDESC_BASE_LAST_MASK) >> ENA_ETH_IO_RX_CDESC_BASE_LAST_SHIFT; } while (!last);
@@ -489,13 +489,13 @@ int ena_com_tx_comp_req_id_get(struct ena_com_io_cq *io_cq, u16 *req_id) * expected, it mean that the device still didn't update * this completion. */ - cdesc_phase = cdesc->flags & ENA_ETH_IO_TX_CDESC_PHASE_MASK; + cdesc_phase = READ_ONCE(cdesc->flags) & ENA_ETH_IO_TX_CDESC_PHASE_MASK; if (cdesc_phase != expected_phase) return -EAGAIN; ena_com_cq_inc_head(io_cq); - *req_id = cdesc->req_id; + *req_id = READ_ONCE(cdesc->req_id); return 0; }
--
2.7.4