diff options
| author | Lijun Pan <ljp@linux.ibm.com> | 2021-01-29 19:19:04 -0600 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2021-02-01 20:21:12 -0800 |
| commit | 665ab1eb18d7e8eaa8377fb8bf4924bfeb63bbce (patch) | |
| tree | 85ab6b88507ea97575cf1e2a1b644fc8f5079e5b /drivers/net/ethernet/ibm/ibmvnic.c | |
| parent | 1a2b60f6f16527ce404a41ad4d201df9422e9aad (diff) | |
ibmvnic: rework to ensure SCRQ entry reads are properly ordered
Move the dma_rmb() between pending_scrq() and ibmvnic_next_scrq()
into the end of pending_scrq() to save the duplicated code since
this dma_rmb will be used 3 times.
Signed-off-by: Lijun Pan <ljp@linux.ibm.com>
Acked-by: Thomas Falcon <tlfalcon@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers/net/ethernet/ibm/ibmvnic.c')
| -rw-r--r-- | drivers/net/ethernet/ibm/ibmvnic.c | 30 |
1 files changed, 11 insertions, 19 deletions
diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c index a40af510018a..331ebca2f57a 100644 --- a/drivers/net/ethernet/ibm/ibmvnic.c +++ b/drivers/net/ethernet/ibm/ibmvnic.c @@ -2444,12 +2444,6 @@ restart_poll: if (!pending_scrq(adapter, rx_scrq)) break; - /* The queue entry at the current index is peeked at above - * to determine that there is a valid descriptor awaiting - * processing. We want to be sure that the current slot - * holds a valid descriptor before reading its contents. - */ - dma_rmb(); next = ibmvnic_next_scrq(adapter, rx_scrq); rx_buff = (struct ibmvnic_rx_buff *)be64_to_cpu(next-> @@ -3189,13 +3183,6 @@ restart_loop: int total_bytes = 0; int num_packets = 0; - /* The queue entry at the current index is peeked at above - * to determine that there is a valid descriptor awaiting - * processing. We want to be sure that the current slot - * holds a valid descriptor before reading its contents. - */ - dma_rmb(); - next = ibmvnic_next_scrq(adapter, scrq); for (i = 0; i < next->tx_comp.num_comps; i++) { if (next->tx_comp.rcs[i]) @@ -3569,11 +3556,16 @@ static int pending_scrq(struct ibmvnic_adapter *adapter, struct ibmvnic_sub_crq_queue *scrq) { union sub_crq *entry = &scrq->msgs[scrq->cur]; + int rc; - if (entry->generic.first & IBMVNIC_CRQ_CMD_RSP) - return 1; - else - return 0; + rc = !!(entry->generic.first & IBMVNIC_CRQ_CMD_RSP); + + /* Ensure that the SCRQ valid flag is loaded prior to loading the + * contents of the SCRQ descriptor + */ + dma_rmb(); + + return rc; } static union sub_crq *ibmvnic_next_scrq(struct ibmvnic_adapter *adapter, @@ -3592,8 +3584,8 @@ static union sub_crq *ibmvnic_next_scrq(struct ibmvnic_adapter *adapter, } spin_unlock_irqrestore(&scrq->lock, flags); - /* Ensure that the entire buffer descriptor has been - * loaded before reading its contents + /* Ensure that the SCRQ valid flag is loaded prior to loading the + * contents of the SCRQ descriptor */ dma_rmb(); |