net: ena: fix missing calls to READ_ONCE

BugLink: http://bugs.launchpad.net/bugs/1792044

Add READ_ONCE calls where necessary (for example when iterating
over a memory field that gets updated by the hardware).
Signed-off-by: Netanel Belgazal <netanel@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 28abf4e9 linux-next)
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Acked-by: Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/net/ethernet/amazon/ena/ena_com.c

@@ -459,7 +459,7 @@ static void ena_com_handle_admin_completion(struct ena_com_admin_queue *admin_qu
 	cqe = &admin_queue->cq.entries[head_masked];
 
 	/* Go over all the completions */
-	while ((cqe->acq_common_descriptor.flags &
+	while ((READ_ONCE(cqe->acq_common_descriptor.flags) &
 			ENA_ADMIN_ACQ_COMMON_DESC_PHASE_MASK) == phase) {
 		/* Do not read the rest of the completion entry before the
 		 * phase bit was validated
@@ -637,7 +637,7 @@ static u32 ena_com_reg_bar_read32(struct ena_com_dev *ena_dev, u16 offset)
 
 	mmiowb();
 	for (i = 0; i < timeout; i++) {
-		if (read_resp->req_id == mmio_read->seq_num)
+		if (READ_ONCE(read_resp->req_id) == mmio_read->seq_num)
 			break;
 
 		udelay(1);
@@ -1796,8 +1796,8 @@ void ena_com_aenq_intr_handler(struct ena_com_dev *dev, void *data)
 	aenq_common = &aenq_e->aenq_common_desc;
 
 	/* Go over all the events */
-	while ((aenq_common->flags & ENA_ADMIN_AENQ_COMMON_DESC_PHASE_MASK) ==
-	       phase) {
+	while ((READ_ONCE(aenq_common->flags) &
+		ENA_ADMIN_AENQ_COMMON_DESC_PHASE_MASK) == phase) {
 		pr_debug("AENQ! Group[%x] Syndrom[%x] timestamp: [%llus]\n",
 			 aenq_common->group, aenq_common->syndrom,
 			 (u64)aenq_common->timestamp_low +