1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 1b9951d2067e..d668682f91df 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -316,6 +316,14 @@ static bool nvme_dbbuf_update_and_check_event(u16 value, u32 *dbbuf_db,
                 old_value = *dbbuf_db;
                 *dbbuf_db = value;
 
+                /*
+                 * Ensure that the doorbell is updated before reading the event
+                 * index from memory.  The controller needs to provide similar
+                 * ordering to ensure the envent index is updated before reading
+                 * the doorbell.
+                 */
+                mb();
+
                 if (!nvme_dbbuf_need_event(*dbbuf_ei, value, old_value))
                         return false;
         }