RDMA/bnxt_re: Add sanity checks on rdev validity

There is a possibility that ulp_irq_stop and ulp_irq_start
callbacks will be called when the device is in detached state.
This can cause a crash due to NULL pointer dereference as
the rdev is already freed.

Fixes: cc5b9b4 ("RDMA/bnxt_re: Recover the device when FW error is detected")
Signed-off-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Link: https://patch.msgid.link/1738657285-23968-3-git-send-email-selvin.xavier@broadcom.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>

Author: Kalesh AP

drivers/infiniband/hw/bnxt_re/main.c

@@ -438,6 +438,8 @@ static void bnxt_re_stop_irq(void *handle, bool reset)
 	int indx;
 
 	rdev = en_info->rdev;
+	if (!rdev)
+		return;
 	rcfw = &rdev->rcfw;
 
 	if (reset) {
@@ -466,6 +468,8 @@ static void bnxt_re_start_irq(void *handle, struct bnxt_msix_entry *ent)
 	int indx, rc;
 
 	rdev = en_info->rdev;
+	if (!rdev)
+		return;
 	msix_ent = rdev->nqr->msix_entries;
 	rcfw = &rdev->rcfw;
 	if (!ent) {
@@ -2438,6 +2442,7 @@ static int bnxt_re_suspend(struct auxiliary_device *adev, pm_message_t state)
 	ibdev_info(&rdev->ibdev, "%s: L2 driver notified to stop en_state 0x%lx",
 		   __func__, en_dev->en_state);
 	bnxt_re_remove_device(rdev, BNXT_RE_PRE_RECOVERY_REMOVE, adev);
+	bnxt_re_update_en_info_rdev(NULL, en_info, adev);
 	mutex_unlock(&bnxt_re_mutex);
 
 	return 0;