[Intel-wired-lan] [PATCH iwl-net v2 4/5] i40e: replace reset polling with wait-bit synchronization

From: Xuanqiang Luo <[email protected]>

i40e_remove() polls on RESET_RECOVERY_PENDING with a fixed sleep while
waiting for an existing reset owner. This adds teardown latency and does
not provide a wait queue for the reset owner to wake.

Use wait_on_bit_lock() so removal sleeps until the reset owner releases the
bit and then atomically claims it. Pair the reset release paths with
clear_and_wake_up_bit() to provide the required release and wakeup
semantics.

Fixes: 5b6d4a7f20b0 ("i40e: Fix crash during removing i40e driver")
Signed-off-by: Xuanqiang Luo <[email protected]>
---
 drivers/net/ethernet/intel/i40e/i40e_main.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 5922f83f324ae..c19d4c81d6532 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -7,6 +7,7 @@
 #include <linux/if_bridge.h>
 #include <linux/if_macvlan.h>
 #include <linux/module.h>
+#include <linux/wait_bit.h>
 #include <net/pkt_cls.h>
 #include <net/xdp_sock_drv.h>
 
@@ -10822,7 +10823,8 @@ static int i40e_reset(struct i40e_pf *pf)
 	if (ret) {
 		dev_info(&pf->pdev->dev, "PF reset failed, %d\n", ret);
 		set_bit(__I40E_RESET_FAILED, pf->state);
-		clear_bit(__I40E_RESET_RECOVERY_PENDING, pf->state);
+		clear_and_wake_up_bit(__I40E_RESET_RECOVERY_PENDING,
+				      pf->state);
 	} else {
 		pf->pfr_count++;
 	}
@@ -11115,7 +11117,7 @@ static void i40e_rebuild(struct i40e_pf *pf, bool reinit, bool lock_acquired)
 end_core_reset:
 	clear_bit(__I40E_RESET_FAILED, pf->state);
 clear_recovery:
-	clear_bit(__I40E_RESET_RECOVERY_PENDING, pf->state);
+	clear_and_wake_up_bit(__I40E_RESET_RECOVERY_PENDING, pf->state);
 	clear_bit(__I40E_TIMEOUT_RECOVERY_PENDING, pf->state);
 }
 
@@ -16169,8 +16171,8 @@ static void i40e_remove(struct pci_dev *pdev)
 		disable_work_sync(&pf->service_task);
 
 	/* Wait for any reset owner before tearing down device resources. */
-	while (test_and_set_bit(__I40E_RESET_RECOVERY_PENDING, pf->state))
-		usleep_range(1000, 2000);
+	wait_on_bit_lock(pf->state, __I40E_RESET_RECOVERY_PENDING,
+			 TASK_UNINTERRUPTIBLE);
 	set_bit(__I40E_IN_REMOVE, pf->state);
 
 	i40e_dbg_pf_exit(pf);
-- 
2.43.0