[PATCH net v3] pds_core: keep the health thread stopped during reset

["Nikhil P. Rao" <nikhil.rao@amd.com>]

Commit d9407ff11809 ("pds_core: Prevent health thread from running
during reset/remove") stops the health thread with cancel_work_sync()
before a reset, but a devcmd timeout during pdsc_fw_down() re-queues
health_work, so pdsc_health_thread() runs again mid-reset and double
allocates the core DMA queues via pdsc_fw_up().

Only the reset path is affected: on remove PDSC_S_STOPPING_DRIVER gates
the health thread and the workqueue is destroyed.

Use disable_work_sync() to cancel health_work and block further
queue_work() on it, and enable_work() in pdsc_restart_health_thread() to
re-allow it after the reset.

disable_work_sync() keeps a disable depth, so every disable must be
matched by one enable. pdsc_reset_prepare() stops the health thread and
pdsc_reset_done() restarts it. On the AER path pdsc_pci_error_detected()
calls pdsc_reset_prepare(), then pdsc_pci_error_resume() re-inits via
pci_reset_function_locked() (pds_core has no .slot_reset handler), which
runs the pair again - stopping the thread twice but restarting it once.
Gate the disable and enable on a health_stopped flag so each fires at
most once per stopped/running transition.

Fixes: d9407ff11809 ("pds_core: Prevent health thread from running during reset/remove")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260629200358.2626129-1-nikhil.rao%40amd.com?part=2
Signed-off-by: Nikhil P. Rao <nikhil.rao@amd.com>
---
 drivers/net/ethernet/amd/pds_core/core.h |  1 +
 drivers/net/ethernet/amd/pds_core/main.c | 10 ++++++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/amd/pds_core/core.h b/drivers/net/ethernet/amd/pds_core/core.h
index b7fe9ad73349..a1d41329209f 100644
--- a/drivers/net/ethernet/amd/pds_core/core.h
+++ b/drivers/net/ethernet/amd/pds_core/core.h
@@ -171,6 +171,7 @@ struct pdsc {
 	struct timer_list wdtimer;
 	unsigned int wdtimer_period;
 	struct work_struct health_work;
+	bool health_stopped;
 	struct devlink_health_reporter *fw_reporter;
 	u32 fw_recoveries;
 
diff --git a/drivers/net/ethernet/amd/pds_core/main.c b/drivers/net/ethernet/amd/pds_core/main.c
index 8d94a4d70395..71a1d4b001c2 100644
--- a/drivers/net/ethernet/amd/pds_core/main.c
+++ b/drivers/net/ethernet/amd/pds_core/main.c
@@ -470,8 +470,10 @@ static void pdsc_stop_health_thread(struct pdsc *pdsc)
 		return;
 
 	timer_shutdown_sync(&pdsc->wdtimer);
-	if (pdsc->health_work.func)
-		cancel_work_sync(&pdsc->health_work);
+	if (pdsc->health_work.func && !pdsc->health_stopped) {
+		disable_work_sync(&pdsc->health_work);
+		pdsc->health_stopped = true;
+	}
 }
 
 static void pdsc_restart_health_thread(struct pdsc *pdsc)
@@ -479,6 +481,10 @@ static void pdsc_restart_health_thread(struct pdsc *pdsc)
 	if (pdsc->pdev->is_virtfn)
 		return;
 
+	if (pdsc->health_stopped) {
+		enable_work(&pdsc->health_work);
+		pdsc->health_stopped = false;
+	}
 	timer_setup(&pdsc->wdtimer, pdsc_wdtimer_cb, 0);
 	mod_timer(&pdsc->wdtimer, jiffies + 1);
 }
-- 
2.43.0