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Add a check for vme_bus_numbers == ~0UL before calling ffz(). Replace the manual loop with ffz() and use BIT(n) for consistency. Suggested-by: David Laight Signed-off-by: Dharanitharan R --- drivers/staging/vme_user/vme.c | 15 +++++++++++++---------- 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/drivers/staging/vme_user/vme.c b/drivers/staging/vme_user/vme.c index 2095de72596a..45381e677475 100644 --- a/drivers/staging/vme_user/vme.c +++ b/drivers/staging/vme_user/vme.c @@ -1765,16 +1765,19 @@ int vme_register_bridge(struct vme_bridge *bridge) int ret = -1; mutex_lock(&vme_buses_lock); - for (i = 0; i < sizeof(vme_bus_numbers) * 8; i++){ - if ((vme_bus_numbers & (1 << i)) == 0) { - vme_bus_numbers |= (1 << i); - bridge->num = i; - INIT_LIST_HEAD(&bridge->devices); - list_add_tail(&bridge->bus_list, &vme_bus_list); - ret = 0; - break; - } + /* Ensure we have a free slot before using ffz() */ + if (vme_bus_numbers == ~0UL) + goto out; /* No free bus number */ + + /* Find the first clear bit */ + i = ffz(vme_bus_numbers); + + vme_bus_numbers |= BIT(i); + bridge->num = i; + INIT_LIST_HEAD(&bridge->devices); + list_add_tail(&bridge->bus_list, &vme_bus_list); + ret = 0; + +out: mutex_unlock(&vme_buses_lock); return ret; @@ -1787,7 +1790,7 @@ void vme_unregister_bridge(struct vme_bridge *bridge) struct vme_dev *tmp; mutex_lock(&vme_buses_lock); - vme_bus_numbers &= ~(1 << bridge->num); + vme_bus_numbers &= ~BIT(bridge->num); list_for_each_entry_safe(vdev, tmp, &bridge->devices, bridge_list) { list_del(&vdev->drv_list); list_del(&vdev->bridge_list); -- 2.43.0