iommu: dmar: Fix RCU list debugging warnings
PATCH 1/1 iommu: dmar: Fix RCU list debugging warnings
dmar_drhd_units is traversed using list_for_each_entry_rcu() outside of an RCU read side critical section but under the protection of dmar_global_lock. Hence add corresponding lockdep expression to silence the following false-positive warnings:
[ 1.603975] ============================= [ 1.603976] WARNING: suspicious RCU usage [ 1.603977] 5.5.4-stable #17 Not tainted [ 1.603978] ----------------------------- [ 1.603980] drivers/iommu/intel-iommu.c:4769 RCU-list traversed in non-reader section!!
[ 1.603869] ============================= [ 1.603870] WARNING: suspicious RCU usage [ 1.603872] 5.5.4-stable #17 Not tainted [ 1.603874] ----------------------------- [ 1.603875] drivers/iommu/dmar.c:293 RCU-list traversed in non-reader section!!
Tested-by Madhuparna Bhowmik <[email protected]>
Signed-off-by Amol Grover <[email protected]>
--- include/linux/dmar.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
include/linux/dmar.h +5 -3
@@ -69,8 +69,9 @@ struct dmar_pci_notify_info {extern struct rw_semaphore dmar_global_lock;extern struct list_head dmar_drhd_units; -#define for_each_drhd_unit (drhd) \ - list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) +#define for_each_drhd_unit (drhd) \ + list_for_each_entry_rcu(drhd, &dmar_drhd_units, list, \ + dmar_rcu_check())#define for_each_active_drhd_unit (drhd) \ list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \
@@ -81,7 +82,8 @@ extern struct list_head dmar_drhd_units; if (i=drhd->iommu, drhd->ignored) {} else#define for_each_iommu (i, drhd) \ - list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \ + list_for_each_entry_rcu(drhd, &dmar_drhd_units, list, \ + dmar_rcu_check()) \ if (i=drhd->iommu, 0) {} elsestatic inline bool dmar_rcu_check (void )
Signature · 1 line
2.24.1