[PATCH 3.16 011/136] iommu/vt-d: Don't register bus-notifier under dmar_global_lock
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STALE3177d
From: Ben Hutchings <hidden>
Date: 2018-02-11 04:58:03
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3.16.54-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Joerg Roedel <redacted>
commit ec154bf56b276a0bb36079a5d22a267b5f417801 upstream.
The notifier function will take the dmar_global_lock too, so
lockdep complains about inverse locking order when the
notifier is registered under the dmar_global_lock.
Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Fixes: 59ce0515cdaf ('iommu/vt-d: Update DRHD/RMRR/ATSR device scope caches when PCI hotplug happens')
Signed-off-by: Joerg Roedel <redacted>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <redacted>
---
drivers/iommu/dmar.c | 7 +++++--
drivers/iommu/intel-iommu.c | 10 ++++++++++
include/linux/dmar.h | 1 +
3 files changed, 16 insertions(+), 2 deletions(-)
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c@@ -718,13 +718,16 @@ int __init dmar_dev_scope_init(void) dmar_free_pci_notify_info(info); } } - - bus_register_notifier(&pci_bus_type, &dmar_pci_bus_nb); } return dmar_dev_scope_status; } +void dmar_register_bus_notifier(void) +{ + bus_register_notifier(&pci_bus_type, &dmar_pci_bus_nb); +} + int __init dmar_table_init(void) { --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c
@@ -4044,6 +4044,16 @@ int __init intel_iommu_init(void) goto out_free_dmar; } + up_write(&dmar_global_lock); + + /* + * The bus notifier takes the dmar_global_lock, so lockdep will + * complain later when we register it under the lock. + */ + dmar_register_bus_notifier(); + + down_write(&dmar_global_lock); + if (no_iommu || dmar_disabled) goto out_free_dmar; --- a/include/linux/dmar.h +++ b/include/linux/dmar.h
@@ -100,6 +100,7 @@ static inline bool dmar_rcu_check(void) extern int dmar_table_init(void); extern int dmar_dev_scope_init(void); +extern void dmar_register_bus_notifier(void); extern int dmar_parse_dev_scope(void *start, void *end, int *cnt, struct dmar_dev_scope **devices, u16 segment); extern void *dmar_alloc_dev_scope(void *start, void *end, int *cnt);