iommu/vt-d: Fix an unbalanced rcu_read_lock/rcu_read_unlock()

commit 4e5973dd2725bb30c3db622f7d73f7a5864ce718 upstream.

If we return -EOPNOTSUPP, the rcu lock remains lock. This is spurious.
Go through the end of the function instead. This way, the missing
'rcu_read_unlock()' is called.

Fixes: 7afd7f6aa21a ("iommu/vt-d: Check FL and SL capability sanity in scalable mode")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/40cc077ca5f543614eab2a10e84d29dd190273f6.1636217517.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20211126135556.397932-2-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/iommu/intel/cap_audit.c b/drivers/iommu/intel/cap_audit.c
index b39d223926a491cd26db5f9573bb1b9b1614ca22..71596fc62822c36d76a8f7ac4c9232b96e5bc6cc 100644 (file)
--- a/drivers/iommu/intel/cap_audit.c
+++ b/drivers/iommu/intel/cap_audit.c
@@ -144,6 +144,7 @@ static int cap_audit_static(struct intel_iommu *iommu, enum cap_audit_type type)
 {
        struct dmar_drhd_unit *d;
        struct intel_iommu *i;
+       int rc = 0;
 
        rcu_read_lock();
        if (list_empty(&dmar_drhd_units))
@@ -169,11 +170,11 @@ static int cap_audit_static(struct intel_iommu *iommu, enum cap_audit_type type)
         */
        if (intel_cap_smts_sanity() &&
            !intel_cap_flts_sanity() && !intel_cap_slts_sanity())
-               return -EOPNOTSUPP;
+               rc = -EOPNOTSUPP;
 
 out:
        rcu_read_unlock();
-       return 0;
+       return rc;
 }
 
 int intel_cap_audit(enum cap_audit_type type, struct intel_iommu *iommu)