[PATCH v1 3/5] iommu: Convert gdev->blocked from bool to enum blocked_reason

[Nicolin Chen <nicolinc@nvidia.com>]

The gdev->blocked flag tracks whether a device is individually being held
in the group->blocking_domain while group->domain is retained. Up to now,
a PCI reset in flight is the only producer, so a bool suffices.

Subsequent changes will add more reasons to keep a device blocked, e.g. a
failed-reset case that must not auto-unblock, or a driver-side quarantine
for a hardware fault. These reasons are cleared by different events, which
a single bool cannot encode.

Convert the "bool blocked" into "enum blocked_reason blocked", provisioned
with two initial values: BLOCKED_NONE and BLOCKED_RESETTING, covering the
existing use cases. All readers keep the "if (gdev->blocked)" form, since
BLOCKED_NONE == 0.

This is a pure type change with no behavior change. Follow-on changes will
add new enum values along with their producers.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/iommu.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index b486b8bbd1fcd..ee026f5f14349 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -73,16 +73,20 @@ struct iommu_group {
 	void *owner;
 };
 
+enum blocked_reason {
+	BLOCKED_NONE = 0, /* Not blocked */
+	BLOCKED_RESETTING, /* PCI reset in flight */
+};
+
 struct group_device {
 	struct list_head list;
 	struct device *dev;
 	char *name;
 	/*
 	 * Device is blocked for a pending recovery while its group->domain is
-	 * retained. This can happen when:
-	 *  - Device is undergoing a reset
+	 * retained.
 	 */
-	bool blocked;
+	enum blocked_reason blocked;
 	unsigned int reset_depth;
 };
 
@@ -4072,7 +4076,7 @@ int pci_dev_reset_iommu_prepare(struct pci_dev *pdev)
 	 * the correct domain in iommu_driver_get_domain_for_dev() that might be
 	 * called in a set_dev_pasid callback function.
 	 */
-	gdev->blocked = true;
+	gdev->blocked = BLOCKED_RESETTING;
 
 	/*
 	 * Stage PASID domains at blocking_domain while retaining pasid_array.
@@ -4198,7 +4202,7 @@ void pci_dev_reset_iommu_done(struct pci_dev *pdev)
 	 * the correct domain in iommu_driver_get_domain_for_dev() that might be
 	 * called in a set_dev_pasid callback function.
 	 */
-	gdev->blocked = false;
+	gdev->blocked = BLOCKED_NONE;
 
 	/*
 	 * Re-attach PASID domains back to the domains retained in pasid_array.
-- 
2.43.0