[PATCH 01/10] drm/xe: Guard configfs attribute reads in getters

[Stuart Summers <stuart.summers@intel.com>]

The configfs getters read dev->config members without holding dev->lock,
so a concurrent store can tear the value being returned. The store paths
and a few of the getters already take the lock; make it consistent by
wrapping every read of dev->config in the getters with a scoped_guard(),
covering the surrounding checks that consume those values as well.

Signed-off-by: Stuart Summers <stuart.summers@intel.com>
Assisted-by: Copilot:claude-opus-5
---
 drivers/gpu/drm/xe/xe_configfs.c | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_configfs.c b/drivers/gpu/drm/xe/xe_configfs.c
index 052cce962161..0a85043a9dd0 100644
--- a/drivers/gpu/drm/xe/xe_configfs.c
+++ b/drivers/gpu/drm/xe/xe_configfs.c
@@ -1185,7 +1185,8 @@ bool xe_configfs_get_survivability_mode(struct pci_dev *pdev)
 	if (!dev)
 		return device_defaults.survivability_mode;
 
-	mode = dev->config.survivability_mode;
+	scoped_guard(mutex, &dev->lock)
+		mode = dev->config.survivability_mode;
 	config_group_put(&dev->group);
 
 	return mode;
@@ -1199,7 +1200,8 @@ static u64 get_gt_types_allowed(struct pci_dev *pdev)
 	if (!dev)
 		return device_defaults.gt_types_allowed;
 
-	mask = dev->config.gt_types_allowed;
+	scoped_guard(mutex, &dev->lock)
+		mask = dev->config.gt_types_allowed;
 	config_group_put(&dev->group);
 
 	return mask;
@@ -1243,7 +1245,8 @@ u64 xe_configfs_get_engines_allowed(struct pci_dev *pdev)
 	if (!dev)
 		return device_defaults.engines_allowed;
 
-	engines_allowed = dev->config.engines_allowed;
+	scoped_guard(mutex, &dev->lock)
+		engines_allowed = dev->config.engines_allowed;
 	config_group_put(&dev->group);
 
 	return engines_allowed;
@@ -1263,7 +1266,8 @@ bool xe_configfs_get_psmi_enabled(struct pci_dev *pdev)
 	if (!dev)
 		return false;
 
-	ret = dev->config.enable_psmi;
+	scoped_guard(mutex, &dev->lock)
+		ret = dev->config.enable_psmi;
 	config_group_put(&dev->group);
 
 	return ret;
@@ -1284,7 +1288,8 @@ bool xe_configfs_get_enable_multi_queue(struct pci_dev *pdev)
 	if (!dev)
 		return true;
 
-	ret = dev->config.enable_multi_queue;
+	scoped_guard(mutex, &dev->lock)
+		ret = dev->config.enable_multi_queue;
 	config_group_put(&dev->group);
 
 	return ret;
@@ -1308,10 +1313,12 @@ u32 xe_configfs_get_ctx_restore_mid_bb(struct pci_dev *pdev,
 	if (!dev)
 		return 0;
 
-	if (cs)
-		*cs = dev->config.ctx_restore_mid_bb[class].cs;
+	scoped_guard(mutex, &dev->lock) {
+		if (cs)
+			*cs = dev->config.ctx_restore_mid_bb[class].cs;
 
-	len = dev->config.ctx_restore_mid_bb[class].len;
+		len = dev->config.ctx_restore_mid_bb[class].len;
+	}
 	config_group_put(&dev->group);
 
 	return len;
@@ -1335,8 +1342,10 @@ u32 xe_configfs_get_ctx_restore_post_bb(struct pci_dev *pdev,
 	if (!dev)
 		return 0;
 
-	*cs = dev->config.ctx_restore_post_bb[class].cs;
-	len = dev->config.ctx_restore_post_bb[class].len;
+	scoped_guard(mutex, &dev->lock) {
+		*cs = dev->config.ctx_restore_post_bb[class].cs;
+		len = dev->config.ctx_restore_post_bb[class].len;
+	}
 	config_group_put(&dev->group);
 
 	return len;
-- 
2.43.0