[PATCH 1/8] 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>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
---
 drivers/gpu/drm/xe/xe_configfs.c | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_configfs.c b/drivers/gpu/drm/xe/xe_configfs.c
index 2ddd707a6dbd..cc442014cf12 100644
--- a/drivers/gpu/drm/xe/xe_configfs.c
+++ b/drivers/gpu/drm/xe/xe_configfs.c
@@ -1282,7 +1282,8 @@ 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;
@@ -1296,7 +1297,8 @@ 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;
@@ -1340,7 +1342,8 @@ 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;
@@ -1360,7 +1363,8 @@ 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;
@@ -1381,7 +1385,8 @@ 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;
@@ -1421,7 +1426,8 @@ bool xe_configfs_get_disable_vram_page_offline(struct pci_dev *pdev)
 	if (!dev)
 		return device_defaults.disable_vram_page_offline;
 
-	ret = dev->config.disable_vram_page_offline;
+	scoped_guard(mutex, &dev->lock)
+		ret = dev->config.disable_vram_page_offline;
 	config_group_put(&dev->group);
 
 	return ret;
@@ -1445,10 +1451,12 @@ 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;
@@ -1472,8 +1480,10 @@ 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