[Intel-xe] [PATCH 02/11] drm/xe: Do not take any action if our device was removed.

[Rodrigo Vivi]

Unfortunately devcoredump infrastructure does not provide and
interface for us to force the device removal upon the pci_remove
time of our device.

The devcoredump is linked at the device level, so when in use
it will prevent the module removal, but it doesn't prevent the
call of the pci_remove callback. This callback cannot fail
anyway and we end up clearing and freeing the entire pci device.

Hence, after we removed the pci device, we shouldn't allow any
read or free operations to avoid segmentation fault.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
Reviewed-by: Matthew Brost <matthew.brost at intel.com>
---
 drivers/gpu/drm/xe/xe_devcoredump.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_devcoredump.c b/drivers/gpu/drm/xe/xe_devcoredump.c
index 132b72be4777..ae6ce92682e8 100644
--- a/drivers/gpu/drm/xe/xe_devcoredump.c
+++ b/drivers/gpu/drm/xe/xe_devcoredump.c
@@ -42,6 +42,11 @@
  * hang capture.
  */
 
+static struct xe_device *coredump_to_xe(const struct xe_devcoredump *coredump)
+{
+	return container_of(coredump, struct xe_device, devcoredump);
+}
+
 static ssize_t xe_devcoredump_read(char *buffer, loff_t offset,
 				   size_t count, void *data, size_t datalen)
 {
@@ -51,6 +56,10 @@ static ssize_t xe_devcoredump_read(char *buffer, loff_t offset,
 	struct drm_print_iterator iter;
 	struct timespec64 ts;
 
+	/* Our device is gone already... */
+	if (!data || !coredump_to_xe(coredump))
+		return -ENODEV;
+
 	iter.data = buffer;
 	iter.offset = 0;
 	iter.start = offset;
@@ -80,12 +89,16 @@ static ssize_t xe_devcoredump_read(char *buffer, loff_t offset,
 static void xe_devcoredump_free(void *data)
 {
 	struct xe_devcoredump *coredump = data;
-	struct xe_device *xe = container_of(coredump, struct xe_device,
-					    devcoredump);
+
+	/* Our device is gone. Nothing to do... */
+	if (!data || !coredump_to_xe(coredump))
+		return;
+
 	mutex_lock(&coredump->lock);
 
 	coredump->faulty_engine = NULL;
-	drm_info(&xe->drm, "Xe device coredump has been deleted.\n");
+	drm_info(&coredump_to_xe(coredump)->drm,
+		 "Xe device coredump has been deleted.\n");
 
 	mutex_unlock(&coredump->lock);
 }
-- 
2.39.2