From: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
commit 941f2f72dbbe0cf8c2d6e0b180a8021a0ec477fa upstream.
Commit 4daa4fba3a38 ("gpu: drm: ttm: Adding new return type vm_fault_t")
broke TTM prefaulting. Since vmf_insert_mixed() typically always returns
VM_FAULT_NOPAGE, prefaulting stops after the second PTE.
Restore (almost) the original behaviour. Unfortunately we can no longer
with the new vm_fault_t return type determine whether a prefaulting
PTE insertion hit an already populated PTE, and terminate the insertion
loop. Instead we continue with the pre-determined number of prefaults.
Fixes: 4daa4fba3a38 ("gpu: drm: ttm: Adding new return type vm_fault_t")
Cc: Souptick Joarder <jrdr.linux@xxxxxxxxx>
Cc: Christian König <christian.koenig@xxxxxxx>
Signed-off-by: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
Reviewed-by: Christian König <christian.koenig@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v4.19+
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
Link: https://patchwork.freedesktop.org/patch/330387/
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/ttm/ttm_bo_vm.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -278,15 +278,13 @@ static vm_fault_t ttm_bo_vm_fault(struct
else
ret = vmf_insert_pfn(&cvma, address, pfn);
- /*
- * Somebody beat us to this PTE or prefaulting to
- * an already populated PTE, or prefaulting error.
- */
-
- if (unlikely((ret == VM_FAULT_NOPAGE && i > 0)))
- break;
- else if (unlikely(ret & VM_FAULT_ERROR))
- goto out_io_unlock;
+ /* Never error on prefaulted PTEs */
+ if (unlikely((ret & VM_FAULT_ERROR))) {
+ if (i == 0)
+ goto out_io_unlock;
+ else
+ break;
+ }
address += PAGE_SIZE;
if (unlikely(++page_offset >= page_last))
