drm/ttm: Make the call to ttm_tt_populate() interruptible when faulting

When swapping in, or under memory pressure ttm_tt_populate() may sleep
for a substantiable amount of time. Allow interrupts during the sleep.
This will also allow us to inject -EINTR errors during swapin in upcoming
patches.

Also avoid returning VM_FAULT_OOM, since that will confuse the core
mm, making it print out a confused message and retrying the fault.
Return VM_FAULT_SIGBUS also under OOM conditions.

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230404200650.11043-4-thomas.hellstrom@linux.intel.com

diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index ca7744b..4bca6b5 100644 (file)
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -218,14 +218,21 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,
        prot = ttm_io_prot(bo, bo->resource, prot);
        if (!bo->resource->bus.is_iomem) {
                struct ttm_operation_ctx ctx = {
-                       .interruptible = false,
+                       .interruptible = true,
                        .no_wait_gpu = false,
                        .force_alloc = true
                };
 
                ttm = bo->ttm;
-               if (ttm_tt_populate(bdev, bo->ttm, &ctx))
-                       return VM_FAULT_OOM;
+               err = ttm_tt_populate(bdev, bo->ttm, &ctx);
+               if (err) {
+                       if (err == -EINTR || err == -ERESTARTSYS ||
+                           err == -EAGAIN)
+                               return VM_FAULT_NOPAGE;
+
+                       pr_debug("TTM fault hit %pe.\n", ERR_PTR(err));
+                       return VM_FAULT_SIGBUS;
+               }
        } else {
                /* Iomem should not be marked encrypted */
                prot = pgprot_decrypted(prot);