gpu: nvgpu: fix patch write error check in update_ctxsw_preemption_mode

Don't attempt to access memory if the patch context can't be mapped, but
print an error message instead.

Change-Id: I374dc94d13674e0bd9d081b790f7c0dac834e868
Signed-off-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-on: http://git-master/r/1157828
GVS: Gerrit_Virtual_Submit
Reviewed-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gp10b/gr_gp10b.c b/drivers/gpu/nvgpu/gp10b/gr_gp10b.c
index 5db65175..4a8a1d8e 100644
--- a/drivers/gpu/nvgpu/gp10b/gr_gp10b.c
+++ b/drivers/gpu/nvgpu/gp10b/gr_gp10b.c
@@ -1118,6 +1118,11 @@ static void gr_gp10b_update_ctxsw_preemption_mode(struct gk20a *g,
                                 gr_ctx->t18x.preempt_ctxsw_buffer.gpu_va >> 8);
 
                 err = gr_gk20a_ctx_patch_write_begin(g, ch_ctx);
+                if (err) {
+                        gk20a_err(dev_from_gk20a(g),
+                                        "can't map patch context");
+                        goto out;
+                }
 
                 addr = (u64_lo32(gr_ctx->t18x.betacb_ctxsw_buffer.gpu_va) >>
                         gr_gpcs_setup_attrib_cb_base_addr_39_12_align_bits_v()) |
@@ -1169,6 +1174,7 @@ static void gr_gp10b_update_ctxsw_preemption_mode(struct gk20a *g,
                 gr_gk20a_ctx_patch_write_end(g, ch_ctx);
         }
 
+out:
         gk20a_dbg_fn("done");
 }