drm/i915: Reduce stack usage in debugfs due to SSEU

sseu_dev_info is already a pretty large structure which will likely
continue to grow when future platforms increase potential DSS and EU
counts.  Let's switch the stack placement of this structure in debugfs
with a dynamic allocation.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220315020805.844962-1-matthew.d.roper@intel.com

diff --git a/drivers/gpu/drm/i915/gt/intel_sseu_debugfs.c b/drivers/gpu/drm/i915/gt/intel_sseu_debugfs.c
index 1e199c0..074d293 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_sseu_debugfs.c
+++ b/drivers/gpu/drm/i915/gt/intel_sseu_debugfs.c
@@ -246,7 +246,7 @@ int intel_sseu_status(struct seq_file *m, struct intel_gt *gt)
 {
        struct drm_i915_private *i915 = gt->i915;
        const struct intel_gt_info *info = &gt->info;
-       struct sseu_dev_info sseu;
+       struct sseu_dev_info *sseu;
        intel_wakeref_t wakeref;
 
        if (GRAPHICS_VER(i915) < 8)
@@ -256,23 +256,29 @@ int intel_sseu_status(struct seq_file *m, struct intel_gt *gt)
        i915_print_sseu_info(m, true, HAS_POOLED_EU(i915), &info->sseu);
 
        seq_puts(m, "SSEU Device Status\n");
-       memset(&sseu, 0, sizeof(sseu));
-       intel_sseu_set_info(&sseu, info->sseu.max_slices,
+
+       sseu = kzalloc(sizeof(*sseu), GFP_KERNEL);
+       if (!sseu)
+               return -ENOMEM;
+
+       intel_sseu_set_info(sseu, info->sseu.max_slices,
                            info->sseu.max_subslices,
                            info->sseu.max_eus_per_subslice);
 
        with_intel_runtime_pm(&i915->runtime_pm, wakeref) {
                if (IS_CHERRYVIEW(i915))
-                       cherryview_sseu_device_status(gt, &sseu);
+                       cherryview_sseu_device_status(gt, sseu);
                else if (IS_BROADWELL(i915))
-                       bdw_sseu_device_status(gt, &sseu);
+                       bdw_sseu_device_status(gt, sseu);
                else if (GRAPHICS_VER(i915) == 9)
-                       gen9_sseu_device_status(gt, &sseu);
+                       gen9_sseu_device_status(gt, sseu);
                else if (GRAPHICS_VER(i915) >= 11)
-                       gen11_sseu_device_status(gt, &sseu);
+                       gen11_sseu_device_status(gt, sseu);
        }
 
-       i915_print_sseu_info(m, false, HAS_POOLED_EU(i915), &sseu);
+       i915_print_sseu_info(m, false, HAS_POOLED_EU(i915), sseu);
+
+       kfree(sseu);
 
        return 0;
 }