From 2bf92d528d34636e0b64dd64fcf6abdd74d0f930 Mon Sep 17 00:00:00 2001
From: Jason Ekstrand <jason@jlekstrand.net>
Date: Wed, 14 Jul 2021 14:34:19 -0500
Subject: Revert "drm/i915: Skip over MI_NOOP when parsing"
Git-commit: 0c6609bb20cf473f48403763aa9a9504ff95fa0f
Patch-mainline: v5.15-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
This reverts a6c5e2aea704 ("drm/i915: Skip over MI_NOOP when parsing").
It complicates the batch parsing code a bit and increases indentation
for no reason other than fast-skipping a command that userspace uses
only rarely. Sure, there may be IGT tests that fill batches with NOOPs
but that's not a case we should optimize for in the kernel. We should
optimize for code clarity instead.
Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Jon Bloomfield <jon.bloomfield@intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210714193419.1459723-6-jason@jlekstrand.net
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/i915_cmd_parser.c | 67 +++++++++++++-------------
1 file changed, 34 insertions(+), 33 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
index a3b4d99d64b9..e0403ce9ce69 100644
--- a/drivers/gpu/drm/i915/i915_cmd_parser.c
+++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
@@ -1468,42 +1468,43 @@ int intel_engine_cmd_parser(struct intel_engine_cs *engine,
* space. Parsing should be faster in some cases this way.
*/
batch_end = cmd + batch_length / sizeof(*batch_end);
- while (*cmd != MI_BATCH_BUFFER_END) {
- u32 length = 1;
-
- if (*cmd != MI_NOOP) { /* MI_NOOP == 0 */
- desc = find_cmd(engine, *cmd, desc, &default_desc);
- if (!desc) {
- DRM_DEBUG("CMD: Unrecognized command: 0x%08X\n", *cmd);
- ret = -EINVAL;
- break;
- }
+ do {
+ u32 length;
- if (desc->flags & CMD_DESC_FIXED)
- length = desc->length.fixed;
- else
- length = (*cmd & desc->length.mask) + LENGTH_BIAS;
+ if (*cmd == MI_BATCH_BUFFER_END)
+ break;
- if ((batch_end - cmd) < length) {
- DRM_DEBUG("CMD: Command length exceeds batch length: 0x%08X length=%u batchlen=%td\n",
- *cmd,
- length,
- batch_end - cmd);
- ret = -EINVAL;
- break;
- }
+ desc = find_cmd(engine, *cmd, desc, &default_desc);
+ if (!desc) {
+ DRM_DEBUG("CMD: Unrecognized command: 0x%08X\n", *cmd);
+ ret = -EINVAL;
+ break;
+ }
- if (!check_cmd(engine, desc, cmd, length)) {
- ret = -EACCES;
- break;
- }
+ if (desc->flags & CMD_DESC_FIXED)
+ length = desc->length.fixed;
+ else
+ length = (*cmd & desc->length.mask) + LENGTH_BIAS;
- if (cmd_desc_is(desc, MI_BATCH_BUFFER_START)) {
- ret = check_bbstart(cmd, offset, length, batch_length,
- batch_addr, shadow_addr,
- jump_whitelist);
- break;
- }
+ if ((batch_end - cmd) < length) {
+ DRM_DEBUG("CMD: Command length exceeds batch length: 0x%08X length=%u batchlen=%td\n",
+ *cmd,
+ length,
+ batch_end - cmd);
+ ret = -EINVAL;
+ break;
+ }
+
+ if (!check_cmd(engine, desc, cmd, length)) {
+ ret = -EACCES;
+ break;
+ }
+
+ if (cmd_desc_is(desc, MI_BATCH_BUFFER_START)) {
+ ret = check_bbstart(cmd, offset, length, batch_length,
+ batch_addr, shadow_addr,
+ jump_whitelist);
+ break;
}
if (!IS_ERR_OR_NULL(jump_whitelist))
@@ -1516,7 +1517,7 @@ int intel_engine_cmd_parser(struct intel_engine_cs *engine,
ret = -EINVAL;
break;
}
- }
+ } while (1);
if (trampoline) {
/*
--
2.38.1