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Revert "drm/i915: Skip over MI_NOOP when parsing"

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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
This commit is contained in:
Jason Ekstrand 2021-07-14 14:34:19 -05:00 committed by Daniel Vetter
parent dc194184d0
commit 0c6609bb20
1 changed files with 33 additions and 32 deletions
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65
drivers/gpu/drm/i915/i915_cmd_parser.c
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@ -1470,42 +1470,43 @@ 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;
do {
u32 length;
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;
}
if (*cmd == MI_BATCH_BUFFER_END)
break;
if (desc->flags & CMD_DESC_FIXED)
length = desc->length.fixed;
else
length = (*cmd & desc->length.mask) + LENGTH_BIAS;
desc = find_cmd(engine, *cmd, desc, &default_desc);
if (!desc) {
DRM_DEBUG("CMD: Unrecognized command: 0x%08X\n", *cmd);
ret = -EINVAL;
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 (desc->flags & CMD_DESC_FIXED)
length = desc->length.fixed;
else
length = (*cmd & desc->length.mask) + LENGTH_BIAS;
if (!check_cmd(engine, desc, cmd, length)) {
ret = -EACCES;
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 (cmd_desc_is(desc, MI_BATCH_BUFFER_START)) {
ret = check_bbstart(cmd, offset, length, batch_length,
batch_addr, shadow_addr,
jump_whitelist);
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))
@ -1518,7 +1519,7 @@ int intel_engine_cmd_parser(struct intel_engine_cs *engine,
ret = -EINVAL;
break;
}
}
} while (1);
if (trampoline) {
/*