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SYNC_BO clflushes an imported BO's scatterlist. An importer may not do
that: the memory belongs to the exporter, and dma-buf gives the importer
no interface to ask for maintenance on it. Refuse the request instead.
is_import_bo() is (obj)->attach, which covers more than foreign buffers.
A userptr BO arrives through a ubuf, and on a carveout device every share
BO and the device heap arrive through a cbuf, so SYNC_BO answers
-EOPNOTSUPP for those too, including the AMDXDNA_BO_DEV path that flushes
through its heap.
Only the ubuf case gives up maintenance it was getting: on a 64 MiB
userptr BO a 4 KiB sync and a full sync both cost 659 us, this arm having
ignored the range. amdxdna_cbuf_map() fills in only the DMA address and
length, so drm_clflush_sg() already walks zero pages on carveout memory.
Userspace maintains these through the mapping it already holds, as XRT's
buffer::sync() does unless it is told to sync through the driver.
Fixes:
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|---|---|---|
| .. | ||
| amdxdna | ||
| ethosu | ||
| habanalabs | ||
| ivpu | ||
| qaic | ||
| rocket | ||
| drm_accel.c | ||
| Kconfig | ||
| Makefile | ||