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83781384a9
Since [1], dma_alloc_coherent() does not accept requests for GFP_COMP
anymore, even on archs that may be able to fulfill this. Functionality that
relied on the receive buffer being a compound page broke at that point:
The SMC-D protocol, that utilizes the ism device driver, passes receive
buffers to the splice processor in a struct splice_pipe_desc with a
single entry list of struct pages. As the buffer is no longer a compound
page, the splice processor now rejects requests to handle more than a
page worth of data.
Replace dma_alloc_coherent() and allocate a buffer with folio_alloc and
create a DMA map for it with dma_map_page(). Since only receive buffers
on ISM devices use DMA, qualify the mapping as FROM_DEVICE.
Since ISM devices are available on arch s390, only, and on that arch all
DMA is coherent, there is no need to introduce and export some kind of
dma_sync_to_cpu() method to be called by the SMC-D protocol layer.
Analogously, replace dma_free_coherent by a two step dma_unmap_page,
then folio_put to free the receive buffer.
[1] https://lore.kernel.org/all/20221113163535.884299-1-hch@lst.de/
Fixes:
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| .. | ||
| block | ||
| char | ||
| cio | ||
| crypto | ||
| net | ||
| scsi | ||
| virtio | ||
| Makefile | ||