s390/pci_dma: split dma_update_trans

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Split dma_update_trans into __dma_update_trans which handles updating
the dma translation tables and __dma_purge_tlb which takes care of
purging associated entries in the dma translation lookaside buffer.

The map_sg API makes use of this split approach by calling
__dma_update_trans once per physically contiguous address range but
__dma_purge_tlb only once per dma contiguous address range.

This results in less invocations of the expensive RPCIT instruction
when using map_sg.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

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Sebastian Ott 2016-09-05 17:49:17 +02:00 • committed by Martin Schwidefsky

parent ee877b81c6

commit 1f166e9e5c

1 changed files with 44 additions and 21 deletions

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arch/s390/pci/pci_dma.c

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