storvsc currently sets .dma_boundary to limit scatterlist entries to 4
Kbytes, which is less efficient with huge pages that offer large chunks of
contiguous physical memory. Improve the algorithm for creating the Hyper-V
guest physical address PFN array so that scatterlist entries with lengths >
4Kbytes are handled. As a result, remove the .dma_boundary setting.
The improved algorithm also adds support for scatterlist entries with
offsets >= 4Kbytes, which is supported by many other SCSI low-level
drivers. And it retains support for architectures where possibly PAGE_SIZE
!= HV_HYP_PAGE_SIZE (such as ARM64).
Link: https://lore.kernel.org/r/1614120294-1930-1-git-send-email-mikelley@microsoft.com
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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