On 4/18/2018 9:08 AM, David Laight wrote:
From: Tom Talpey
Sent: 18 April 2018 12:32
...
On 4/17/2018 8:33 PM, Long Li wrote:
From: Long Li <longli@xxxxxxxxxxxxx>
The data buffer allocated on the stack can't be DMA'ed, and hence can't send
through RDMA via SMB Direct.
This comment is confusing. Any registered memory can be DMA'd, need to
state the reason for the choice here more clearly.
The stack could be allocated with vmalloc().
In which case the pages might not be physically contiguous and there is no
(sensible) call to get the physical address required by the dma controller
(or other bus master).
Memory registration does not requires pages to be physically contiguous.
RDMA Regions can and do support very large physical page scatter/gather,
and the adapter DMA's them readily. Is this the only reason?
Tom.