xprtrdma: Byte-align FRWR registration

The RPC/RDMA transport's FRWR registration logic registers whole
pages. This means areas in the first and last pages that are not
involved in the RDMA I/O are needlessly exposed to the server.

Buffered I/O is typically page-aligned, so not a problem there. But
for direct I/O, which can be byte-aligned, and for reply chunks,
which are nearly always smaller than a page, the transport could
expose memory outside the I/O buffer.

FRWR allows byte-aligned memory registration, so let's use it as
it was intended.

Reported-by: Sagi Grimberg <[email protected]>
Signed-off-by: Chuck Lever <[email protected]>
Tested-by: Devesh Sharma <[email protected]>
Tested-by: Meghana Cheripady <[email protected]>
Tested-by: Veeresh U. Kokatnur <[email protected]>
Signed-off-by: Anna Schumaker <[email protected]>

0 files changed, 0 insertions, 0 deletions