Fast Memory Registration (fmr) is used to register for rdma an sg whose
elements are not linearly sequential after dma mapping.

The IB verbs layer provides an "all dma memory MR (memory region)" which
can be used for RDMA-ing a dma linearly sequential buffer.

Change the code to use the dma mr instead of doing fmr when dma mapping
produces a single dma entry sg.
Signed-off-by: NErez Zilber <erezz@voltaire.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

As iser is able to use at most one rdma operation for the
execution of a scsi command, and registration of the sg
associated with scsi command has its restrictions, the code
checks if an sg is "aligned for rdma".

Alignment for rdma is measured in "fmr page" units whose
possible resolutions are different between HCAs and can be
smaller, equal or bigger to the system page size.

When the system page size is bigger than 4KB (eg the default
with ia64 kernels) there a bigger chance that an sg would be
aligned for rdma if the fmr page size is 4KB.

Change the code to create FMR whose pages are of size 4KB
and to take that into account when processing the sg.
Signed-off-by: NErez Zilber <erezz@voltaire.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

ib_fmr_pool_map_phys gets the virtual address by pointer but never writes
there, and users (e.g.  srp) seem to assume this and ignore the value
returned.  This patch cleans up the API to get the VA by value, and updates
all users.
Signed-off-by: NMichael S. Tsirkin <mst@mellanox.co.il>
Acked-by: NRoland Dreier <rolandd@cisco.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This file contains the low level interaction with the RDMA CM
and the IB verbs, where iSER is consumer of both.
Signed-off-by: NOr Gerlitz <ogerlitz@voltaire.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>