[PATCH 4.8 10/67] IB/rdmavt: rdmavt can handle non aligned page maps

From: Greg Kroah-Hartman
Date: Thu Nov 24 2016 - 10:44:07 EST

4.8-stable review patch. If anyone has any objections, please let me know.


From: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>

commit e1fafdcbe0e3e769c6a83317dd845bc99b4fe61d upstream.

The initial code for rdmavt carried with it a restriction that was a
vestige from the qib driver, that to dma map a page it had to be less
than a page size. This is not the case on modern hardware, both qib and
hfi1 will be just fine with unaligned map requests.

This fixes a 4.8 regression where by an IPoIB transfer of > PAGE_SIZE
will hang because the dma map page call always fails. This was
introduced after commit 5faba5469522 ("IB/ipoib: Report SG feature
regardless of HW UD CSUM capability") added the capability to use SG by
default. Rather than override this, the HW supports it, so allow SG.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/infiniband/sw/rdmavt/dma.c | 3 ---
1 file changed, 3 deletions(-)

--- a/drivers/infiniband/sw/rdmavt/dma.c
+++ b/drivers/infiniband/sw/rdmavt/dma.c
@@ -90,9 +90,6 @@ static u64 rvt_dma_map_page(struct ib_de
if (WARN_ON(!valid_dma_direction(direction)))

- if (offset + size > PAGE_SIZE)
addr = (u64)page_address(page);
if (addr)
addr += offset;