[rds-devel] [PATCH net 1/1] net/rds: dma_map_sg is entitled to merge entries

[Santosh Shilimkar]

> On Aug 17, 2021, at 10:04 AM, Gerd Rausch <gerd.rausch at oracle.com> wrote:
> 
> Function "dma_map_sg" is entitled to merge adjacent entries
> and return a value smaller than what was passed as "nents".
> 
> Subsequently "ib_map_mr_sg" needs to work with this value ("sg_dma_len")
> rather than the original "nents" parameter ("sg_len").
> 
> This old RDS bug was exposed and reliably causes kernel panics
> (using RDMA operations "rds-stress -D") on x86_64 starting with:
> commit c588072bba6b ("iommu/vt-d: Convert intel iommu driver to the iommu ops")
> 
> Simply put: Linux 5.11 and later.
> 
> Signed-off-by: Gerd Rausch <gerd.rausch at oracle.com>
> ---
> net/rds/ib_frmr.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)

Looks good to me Gerd. Thanks !!

Acked-by: Santosh Shilimkar <santosh.shilimkar at oracle.com>