On Mon, Oct 24, 2016 at 05:16:42PM +0200, Arnd Bergmann wrote: > We get a false-positive warning in linux-next for the mlx5 driver: > > infiniband/hw/mlx5/mr.c: In function ‘mlx5_ib_reg_user_mr’: > infiniband/hw/mlx5/mr.c:1172:5: error: ‘order’ may be used uninitialized in > this function [-Werror=maybe-uninitialized] > infiniband/hw/mlx5/mr.c:1161:6: note: ‘order’ was declared here > infiniband/hw/mlx5/mr.c:1173:6: error: ‘ncont’ may be used uninitialized in > this function [-Werror=maybe-uninitialized] > infiniband/hw/mlx5/mr.c:1160:6: note: ‘ncont’ was declared here > infiniband/hw/mlx5/mr.c:1173:6: error: ‘page_shift’ may be used uninitialized > in this function [-Werror=maybe-uninitialized] > infiniband/hw/mlx5/mr.c:1158:6: note: ‘page_shift’ was declared here > infiniband/hw/mlx5/mr.c:1143:13: error: ‘npages’ may be used uninitialized in > this function [-Werror=maybe-uninitialized] > infiniband/hw/mlx5/mr.c:1159:6: note: ‘npages’ was declared here > > I had a trivial workaround for gcc-5 or higher, but that didn't work > on gcc-4.9 unfortunately. > > The only way I found to avoid the warnings for gcc-4.9, short of > initializing each of the arguments first was to change the calling > conventions to separate the error code from the umem pointer. This > avoids casting the error codes from one pointer to another incompatible > pointer, and lets gcc figure out when that the data is actually valid > whenever we return successfully. > > Signed-off-by: Arnd Bergmann <[email protected]>
Thanks Arnd for fixing it. I have a very small comment which is not related to functionality. Rather than that, Acked-by: Leon Romanovsky <[email protected]> > --- > drivers/infiniband/hw/mlx5/mr.c | 39 +++++++++++++++++++++------------------ > 1 file changed, 21 insertions(+), 18 deletions(-) > > diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c > index d4ad672b905b..88d8d292677b 100644 > --- a/drivers/infiniband/hw/mlx5/mr.c > +++ b/drivers/infiniband/hw/mlx5/mr.c > @@ -815,29 +815,33 @@ static void prep_umr_unreg_wqe(struct mlx5_ib_dev *dev, > umrwr->mkey = key; > } > > -static struct ib_umem *mr_umem_get(struct ib_pd *pd, u64 start, u64 length, > - int access_flags, int *npages, > - int *page_shift, int *ncont, int *order) > +static int mr_umem_get(struct ib_pd *pd, u64 start, u64 length, > + int access_flags, struct ib_umem ** umem, I wonder if checkpatch does differentiate between "struct ib_umem ** umem" and "struct ib_umem **umem". According to coding style, the second is preferable. > + int *npages, int *page_shift, int *ncont, > + int *order)
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