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([78.43.20.153]) by mrelayeu.kundenserver.de (mreue004) with ESMTPA (Nemesis) id 0Ltj2f-1cxaHk41jR-011BsM; Mon, 24 Oct 2016 22:48:34 +0200 From: Arnd Bergmann To: Doug Ledford , Sean Hefty , Hal Rosenstock Cc: Arnd Bergmann , Matan Barak , Leon Romanovsky , Sagi Grimberg , Bart Van Assche , Noa Osherovich , Saeed Mahameed , linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] IB/mlx5: avoid bogus -Wmaybe-uninitialized warning Date: Mon, 24 Oct 2016 22:48:21 +0200 Message-Id: <20161024204830.620592-1-arnd@arndb.de> X-Mailer: git-send-email 2.9.0 MIME-Version: 1.0 X-Provags-ID: V03:K0:r7de9oIiT/9x10hRur4PhLGi2TjF/OisVW63N+pyoGIYgPO7pc0 Yhx6RNE1Odl0GF1i0ipXPbaVvPt5MFppuNs7eWYdzDuxGHYWA6PqzDXGNFc5aZyscCr3VyG 701hM94E2lb8ddqShD59vN9gt0Qa172l2r4+Kq11Jbkx7jKghO4bqjPRR+3iri5OqsDoJZS huE+vxttIcSvohnjTrmjA== X-UI-Out-Filterresults: notjunk:1; V01:K0:4N9acKSU9kI=:jpEar+uQAElM+x8mv6fpTU 8Y99vj/mGHALGI3tyOU3LqQXApAQDhrs9aHPtuQo2byIS2jdKQPeYNsaCVQUdwVjEGWlmihjI zc0AibHW5wYqYuVktJswZQotO9NnmeiX4NJaYfrJS/JF6IYO7D076SpkOPhfzzWAH05ncDFWw UjeYblYPQ+KGt9y2boDlF4Bsfd3YTlVn8aocGOyfQMi4AYUCiEiOLnGpZVTWJM/QtWxEu3WIb 9nst38G1o4rvFoIkrwcLnOQnkRfVeX4fKwee1JCn5aM9Lmh89hTznQJLpEnSjcY+Ji1BnebLA XpFhoAnfQrmJq1PIn1BYC/vOQ5ZzJP4zhxK7EUjiWhZcuoJQ3Sny70oXZPJX25CS81WemtvuD ipF7ievXRqaXwDei3AJGtR/L8RseWayEedI0OciNUyRihuaZ1JHDM+mhBFKsp5W//UhkErsE3 r9I+f1T5x3+SDGeCLfb+K+rziU6PSrEoVxejxv8d4I13ULvO1Eo54ygOjpXmwuNXAdsZd4Rmu AIdYGm/tvAihhPw0dXGp+ruQJyqxouGNW4ej7Kl1OqfjGa2kbUH5rQPhN/LE6IPk6awQbSDD0 PbphuVJ6M38t0zQP6QkF5zBFb1WohssinLmbMYd7wbXiq4CsFnkT0BdaRS+AO8gky1FbUimnu 0jpCNpVbgVrVRkdO38jCmcuZaqbJg9Q/7VjxUbgWfoYsKkNeySwwP6ZCH1zASVHGR9x+RV0rS p42pOXhkJiS7O9ct Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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. Acked-by: Leon Romanovsky Signed-off-by: Arnd Bergmann --- drivers/infiniband/hw/mlx5/mr.c | 39 +++++++++++++++++++++------------------ 1 file changed, 21 insertions(+), 18 deletions(-) v2: fix whitespace typo diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c index d4ad672b905b..9ea74fca568a 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, + int *npages, int *page_shift, int *ncont, + int *order) { struct mlx5_ib_dev *dev = to_mdev(pd->device); - struct ib_umem *umem = ib_umem_get(pd->uobject->context, start, length, - access_flags, 0); - if (IS_ERR(umem)) { + int err; + + *umem = ib_umem_get(pd->uobject->context, start, length, + access_flags, 0); + err = PTR_ERR_OR_ZERO(*umem); + if (err < 0) { mlx5_ib_err(dev, "umem get failed (%ld)\n", PTR_ERR(umem)); - return (void *)umem; + return err; } - mlx5_ib_cont_pages(umem, start, npages, page_shift, ncont, order); + mlx5_ib_cont_pages(*umem, start, npages, page_shift, ncont, order); if (!*npages) { mlx5_ib_warn(dev, "avoid zero region\n"); - ib_umem_release(umem); - return ERR_PTR(-EINVAL); + ib_umem_release(*umem); + return -EINVAL; } mlx5_ib_dbg(dev, "npages %d, ncont %d, order %d, page_shift %d\n", *npages, *ncont, *order, *page_shift); - return umem; + return 0; } static void mlx5_ib_umr_done(struct ib_cq *cq, struct ib_wc *wc) @@ -1163,11 +1167,11 @@ struct ib_mr *mlx5_ib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length, mlx5_ib_dbg(dev, "start 0x%llx, virt_addr 0x%llx, length 0x%llx, access_flags 0x%x\n", start, virt_addr, length, access_flags); - umem = mr_umem_get(pd, start, length, access_flags, &npages, + err = mr_umem_get(pd, start, length, access_flags, &umem, &npages, &page_shift, &ncont, &order); - if (IS_ERR(umem)) - return (void *)umem; + if (err < 0) + return ERR_PTR(err); if (use_umr(order)) { mr = reg_umr(pd, umem, virt_addr, length, ncont, page_shift, @@ -1341,10 +1345,9 @@ int mlx5_ib_rereg_user_mr(struct ib_mr *ib_mr, int flags, u64 start, */ flags |= IB_MR_REREG_TRANS; ib_umem_release(mr->umem); - mr->umem = mr_umem_get(pd, addr, len, access_flags, &npages, - &page_shift, &ncont, &order); - if (IS_ERR(mr->umem)) { - err = PTR_ERR(mr->umem); + err = mr_umem_get(pd, addr, len, access_flags, &mr->umem, + &npages, &page_shift, &ncont, &order); + if (err < 0) { mr->umem = NULL; return err; }