RDMA/hns: Add a check to ensure integer mtu is positive

mainline inclusion
from mainline-v5.12-rc1
commit fe331da0
category: bugfix
bugzilla: 174002
CVE:NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fe331da0f210c60342b042a03fe53f1b564b412b

----------------------------------------------------------------------

    GCC may reports an running time assert error when a value calculated from
    ib_mtu_enum_to_int() is using as 'val' in FIELD_PREDP:

    include/linux/compiler_types.h:328:38: error: call to
    '__compiletime_assert_1524' declared with attribute error: FIELD_PREP:
    value too large for the field

    So a check is added about whether integer mtu from ib_mtu_enum_to_int() is
    negative to avoid this warning.

    Link: https://lore.kernel.org/r/1624262443-24528-3-git-send-email-liweihang@huawei.comReported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NWeihang Li <liweihang@huawei.com>
Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>
Reviewed-by: NChunZhi Hu <huchunzhi@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/infiniband/hw/hns/hns_roce_hw_v2.c

@@ -4491,11 +4491,12 @@ static int modify_qp_init_to_rtr(struct ib_qp *ibqp,
 	struct ib_device *ibdev = &hr_dev->ib_dev;
 	dma_addr_t trrl_ba;
 	dma_addr_t irrl_ba;
-	enum ib_mtu mtu;
+	enum ib_mtu ib_mtu;
 	u8 lp_pktn_ini;
 	u64 *mtts;
 	u8 *dmac;
 	u8 *smac;
+	int mtu;
 	int port;
 	int ret;
 
@@ -4580,19 +4581,23 @@ static int modify_qp_init_to_rtr(struct ib_qp *ibqp,
 	roce_set_field(qpc_mask->byte_52_udpspn_dmac, V2_QPC_BYTE_52_DMAC_M,
 		       V2_QPC_BYTE_52_DMAC_S, 0);
 
-	mtu = get_mtu(ibqp, attr);
-	hr_qp->path_mtu = mtu;
+	ib_mtu = get_mtu(ibqp, attr);
+	hr_qp->path_mtu = ib_mtu;
+
+	mtu = ib_mtu_enum_to_int(ib_mtu);
+	if (WARN_ON(mtu < 0))
+		return -EINVAL;
 
 	if (attr_mask & IB_QP_PATH_MTU) {
 		roce_set_field(context->byte_24_mtu_tc, V2_QPC_BYTE_24_MTU_M,
-			       V2_QPC_BYTE_24_MTU_S, mtu);
+			       V2_QPC_BYTE_24_MTU_S, ib_mtu);
 		roce_set_field(qpc_mask->byte_24_mtu_tc, V2_QPC_BYTE_24_MTU_M,
 			       V2_QPC_BYTE_24_MTU_S, 0);
 	}
 
 #define MAX_LP_MSG_LEN 65536
 	/* MTU * (2 ^ LP_PKTN_INI) shouldn't be bigger than 64KB */
-	lp_pktn_ini = ilog2(MAX_LP_MSG_LEN / ib_mtu_enum_to_int(mtu));
+	lp_pktn_ini = ilog2(MAX_LP_MSG_LEN / mtu);
 
 	roce_set_field(context->byte_56_dqpn_err, V2_QPC_BYTE_56_LP_PKTN_INI_M,
 		       V2_QPC_BYTE_56_LP_PKTN_INI_S, lp_pktn_ini);