From: Jason Gunthorpe <jgg@nvidia.com>
Date: Tue, 3 Mar 2026 19:50:10 +0000 (-0400)
Subject: RDMA: Add IB_UVERBS_CORE_SUPPORT_ROBUST_UDATA
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=613713f251c89d089a0da7241573149b9ae8b8ab;p=thirdparty%2Fkernel%2Flinux.git

RDMA: Add IB_UVERBS_CORE_SUPPORT_ROBUST_UDATA

This flag can be set by drivers once they have finished auditing and
implementing the full udata support on every udata operation.

My intention going forward is that driver authors proposing new udata uAPI
for their drivers must first do the work and set this flag.

If this flag is not set the userspace should not try to use udata based
uAPI newer than this commit, though on a case by case basis it may be OK
based on what checks historical kernels performed on the specific call.

Since bnxt_re is audited now, it is the first driver to set the flag.

Link: https://patch.msgid.link/r/13-v3-bd56dd443069+49-bnxt_re_uapi_jgg@nvidia.com
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---

diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index 2ad760e34122..236061a33bf6 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -2706,6 +2706,7 @@ void ib_set_device_ops(struct ib_device *dev, const struct ib_device_ops *ops)
 
 	dev_ops->uverbs_no_driver_id_binding |=
 		ops->uverbs_no_driver_id_binding;
+	dev_ops->uverbs_robust_udata |= ops->uverbs_robust_udata;
 
 	SET_DEVICE_OP(dev_ops, add_gid);
 	SET_DEVICE_OP(dev_ops, add_sub_dev);
diff --git a/drivers/infiniband/core/uverbs_std_types_device.c b/drivers/infiniband/core/uverbs_std_types_device.c
index a28f9f21bed8..12ca15739cd2 100644
--- a/drivers/infiniband/core/uverbs_std_types_device.c
+++ b/drivers/infiniband/core/uverbs_std_types_device.c
@@ -247,13 +247,21 @@ static int UVERBS_HANDLER(UVERBS_METHOD_GET_CONTEXT)(
 {
 	u32 num_comp = attrs->ufile->device->num_comp_vectors;
 	u64 core_support = IB_UVERBS_CORE_SUPPORT_OPTIONAL_MR_ACCESS;
+	struct ib_device *ib_dev;
 	int ret;
 
+	ib_dev = srcu_dereference(attrs->ufile->device->ib_dev,
+				  &attrs->ufile->device->disassociate_srcu);
+	if (!ib_dev)
+		return -EIO;
+
 	ret = uverbs_copy_to(attrs, UVERBS_ATTR_GET_CONTEXT_NUM_COMP_VECTORS,
 			     &num_comp, sizeof(num_comp));
 	if (IS_UVERBS_COPY_ERR(ret))
 		return ret;
 
+	if (ib_dev->ops.uverbs_robust_udata)
+		core_support |= IB_UVERBS_CORE_SUPPORT_ROBUST_UDATA;
 	ret = uverbs_copy_to(attrs, UVERBS_ATTR_GET_CONTEXT_CORE_SUPPORT,
 			     &core_support, sizeof(core_support));
 	if (IS_UVERBS_COPY_ERR(ret))
diff --git a/drivers/infiniband/hw/bnxt_re/main.c b/drivers/infiniband/hw/bnxt_re/main.c
index b576f05e3b26..7af514524632 100644
--- a/drivers/infiniband/hw/bnxt_re/main.c
+++ b/drivers/infiniband/hw/bnxt_re/main.c
@@ -1326,6 +1326,7 @@ static const struct ib_device_ops bnxt_re_dev_ops = {
 	.owner = THIS_MODULE,
 	.driver_id = RDMA_DRIVER_BNXT_RE,
 	.uverbs_abi_ver = BNXT_RE_ABI_VERSION,
+	.uverbs_robust_udata = true,
 
 	.add_gid = bnxt_re_add_gid,
 	.alloc_hw_port_stats = bnxt_re_ib_alloc_hw_port_stats,
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index effcaff455ca..6354c613e9a8 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -2481,6 +2481,12 @@ struct ib_device_ops {
 	enum rdma_driver_id driver_id;
 	u32 uverbs_abi_ver;
 	unsigned int uverbs_no_driver_id_binding:1;
+	/*
+	 * Indicates the driver checks every op accepting a udata for the
+	 * correct size on input and always handles the output using the udata
+	 * helpers.
+	 */
+	unsigned int uverbs_robust_udata:1;
 
 	/*
 	 * NOTE: New drivers should not make use of device_group; instead new
diff --git a/include/uapi/rdma/ib_user_ioctl_verbs.h b/include/uapi/rdma/ib_user_ioctl_verbs.h
index 89e6a3f13191..90c5cd8e7753 100644
--- a/include/uapi/rdma/ib_user_ioctl_verbs.h
+++ b/include/uapi/rdma/ib_user_ioctl_verbs.h
@@ -46,6 +46,7 @@
 
 enum ib_uverbs_core_support {
 	IB_UVERBS_CORE_SUPPORT_OPTIONAL_MR_ACCESS = 1 << 0,
+	IB_UVERBS_CORE_SUPPORT_ROBUST_UDATA = 1 << 1,
 };
 
 enum ib_uverbs_access_flags {