[PATCH for-next v4 3/4] RDMA/bnxt_re: Add uverbs object handle path for CQ/SRQ toggle page

[Selvin Xavier <selvin.xavier@broadcom.com>]

The current GET_TOGGLE_MEM ioctl requires the caller to supply
a type enum and a raw hardware queue ID (RES_ID). The kernel
looks up the CQ or SRQ by that ID without verifying that the
caller owns the resource.

Add a new, preferred code path that accepts standard uverbs
object handles (BNXT_RE_TOGGLE_MEM_CQ_HANDLE /
BNXT_RE_TOGGLE_MEM_SRQ_HANDLE) instead. The uverbs core validates
that the handle belongs to the calling context as part of resolving
it, so this path no longer needs the driver's own XArray lookup for
ownership checking. As with the legacy path, the toggle_entry's own
mmap-entry refcount (not a CQ/SRQ uobject reference) is what pins
the toggle page for the life of the GET_TOGGLE_MEM handle.

Only newer rdma-core versions support this path, if the
driver reports the supported resp mask
(BNXT_RE_UCNTX_CMASK_TOGGLE_MEM_UOBJ_SUPPORT).
The existing TYPE + RES_ID path is retained for backward
compatibility with older rdma-core.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
---
 drivers/infiniband/hw/bnxt_re/ib_verbs.c |  2 +
 drivers/infiniband/hw/bnxt_re/uapi.c     | 55 +++++++++++++++++++++---
 include/uapi/rdma/bnxt_re-abi.h          |  4 ++
 3 files changed, 56 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/hw/bnxt_re/ib_verbs.c b/drivers/infiniband/hw/bnxt_re/ib_verbs.c
index 0ff862ca982c..a14b17d4261f 100644
--- a/drivers/infiniband/hw/bnxt_re/ib_verbs.c
+++ b/drivers/infiniband/hw/bnxt_re/ib_verbs.c
@@ -4872,6 +4872,8 @@ int bnxt_re_alloc_ucontext(struct ib_ucontext *ctx, struct ib_udata *udata)
 	if (_is_modify_qp_rate_limit_supported(dev_attr->dev_cap_flags2))
 		resp.comp_mask |= BNXT_RE_UCNTX_CMASK_QP_RATE_LIMIT_ENABLED;
 
+	resp.comp_mask |= BNXT_RE_UCNTX_CMASK_TOGGLE_MEM_UOBJ_SUPPORT;
+
 	if (udata->inlen) {
 		rc = ib_copy_validate_udata_in_cm(
 			udata, ureq, comp_mask,
diff --git a/drivers/infiniband/hw/bnxt_re/uapi.c b/drivers/infiniband/hw/bnxt_re/uapi.c
index 97bc0e755511..feaf98631fc5 100644
--- a/drivers/infiniband/hw/bnxt_re/uapi.c
+++ b/drivers/infiniband/hw/bnxt_re/uapi.c
@@ -237,16 +237,52 @@ static int UVERBS_HANDLER(BNXT_RE_METHOD_GET_TOGGLE_MEM)(struct uverbs_attr_bund
 	if (IS_ERR(ib_uctx))
 		return PTR_ERR(ib_uctx);
 
+	uctx = container_of(ib_uctx, struct bnxt_re_ucontext, ib_uctx);
+
+	/* New path: updated libbnxt_re passes the CQ or SRQ uverbs handle */
+	if (uverbs_attr_is_valid(attrs, BNXT_RE_TOGGLE_MEM_CQ_HANDLE)) {
+		struct bnxt_re_cq *cq;
+
+		res_uobj = uverbs_attr_get_uobject(attrs,
+						   BNXT_RE_TOGGLE_MEM_CQ_HANDLE);
+		if (IS_ERR(res_uobj))
+			return PTR_ERR(res_uobj);
+		cq = container_of(res_uobj->object, struct bnxt_re_cq, ib_cq);
+		if (!cq->toggle_entry)
+			return -EOPNOTSUPP;
+		mmap_offset = rdma_user_mmap_get_offset(&cq->toggle_entry->rdma_entry);
+		if (!mmap_offset)
+			return -EOPNOTSUPP;
+		kref_get(&cq->toggle_entry->rdma_entry.ref);
+		toggle_entry = cq->toggle_entry;
+		goto alloc_tmem;
+	} else if (uverbs_attr_is_valid(attrs, BNXT_RE_TOGGLE_MEM_SRQ_HANDLE)) {
+		struct bnxt_re_srq *srq;
+
+		res_uobj = uverbs_attr_get_uobject(attrs,
+						   BNXT_RE_TOGGLE_MEM_SRQ_HANDLE);
+		if (IS_ERR(res_uobj))
+			return PTR_ERR(res_uobj);
+		srq = container_of(res_uobj->object, struct bnxt_re_srq, ib_srq);
+		if (!srq->toggle_entry)
+			return -EOPNOTSUPP;
+		mmap_offset = rdma_user_mmap_get_offset(&srq->toggle_entry->rdma_entry);
+		if (!mmap_offset)
+			return -EOPNOTSUPP;
+		kref_get(&srq->toggle_entry->rdma_entry.ref);
+		toggle_entry = srq->toggle_entry;
+		goto alloc_tmem;
+	}
+
 	err = uverbs_get_const(&res_type, attrs, BNXT_RE_TOGGLE_MEM_TYPE);
 	if (err)
 		return err;
-
-	uctx = container_of(ib_uctx, struct bnxt_re_ucontext, ib_uctx);
 	err = uverbs_copy_from(&res_id, attrs, BNXT_RE_TOGGLE_MEM_RES_ID);
 	if (err)
 		return err;
 
 	/*
+	 * Legacy path: old libbnxt_re sends TYPE + RES_ID.
 	 * Hold xa_lock across xa_load + kref_get so that a concurrent
 	 * bnxt_re_destroy_cq/srq cannot call __xa_erase and remove the
 	 * toggle_entry between our load and our reference on it.
@@ -297,6 +333,7 @@ static int UVERBS_HANDLER(BNXT_RE_METHOD_GET_TOGGLE_MEM)(struct uverbs_attr_bund
 	if (!mmap_offset)
 		return -EOPNOTSUPP;
 
+alloc_tmem:
 	tmem = kzalloc_obj(*tmem);
 	if (!tmem) {
 		rdma_user_mmap_entry_put(&toggle_entry->rdma_entry);
@@ -343,10 +380,10 @@ DECLARE_UVERBS_NAMED_METHOD(BNXT_RE_METHOD_GET_TOGGLE_MEM,
 					    UA_MANDATORY),
 			    UVERBS_ATTR_CONST_IN(BNXT_RE_TOGGLE_MEM_TYPE,
 						 enum bnxt_re_get_toggle_mem_type,
-						 UA_MANDATORY),
+						 UA_OPTIONAL),
 			    UVERBS_ATTR_PTR_IN(BNXT_RE_TOGGLE_MEM_RES_ID,
 					       UVERBS_ATTR_TYPE(u32),
-					       UA_MANDATORY),
+					       UA_OPTIONAL),
 			    UVERBS_ATTR_PTR_OUT(BNXT_RE_TOGGLE_MEM_MMAP_PAGE,
 						UVERBS_ATTR_TYPE(u64),
 						UA_MANDATORY),
@@ -355,7 +392,15 @@ DECLARE_UVERBS_NAMED_METHOD(BNXT_RE_METHOD_GET_TOGGLE_MEM,
 						UA_MANDATORY),
 			    UVERBS_ATTR_PTR_OUT(BNXT_RE_TOGGLE_MEM_MMAP_LENGTH,
 						UVERBS_ATTR_TYPE(u32),
-						UA_MANDATORY));
+						UA_MANDATORY),
+			    UVERBS_ATTR_IDR(BNXT_RE_TOGGLE_MEM_CQ_HANDLE,
+					    UVERBS_OBJECT_CQ,
+					    UVERBS_ACCESS_READ,
+					    UA_OPTIONAL),
+			    UVERBS_ATTR_IDR(BNXT_RE_TOGGLE_MEM_SRQ_HANDLE,
+					    UVERBS_OBJECT_SRQ,
+					    UVERBS_ACCESS_READ,
+					    UA_OPTIONAL));
 
 DECLARE_UVERBS_NAMED_METHOD_DESTROY(BNXT_RE_METHOD_RELEASE_TOGGLE_MEM,
 				    UVERBS_ATTR_IDR(BNXT_RE_RELEASE_TOGGLE_MEM_HANDLE,
diff --git a/include/uapi/rdma/bnxt_re-abi.h b/include/uapi/rdma/bnxt_re-abi.h
index a4599d7b736a..c0ee9ce389ac 100644
--- a/include/uapi/rdma/bnxt_re-abi.h
+++ b/include/uapi/rdma/bnxt_re-abi.h
@@ -57,6 +57,8 @@ enum {
 	BNXT_RE_UCNTX_CMASK_POW2_DISABLED = 0x10ULL,
 	BNXT_RE_UCNTX_CMASK_MSN_TABLE_ENABLED = 0x40,
 	BNXT_RE_UCNTX_CMASK_QP_RATE_LIMIT_ENABLED = 0x80ULL,
+	 /* Some reserved fields to manage compatibility with Out of tree drivers */
+	BNXT_RE_UCNTX_CMASK_TOGGLE_MEM_UOBJ_SUPPORT = 0x400000ULL,
 };
 
 enum bnxt_re_wqe_mode {
@@ -218,6 +220,8 @@ enum bnxt_re_var_toggle_mem_attrs {
 	BNXT_RE_TOGGLE_MEM_MMAP_PAGE,
 	BNXT_RE_TOGGLE_MEM_MMAP_OFFSET,
 	BNXT_RE_TOGGLE_MEM_MMAP_LENGTH,
+	BNXT_RE_TOGGLE_MEM_CQ_HANDLE,
+	BNXT_RE_TOGGLE_MEM_SRQ_HANDLE,
 };
 
 enum bnxt_re_toggle_mem_attrs {
-- 
2.39.3