RDMA/rxe: Add elem_offset field to rxe_type_info

The rxe verbs objects each include an rdma-core object 'ib_xxx'
and a rxe_pool_entry 'pelem' in addition to rxe specific data.
Originally these all had pelem first and ib_xxx second. Currently
about half have ib_xxx first and half have pelem first. Saving
the offset of the pelem field in rxe_type info will enable making
the rxe_pool APIs type safe as the pelem field continues to vary.

Link: https://lore.kernel.org/r/20201216231550.27224-4-rpearson@hpe.comSigned-off-by: Bob Pearson <rpearson@hpe.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/sw/rxe/rxe_pool.c

@@ -15,21 +15,25 @@ struct rxe_type_info rxe_type_info[RXE_NUM_TYPES] = {
 	[RXE_TYPE_UC] = {
 		.name		= "rxe-uc",
 		.size		= sizeof(struct rxe_ucontext),
+		.elem_offset	= offsetof(struct rxe_ucontext, pelem),
 		.flags          = RXE_POOL_NO_ALLOC,
 	},
 	[RXE_TYPE_PD] = {
 		.name		= "rxe-pd",
 		.size		= sizeof(struct rxe_pd),
+		.elem_offset	= offsetof(struct rxe_pd, pelem),
 		.flags		= RXE_POOL_NO_ALLOC,
 	},
 	[RXE_TYPE_AH] = {
 		.name		= "rxe-ah",
 		.size		= sizeof(struct rxe_ah),
+		.elem_offset	= offsetof(struct rxe_ah, pelem),
 		.flags		= RXE_POOL_NO_ALLOC,
 	},
 	[RXE_TYPE_SRQ] = {
 		.name		= "rxe-srq",
 		.size		= sizeof(struct rxe_srq),
+		.elem_offset	= offsetof(struct rxe_srq, pelem),
 		.flags		= RXE_POOL_INDEX | RXE_POOL_NO_ALLOC,
 		.min_index	= RXE_MIN_SRQ_INDEX,
 		.max_index	= RXE_MAX_SRQ_INDEX,
@@ -37,6 +41,7 @@ struct rxe_type_info rxe_type_info[RXE_NUM_TYPES] = {
 	[RXE_TYPE_QP] = {
 		.name		= "rxe-qp",
 		.size		= sizeof(struct rxe_qp),
+		.elem_offset	= offsetof(struct rxe_qp, pelem),
 		.cleanup	= rxe_qp_cleanup,
 		.flags		= RXE_POOL_INDEX,
 		.min_index	= RXE_MIN_QP_INDEX,
@@ -45,12 +50,14 @@ struct rxe_type_info rxe_type_info[RXE_NUM_TYPES] = {
 	[RXE_TYPE_CQ] = {
 		.name		= "rxe-cq",
 		.size		= sizeof(struct rxe_cq),
+		.elem_offset	= offsetof(struct rxe_cq, pelem),
 		.flags          = RXE_POOL_NO_ALLOC,
 		.cleanup	= rxe_cq_cleanup,
 	},
 	[RXE_TYPE_MR] = {
 		.name		= "rxe-mr",
 		.size		= sizeof(struct rxe_mem),
+		.elem_offset	= offsetof(struct rxe_mem, pelem),
 		.cleanup	= rxe_mem_cleanup,
 		.flags		= RXE_POOL_INDEX,
 		.max_index	= RXE_MAX_MR_INDEX,
@@ -59,6 +66,7 @@ struct rxe_type_info rxe_type_info[RXE_NUM_TYPES] = {
 	[RXE_TYPE_MW] = {
 		.name		= "rxe-mw",
 		.size		= sizeof(struct rxe_mem),
+		.elem_offset	= offsetof(struct rxe_mem, pelem),
 		.flags		= RXE_POOL_INDEX,
 		.max_index	= RXE_MAX_MW_INDEX,
 		.min_index	= RXE_MIN_MW_INDEX,
@@ -66,6 +74,7 @@ struct rxe_type_info rxe_type_info[RXE_NUM_TYPES] = {
 	[RXE_TYPE_MC_GRP] = {
 		.name		= "rxe-mc_grp",
 		.size		= sizeof(struct rxe_mc_grp),
+		.elem_offset	= offsetof(struct rxe_mc_grp, pelem),
 		.cleanup	= rxe_mc_cleanup,
 		.flags		= RXE_POOL_KEY,
 		.key_offset	= offsetof(struct rxe_mc_grp, mgid),
@@ -74,6 +83,7 @@ struct rxe_type_info rxe_type_info[RXE_NUM_TYPES] = {
 	[RXE_TYPE_MC_ELEM] = {
 		.name		= "rxe-mc_elem",
 		.size		= sizeof(struct rxe_mc_elem),
+		.elem_offset	= offsetof(struct rxe_mc_elem, pelem),
 		.flags		= RXE_POOL_ATOMIC,
 	},
 };

drivers/infiniband/sw/rxe/rxe_pool.h

@@ -36,6 +36,7 @@ struct rxe_pool_entry;
 struct rxe_type_info {
 	const char		*name;
 	size_t			size;
+	size_t			elem_offset;
 	void			(*cleanup)(struct rxe_pool_entry *obj);
 	enum rxe_pool_flags	flags;
 	u32			max_index;