RDMA/rxe: Create duplicate mapping tables for FMRs

For fast memory regions create duplicate mapping tables so ib_map_mr_sg()
can build a new mapping table which is then swapped into place
synchronously with the execution of an IB_WR_REG_MR work request.

Currently the rxe driver uses the same table for receiving RDMA operations
and for building new tables in preparation for reusing the MR. This
exposes users to potentially incorrect results.

Link: https://lore.kernel.org/r/20210914164206.19768-5-rpearsonhpe@gmail.com
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

5 files changed, 161 insertions, 102 deletions

diff --git a/drivers/infiniband/sw/rxe/rxe_loc.h b/drivers/infiniband/sw/rxe/rxe_loc.h
index 4fd73b51fabf..1ca43b859d80 100644
--- a/drivers/infiniband/sw/rxe/rxe_loc.h
+++ b/drivers/infiniband/sw/rxe/rxe_loc.h
@@ -87,6 +87,7 @@ int mr_check_range(struct rxe_mr *mr, u64 iova, size_t length);
 int advance_dma_data(struct rxe_dma_info *dma, unsigned int length);
 int rxe_invalidate_mr(struct rxe_qp *qp, u32 rkey);
 int rxe_reg_fast_mr(struct rxe_qp *qp, struct rxe_send_wqe *wqe);
+int rxe_mr_set_page(struct ib_mr *ibmr, u64 addr);
 int rxe_dereg_mr(struct ib_mr *ibmr, struct ib_udata *udata);
 void rxe_mr_cleanup(struct rxe_pool_entry *arg);
 
diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
index 370212801abc..8d658d42abed 100644
--- a/drivers/infiniband/sw/rxe/rxe_mr.c
+++ b/drivers/infiniband/sw/rxe/rxe_mr.c
@@ -24,7 +24,7 @@ u8 rxe_get_next_key(u32 last_key)
 
 int mr_check_range(struct rxe_mr *mr, u64 iova, size_t length)
 {
-
+	struct rxe_map_set *set = mr->cur_map_set;
 
 	switch (mr->type) {
 	case IB_MR_TYPE_DMA:
@@ -32,8 +32,8 @@ int mr_check_range(struct rxe_mr *mr, u64 iova, size_t length)
 
 	case IB_MR_TYPE_USER:
 	case IB_MR_TYPE_MEM_REG:
-		if (iova < mr->iova || length > mr->length ||
-		    iova > mr->iova + mr->length - length)
+		if (iova < set->iova || length > set->length ||
+		    iova > set->iova + set->length - length)
 			return -EFAULT;
 		return 0;
 
@@ -65,41 +65,89 @@ static void rxe_mr_init(int access, struct rxe_mr *mr)
 	mr->map_shift = ilog2(RXE_BUF_PER_MAP);
 }
 
-static int rxe_mr_alloc(struct rxe_mr *mr, int num_buf)
+static void rxe_mr_free_map_set(int num_map, struct rxe_map_set *set)
 {
 	int i;
-	int num_map;
-	struct rxe_map **map = mr->map;
 
-	num_map = (num_buf + RXE_BUF_PER_MAP - 1) / RXE_BUF_PER_MAP;
+	for (i = 0; i < num_map; i++)
+		kfree(set->map[i]);
 
-	mr->map = kmalloc_array(num_map, sizeof(*map), GFP_KERNEL);
-	if (!mr->map)
-		goto err1;
+	kfree(set->map);
+	kfree(set);
+}
+
+static int rxe_mr_alloc_map_set(int num_map, struct rxe_map_set **setp)
+{
+	int i;
+	struct rxe_map_set *set;
+
+	set = kmalloc(sizeof(*set), GFP_KERNEL);
+	if (!set)
+		goto err_out;
+
+	set->map = kmalloc_array(num_map, sizeof(struct rxe_map *), GFP_KERNEL);
+	if (!set->map)
+		goto err_free_set;
 
 	for (i = 0; i < num_map; i++) {
-		mr->map[i] = kmalloc(sizeof(**map), GFP_KERNEL);
-		if (!mr->map[i])
-			goto err2;
+		set->map[i] = kmalloc(sizeof(struct rxe_map), GFP_KERNEL);
+		if (!set->map[i])
+			goto err_free_map;
 	}
 
+	*setp = set;
+
+	return 0;
+
+err_free_map:
+	for (i--; i >= 0; i--)
+		kfree(set->map[i]);
+
+	kfree(set->map);
+err_free_set:
+	kfree(set);
+err_out:
+	return -ENOMEM;
+}
+
+/**
+ * rxe_mr_alloc() - Allocate memory map array(s) for MR
+ * @mr: Memory region
+ * @num_buf: Number of buffer descriptors to support
+ * @both: If non zero allocate both mr->map and mr->next_map
+ *	  else just allocate mr->map. Used for fast MRs
+ *
+ * Return: 0 on success else an error
+ */
+static int rxe_mr_alloc(struct rxe_mr *mr, int num_buf, int both)
+{
+	int ret;
+	int num_map;
+
 	BUILD_BUG_ON(!is_power_of_2(RXE_BUF_PER_MAP));
+	num_map = (num_buf + RXE_BUF_PER_MAP - 1) / RXE_BUF_PER_MAP;
 
 	mr->map_shift = ilog2(RXE_BUF_PER_MAP);
 	mr->map_mask = RXE_BUF_PER_MAP - 1;
-
 	mr->num_buf = num_buf;
-	mr->num_map = num_map;
 	mr->max_buf = num_map * RXE_BUF_PER_MAP;
+	mr->num_map = num_map;
 
-	return 0;
+	ret = rxe_mr_alloc_map_set(num_map, &mr->cur_map_set);
+	if (ret)
+		goto err_out;
 
-err2:
-	for (i--; i >= 0; i--)
-		kfree(mr->map[i]);
+	if (both) {
+		ret = rxe_mr_alloc_map_set(num_map, &mr->next_map_set);
+		if (ret) {
+			rxe_mr_free_map_set(mr->num_map, mr->cur_map_set);
+			goto err_out;
+		}
+	}
 
-	kfree(mr->map);
-err1:
+	return 0;
+
+err_out:
 	return -ENOMEM;
 }
 
@@ -116,6 +164,7 @@ void rxe_mr_init_dma(struct rxe_pd *pd, int access, struct rxe_mr *mr)
 int rxe_mr_init_user(struct rxe_pd *pd, u64 start, u64 length, u64 iova,
 		     int access, struct rxe_mr *mr)
 {
+	struct rxe_map_set	*set;
 	struct rxe_map		**map;
 	struct rxe_phys_buf	*buf = NULL;
 	struct ib_umem		*umem;
@@ -123,7 +172,6 @@ int rxe_mr_init_user(struct rxe_pd *pd, u64 start, u64 length, u64 iova,
 	int			num_buf;
 	void			*vaddr;
 	int err;
-	int i;
 
 	umem = ib_umem_get(pd->ibpd.device, start, length, access);
 	if (IS_ERR(umem)) {
@@ -137,18 +185,20 @@ int rxe_mr_init_user(struct rxe_pd *pd, u64 start, u64 length, u64 iova,
 
 	rxe_mr_init(access, mr);
 
-	err = rxe_mr_alloc(mr, num_buf);
+	err = rxe_mr_alloc(mr, num_buf, 0);
 	if (err) {
 		pr_warn("%s: Unable to allocate memory for map\n",
 				__func__);
 		goto err_release_umem;
 	}
 
-	mr->page_shift = PAGE_SHIFT;
-	mr->page_mask = PAGE_SIZE - 1;
+	set = mr->cur_map_set;
+	set->page_shift = PAGE_SHIFT;
+	set->page_mask = PAGE_SIZE - 1;
+
+	num_buf = 0;
+	map = set->map;
 
-	num_buf			= 0;
-	map = mr->map;
 	if (length > 0) {
 		buf = map[0]->buf;
 
@@ -171,26 +221,24 @@ int rxe_mr_init_user(struct rxe_pd *pd, u64 start, u64 length, u64 iova,
 			buf->size = PAGE_SIZE;
 			num_buf++;
 			buf++;
-
 		}
 	}
 
 	mr->ibmr.pd = &pd->ibpd;
 	mr->umem = umem;
 	mr->access = access;
-	mr->length = length;
-	mr->iova = iova;
-	mr->va = start;
-	mr->offset = ib_umem_offset(umem);
 	mr->state = RXE_MR_STATE_VALID;
 	mr->type = IB_MR_TYPE_USER;
 
+	set->length = length;
+	set->iova = iova;
+	set->va = start;
+	set->offset = ib_umem_offset(umem);
+
 	return 0;
 
 err_cleanup_map:
-	for (i = 0; i < mr->num_map; i++)
-		kfree(mr->map[i]);
-	kfree(mr->map);
+	rxe_mr_free_map_set(mr->num_map, mr->cur_map_set);
 err_release_umem:
 	ib_umem_release(umem);
 err_out:
@@ -204,7 +252,7 @@ int rxe_mr_init_fast(struct rxe_pd *pd, int max_pages, struct rxe_mr *mr)
 	/* always allow remote access for FMRs */
 	rxe_mr_init(IB_ACCESS_REMOTE, mr);
 
-	err = rxe_mr_alloc(mr, max_pages);
+	err = rxe_mr_alloc(mr, max_pages, 1);
 	if (err)
 		goto err1;
 
@@ -222,21 +270,24 @@ err1:
 static void lookup_iova(struct rxe_mr *mr, u64 iova, int *m_out, int *n_out,
 			size_t *offset_out)
 {
-	size_t offset = iova - mr->iova + mr->offset;
+	struct rxe_map_set *set = mr->cur_map_set;
+	size_t offset = iova - set->iova + set->offset;
 	int			map_index;
 	int			buf_index;
 	u64			length;
+	struct rxe_map *map;
 
-	if (likely(mr->page_shift)) {
-		*offset_out = offset & mr->page_mask;
-		offset >>= mr->page_shift;
+	if (likely(set->page_shift)) {
+		*offset_out = offset & set->page_mask;
+		offset >>= set->page_shift;
 		*n_out = offset & mr->map_mask;
 		*m_out = offset >> mr->map_shift;
 	} else {
 		map_index = 0;
 		buf_index = 0;
 
-		length = mr->map[map_index]->buf[buf_index].size;
+		map = set->map[map_index];
+		length = map->buf[buf_index].size;
 
 		while (offset >= length) {
 			offset -= length;
@@ -246,7 +297,8 @@ static void lookup_iova(struct rxe_mr *mr, u64 iova, int *m_out, int *n_out,
 				map_index++;
 				buf_index = 0;
 			}
-			length = mr->map[map_index]->buf[buf_index].size;
+			map = set->map[map_index];
+			length = map->buf[buf_index].size;
 		}
 
 		*m_out = map_index;
@@ -267,7 +319,7 @@ void *iova_to_vaddr(struct rxe_mr *mr, u64 iova, int length)
 		goto out;
 	}
 
-	if (!mr->map) {
+	if (!mr->cur_map_set) {
 		addr = (void *)(uintptr_t)iova;
 		goto out;
 	}
@@ -280,13 +332,13 @@ void *iova_to_vaddr(struct rxe_mr *mr, u64 iova, int length)
 
 	lookup_iova(mr, iova, &m, &n, &offset);
 
-	if (offset + length > mr->map[m]->buf[n].size) {
+	if (offset + length > mr->cur_map_set->map[m]->buf[n].size) {
 		pr_warn("crosses page boundary\n");
 		addr = NULL;
 		goto out;
 	}
 
-	addr = (void *)(uintptr_t)mr->map[m]->buf[n].addr + offset;
+	addr = (void *)(uintptr_t)mr->cur_map_set->map[m]->buf[n].addr + offset;
 
 out:
 	return addr;
@@ -322,7 +374,7 @@ int rxe_mr_copy(struct rxe_mr *mr, u64 iova, void *addr, int length,
 		return 0;
 	}
 
-	WARN_ON_ONCE(!mr->map);
+	WARN_ON_ONCE(!mr->cur_map_set);
 
 	err = mr_check_range(mr, iova, length);
 	if (err) {
@@ -332,7 +384,7 @@ int rxe_mr_copy(struct rxe_mr *mr, u64 iova, void *addr, int length,
 
 	lookup_iova(mr, iova, &m, &i, &offset);
 
-	map = mr->map + m;
+	map = mr->cur_map_set->map + m;
 	buf	= map[0]->buf + i;
 
 	while (length > 0) {
@@ -572,8 +624,9 @@ err:
 int rxe_reg_fast_mr(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
 {
 	struct rxe_mr *mr = to_rmr(wqe->wr.wr.reg.mr);
-	u32 key = wqe->wr.wr.reg.key;
+	u32 key = wqe->wr.wr.reg.key & 0xff;
 	u32 access = wqe->wr.wr.reg.access;
+	struct rxe_map_set *set;
 
 	/* user can only register MR in free state */
 	if (unlikely(mr->state != RXE_MR_STATE_FREE)) {
@@ -589,19 +642,36 @@ int rxe_reg_fast_mr(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
 		return -EINVAL;
 	}
 
-	/* user is only allowed to change key portion of l/rkey */
-	if (unlikely((mr->lkey & ~0xff) != (key & ~0xff))) {
-		pr_warn("%s: key = 0x%x has wrong index mr->lkey = 0x%x\n",
-			__func__, key, mr->lkey);
-		return -EINVAL;
-	}
-
 	mr->access = access;
-	mr->lkey = key;
-	mr->rkey = (access & IB_ACCESS_REMOTE) ? key : 0;
-	mr->iova = wqe->wr.wr.reg.mr->iova;
+	mr->lkey = (mr->lkey & ~0xff) | key;
+	mr->rkey = (access & IB_ACCESS_REMOTE) ? mr->lkey : 0;
 	mr->state = RXE_MR_STATE_VALID;
 
+	set = mr->cur_map_set;
+	mr->cur_map_set = mr->next_map_set;
+	mr->cur_map_set->iova = wqe->wr.wr.reg.mr->iova;
+	mr->next_map_set = set;
+
+	return 0;
+}
+
+int rxe_mr_set_page(struct ib_mr *ibmr, u64 addr)
+{
+	struct rxe_mr *mr = to_rmr(ibmr);
+	struct rxe_map_set *set = mr->next_map_set;
+	struct rxe_map *map;
+	struct rxe_phys_buf *buf;
+
+	if (unlikely(set->nbuf == mr->num_buf))
+		return -ENOMEM;
+
+	map = set->map[set->nbuf / RXE_BUF_PER_MAP];
+	buf = &map->buf[set->nbuf % RXE_BUF_PER_MAP];
+
+	buf->addr = addr;
+	buf->size = ibmr->page_size;
+	set->nbuf++;
+
 	return 0;
 }
 
@@ -626,14 +696,12 @@ int rxe_dereg_mr(struct ib_mr *ibmr, struct ib_udata *udata)
 void rxe_mr_cleanup(struct rxe_pool_entry *arg)
 {
 	struct rxe_mr *mr = container_of(arg, typeof(*mr), pelem);
-	int i;
 
 	ib_umem_release(mr->umem);
 
-	if (mr->map) {
-		for (i = 0; i < mr->num_map; i++)
-			kfree(mr->map[i]);
+	if (mr->cur_map_set)
+		rxe_mr_free_map_set(mr->num_map, mr->cur_map_set);
 
-		kfree(mr->map);
-	}
+	if (mr->next_map_set)
+		rxe_mr_free_map_set(mr->num_map, mr->next_map_set);
 }
diff --git a/drivers/infiniband/sw/rxe/rxe_mw.c b/drivers/infiniband/sw/rxe/rxe_mw.c
index a5e2ea7d80f0..9534a7fe1a98 100644
--- a/drivers/infiniband/sw/rxe/rxe_mw.c
+++ b/drivers/infiniband/sw/rxe/rxe_mw.c
@@ -142,15 +142,15 @@ static int rxe_check_bind_mw(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
 
 	/* C10-75 */
 	if (mw->access & IB_ZERO_BASED) {
-		if (unlikely(wqe->wr.wr.mw.length > mr->length)) {
+		if (unlikely(wqe->wr.wr.mw.length > mr->cur_map_set->length)) {
 			pr_err_once(
 				"attempt to bind a ZB MW outside of the MR\n");
 			return -EINVAL;
 		}
 	} else {
-		if (unlikely((wqe->wr.wr.mw.addr < mr->iova) ||
+		if (unlikely((wqe->wr.wr.mw.addr < mr->cur_map_set->iova) ||
 			     ((wqe->wr.wr.mw.addr + wqe->wr.wr.mw.length) >
-			      (mr->iova + mr->length)))) {
+			      (mr->cur_map_set->iova + mr->cur_map_set->length)))) {
 			pr_err_once(
 				"attempt to bind a VA MW outside of the MR\n");
 			return -EINVAL;
diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.c b/drivers/infiniband/sw/rxe/rxe_verbs.c
index 571cbbeed5d6..9d0bb9aa7514 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.c
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.c
@@ -951,41 +951,26 @@ err1:
 	return ERR_PTR(err);
 }
 
-static int rxe_set_page(struct ib_mr *ibmr, u64 addr)
-{
-	struct rxe_mr *mr = to_rmr(ibmr);
-	struct rxe_map *map;
-	struct rxe_phys_buf *buf;
-
-	if (unlikely(mr->nbuf == mr->num_buf))
-		return -ENOMEM;
-
-	map = mr->map[mr->nbuf / RXE_BUF_PER_MAP];
-	buf = &map->buf[mr->nbuf % RXE_BUF_PER_MAP];
-
-	buf->addr = addr;
-	buf->size = ibmr->page_size;
-	mr->nbuf++;
-
-	return 0;
-}
-
+/* build next_map_set from scatterlist
+ * The IB_WR_REG_MR WR will swap map_sets
+ */
 static int rxe_map_mr_sg(struct ib_mr *ibmr, struct scatterlist *sg,
 			 int sg_nents, unsigned int *sg_offset)
 {
 	struct rxe_mr *mr = to_rmr(ibmr);
+	struct rxe_map_set *set = mr->next_map_set;
 	int n;
 
-	mr->nbuf = 0;
+	set->nbuf = 0;
 
-	n = ib_sg_to_pages(ibmr, sg, sg_nents, sg_offset, rxe_set_page);
+	n = ib_sg_to_pages(ibmr, sg, sg_nents, sg_offset, rxe_mr_set_page);
 
-	mr->va = ibmr->iova;
-	mr->iova = ibmr->iova;
-	mr->length = ibmr->length;
-	mr->page_shift = ilog2(ibmr->page_size);
-	mr->page_mask = ibmr->page_size - 1;
-	mr->offset = mr->iova & mr->page_mask;
+	set->va = ibmr->iova;
+	set->iova = ibmr->iova;
+	set->length = ibmr->length;
+	set->page_shift = ilog2(ibmr->page_size);
+	set->page_mask = ibmr->page_size - 1;
+	set->offset = set->iova & set->page_mask;
 
 	return n;
 }
diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.h b/drivers/infiniband/sw/rxe/rxe_verbs.h
index b330e56609af..c807639435eb 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.h
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.h
@@ -292,6 +292,17 @@ struct rxe_map {
 	struct rxe_phys_buf	buf[RXE_BUF_PER_MAP];
 };
 
+struct rxe_map_set {
+	struct rxe_map		**map;
+	u64			va;
+	u64			iova;
+	size_t			length;
+	u32			offset;
+	u32			nbuf;
+	int			page_shift;
+	int			page_mask;
+};
+
 static inline int rkey_is_mw(u32 rkey)
 {
 	u32 index = rkey >> 8;
@@ -309,26 +320,20 @@ struct rxe_mr {
 	u32			rkey;
 	enum rxe_mr_state	state;
 	enum ib_mr_type		type;
-	u64			va;
-	u64			iova;
-	size_t			length;
-	u32			offset;
 	int			access;
 
-	int			page_shift;
-	int			page_mask;
 	int			map_shift;
 	int			map_mask;
 
 	u32			num_buf;
-	u32			nbuf;
 
 	u32			max_buf;
 	u32			num_map;
 
 	atomic_t		num_mw;
 
-	struct rxe_map		**map;
+	struct rxe_map_set	*cur_map_set;
+	struct rxe_map_set	*next_map_set;
 };
 
 enum rxe_mw_state {