RDMA: Move DMA block iterator logic into dedicated files

The DMA iterator logic was mixed into verbs and umem-specific code,
forcing all users to include rdma/ib_umem.h. Move the block iterator
logic into iter.c and rdma/iter.h so that rdma/ib_umem.h and
rdma/ib_verbs.h can be separated in a follow-up patch.

Link: https://patch.msgid.link/20260213-refactor-umem-v1-1-f3be85847922@nvidia.com
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>

drivers/infiniband/core/Makefile

@@ -12,7 +12,7 @@ ib_core-y :=			packer.o ud_header.o verbs.o cq.o rw.o sysfs.o \
 				roce_gid_mgmt.o mr_pool.o addr.o sa_query.o \
 				multicast.o mad.o smi.o agent.o mad_rmpp.o \
 				nldev.o restrack.o counters.o ib_core_uverbs.o \
-				trace.o lag.o
+				trace.o lag.o iter.o
 
 ib_core-$(CONFIG_SECURITY_INFINIBAND) += security.o
 ib_core-$(CONFIG_CGROUP_RDMA) += cgroup.o

drivers/infiniband/core/iter.c

@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/* Copyright (c) 2026, NVIDIA CORPORATION & AFFILIATES. */
+
+#include <linux/export.h>
+#include <rdma/iter.h>
+
+void __rdma_block_iter_start(struct ib_block_iter *biter,
+			     struct scatterlist *sglist, unsigned int nents,
+			     unsigned long pgsz)
+{
+	memset(biter, 0, sizeof(struct ib_block_iter));
+	biter->__sg = sglist;
+	biter->__sg_nents = nents;
+
+	/* Driver provides best block size to use */
+	biter->__pg_bit = __fls(pgsz);
+}
+EXPORT_SYMBOL(__rdma_block_iter_start);
+
+bool __rdma_block_iter_next(struct ib_block_iter *biter)
+{
+	unsigned int block_offset;
+	unsigned int delta;
+
+	if (!biter->__sg_nents || !biter->__sg)
+		return false;
+
+	biter->__dma_addr = sg_dma_address(biter->__sg) + biter->__sg_advance;
+	block_offset = biter->__dma_addr & (BIT_ULL(biter->__pg_bit) - 1);
+	delta = BIT_ULL(biter->__pg_bit) - block_offset;
+
+	while (biter->__sg_nents && biter->__sg &&
+	       sg_dma_len(biter->__sg) - biter->__sg_advance <= delta) {
+		delta -= sg_dma_len(biter->__sg) - biter->__sg_advance;
+		biter->__sg_advance = 0;
+		biter->__sg = sg_next(biter->__sg);
+		biter->__sg_nents--;
+	}
+	biter->__sg_advance += delta;
+
+	return true;
+}
+EXPORT_SYMBOL(__rdma_block_iter_next);

drivers/infiniband/core/verbs.c

@@ -3154,44 +3154,6 @@ int rdma_init_netdev(struct ib_device *device, u32 port_num,
 }
 EXPORT_SYMBOL(rdma_init_netdev);
 
-void __rdma_block_iter_start(struct ib_block_iter *biter,
-			     struct scatterlist *sglist, unsigned int nents,
-			     unsigned long pgsz)
-{
-	memset(biter, 0, sizeof(struct ib_block_iter));
-	biter->__sg = sglist;
-	biter->__sg_nents = nents;
-
-	/* Driver provides best block size to use */
-	biter->__pg_bit = __fls(pgsz);
-}
-EXPORT_SYMBOL(__rdma_block_iter_start);
-
-bool __rdma_block_iter_next(struct ib_block_iter *biter)
-{
-	unsigned int block_offset;
-	unsigned int delta;
-
-	if (!biter->__sg_nents || !biter->__sg)
-		return false;
-
-	biter->__dma_addr = sg_dma_address(biter->__sg) + biter->__sg_advance;
-	block_offset = biter->__dma_addr & (BIT_ULL(biter->__pg_bit) - 1);
-	delta = BIT_ULL(biter->__pg_bit) - block_offset;
-
-	while (biter->__sg_nents && biter->__sg &&
-	       sg_dma_len(biter->__sg) - biter->__sg_advance <= delta) {
-		delta -= sg_dma_len(biter->__sg) - biter->__sg_advance;
-		biter->__sg_advance = 0;
-		biter->__sg = sg_next(biter->__sg);
-		biter->__sg_nents--;
-	}
-	biter->__sg_advance += delta;
-
-	return true;
-}
-EXPORT_SYMBOL(__rdma_block_iter_next);
-
 /**
  * rdma_alloc_hw_stats_struct - Helper function to allocate dynamic struct
  *   for the drivers.

drivers/infiniband/hw/bnxt_re/qplib_res.c

@@ -46,7 +46,7 @@
 #include <linux/if_vlan.h>
 #include <linux/vmalloc.h>
 #include <rdma/ib_verbs.h>
-#include <rdma/ib_umem.h>
+#include <rdma/iter.h>
 
 #include "roce_hsi.h"
 #include "qplib_res.h"

drivers/infiniband/hw/cxgb4/mem.c

@@ -32,9 +32,9 @@
 
 #include <linux/module.h>
 #include <linux/moduleparam.h>
-#include <rdma/ib_umem.h>
 #include <linux/atomic.h>
 #include <rdma/ib_user_verbs.h>
+#include <rdma/iter.h>
 
 #include "iw_cxgb4.h"
 

drivers/infiniband/hw/efa/efa_verbs.c

@@ -9,9 +9,9 @@
 #include <linux/log2.h>
 
 #include <rdma/ib_addr.h>
-#include <rdma/ib_umem.h>
 #include <rdma/ib_user_verbs.h>
 #include <rdma/ib_verbs.h>
+#include <rdma/iter.h>
 #include <rdma/uverbs_ioctl.h>
 #define UVERBS_MODULE_NAME efa_ib
 #include <rdma/uverbs_named_ioctl.h>

drivers/infiniband/hw/erdma/erdma_verbs.c

@@ -12,7 +12,7 @@
 #include <linux/vmalloc.h>
 #include <net/addrconf.h>
 #include <rdma/erdma-abi.h>
-#include <rdma/ib_umem.h>
+#include <rdma/iter.h>
 #include <rdma/uverbs_ioctl.h>
 
 #include "erdma.h"

drivers/infiniband/hw/hns/hns_roce_alloc.c

@@ -32,7 +32,7 @@
  */
 
 #include <linux/vmalloc.h>
-#include <rdma/ib_umem.h>
+#include <rdma/iter.h>
 #include "hns_roce_device.h"
 
 void hns_roce_buf_free(struct hns_roce_dev *hr_dev, struct hns_roce_buf *buf)

drivers/infiniband/hw/ionic/ionic_ibdev.h

@@ -4,9 +4,9 @@
 #ifndef _IONIC_IBDEV_H_
 #define _IONIC_IBDEV_H_
 
-#include <rdma/ib_umem.h>
 #include <rdma/ib_verbs.h>
 #include <rdma/ib_pack.h>
+#include <rdma/iter.h>
 #include <rdma/uverbs_ioctl.h>
 
 #include <rdma/ionic-abi.h>

drivers/infiniband/hw/irdma/main.h

@@ -37,8 +37,8 @@
 #include <rdma/rdma_cm.h>
 #include <rdma/iw_cm.h>
 #include <rdma/ib_user_verbs.h>
-#include <rdma/ib_umem.h>
 #include <rdma/ib_cache.h>
+#include <rdma/iter.h>
 #include <rdma/uverbs_ioctl.h>
 #include "osdep.h"
 #include "defs.h"

drivers/infiniband/hw/mana/mana_ib.h

@@ -8,7 +8,7 @@
 
 #include <rdma/ib_verbs.h>
 #include <rdma/ib_mad.h>
-#include <rdma/ib_umem.h>
+#include <rdma/iter.h>
 #include <rdma/mana-abi.h>
 #include <rdma/uverbs_ioctl.h>
 #include <linux/dmapool.h>

drivers/infiniband/hw/mlx4/mr.c

@@ -33,6 +33,7 @@
 
 #include <linux/slab.h>
 #include <rdma/ib_user_verbs.h>
+#include <rdma/iter.h>
 
 #include "mlx4_ib.h"
 

drivers/infiniband/hw/mlx5/mem.c

@@ -31,6 +31,7 @@
  */
 
 #include <rdma/ib_umem_odp.h>
+#include <rdma/iter.h>
 #include "mlx5_ib.h"
 
 /*

drivers/infiniband/hw/mlx5/umr.c

@@ -2,6 +2,7 @@
 /* Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES. */
 
 #include <rdma/ib_umem_odp.h>
+#include <rdma/iter.h>
 #include "mlx5_ib.h"
 #include "umr.h"
 #include "wr.h"

drivers/infiniband/hw/mthca/mthca_provider.c

@@ -35,8 +35,8 @@
  */
 
 #include <rdma/ib_smi.h>
-#include <rdma/ib_umem.h>
 #include <rdma/ib_user_verbs.h>
+#include <rdma/iter.h>
 #include <rdma/uverbs_ioctl.h>
 
 #include <linux/sched.h>

drivers/infiniband/hw/ocrdma/ocrdma_verbs.c

@@ -45,9 +45,9 @@
 #include <rdma/ib_verbs.h>
 #include <rdma/ib_user_verbs.h>
 #include <rdma/iw_cm.h>
-#include <rdma/ib_umem.h>
 #include <rdma/ib_addr.h>
 #include <rdma/ib_cache.h>
+#include <rdma/iter.h>
 #include <rdma/uverbs_ioctl.h>
 
 #include "ocrdma.h"

drivers/infiniband/hw/qedr/verbs.c

@@ -39,9 +39,9 @@
 #include <rdma/ib_verbs.h>
 #include <rdma/ib_user_verbs.h>
 #include <rdma/iw_cm.h>
-#include <rdma/ib_umem.h>
 #include <rdma/ib_addr.h>
 #include <rdma/ib_cache.h>
+#include <rdma/iter.h>
 #include <rdma/uverbs_ioctl.h>
 
 #include <linux/qed/common_hsi.h>

drivers/infiniband/hw/vmw_pvrdma/pvrdma.h

@@ -53,8 +53,8 @@
 #include <linux/pci.h>
 #include <linux/semaphore.h>
 #include <linux/workqueue.h>
-#include <rdma/ib_umem.h>
 #include <rdma/ib_verbs.h>
+#include <rdma/iter.h>
 #include <rdma/vmw_pvrdma-abi.h>
 
 #include "pvrdma_ring.h"

include/rdma/ib_umem.h

@@ -75,38 +75,6 @@ static inline size_t ib_umem_num_pages(struct ib_umem *umem)
 {
 	return ib_umem_num_dma_blocks(umem, PAGE_SIZE);
 }
-
-static inline void __rdma_umem_block_iter_start(struct ib_block_iter *biter,
-						struct ib_umem *umem,
-						unsigned long pgsz)
-{
-	__rdma_block_iter_start(biter, umem->sgt_append.sgt.sgl,
-				umem->sgt_append.sgt.nents, pgsz);
-	biter->__sg_advance = ib_umem_offset(umem) & ~(pgsz - 1);
-	biter->__sg_numblocks = ib_umem_num_dma_blocks(umem, pgsz);
-}
-
-static inline bool __rdma_umem_block_iter_next(struct ib_block_iter *biter)
-{
-	return __rdma_block_iter_next(biter) && biter->__sg_numblocks--;
-}
-
-/**
- * rdma_umem_for_each_dma_block - iterate over contiguous DMA blocks of the umem
- * @umem: umem to iterate over
- * @biter: block iterator variable
- * @pgsz: Page size to split the list into
- *
- * pgsz must be <= PAGE_SIZE or computed by ib_umem_find_best_pgsz(). The
- * returned DMA blocks will be aligned to pgsz and span the range:
- * ALIGN_DOWN(umem->address, pgsz) to ALIGN(umem->address + umem->length, pgsz)
- *
- * Performs exactly ib_umem_num_dma_blocks() iterations.
- */
-#define rdma_umem_for_each_dma_block(umem, biter, pgsz)                        \
-	for (__rdma_umem_block_iter_start(biter, umem, pgsz);                  \
-	     __rdma_umem_block_iter_next(biter);)
-
 #ifdef CONFIG_INFINIBAND_USER_MEM
 
 struct ib_umem *ib_umem_get(struct ib_device *device, unsigned long addr,

include/rdma/ib_verbs.h

@@ -2959,22 +2959,6 @@ struct ib_client {
 	u8 no_kverbs_req:1;
 };
 
-/*
- * IB block DMA iterator
- *
- * Iterates the DMA-mapped SGL in contiguous memory blocks aligned
- * to a HW supported page size.
- */
-struct ib_block_iter {
-	/* internal states */
-	struct scatterlist *__sg;	/* sg holding the current aligned block */
-	dma_addr_t __dma_addr;		/* unaligned DMA address of this block */
-	size_t __sg_numblocks;		/* ib_umem_num_dma_blocks() */
-	unsigned int __sg_nents;	/* number of SG entries */
-	unsigned int __sg_advance;	/* number of bytes to advance in sg in next step */
-	unsigned int __pg_bit;		/* alignment of current block */
-};
-
 struct ib_device *_ib_alloc_device(size_t size, struct net *net);
 #define ib_alloc_device(drv_struct, member)                                    \
 	container_of(_ib_alloc_device(sizeof(struct drv_struct) +              \
@@ -3003,38 +2987,6 @@ void ib_unregister_device_queued(struct ib_device *ib_dev);
 int ib_register_client   (struct ib_client *client);
 void ib_unregister_client(struct ib_client *client);
 
-void __rdma_block_iter_start(struct ib_block_iter *biter,
-			     struct scatterlist *sglist,
-			     unsigned int nents,
-			     unsigned long pgsz);
-bool __rdma_block_iter_next(struct ib_block_iter *biter);
-
-/**
- * rdma_block_iter_dma_address - get the aligned dma address of the current
- * block held by the block iterator.
- * @biter: block iterator holding the memory block
- */
-static inline dma_addr_t
-rdma_block_iter_dma_address(struct ib_block_iter *biter)
-{
-	return biter->__dma_addr & ~(BIT_ULL(biter->__pg_bit) - 1);
-}
-
-/**
- * rdma_for_each_block - iterate over contiguous memory blocks of the sg list
- * @sglist: sglist to iterate over
- * @biter: block iterator holding the memory block
- * @nents: maximum number of sg entries to iterate over
- * @pgsz: best HW supported page size to use
- *
- * Callers may use rdma_block_iter_dma_address() to get each
- * blocks aligned DMA address.
- */
-#define rdma_for_each_block(sglist, biter, nents, pgsz)		\
-	for (__rdma_block_iter_start(biter, sglist, nents,	\
-				     pgsz);			\
-	     __rdma_block_iter_next(biter);)
-
 /**
  * ib_get_client_data - Get IB client context
  * @device:Device to get context for

include/rdma/iter.h

@@ -0,0 +1,88 @@
+/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
+/* Copyright (c) 2026, NVIDIA CORPORATION & AFFILIATES. */
+
+#ifndef _RDMA_ITER_H_
+#define _RDMA_ITER_H_
+
+#include <linux/scatterlist.h>
+#include <rdma/ib_umem.h>
+
+/**
+ * IB block DMA iterator
+ *
+ * Iterates the DMA-mapped SGL in contiguous memory blocks aligned
+ * to a HW supported page size.
+ */
+struct ib_block_iter {
+	/* internal states */
+	struct scatterlist *__sg;	/* sg holding the current aligned block */
+	dma_addr_t __dma_addr;		/* unaligned DMA address of this block */
+	size_t __sg_numblocks;		/* ib_umem_num_dma_blocks() */
+	unsigned int __sg_nents;	/* number of SG entries */
+	unsigned int __sg_advance;	/* number of bytes to advance in sg in next step */
+	unsigned int __pg_bit;		/* alignment of current block */
+};
+
+void __rdma_block_iter_start(struct ib_block_iter *biter,
+			     struct scatterlist *sglist,
+			     unsigned int nents,
+			     unsigned long pgsz);
+bool __rdma_block_iter_next(struct ib_block_iter *biter);
+
+/**
+ * rdma_block_iter_dma_address - get the aligned dma address of the current
+ * block held by the block iterator.
+ * @biter: block iterator holding the memory block
+ */
+static inline dma_addr_t
+rdma_block_iter_dma_address(struct ib_block_iter *biter)
+{
+	return biter->__dma_addr & ~(BIT_ULL(biter->__pg_bit) - 1);
+}
+
+/**
+ * rdma_for_each_block - iterate over contiguous memory blocks of the sg list
+ * @sglist: sglist to iterate over
+ * @biter: block iterator holding the memory block
+ * @nents: maximum number of sg entries to iterate over
+ * @pgsz: best HW supported page size to use
+ *
+ * Callers may use rdma_block_iter_dma_address() to get each
+ * blocks aligned DMA address.
+ */
+#define rdma_for_each_block(sglist, biter, nents, pgsz)		\
+	for (__rdma_block_iter_start(biter, sglist, nents,	\
+				     pgsz);			\
+	     __rdma_block_iter_next(biter);)
+
+static inline void __rdma_umem_block_iter_start(struct ib_block_iter *biter,
+						struct ib_umem *umem,
+						unsigned long pgsz)
+{
+	__rdma_block_iter_start(biter, umem->sgt_append.sgt.sgl,
+				umem->sgt_append.sgt.nents, pgsz);
+	biter->__sg_advance = ib_umem_offset(umem) & ~(pgsz - 1);
+	biter->__sg_numblocks = ib_umem_num_dma_blocks(umem, pgsz);
+}
+
+static inline bool __rdma_umem_block_iter_next(struct ib_block_iter *biter)
+{
+	return __rdma_block_iter_next(biter) && biter->__sg_numblocks--;
+}
+
+/**
+ * rdma_umem_for_each_dma_block - iterate over contiguous DMA blocks of the umem
+ * @umem: umem to iterate over
+ * @pgsz: Page size to split the list into
+ *
+ * pgsz must be <= PAGE_SIZE or computed by ib_umem_find_best_pgsz(). The
+ * returned DMA blocks will be aligned to pgsz and span the range:
+ * ALIGN_DOWN(umem->address, pgsz) to ALIGN(umem->address + umem->length, pgsz)
+ *
+ * Performs exactly ib_umem_num_dma_blocks() iterations.
+ */
+#define rdma_umem_for_each_dma_block(umem, biter, pgsz)                        \
+	for (__rdma_umem_block_iter_start(biter, umem, pgsz);                  \
+	     __rdma_umem_block_iter_next(biter);)
+
+#endif /* _RDMA_ITER_H_ */