net/sunrpc/xprtrdma/frwr_ops.c - kernel/mindspeed - Git at Google

 /*
  * Copyright (c) 2015 Oracle.  All rights reserved.
  * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
  */

 /* Lightweight memory registration using Fast Registration Work
  * Requests (FRWR). Also referred to sometimes as FRMR mode.
  *
  * FRWR features ordered asynchronous registration and deregistration
  * of arbitrarily sized memory regions. This is the fastest and safest
  * but most complex memory registration mode.
  */

 #include "xprt_rdma.h"

 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 # define RPCDBG_FACILITY	RPCDBG_TRANS
 #endif

 static int
 __frwr_init(struct rpcrdma_mw *r, struct ib_pd *pd, struct ib_device *device,
 	    unsigned int depth)
 {
 	struct rpcrdma_frmr *f = &r->r.frmr;
 	int rc;

 	f->fr_mr = ib_alloc_fast_reg_mr(pd, depth);
 	if (IS_ERR(f->fr_mr))
 		goto out_mr_err;
 	f->fr_pgl = ib_alloc_fast_reg_page_list(device, depth);
 	if (IS_ERR(f->fr_pgl))
 		goto out_list_err;
 	return 0;

 out_mr_err:
 	rc = PTR_ERR(f->fr_mr);
 	dprintk("RPC:       %s: ib_alloc_fast_reg_mr status %i\n",
 		__func__, rc);
 	return rc;

 out_list_err:
 	rc = PTR_ERR(f->fr_pgl);
 	dprintk("RPC:       %s: ib_alloc_fast_reg_page_list status %i\n",
 		__func__, rc);
 	ib_dereg_mr(f->fr_mr);
 	return rc;
 }

 static void
 __frwr_release(struct rpcrdma_mw *r)
 {
 	int rc;

 	rc = ib_dereg_mr(r->r.frmr.fr_mr);
 	if (rc)
 		dprintk("RPC:       %s: ib_dereg_mr status %i\n",
 			__func__, rc);
 	ib_free_fast_reg_page_list(r->r.frmr.fr_pgl);
 }

 static int
 frwr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep,
 	     struct rpcrdma_create_data_internal *cdata)
 {
 	struct ib_device_attr *devattr = &ia->ri_devattr;
 	int depth, delta;

 	ia->ri_max_frmr_depth =
 			min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,
 			      devattr->max_fast_reg_page_list_len);
 	dprintk("RPC:       %s: device's max FR page list len = %u\n",
 		__func__, ia->ri_max_frmr_depth);

 	/* Add room for frmr register and invalidate WRs.
 	 * 1. FRMR reg WR for head
 	 * 2. FRMR invalidate WR for head
 	 * 3. N FRMR reg WRs for pagelist
 	 * 4. N FRMR invalidate WRs for pagelist
 	 * 5. FRMR reg WR for tail
 	 * 6. FRMR invalidate WR for tail
 	 * 7. The RDMA_SEND WR
 	 */
 	depth = 7;

 	/* Calculate N if the device max FRMR depth is smaller than
 	 * RPCRDMA_MAX_DATA_SEGS.
 	 */
 	if (ia->ri_max_frmr_depth < RPCRDMA_MAX_DATA_SEGS) {
 		delta = RPCRDMA_MAX_DATA_SEGS - ia->ri_max_frmr_depth;
 		do {
 			depth += 2; /* FRMR reg + invalidate */
 			delta -= ia->ri_max_frmr_depth;
 		} while (delta > 0);
 	}

 	ep->rep_attr.cap.max_send_wr *= depth;
 	if (ep->rep_attr.cap.max_send_wr > devattr->max_qp_wr) {
 		cdata->max_requests = devattr->max_qp_wr / depth;
 		if (!cdata->max_requests)
 			return -EINVAL;
 		ep->rep_attr.cap.max_send_wr = cdata->max_requests *
 					       depth;
 	}

 	return 0;
 }

 /* FRWR mode conveys a list of pages per chunk segment. The
  * maximum length of that list is the FRWR page list depth.
  */
 static size_t
 frwr_op_maxpages(struct rpcrdma_xprt *r_xprt)
 {
 	struct rpcrdma_ia *ia = &r_xprt->rx_ia;

 	return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,
 		     rpcrdma_max_segments(r_xprt) * ia->ri_max_frmr_depth);
 }

 /* If FAST_REG or LOCAL_INV failed, indicate the frmr needs to be reset. */
 static void
 frwr_sendcompletion(struct ib_wc *wc)
 {
 	struct rpcrdma_mw *r;

 	if (likely(wc->status == IB_WC_SUCCESS))
 		return;

 	/* WARNING: Only wr_id and status are reliable at this point */
 	r = (struct rpcrdma_mw *)(unsigned long)wc->wr_id;
 	dprintk("RPC:       %s: frmr %p (stale), status %d\n",
 		__func__, r, wc->status);
 	r->r.frmr.fr_state = FRMR_IS_STALE;
 }

 static int
 frwr_op_init(struct rpcrdma_xprt *r_xprt)
 {
 	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
 	struct ib_device *device = r_xprt->rx_ia.ri_id->device;
 	unsigned int depth = r_xprt->rx_ia.ri_max_frmr_depth;
 	struct ib_pd *pd = r_xprt->rx_ia.ri_pd;
 	int i;

 	INIT_LIST_HEAD(&buf->rb_mws);
 	INIT_LIST_HEAD(&buf->rb_all);

 	i = (buf->rb_max_requests + 1) * RPCRDMA_MAX_SEGS;
 	dprintk("RPC:       %s: initializing %d FRMRs\n", __func__, i);

 	while (i--) {
 		struct rpcrdma_mw *r;
 		int rc;

 		r = kzalloc(sizeof(*r), GFP_KERNEL);
 		if (!r)
 			return -ENOMEM;

 		rc = __frwr_init(r, pd, device, depth);
 		if (rc) {
 			kfree(r);
 			return rc;
 		}

 		list_add(&r->mw_list, &buf->rb_mws);
 		list_add(&r->mw_all, &buf->rb_all);
 		r->mw_sendcompletion = frwr_sendcompletion;
 	}

 	return 0;
 }

 /* Post a FAST_REG Work Request to register a memory region
  * for remote access via RDMA READ or RDMA WRITE.
  */
 static int
 frwr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
 	    int nsegs, bool writing)
 {
 	struct rpcrdma_ia *ia = &r_xprt->rx_ia;
 	struct ib_device *device = ia->ri_id->device;
 	enum dma_data_direction direction = rpcrdma_data_dir(writing);
 	struct rpcrdma_mr_seg *seg1 = seg;
 	struct rpcrdma_mw *mw = seg1->rl_mw;
 	struct rpcrdma_frmr *frmr = &mw->r.frmr;
 	struct ib_mr *mr = frmr->fr_mr;
 	struct ib_send_wr fastreg_wr, *bad_wr;
 	u8 key;
 	int len, pageoff;
 	int i, rc;
 	int seg_len;
 	u64 pa;
 	int page_no;

 	pageoff = offset_in_page(seg1->mr_offset);
 	seg1->mr_offset -= pageoff;	/* start of page */
 	seg1->mr_len += pageoff;
 	len = -pageoff;
 	if (nsegs > ia->ri_max_frmr_depth)
 		nsegs = ia->ri_max_frmr_depth;
 	for (page_no = i = 0; i < nsegs;) {
 		rpcrdma_map_one(device, seg, direction);
 		pa = seg->mr_dma;
 		for (seg_len = seg->mr_len; seg_len > 0; seg_len -= PAGE_SIZE) {
 			frmr->fr_pgl->page_list[page_no++] = pa;
 			pa += PAGE_SIZE;
 		}
 		len += seg->mr_len;
 		++seg;
 		++i;
 		/* Check for holes */
 		if ((i < nsegs && offset_in_page(seg->mr_offset)) ||
 		    offset_in_page((seg-1)->mr_offset + (seg-1)->mr_len))
 			break;
 	}
 	dprintk("RPC:       %s: Using frmr %p to map %d segments (%d bytes)\n",
 		__func__, mw, i, len);

 	frmr->fr_state = FRMR_IS_VALID;

 	memset(&fastreg_wr, 0, sizeof(fastreg_wr));
 	fastreg_wr.wr_id = (unsigned long)(void *)mw;
 	fastreg_wr.opcode = IB_WR_FAST_REG_MR;
 	fastreg_wr.wr.fast_reg.iova_start = seg1->mr_dma + pageoff;
 	fastreg_wr.wr.fast_reg.page_list = frmr->fr_pgl;
 	fastreg_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
 	fastreg_wr.wr.fast_reg.page_list_len = page_no;
 	fastreg_wr.wr.fast_reg.length = len;
 	fastreg_wr.wr.fast_reg.access_flags = writing ?
 				IB_ACCESS_REMOTE_WRITE | IB_ACCESS_LOCAL_WRITE :
 				IB_ACCESS_REMOTE_READ;
 	key = (u8)(mr->rkey & 0x000000FF);
 	ib_update_fast_reg_key(mr, ++key);
 	fastreg_wr.wr.fast_reg.rkey = mr->rkey;

 	DECR_CQCOUNT(&r_xprt->rx_ep);
 	rc = ib_post_send(ia->ri_id->qp, &fastreg_wr, &bad_wr);
 	if (rc)
 		goto out_senderr;

 	seg1->mr_rkey = mr->rkey;
 	seg1->mr_base = seg1->mr_dma + pageoff;
 	seg1->mr_nsegs = i;
 	seg1->mr_len = len;
 	return i;

 out_senderr:
 	dprintk("RPC:       %s: ib_post_send status %i\n", __func__, rc);
 	ib_update_fast_reg_key(mr, --key);
 	frmr->fr_state = FRMR_IS_INVALID;
 	while (i--)
 		rpcrdma_unmap_one(device, --seg);
 	return rc;
 }

 /* Post a LOCAL_INV Work Request to prevent further remote access
  * via RDMA READ or RDMA WRITE.
  */
 static int
 frwr_op_unmap(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg)
 {
 	struct rpcrdma_mr_seg *seg1 = seg;
 	struct rpcrdma_ia *ia = &r_xprt->rx_ia;
 	struct ib_send_wr invalidate_wr, *bad_wr;
 	int rc, nsegs = seg->mr_nsegs;
 	struct ib_device *device;

 	seg1->rl_mw->r.frmr.fr_state = FRMR_IS_INVALID;

 	memset(&invalidate_wr, 0, sizeof(invalidate_wr));
 	invalidate_wr.wr_id = (unsigned long)(void *)seg1->rl_mw;
 	invalidate_wr.opcode = IB_WR_LOCAL_INV;
 	invalidate_wr.ex.invalidate_rkey = seg1->rl_mw->r.frmr.fr_mr->rkey;
 	DECR_CQCOUNT(&r_xprt->rx_ep);

 	read_lock(&ia->ri_qplock);
 	device = ia->ri_id->device;
 	while (seg1->mr_nsegs--)
 		rpcrdma_unmap_one(device, seg++);
 	rc = ib_post_send(ia->ri_id->qp, &invalidate_wr, &bad_wr);
 	read_unlock(&ia->ri_qplock);
 	if (rc)
 		goto out_err;
 	return nsegs;

 out_err:
 	/* Force rpcrdma_buffer_get() to retry */
 	seg1->rl_mw->r.frmr.fr_state = FRMR_IS_STALE;
 	dprintk("RPC:       %s: ib_post_send status %i\n", __func__, rc);
 	return nsegs;
 }

 /* After a disconnect, a flushed FAST_REG_MR can leave an FRMR in
  * an unusable state. Find FRMRs in this state and dereg / reg
  * each.  FRMRs that are VALID and attached to an rpcrdma_req are
  * also torn down.
  *
  * This gives all in-use FRMRs a fresh rkey and leaves them INVALID.
  *
  * This is invoked only in the transport connect worker in order
  * to serialize with rpcrdma_register_frmr_external().
  */
 static void
 frwr_op_reset(struct rpcrdma_xprt *r_xprt)
 {
 	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
 	struct ib_device *device = r_xprt->rx_ia.ri_id->device;
 	unsigned int depth = r_xprt->rx_ia.ri_max_frmr_depth;
 	struct ib_pd *pd = r_xprt->rx_ia.ri_pd;
 	struct rpcrdma_mw *r;
 	int rc;

 	list_for_each_entry(r, &buf->rb_all, mw_all) {
 		if (r->r.frmr.fr_state == FRMR_IS_INVALID)
 			continue;

 		__frwr_release(r);
 		rc = __frwr_init(r, pd, device, depth);
 		if (rc) {
 			dprintk("RPC:       %s: mw %p left %s\n",
 				__func__, r,
 				(r->r.frmr.fr_state == FRMR_IS_STALE ?
 					"stale" : "valid"));
 			continue;
 		}

 		r->r.frmr.fr_state = FRMR_IS_INVALID;
 	}
 }

 static void
 frwr_op_destroy(struct rpcrdma_buffer *buf)
 {
 	struct rpcrdma_mw *r;

 	while (!list_empty(&buf->rb_all)) {
 		r = list_entry(buf->rb_all.next, struct rpcrdma_mw, mw_all);
 		list_del(&r->mw_all);
 		__frwr_release(r);
 		kfree(r);
 	}
 }

 const struct rpcrdma_memreg_ops rpcrdma_frwr_memreg_ops = {
 	.ro_map				= frwr_op_map,
 	.ro_unmap			= frwr_op_unmap,
 	.ro_open			= frwr_op_open,
 	.ro_maxpages			= frwr_op_maxpages,
 	.ro_init			= frwr_op_init,
 	.ro_reset			= frwr_op_reset,
 	.ro_destroy			= frwr_op_destroy,
 	.ro_displayname			= "frwr",
 };
	/*
	* Copyright (c) 2015 Oracle. All rights reserved.
	* Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
	*/

	/* Lightweight memory registration using Fast Registration Work
	* Requests (FRWR). Also referred to sometimes as FRMR mode.
	*
	* FRWR features ordered asynchronous registration and deregistration
	* of arbitrarily sized memory regions. This is the fastest and safest
	* but most complex memory registration mode.
	*/

	#include "xprt_rdma.h"

	#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
	# define RPCDBG_FACILITY RPCDBG_TRANS
	#endif

	static int
	__frwr_init(struct rpcrdma_mw r, struct ib_pd pd, struct ib_device *device,
	unsigned int depth)
	{
	struct rpcrdma_frmr *f = &r->r.frmr;
	int rc;

	f->fr_mr = ib_alloc_fast_reg_mr(pd, depth);
	if (IS_ERR(f->fr_mr))
	goto out_mr_err;
	f->fr_pgl = ib_alloc_fast_reg_page_list(device, depth);
	if (IS_ERR(f->fr_pgl))
	goto out_list_err;
	return 0;

	out_mr_err:
	rc = PTR_ERR(f->fr_mr);
	dprintk("RPC: %s: ib_alloc_fast_reg_mr status %i\n",
	__func__, rc);
	return rc;

	out_list_err:
	rc = PTR_ERR(f->fr_pgl);
	dprintk("RPC: %s: ib_alloc_fast_reg_page_list status %i\n",
	__func__, rc);
	ib_dereg_mr(f->fr_mr);
	return rc;
	}

	static void
	__frwr_release(struct rpcrdma_mw *r)
	{
	int rc;

	rc = ib_dereg_mr(r->r.frmr.fr_mr);
	if (rc)
	dprintk("RPC: %s: ib_dereg_mr status %i\n",
	__func__, rc);
	ib_free_fast_reg_page_list(r->r.frmr.fr_pgl);
	}

	static int
	frwr_op_open(struct rpcrdma_ia ia, struct rpcrdma_ep ep,
	struct rpcrdma_create_data_internal *cdata)
	{
	struct ib_device_attr *devattr = &ia->ri_devattr;
	int depth, delta;

	ia->ri_max_frmr_depth =
	min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,
	devattr->max_fast_reg_page_list_len);
	dprintk("RPC: %s: device's max FR page list len = %u\n",
	__func__, ia->ri_max_frmr_depth);

	/* Add room for frmr register and invalidate WRs.
	* 1. FRMR reg WR for head
	* 2. FRMR invalidate WR for head
	* 3. N FRMR reg WRs for pagelist
	* 4. N FRMR invalidate WRs for pagelist
	* 5. FRMR reg WR for tail
	* 6. FRMR invalidate WR for tail
	* 7. The RDMA_SEND WR
	*/
	depth = 7;

	/* Calculate N if the device max FRMR depth is smaller than
	* RPCRDMA_MAX_DATA_SEGS.
	*/
	if (ia->ri_max_frmr_depth < RPCRDMA_MAX_DATA_SEGS) {
	delta = RPCRDMA_MAX_DATA_SEGS - ia->ri_max_frmr_depth;
	do {
	depth += 2; /* FRMR reg + invalidate */
	delta -= ia->ri_max_frmr_depth;
	} while (delta > 0);
	}

	ep->rep_attr.cap.max_send_wr *= depth;
	if (ep->rep_attr.cap.max_send_wr > devattr->max_qp_wr) {
	cdata->max_requests = devattr->max_qp_wr / depth;
	if (!cdata->max_requests)
	return -EINVAL;
	ep->rep_attr.cap.max_send_wr = cdata->max_requests *
	depth;
	}

	return 0;
	}

	/* FRWR mode conveys a list of pages per chunk segment. The
	* maximum length of that list is the FRWR page list depth.
	*/
	static size_t
	frwr_op_maxpages(struct rpcrdma_xprt *r_xprt)
	{
	struct rpcrdma_ia *ia = &r_xprt->rx_ia;

	return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,
	rpcrdma_max_segments(r_xprt) * ia->ri_max_frmr_depth);
	}

	/* If FAST_REG or LOCAL_INV failed, indicate the frmr needs to be reset. */
	static void
	frwr_sendcompletion(struct ib_wc *wc)
	{
	struct rpcrdma_mw *r;

	if (likely(wc->status == IB_WC_SUCCESS))
	return;

	/* WARNING: Only wr_id and status are reliable at this point */
	r = (struct rpcrdma_mw *)(unsigned long)wc->wr_id;
	dprintk("RPC: %s: frmr %p (stale), status %d\n",
	__func__, r, wc->status);
	r->r.frmr.fr_state = FRMR_IS_STALE;
	}

	static int
	frwr_op_init(struct rpcrdma_xprt *r_xprt)
	{
	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
	struct ib_device *device = r_xprt->rx_ia.ri_id->device;
	unsigned int depth = r_xprt->rx_ia.ri_max_frmr_depth;
	struct ib_pd *pd = r_xprt->rx_ia.ri_pd;
	int i;

	INIT_LIST_HEAD(&buf->rb_mws);
	INIT_LIST_HEAD(&buf->rb_all);

	i = (buf->rb_max_requests + 1) * RPCRDMA_MAX_SEGS;
	dprintk("RPC: %s: initializing %d FRMRs\n", __func__, i);

	while (i--) {
	struct rpcrdma_mw *r;
	int rc;

	r = kzalloc(sizeof(*r), GFP_KERNEL);
	if (!r)
	return -ENOMEM;

	rc = __frwr_init(r, pd, device, depth);
	if (rc) {
	kfree(r);
	return rc;
	}

	list_add(&r->mw_list, &buf->rb_mws);
	list_add(&r->mw_all, &buf->rb_all);
	r->mw_sendcompletion = frwr_sendcompletion;
	}

	return 0;
	}

	/* Post a FAST_REG Work Request to register a memory region
	* for remote access via RDMA READ or RDMA WRITE.
	*/
	static int
	frwr_op_map(struct rpcrdma_xprt r_xprt, struct rpcrdma_mr_seg seg,
	int nsegs, bool writing)
	{
	struct rpcrdma_ia *ia = &r_xprt->rx_ia;
	struct ib_device *device = ia->ri_id->device;
	enum dma_data_direction direction = rpcrdma_data_dir(writing);
	struct rpcrdma_mr_seg *seg1 = seg;
	struct rpcrdma_mw *mw = seg1->rl_mw;
	struct rpcrdma_frmr *frmr = &mw->r.frmr;
	struct ib_mr *mr = frmr->fr_mr;
	struct ib_send_wr fastreg_wr, *bad_wr;
	u8 key;
	int len, pageoff;
	int i, rc;
	int seg_len;
	u64 pa;
	int page_no;

	pageoff = offset_in_page(seg1->mr_offset);
	seg1->mr_offset -= pageoff; /* start of page */
	seg1->mr_len += pageoff;
	len = -pageoff;
	if (nsegs > ia->ri_max_frmr_depth)
	nsegs = ia->ri_max_frmr_depth;
	for (page_no = i = 0; i < nsegs;) {
	rpcrdma_map_one(device, seg, direction);
	pa = seg->mr_dma;
	for (seg_len = seg->mr_len; seg_len > 0; seg_len -= PAGE_SIZE) {
	frmr->fr_pgl->page_list[page_no++] = pa;
	pa += PAGE_SIZE;
	}
	len += seg->mr_len;
	++seg;
	++i;
	/* Check for holes */
	if ((i < nsegs && offset_in_page(seg->mr_offset)) \|\|
	offset_in_page((seg-1)->mr_offset + (seg-1)->mr_len))
	break;
	}
	dprintk("RPC: %s: Using frmr %p to map %d segments (%d bytes)\n",
	__func__, mw, i, len);

	frmr->fr_state = FRMR_IS_VALID;

	memset(&fastreg_wr, 0, sizeof(fastreg_wr));
	fastreg_wr.wr_id = (unsigned long)(void *)mw;
	fastreg_wr.opcode = IB_WR_FAST_REG_MR;
	fastreg_wr.wr.fast_reg.iova_start = seg1->mr_dma + pageoff;
	fastreg_wr.wr.fast_reg.page_list = frmr->fr_pgl;
	fastreg_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
	fastreg_wr.wr.fast_reg.page_list_len = page_no;
	fastreg_wr.wr.fast_reg.length = len;
	fastreg_wr.wr.fast_reg.access_flags = writing ?
	IB_ACCESS_REMOTE_WRITE \| IB_ACCESS_LOCAL_WRITE :
	IB_ACCESS_REMOTE_READ;
	key = (u8)(mr->rkey & 0x000000FF);
	ib_update_fast_reg_key(mr, ++key);
	fastreg_wr.wr.fast_reg.rkey = mr->rkey;

	DECR_CQCOUNT(&r_xprt->rx_ep);
	rc = ib_post_send(ia->ri_id->qp, &fastreg_wr, &bad_wr);
	if (rc)
	goto out_senderr;

	seg1->mr_rkey = mr->rkey;
	seg1->mr_base = seg1->mr_dma + pageoff;
	seg1->mr_nsegs = i;
	seg1->mr_len = len;
	return i;

	out_senderr:
	dprintk("RPC: %s: ib_post_send status %i\n", __func__, rc);
	ib_update_fast_reg_key(mr, --key);
	frmr->fr_state = FRMR_IS_INVALID;
	while (i--)
	rpcrdma_unmap_one(device, --seg);
	return rc;
	}

	/* Post a LOCAL_INV Work Request to prevent further remote access
	* via RDMA READ or RDMA WRITE.
	*/
	static int
	frwr_op_unmap(struct rpcrdma_xprt r_xprt, struct rpcrdma_mr_seg seg)
	{
	struct rpcrdma_mr_seg *seg1 = seg;
	struct rpcrdma_ia *ia = &r_xprt->rx_ia;
	struct ib_send_wr invalidate_wr, *bad_wr;
	int rc, nsegs = seg->mr_nsegs;
	struct ib_device *device;

	seg1->rl_mw->r.frmr.fr_state = FRMR_IS_INVALID;

	memset(&invalidate_wr, 0, sizeof(invalidate_wr));
	invalidate_wr.wr_id = (unsigned long)(void *)seg1->rl_mw;
	invalidate_wr.opcode = IB_WR_LOCAL_INV;
	invalidate_wr.ex.invalidate_rkey = seg1->rl_mw->r.frmr.fr_mr->rkey;
	DECR_CQCOUNT(&r_xprt->rx_ep);

	read_lock(&ia->ri_qplock);
	device = ia->ri_id->device;
	while (seg1->mr_nsegs--)
	rpcrdma_unmap_one(device, seg++);
	rc = ib_post_send(ia->ri_id->qp, &invalidate_wr, &bad_wr);
	read_unlock(&ia->ri_qplock);
	if (rc)
	goto out_err;
	return nsegs;

	out_err:
	/* Force rpcrdma_buffer_get() to retry */
	seg1->rl_mw->r.frmr.fr_state = FRMR_IS_STALE;
	dprintk("RPC: %s: ib_post_send status %i\n", __func__, rc);
	return nsegs;
	}

	/* After a disconnect, a flushed FAST_REG_MR can leave an FRMR in
	* an unusable state. Find FRMRs in this state and dereg / reg
	* each. FRMRs that are VALID and attached to an rpcrdma_req are
	* also torn down.
	*
	* This gives all in-use FRMRs a fresh rkey and leaves them INVALID.
	*
	* This is invoked only in the transport connect worker in order
	* to serialize with rpcrdma_register_frmr_external().
	*/
	static void
	frwr_op_reset(struct rpcrdma_xprt *r_xprt)
	{
	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
	struct ib_device *device = r_xprt->rx_ia.ri_id->device;
	unsigned int depth = r_xprt->rx_ia.ri_max_frmr_depth;
	struct ib_pd *pd = r_xprt->rx_ia.ri_pd;
	struct rpcrdma_mw *r;
	int rc;

	list_for_each_entry(r, &buf->rb_all, mw_all) {
	if (r->r.frmr.fr_state == FRMR_IS_INVALID)
	continue;

	__frwr_release(r);
	rc = __frwr_init(r, pd, device, depth);
	if (rc) {
	dprintk("RPC: %s: mw %p left %s\n",
	__func__, r,
	(r->r.frmr.fr_state == FRMR_IS_STALE ?
	"stale" : "valid"));
	continue;
	}

	r->r.frmr.fr_state = FRMR_IS_INVALID;
	}
	}

	static void
	frwr_op_destroy(struct rpcrdma_buffer *buf)
	{
	struct rpcrdma_mw *r;

	while (!list_empty(&buf->rb_all)) {
	r = list_entry(buf->rb_all.next, struct rpcrdma_mw, mw_all);
	list_del(&r->mw_all);
	__frwr_release(r);
	kfree(r);
	}
	}

	const struct rpcrdma_memreg_ops rpcrdma_frwr_memreg_ops = {
	.ro_map = frwr_op_map,
	.ro_unmap = frwr_op_unmap,
	.ro_open = frwr_op_open,
	.ro_maxpages = frwr_op_maxpages,
	.ro_init = frwr_op_init,
	.ro_reset = frwr_op_reset,
	.ro_destroy = frwr_op_destroy,
	.ro_displayname = "frwr",
	};