/*
* 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_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_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;
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);
while (seg1->mr_nsegs--)
rpcrdma_unmap_one(ia->ri_device, seg++);
read_lock(&ia->ri_qplock);
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_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",
};
