swh:1:snp:49cd9498d6cccc5e78252c27dcb645bcf7bf0c91
Tip revision: c470abd4fde40ea6a0846a2beab642a578c0b8cd authored by Linus Torvalds on 19 February 2017, 22:34:00 UTC
Linux 4.10
Linux 4.10
Tip revision: c470abd
frwr_ops.c
/*
* 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.
*/
/* Normal operation
*
* A Memory Region is prepared for RDMA READ or WRITE using a FAST_REG
* Work Request (frmr_op_map). When the RDMA operation is finished, this
* Memory Region is invalidated using a LOCAL_INV Work Request
* (frmr_op_unmap).
*
* Typically these Work Requests are not signaled, and neither are RDMA
* SEND Work Requests (with the exception of signaling occasionally to
* prevent provider work queue overflows). This greatly reduces HCA
* interrupt workload.
*
* As an optimization, frwr_op_unmap marks MRs INVALID before the
* LOCAL_INV WR is posted. If posting succeeds, the MR is placed on
* rb_mws immediately so that no work (like managing a linked list
* under a spinlock) is needed in the completion upcall.
*
* But this means that frwr_op_map() can occasionally encounter an MR
* that is INVALID but the LOCAL_INV WR has not completed. Work Queue
* ordering prevents a subsequent FAST_REG WR from executing against
* that MR while it is still being invalidated.
*/
/* Transport recovery
*
* ->op_map and the transport connect worker cannot run at the same
* time, but ->op_unmap can fire while the transport connect worker
* is running. Thus MR recovery is handled in ->op_map, to guarantee
* that recovered MRs are owned by a sending RPC, and not one where
* ->op_unmap could fire at the same time transport reconnect is
* being done.
*
* When the underlying transport disconnects, MRs are left in one of
* four states:
*
* INVALID: The MR was not in use before the QP entered ERROR state.
*
* VALID: The MR was registered before the QP entered ERROR state.
*
* FLUSHED_FR: The MR was being registered when the QP entered ERROR
* state, and the pending WR was flushed.
*
* FLUSHED_LI: The MR was being invalidated when the QP entered ERROR
* state, and the pending WR was flushed.
*
* When frwr_op_map encounters FLUSHED and VALID MRs, they are recovered
* with ib_dereg_mr and then are re-initialized. Because MR recovery
* allocates fresh resources, it is deferred to a workqueue, and the
* recovered MRs are placed back on the rb_mws list when recovery is
* complete. frwr_op_map allocates another MR for the current RPC while
* the broken MR is reset.
*
* To ensure that frwr_op_map doesn't encounter an MR that is marked
* INVALID but that is about to be flushed due to a previous transport
* disconnect, the transport connect worker attempts to drain all
* pending send queue WRs before the transport is reconnected.
*/
#include <linux/sunrpc/rpc_rdma.h>
#include "xprt_rdma.h"
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
# define RPCDBG_FACILITY RPCDBG_TRANS
#endif
bool
frwr_is_supported(struct rpcrdma_ia *ia)
{
struct ib_device_attr *attrs = &ia->ri_device->attrs;
if (!(attrs->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS))
goto out_not_supported;
if (attrs->max_fast_reg_page_list_len == 0)
goto out_not_supported;
return true;
out_not_supported:
pr_info("rpcrdma: 'frwr' mode is not supported by device %s\n",
ia->ri_device->name);
return false;
}
static int
frwr_op_init_mr(struct rpcrdma_ia *ia, struct rpcrdma_mw *r)
{
unsigned int depth = ia->ri_max_frmr_depth;
struct rpcrdma_frmr *f = &r->frmr;
int rc;
f->fr_mr = ib_alloc_mr(ia->ri_pd, ia->ri_mrtype, depth);
if (IS_ERR(f->fr_mr))
goto out_mr_err;
r->mw_sg = kcalloc(depth, sizeof(*r->mw_sg), GFP_KERNEL);
if (!r->mw_sg)
goto out_list_err;
sg_init_table(r->mw_sg, depth);
init_completion(&f->fr_linv_done);
return 0;
out_mr_err:
rc = PTR_ERR(f->fr_mr);
dprintk("RPC: %s: ib_alloc_mr status %i\n",
__func__, rc);
return rc;
out_list_err:
rc = -ENOMEM;
dprintk("RPC: %s: sg allocation failure\n",
__func__);
ib_dereg_mr(f->fr_mr);
return rc;
}
static void
frwr_op_release_mr(struct rpcrdma_mw *r)
{
int rc;
/* Ensure MW is not on any rl_registered list */
if (!list_empty(&r->mw_list))
list_del(&r->mw_list);
rc = ib_dereg_mr(r->frmr.fr_mr);
if (rc)
pr_err("rpcrdma: final ib_dereg_mr for %p returned %i\n",
r, rc);
kfree(r->mw_sg);
kfree(r);
}
static int
__frwr_reset_mr(struct rpcrdma_ia *ia, struct rpcrdma_mw *r)
{
struct rpcrdma_frmr *f = &r->frmr;
int rc;
rc = ib_dereg_mr(f->fr_mr);
if (rc) {
pr_warn("rpcrdma: ib_dereg_mr status %d, frwr %p orphaned\n",
rc, r);
return rc;
}
f->fr_mr = ib_alloc_mr(ia->ri_pd, ia->ri_mrtype,
ia->ri_max_frmr_depth);
if (IS_ERR(f->fr_mr)) {
pr_warn("rpcrdma: ib_alloc_mr status %ld, frwr %p orphaned\n",
PTR_ERR(f->fr_mr), r);
return PTR_ERR(f->fr_mr);
}
dprintk("RPC: %s: recovered FRMR %p\n", __func__, f);
f->fr_state = FRMR_IS_INVALID;
return 0;
}
/* Reset of a single FRMR. Generate a fresh rkey by replacing the MR.
*/
static void
frwr_op_recover_mr(struct rpcrdma_mw *mw)
{
enum rpcrdma_frmr_state state = mw->frmr.fr_state;
struct rpcrdma_xprt *r_xprt = mw->mw_xprt;
struct rpcrdma_ia *ia = &r_xprt->rx_ia;
int rc;
rc = __frwr_reset_mr(ia, mw);
if (state != FRMR_FLUSHED_LI)
ib_dma_unmap_sg(ia->ri_device,
mw->mw_sg, mw->mw_nents, mw->mw_dir);
if (rc)
goto out_release;
rpcrdma_put_mw(r_xprt, mw);
r_xprt->rx_stats.mrs_recovered++;
return;
out_release:
pr_err("rpcrdma: FRMR reset failed %d, %p release\n", rc, mw);
r_xprt->rx_stats.mrs_orphaned++;
spin_lock(&r_xprt->rx_buf.rb_mwlock);
list_del(&mw->mw_all);
spin_unlock(&r_xprt->rx_buf.rb_mwlock);
frwr_op_release_mr(mw);
}
static int
frwr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep,
struct rpcrdma_create_data_internal *cdata)
{
struct ib_device_attr *attrs = &ia->ri_device->attrs;
int depth, delta;
ia->ri_mrtype = IB_MR_TYPE_MEM_REG;
if (attrs->device_cap_flags & IB_DEVICE_SG_GAPS_REG)
ia->ri_mrtype = IB_MR_TYPE_SG_GAPS;
ia->ri_max_frmr_depth =
min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,
attrs->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 > attrs->max_qp_wr) {
cdata->max_requests = attrs->max_qp_wr / depth;
if (!cdata->max_requests)
return -EINVAL;
ep->rep_attr.cap.max_send_wr = cdata->max_requests *
depth;
}
ia->ri_max_segs = max_t(unsigned int, 1, RPCRDMA_MAX_DATA_SEGS /
ia->ri_max_frmr_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_HDR_SEGS * ia->ri_max_frmr_depth);
}
static void
__frwr_sendcompletion_flush(struct ib_wc *wc, const char *wr)
{
if (wc->status != IB_WC_WR_FLUSH_ERR)
pr_err("rpcrdma: %s: %s (%u/0x%x)\n",
wr, ib_wc_status_msg(wc->status),
wc->status, wc->vendor_err);
}
/**
* frwr_wc_fastreg - Invoked by RDMA provider for each polled FastReg WC
* @cq: completion queue (ignored)
* @wc: completed WR
*
*/
static void
frwr_wc_fastreg(struct ib_cq *cq, struct ib_wc *wc)
{
struct rpcrdma_frmr *frmr;
struct ib_cqe *cqe;
/* WARNING: Only wr_cqe and status are reliable at this point */
if (wc->status != IB_WC_SUCCESS) {
cqe = wc->wr_cqe;
frmr = container_of(cqe, struct rpcrdma_frmr, fr_cqe);
frmr->fr_state = FRMR_FLUSHED_FR;
__frwr_sendcompletion_flush(wc, "fastreg");
}
}
/**
* frwr_wc_localinv - Invoked by RDMA provider for each polled LocalInv WC
* @cq: completion queue (ignored)
* @wc: completed WR
*
*/
static void
frwr_wc_localinv(struct ib_cq *cq, struct ib_wc *wc)
{
struct rpcrdma_frmr *frmr;
struct ib_cqe *cqe;
/* WARNING: Only wr_cqe and status are reliable at this point */
if (wc->status != IB_WC_SUCCESS) {
cqe = wc->wr_cqe;
frmr = container_of(cqe, struct rpcrdma_frmr, fr_cqe);
frmr->fr_state = FRMR_FLUSHED_LI;
__frwr_sendcompletion_flush(wc, "localinv");
}
}
/**
* frwr_wc_localinv - Invoked by RDMA provider for each polled LocalInv WC
* @cq: completion queue (ignored)
* @wc: completed WR
*
* Awaken anyone waiting for an MR to finish being fenced.
*/
static void
frwr_wc_localinv_wake(struct ib_cq *cq, struct ib_wc *wc)
{
struct rpcrdma_frmr *frmr;
struct ib_cqe *cqe;
/* WARNING: Only wr_cqe and status are reliable at this point */
cqe = wc->wr_cqe;
frmr = container_of(cqe, struct rpcrdma_frmr, fr_cqe);
if (wc->status != IB_WC_SUCCESS) {
frmr->fr_state = FRMR_FLUSHED_LI;
__frwr_sendcompletion_flush(wc, "localinv");
}
complete(&frmr->fr_linv_done);
}
/* Post a REG_MR 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_mw **out)
{
struct rpcrdma_ia *ia = &r_xprt->rx_ia;
bool holes_ok = ia->ri_mrtype == IB_MR_TYPE_SG_GAPS;
struct rpcrdma_mw *mw;
struct rpcrdma_frmr *frmr;
struct ib_mr *mr;
struct ib_reg_wr *reg_wr;
struct ib_send_wr *bad_wr;
int rc, i, n, dma_nents;
u8 key;
mw = NULL;
do {
if (mw)
rpcrdma_defer_mr_recovery(mw);
mw = rpcrdma_get_mw(r_xprt);
if (!mw)
return -ENOBUFS;
} while (mw->frmr.fr_state != FRMR_IS_INVALID);
frmr = &mw->frmr;
frmr->fr_state = FRMR_IS_VALID;
mr = frmr->fr_mr;
reg_wr = &frmr->fr_regwr;
if (nsegs > ia->ri_max_frmr_depth)
nsegs = ia->ri_max_frmr_depth;
for (i = 0; i < nsegs;) {
if (seg->mr_page)
sg_set_page(&mw->mw_sg[i],
seg->mr_page,
seg->mr_len,
offset_in_page(seg->mr_offset));
else
sg_set_buf(&mw->mw_sg[i], seg->mr_offset,
seg->mr_len);
++seg;
++i;
if (holes_ok)
continue;
if ((i < nsegs && offset_in_page(seg->mr_offset)) ||
offset_in_page((seg-1)->mr_offset + (seg-1)->mr_len))
break;
}
mw->mw_nents = i;
mw->mw_dir = rpcrdma_data_dir(writing);
if (i == 0)
goto out_dmamap_err;
dma_nents = ib_dma_map_sg(ia->ri_device,
mw->mw_sg, mw->mw_nents, mw->mw_dir);
if (!dma_nents)
goto out_dmamap_err;
n = ib_map_mr_sg(mr, mw->mw_sg, mw->mw_nents, NULL, PAGE_SIZE);
if (unlikely(n != mw->mw_nents))
goto out_mapmr_err;
dprintk("RPC: %s: Using frmr %p to map %u segments (%u bytes)\n",
__func__, frmr, mw->mw_nents, mr->length);
key = (u8)(mr->rkey & 0x000000FF);
ib_update_fast_reg_key(mr, ++key);
reg_wr->wr.next = NULL;
reg_wr->wr.opcode = IB_WR_REG_MR;
frmr->fr_cqe.done = frwr_wc_fastreg;
reg_wr->wr.wr_cqe = &frmr->fr_cqe;
reg_wr->wr.num_sge = 0;
reg_wr->wr.send_flags = 0;
reg_wr->mr = mr;
reg_wr->key = mr->rkey;
reg_wr->access = writing ?
IB_ACCESS_REMOTE_WRITE | IB_ACCESS_LOCAL_WRITE :
IB_ACCESS_REMOTE_READ;
rpcrdma_set_signaled(&r_xprt->rx_ep, ®_wr->wr);
rc = ib_post_send(ia->ri_id->qp, ®_wr->wr, &bad_wr);
if (rc)
goto out_senderr;
mw->mw_handle = mr->rkey;
mw->mw_length = mr->length;
mw->mw_offset = mr->iova;
*out = mw;
return mw->mw_nents;
out_dmamap_err:
pr_err("rpcrdma: failed to dma map sg %p sg_nents %u\n",
mw->mw_sg, mw->mw_nents);
rpcrdma_defer_mr_recovery(mw);
return -EIO;
out_mapmr_err:
pr_err("rpcrdma: failed to map mr %p (%u/%u)\n",
frmr->fr_mr, n, mw->mw_nents);
rpcrdma_defer_mr_recovery(mw);
return -EIO;
out_senderr:
pr_err("rpcrdma: FRMR registration ib_post_send returned %i\n", rc);
rpcrdma_defer_mr_recovery(mw);
return -ENOTCONN;
}
/* Invalidate all memory regions that were registered for "req".
*
* Sleeps until it is safe for the host CPU to access the
* previously mapped memory regions.
*
* Caller ensures that req->rl_registered is not empty.
*/
static void
frwr_op_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
{
struct ib_send_wr *first, **prev, *last, *bad_wr;
struct rpcrdma_rep *rep = req->rl_reply;
struct rpcrdma_ia *ia = &r_xprt->rx_ia;
struct rpcrdma_mw *mw, *tmp;
struct rpcrdma_frmr *f;
int count, rc;
dprintk("RPC: %s: req %p\n", __func__, req);
/* ORDER: Invalidate all of the req's MRs first
*
* Chain the LOCAL_INV Work Requests and post them with
* a single ib_post_send() call.
*/
f = NULL;
count = 0;
prev = &first;
list_for_each_entry(mw, &req->rl_registered, mw_list) {
mw->frmr.fr_state = FRMR_IS_INVALID;
if ((rep->rr_wc_flags & IB_WC_WITH_INVALIDATE) &&
(mw->mw_handle == rep->rr_inv_rkey))
continue;
f = &mw->frmr;
dprintk("RPC: %s: invalidating frmr %p\n",
__func__, f);
f->fr_cqe.done = frwr_wc_localinv;
last = &f->fr_invwr;
memset(last, 0, sizeof(*last));
last->wr_cqe = &f->fr_cqe;
last->opcode = IB_WR_LOCAL_INV;
last->ex.invalidate_rkey = mw->mw_handle;
count++;
*prev = last;
prev = &last->next;
}
if (!f)
goto unmap;
/* Strong send queue ordering guarantees that when the
* last WR in the chain completes, all WRs in the chain
* are complete.
*/
last->send_flags = IB_SEND_SIGNALED;
f->fr_cqe.done = frwr_wc_localinv_wake;
reinit_completion(&f->fr_linv_done);
/* Initialize CQ count, since there is always a signaled
* WR being posted here. The new cqcount depends on how
* many SQEs are about to be consumed.
*/
rpcrdma_init_cqcount(&r_xprt->rx_ep, count);
/* Transport disconnect drains the receive CQ before it
* replaces the QP. The RPC reply handler won't call us
* unless ri_id->qp is a valid pointer.
*/
r_xprt->rx_stats.local_inv_needed++;
rc = ib_post_send(ia->ri_id->qp, first, &bad_wr);
if (rc)
goto reset_mrs;
wait_for_completion(&f->fr_linv_done);
/* ORDER: Now DMA unmap all of the req's MRs, and return
* them to the free MW list.
*/
unmap:
list_for_each_entry_safe(mw, tmp, &req->rl_registered, mw_list) {
dprintk("RPC: %s: DMA unmapping frmr %p\n",
__func__, &mw->frmr);
list_del_init(&mw->mw_list);
ib_dma_unmap_sg(ia->ri_device,
mw->mw_sg, mw->mw_nents, mw->mw_dir);
rpcrdma_put_mw(r_xprt, mw);
}
return;
reset_mrs:
pr_err("rpcrdma: FRMR invalidate ib_post_send returned %i\n", rc);
rdma_disconnect(ia->ri_id);
/* Find and reset the MRs in the LOCAL_INV WRs that did not
* get posted. This is synchronous, and slow.
*/
list_for_each_entry(mw, &req->rl_registered, mw_list) {
f = &mw->frmr;
if (mw->mw_handle == bad_wr->ex.invalidate_rkey) {
__frwr_reset_mr(ia, mw);
bad_wr = bad_wr->next;
}
}
goto unmap;
}
/* Use a slow, safe mechanism to invalidate all memory regions
* that were registered for "req".
*/
static void
frwr_op_unmap_safe(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req,
bool sync)
{
struct rpcrdma_mw *mw;
while (!list_empty(&req->rl_registered)) {
mw = list_first_entry(&req->rl_registered,
struct rpcrdma_mw, mw_list);
list_del_init(&mw->mw_list);
if (sync)
frwr_op_recover_mr(mw);
else
rpcrdma_defer_mr_recovery(mw);
}
}
const struct rpcrdma_memreg_ops rpcrdma_frwr_memreg_ops = {
.ro_map = frwr_op_map,
.ro_unmap_sync = frwr_op_unmap_sync,
.ro_unmap_safe = frwr_op_unmap_safe,
.ro_recover_mr = frwr_op_recover_mr,
.ro_open = frwr_op_open,
.ro_maxpages = frwr_op_maxpages,
.ro_init_mr = frwr_op_init_mr,
.ro_release_mr = frwr_op_release_mr,
.ro_displayname = "frwr",
.ro_send_w_inv_ok = RPCRDMA_CMP_F_SND_W_INV_OK,
};