linux-stable/net/sunrpc/xprtrdma/fmr_ops.c

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/*
* Copyright (c) 2015 Oracle. All rights reserved.
* Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
*/
/* Lightweight memory registration using Fast Memory Regions (FMR).
* Referred to sometimes as MTHCAFMR mode.
*
* FMR uses synchronous memory registration and deregistration.
* FMR registration is known to be fast, but FMR deregistration
* can take tens of usecs to complete.
*/
/* Normal operation
*
* A Memory Region is prepared for RDMA READ or WRITE using the
* ib_map_phys_fmr verb (fmr_op_map). When the RDMA operation is
* finished, the Memory Region is unmapped using the ib_unmap_fmr
* verb (fmr_op_unmap).
*/
#include "xprt_rdma.h"
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
# define RPCDBG_FACILITY RPCDBG_TRANS
#endif
/* Maximum scatter/gather per FMR */
#define RPCRDMA_MAX_FMR_SGES (64)
/* Access mode of externally registered pages */
enum {
RPCRDMA_FMR_ACCESS_FLAGS = IB_ACCESS_REMOTE_WRITE |
IB_ACCESS_REMOTE_READ,
};
bool
fmr_is_supported(struct rpcrdma_ia *ia)
{
if (!ia->ri_device->alloc_fmr) {
pr_info("rpcrdma: 'fmr' mode is not supported by device %s\n",
ia->ri_device->name);
return false;
}
return true;
}
static int
fmr_op_init_mr(struct rpcrdma_ia *ia, struct rpcrdma_mw *mw)
{
static struct ib_fmr_attr fmr_attr = {
.max_pages = RPCRDMA_MAX_FMR_SGES,
.max_maps = 1,
.page_shift = PAGE_SHIFT
};
mw->fmr.fm_physaddrs = kcalloc(RPCRDMA_MAX_FMR_SGES,
sizeof(u64), GFP_KERNEL);
if (!mw->fmr.fm_physaddrs)
goto out_free;
mw->mw_sg = kcalloc(RPCRDMA_MAX_FMR_SGES,
sizeof(*mw->mw_sg), GFP_KERNEL);
if (!mw->mw_sg)
goto out_free;
sg_init_table(mw->mw_sg, RPCRDMA_MAX_FMR_SGES);
mw->fmr.fm_mr = ib_alloc_fmr(ia->ri_pd, RPCRDMA_FMR_ACCESS_FLAGS,
&fmr_attr);
if (IS_ERR(mw->fmr.fm_mr))
goto out_fmr_err;
return 0;
out_fmr_err:
dprintk("RPC: %s: ib_alloc_fmr returned %ld\n", __func__,
PTR_ERR(mw->fmr.fm_mr));
out_free:
kfree(mw->mw_sg);
kfree(mw->fmr.fm_physaddrs);
return -ENOMEM;
}
static int
__fmr_unmap(struct rpcrdma_mw *mw)
{
LIST_HEAD(l);
int rc;
list_add(&mw->fmr.fm_mr->list, &l);
rc = ib_unmap_fmr(&l);
list_del_init(&mw->fmr.fm_mr->list);
return rc;
}
static void
fmr_op_release_mr(struct rpcrdma_mw *r)
{
LIST_HEAD(unmap_list);
int rc;
/* Ensure MW is not on any rl_registered list */
if (!list_empty(&r->mw_list))
list_del(&r->mw_list);
kfree(r->fmr.fm_physaddrs);
kfree(r->mw_sg);
/* In case this one was left mapped, try to unmap it
* to prevent dealloc_fmr from failing with EBUSY
*/
rc = __fmr_unmap(r);
if (rc)
pr_err("rpcrdma: final ib_unmap_fmr for %p failed %i\n",
r, rc);
rc = ib_dealloc_fmr(r->fmr.fm_mr);
if (rc)
pr_err("rpcrdma: final ib_dealloc_fmr for %p returned %i\n",
r, rc);
kfree(r);
}
/* Reset of a single FMR.
*/
static void
fmr_op_recover_mr(struct rpcrdma_mw *mw)
{
struct rpcrdma_xprt *r_xprt = mw->mw_xprt;
int rc;
/* ORDER: invalidate first */
rc = __fmr_unmap(mw);
/* ORDER: then DMA unmap */
ib_dma_unmap_sg(r_xprt->rx_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: FMR reset failed (%d), %p released\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);
fmr_op_release_mr(mw);
}
static int
fmr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep,
struct rpcrdma_create_data_internal *cdata)
{
rpcrdma_set_max_header_sizes(ia, cdata, max_t(unsigned int, 1,
RPCRDMA_MAX_DATA_SEGS /
RPCRDMA_MAX_FMR_SGES));
return 0;
}
/* FMR mode conveys up to 64 pages of payload per chunk segment.
*/
static size_t
fmr_op_maxpages(struct rpcrdma_xprt *r_xprt)
{
return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,
xprtrdma: Limit number of RDMA segments in RPC-over-RDMA headers Send buffer space is shared between the RPC-over-RDMA header and an RPC message. A large RPC-over-RDMA header means less space is available for the associated RPC message, which then has to be moved via an RDMA Read or Write. As more segments are added to the chunk lists, the header increases in size. Typical modern hardware needs only a few segments to convey the maximum payload size, but some devices and registration modes may need a lot of segments to convey data payload. Sometimes so many are needed that the remaining space in the Send buffer is not enough for the RPC message. Sending such a message usually fails. To ensure a transport can always make forward progress, cap the number of RDMA segments that are allowed in chunk lists. This prevents less-capable devices and memory registrations from consuming a large portion of the Send buffer by reducing the maximum data payload that can be conveyed with such devices. For now I choose an arbitrary maximum of 8 RDMA segments. This allows a maximum size RPC-over-RDMA header to fit nicely in the current 1024 byte inline threshold with over 700 bytes remaining for an inline RPC message. The current maximum data payload of NFS READ or WRITE requests is one megabyte. To convey that payload on a client with 4KB pages, each chunk segment would need to handle 32 or more data pages. This is well within the capabilities of FMR. For physical registration, the maximum payload size on platforms with 4KB pages is reduced to 32KB. For FRWR, a device's maximum page list depth would need to be at least 34 to support the maximum 1MB payload. A device with a smaller maximum page list depth means the maximum data payload is reduced when using that device. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Steve Wise <swise@opengridcomputing.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-05-02 18:40:56 +00:00
RPCRDMA_MAX_HDR_SEGS * RPCRDMA_MAX_FMR_SGES);
}
/* Use the ib_map_phys_fmr() verb to register a memory region
* for remote access via RDMA READ or RDMA WRITE.
*/
static int
fmr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
int nsegs, bool writing, struct rpcrdma_mw **out)
{
struct rpcrdma_mr_seg *seg1 = seg;
int len, pageoff, i, rc;
struct rpcrdma_mw *mw;
xprtrdma: Use scatterlist for DMA mapping and unmapping under FMR The use of a scatterlist for handling DMA mapping and unmapping was recently introduced in frwr_ops.c in commit 4143f34e01e9 ("xprtrdma: Port to new memory registration API"). That commit did not make a similar update to xprtrdma's FMR support because the core ib_map_phys_fmr() and ib_unmap_fmr() APIs have not been changed to take a scatterlist argument. However, FMR still needs to do DMA mapping and unmapping. It appears that RDS, for example, uses a scatterlist for this, then builds the DMA addr array for the ib_map_phys_fmr call separately. I see that SRP also utilizes a scatterlist for DMA mapping. xprtrdma can do something similar. This modernization is used immediately to properly defer DMA unmapping during fmr_unmap_safe (a FIXME). It separates the DMA unmapping coordinates from the rl_segments array. This array, being part of an rpcrdma_req, is always re-used immediately when an RPC exits. A scatterlist is allocated in memory independent of the rl_segments array, so it can be preserved indefinitely (ie, until the MR invalidation and DMA unmapping can actually be done by a worker thread). The FRWR and FMR DMA mapping code are slightly different from each other now, and will diverge further when the "Check for holes" logic can be removed from FRWR (support for SG_GAP MRs). So I chose not to create helpers for the common-looking code. Fixes: ead3f26e359e ("xprtrdma: Add ro_unmap_safe memreg method") Suggested-by: Sagi Grimberg <sagi@lightbits.io> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Steve Wise <swise@opengridcomputing.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-06-29 17:52:45 +00:00
u64 *dma_pages;
mw = rpcrdma_get_mw(r_xprt);
if (!mw)
return -ENOBUFS;
pageoff = offset_in_page(seg1->mr_offset);
seg1->mr_offset -= pageoff; /* start of page */
seg1->mr_len += pageoff;
len = -pageoff;
if (nsegs > RPCRDMA_MAX_FMR_SGES)
nsegs = RPCRDMA_MAX_FMR_SGES;
for (i = 0; i < nsegs;) {
xprtrdma: Use scatterlist for DMA mapping and unmapping under FMR The use of a scatterlist for handling DMA mapping and unmapping was recently introduced in frwr_ops.c in commit 4143f34e01e9 ("xprtrdma: Port to new memory registration API"). That commit did not make a similar update to xprtrdma's FMR support because the core ib_map_phys_fmr() and ib_unmap_fmr() APIs have not been changed to take a scatterlist argument. However, FMR still needs to do DMA mapping and unmapping. It appears that RDS, for example, uses a scatterlist for this, then builds the DMA addr array for the ib_map_phys_fmr call separately. I see that SRP also utilizes a scatterlist for DMA mapping. xprtrdma can do something similar. This modernization is used immediately to properly defer DMA unmapping during fmr_unmap_safe (a FIXME). It separates the DMA unmapping coordinates from the rl_segments array. This array, being part of an rpcrdma_req, is always re-used immediately when an RPC exits. A scatterlist is allocated in memory independent of the rl_segments array, so it can be preserved indefinitely (ie, until the MR invalidation and DMA unmapping can actually be done by a worker thread). The FRWR and FMR DMA mapping code are slightly different from each other now, and will diverge further when the "Check for holes" logic can be removed from FRWR (support for SG_GAP MRs). So I chose not to create helpers for the common-looking code. Fixes: ead3f26e359e ("xprtrdma: Add ro_unmap_safe memreg method") Suggested-by: Sagi Grimberg <sagi@lightbits.io> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Steve Wise <swise@opengridcomputing.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-06-29 17:52:45 +00:00
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);
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;
}
xprtrdma: Use scatterlist for DMA mapping and unmapping under FMR The use of a scatterlist for handling DMA mapping and unmapping was recently introduced in frwr_ops.c in commit 4143f34e01e9 ("xprtrdma: Port to new memory registration API"). That commit did not make a similar update to xprtrdma's FMR support because the core ib_map_phys_fmr() and ib_unmap_fmr() APIs have not been changed to take a scatterlist argument. However, FMR still needs to do DMA mapping and unmapping. It appears that RDS, for example, uses a scatterlist for this, then builds the DMA addr array for the ib_map_phys_fmr call separately. I see that SRP also utilizes a scatterlist for DMA mapping. xprtrdma can do something similar. This modernization is used immediately to properly defer DMA unmapping during fmr_unmap_safe (a FIXME). It separates the DMA unmapping coordinates from the rl_segments array. This array, being part of an rpcrdma_req, is always re-used immediately when an RPC exits. A scatterlist is allocated in memory independent of the rl_segments array, so it can be preserved indefinitely (ie, until the MR invalidation and DMA unmapping can actually be done by a worker thread). The FRWR and FMR DMA mapping code are slightly different from each other now, and will diverge further when the "Check for holes" logic can be removed from FRWR (support for SG_GAP MRs). So I chose not to create helpers for the common-looking code. Fixes: ead3f26e359e ("xprtrdma: Add ro_unmap_safe memreg method") Suggested-by: Sagi Grimberg <sagi@lightbits.io> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Steve Wise <swise@opengridcomputing.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-06-29 17:52:45 +00:00
mw->mw_nents = i;
mw->mw_dir = rpcrdma_data_dir(writing);
if (i == 0)
goto out_dmamap_err;
xprtrdma: Use scatterlist for DMA mapping and unmapping under FMR The use of a scatterlist for handling DMA mapping and unmapping was recently introduced in frwr_ops.c in commit 4143f34e01e9 ("xprtrdma: Port to new memory registration API"). That commit did not make a similar update to xprtrdma's FMR support because the core ib_map_phys_fmr() and ib_unmap_fmr() APIs have not been changed to take a scatterlist argument. However, FMR still needs to do DMA mapping and unmapping. It appears that RDS, for example, uses a scatterlist for this, then builds the DMA addr array for the ib_map_phys_fmr call separately. I see that SRP also utilizes a scatterlist for DMA mapping. xprtrdma can do something similar. This modernization is used immediately to properly defer DMA unmapping during fmr_unmap_safe (a FIXME). It separates the DMA unmapping coordinates from the rl_segments array. This array, being part of an rpcrdma_req, is always re-used immediately when an RPC exits. A scatterlist is allocated in memory independent of the rl_segments array, so it can be preserved indefinitely (ie, until the MR invalidation and DMA unmapping can actually be done by a worker thread). The FRWR and FMR DMA mapping code are slightly different from each other now, and will diverge further when the "Check for holes" logic can be removed from FRWR (support for SG_GAP MRs). So I chose not to create helpers for the common-looking code. Fixes: ead3f26e359e ("xprtrdma: Add ro_unmap_safe memreg method") Suggested-by: Sagi Grimberg <sagi@lightbits.io> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Steve Wise <swise@opengridcomputing.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-06-29 17:52:45 +00:00
if (!ib_dma_map_sg(r_xprt->rx_ia.ri_device,
mw->mw_sg, mw->mw_nents, mw->mw_dir))
goto out_dmamap_err;
xprtrdma: Use scatterlist for DMA mapping and unmapping under FMR The use of a scatterlist for handling DMA mapping and unmapping was recently introduced in frwr_ops.c in commit 4143f34e01e9 ("xprtrdma: Port to new memory registration API"). That commit did not make a similar update to xprtrdma's FMR support because the core ib_map_phys_fmr() and ib_unmap_fmr() APIs have not been changed to take a scatterlist argument. However, FMR still needs to do DMA mapping and unmapping. It appears that RDS, for example, uses a scatterlist for this, then builds the DMA addr array for the ib_map_phys_fmr call separately. I see that SRP also utilizes a scatterlist for DMA mapping. xprtrdma can do something similar. This modernization is used immediately to properly defer DMA unmapping during fmr_unmap_safe (a FIXME). It separates the DMA unmapping coordinates from the rl_segments array. This array, being part of an rpcrdma_req, is always re-used immediately when an RPC exits. A scatterlist is allocated in memory independent of the rl_segments array, so it can be preserved indefinitely (ie, until the MR invalidation and DMA unmapping can actually be done by a worker thread). The FRWR and FMR DMA mapping code are slightly different from each other now, and will diverge further when the "Check for holes" logic can be removed from FRWR (support for SG_GAP MRs). So I chose not to create helpers for the common-looking code. Fixes: ead3f26e359e ("xprtrdma: Add ro_unmap_safe memreg method") Suggested-by: Sagi Grimberg <sagi@lightbits.io> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Steve Wise <swise@opengridcomputing.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-06-29 17:52:45 +00:00
for (i = 0, dma_pages = mw->fmr.fm_physaddrs; i < mw->mw_nents; i++)
dma_pages[i] = sg_dma_address(&mw->mw_sg[i]);
rc = ib_map_phys_fmr(mw->fmr.fm_mr, dma_pages, mw->mw_nents,
dma_pages[0]);
if (rc)
goto out_maperr;
mw->mw_handle = mw->fmr.fm_mr->rkey;
mw->mw_length = len;
mw->mw_offset = dma_pages[0] + pageoff;
*out = mw;
xprtrdma: Use scatterlist for DMA mapping and unmapping under FMR The use of a scatterlist for handling DMA mapping and unmapping was recently introduced in frwr_ops.c in commit 4143f34e01e9 ("xprtrdma: Port to new memory registration API"). That commit did not make a similar update to xprtrdma's FMR support because the core ib_map_phys_fmr() and ib_unmap_fmr() APIs have not been changed to take a scatterlist argument. However, FMR still needs to do DMA mapping and unmapping. It appears that RDS, for example, uses a scatterlist for this, then builds the DMA addr array for the ib_map_phys_fmr call separately. I see that SRP also utilizes a scatterlist for DMA mapping. xprtrdma can do something similar. This modernization is used immediately to properly defer DMA unmapping during fmr_unmap_safe (a FIXME). It separates the DMA unmapping coordinates from the rl_segments array. This array, being part of an rpcrdma_req, is always re-used immediately when an RPC exits. A scatterlist is allocated in memory independent of the rl_segments array, so it can be preserved indefinitely (ie, until the MR invalidation and DMA unmapping can actually be done by a worker thread). The FRWR and FMR DMA mapping code are slightly different from each other now, and will diverge further when the "Check for holes" logic can be removed from FRWR (support for SG_GAP MRs). So I chose not to create helpers for the common-looking code. Fixes: ead3f26e359e ("xprtrdma: Add ro_unmap_safe memreg method") Suggested-by: Sagi Grimberg <sagi@lightbits.io> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Steve Wise <swise@opengridcomputing.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-06-29 17:52:45 +00:00
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_maperr:
xprtrdma: Use scatterlist for DMA mapping and unmapping under FMR The use of a scatterlist for handling DMA mapping and unmapping was recently introduced in frwr_ops.c in commit 4143f34e01e9 ("xprtrdma: Port to new memory registration API"). That commit did not make a similar update to xprtrdma's FMR support because the core ib_map_phys_fmr() and ib_unmap_fmr() APIs have not been changed to take a scatterlist argument. However, FMR still needs to do DMA mapping and unmapping. It appears that RDS, for example, uses a scatterlist for this, then builds the DMA addr array for the ib_map_phys_fmr call separately. I see that SRP also utilizes a scatterlist for DMA mapping. xprtrdma can do something similar. This modernization is used immediately to properly defer DMA unmapping during fmr_unmap_safe (a FIXME). It separates the DMA unmapping coordinates from the rl_segments array. This array, being part of an rpcrdma_req, is always re-used immediately when an RPC exits. A scatterlist is allocated in memory independent of the rl_segments array, so it can be preserved indefinitely (ie, until the MR invalidation and DMA unmapping can actually be done by a worker thread). The FRWR and FMR DMA mapping code are slightly different from each other now, and will diverge further when the "Check for holes" logic can be removed from FRWR (support for SG_GAP MRs). So I chose not to create helpers for the common-looking code. Fixes: ead3f26e359e ("xprtrdma: Add ro_unmap_safe memreg method") Suggested-by: Sagi Grimberg <sagi@lightbits.io> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Steve Wise <swise@opengridcomputing.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-06-29 17:52:45 +00:00
pr_err("rpcrdma: ib_map_phys_fmr %u@0x%llx+%i (%d) status %i\n",
len, (unsigned long long)dma_pages[0],
pageoff, mw->mw_nents, rc);
rpcrdma_defer_mr_recovery(mw);
return -EIO;
}
/* 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
fmr_op_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
{
struct rpcrdma_mw *mw, *tmp;
LIST_HEAD(unmap_list);
int rc;
dprintk("RPC: %s: req %p\n", __func__, req);
/* ORDER: Invalidate all of the req's MRs first
*
* ib_unmap_fmr() is slow, so use a single call instead
* of one call per mapped FMR.
*/
list_for_each_entry(mw, &req->rl_registered, mw_list)
list_add_tail(&mw->fmr.fm_mr->list, &unmap_list);
rc = ib_unmap_fmr(&unmap_list);
if (rc)
goto out_reset;
/* ORDER: Now DMA unmap all of the req's MRs, and return
* them to the free MW list.
*/
list_for_each_entry_safe(mw, tmp, &req->rl_registered, mw_list) {
list_del_init(&mw->mw_list);
list_del_init(&mw->fmr.fm_mr->list);
ib_dma_unmap_sg(r_xprt->rx_ia.ri_device,
mw->mw_sg, mw->mw_nents, mw->mw_dir);
rpcrdma_put_mw(r_xprt, mw);
}
return;
out_reset:
pr_err("rpcrdma: ib_unmap_fmr failed (%i)\n", rc);
list_for_each_entry_safe(mw, tmp, &req->rl_registered, mw_list) {
list_del_init(&mw->fmr.fm_mr->list);
fmr_op_recover_mr(mw);
}
}
/* Use a slow, safe mechanism to invalidate all memory regions
* that were registered for "req".
*/
static void
fmr_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);
xprtrdma: Use scatterlist for DMA mapping and unmapping under FMR The use of a scatterlist for handling DMA mapping and unmapping was recently introduced in frwr_ops.c in commit 4143f34e01e9 ("xprtrdma: Port to new memory registration API"). That commit did not make a similar update to xprtrdma's FMR support because the core ib_map_phys_fmr() and ib_unmap_fmr() APIs have not been changed to take a scatterlist argument. However, FMR still needs to do DMA mapping and unmapping. It appears that RDS, for example, uses a scatterlist for this, then builds the DMA addr array for the ib_map_phys_fmr call separately. I see that SRP also utilizes a scatterlist for DMA mapping. xprtrdma can do something similar. This modernization is used immediately to properly defer DMA unmapping during fmr_unmap_safe (a FIXME). It separates the DMA unmapping coordinates from the rl_segments array. This array, being part of an rpcrdma_req, is always re-used immediately when an RPC exits. A scatterlist is allocated in memory independent of the rl_segments array, so it can be preserved indefinitely (ie, until the MR invalidation and DMA unmapping can actually be done by a worker thread). The FRWR and FMR DMA mapping code are slightly different from each other now, and will diverge further when the "Check for holes" logic can be removed from FRWR (support for SG_GAP MRs). So I chose not to create helpers for the common-looking code. Fixes: ead3f26e359e ("xprtrdma: Add ro_unmap_safe memreg method") Suggested-by: Sagi Grimberg <sagi@lightbits.io> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Steve Wise <swise@opengridcomputing.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-06-29 17:52:45 +00:00
if (sync)
fmr_op_recover_mr(mw);
xprtrdma: Use scatterlist for DMA mapping and unmapping under FMR The use of a scatterlist for handling DMA mapping and unmapping was recently introduced in frwr_ops.c in commit 4143f34e01e9 ("xprtrdma: Port to new memory registration API"). That commit did not make a similar update to xprtrdma's FMR support because the core ib_map_phys_fmr() and ib_unmap_fmr() APIs have not been changed to take a scatterlist argument. However, FMR still needs to do DMA mapping and unmapping. It appears that RDS, for example, uses a scatterlist for this, then builds the DMA addr array for the ib_map_phys_fmr call separately. I see that SRP also utilizes a scatterlist for DMA mapping. xprtrdma can do something similar. This modernization is used immediately to properly defer DMA unmapping during fmr_unmap_safe (a FIXME). It separates the DMA unmapping coordinates from the rl_segments array. This array, being part of an rpcrdma_req, is always re-used immediately when an RPC exits. A scatterlist is allocated in memory independent of the rl_segments array, so it can be preserved indefinitely (ie, until the MR invalidation and DMA unmapping can actually be done by a worker thread). The FRWR and FMR DMA mapping code are slightly different from each other now, and will diverge further when the "Check for holes" logic can be removed from FRWR (support for SG_GAP MRs). So I chose not to create helpers for the common-looking code. Fixes: ead3f26e359e ("xprtrdma: Add ro_unmap_safe memreg method") Suggested-by: Sagi Grimberg <sagi@lightbits.io> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Tested-by: Steve Wise <swise@opengridcomputing.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-06-29 17:52:45 +00:00
else
rpcrdma_defer_mr_recovery(mw);
}
}
const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops = {
.ro_map = fmr_op_map,
.ro_unmap_sync = fmr_op_unmap_sync,
.ro_unmap_safe = fmr_op_unmap_safe,
.ro_recover_mr = fmr_op_recover_mr,
.ro_open = fmr_op_open,
.ro_maxpages = fmr_op_maxpages,
.ro_init_mr = fmr_op_init_mr,
.ro_release_mr = fmr_op_release_mr,
.ro_displayname = "fmr",
};