[PATCH 05/10] rds: stop using dmapool

Christoph Hellwig
2020-11-06T18:20:10Z

RDMA ULPs should only perform DMA through the ib_dma_* API instead of
using the hidden dma_device directly. In addition using the dma coherent
API family that dmapool is a part of can be very ineffcient on plaforms
that are not DMA coherent. Switch to use slab allocations and the
ib_dma_* APIs instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
net/rds/ib.c | 10 ----
net/rds/ib.h | 6 ---
net/rds/ib_cm.c | 128 ++++++++++++++++++++++++++++------------------
net/rds/ib_recv.c | 18 +++++--
net/rds/ib_send.c | 8 +++
5 files changed, 101 insertions(+), 69 deletions(-)

diff --git a/net/rds/ib.c b/net/rds/ib.c
index deecbdcdae84ef..24c9a9005a6fba 100644
--- a/net/rds/ib.c
+++ b/net/rds/ib.c
@@ -30,7 +30,6 @@
* SOFTWARE.
*
*/
-#include <linux/dmapool.h>
#include <linux/kernel.h>
#include <linux/in.h>
#include <linux/if.h>
@@ -108,7 +107,6 @@ static void rds_ib_dev_free(struct work_struct *work)
rds_ib_destroy_mr_pool(rds_ibdev->mr_1m_pool);
if (rds_ibdev->pd)
ib_dealloc_pd(rds_ibdev->pd);
- dma_pool_destroy(rds_ibdev->rid_hdrs_pool);

list_for_each_entry_safe(i_ipaddr, i_next, &rds_ibdev->ipaddr_list, list) {
list_del(&i_ipaddr->list);
@@ -191,14 +189,6 @@ static int rds_ib_add_one(struct ib_device *device)
rds_ibdev->pd = NULL;
goto put_dev;
}
- rds_ibdev->rid_hdrs_pool = dma_pool_create(device->name,
- device->dma_device,
- sizeof(struct rds_header),
- L1_CACHE_BYTES, 0);
- if (!rds_ibdev->rid_hdrs_pool) {
- ret = -ENOMEM;
- goto put_dev;
- }

rds_ibdev->mr_1m_pool =
rds_ib_create_mr_pool(rds_ibdev, RDS_IB_MR_1M_POOL);
diff --git a/net/rds/ib.h b/net/rds/ib.h
index c23a11d9ad3628..2ba71102b1f1f2 100644
--- a/net/rds/ib.h
+++ b/net/rds/ib.h
@@ -246,7 +246,6 @@ struct rds_ib_device {
struct list_head conn_list;
struct ib_device *dev;
struct ib_pd *pd;
- struct dma_pool *rid_hdrs_pool; /* RDS headers DMA pool */
u8 odp_capable:1;

unsigned int max_mrs;
@@ -380,11 +379,6 @@ int rds_ib_cm_handle_connect(struct rdma_cm_id *cm_id,
int rds_ib_cm_initiate_connect(struct rdma_cm_id *cm_id, bool isv6);
void rds_ib_cm_connect_complete(struct rds_connection *conn,
struct rdma_cm_event *event);
-struct rds_header **rds_dma_hdrs_alloc(struct ib_device *ibdev,
- struct dma_pool *pool,
- dma_addr_t **dma_addrs, u32 num_hdrs);
-void rds_dma_hdrs_free(struct dma_pool *pool, struct rds_header **hdrs,
- dma_addr_t *dma_addrs, u32 num_hdrs);

#define rds_ib_conn_error(conn, fmt...) \
__rds_ib_conn_error(conn, KERN_WARNING "RDS/IB: " fmt)
diff --git a/net/rds/ib_cm.c b/net/rds/ib_cm.c
index b36b60668b1da9..f5cbe963cd8f78 100644
--- a/net/rds/ib_cm.c
+++ b/net/rds/ib_cm.c
@@ -30,7 +30,6 @@
* SOFTWARE.
*
*/
-#include <linux/dmapool.h>
#include <linux/kernel.h>
#include <linux/in.h>
#include <linux/slab.h>
@@ -441,42 +440,87 @@ static inline void ibdev_put_vector(struct rds_ib_device *rds_ibdev, int index)
rds_ibdev->vector_load[index]--;
}

+static void rds_dma_hdr_free(struct ib_device *dev, struct rds_header *hdr,
+ dma_addr_t dma_addr, enum dma_data_direction dir)
+{
+ ib_dma_unmap_single(dev, dma_addr, sizeof(*hdr), dir);
+ kfree(hdr);
+}
+
+static struct rds_header *rds_dma_hdr_alloc(struct ib_device *dev,
+ dma_addr_t *dma_addr, enum dma_data_direction dir)
+{
+ struct rds_header *hdr;
+
+ hdr = kzalloc_node(sizeof(*hdr), GFP_KERNEL, ibdev_to_node(dev));
+ if (!hdr)
+ return NULL;
+
+ *dma_addr = ib_dma_map_single(dev, hdr, sizeof(*hdr),
+ DMA_BIDIRECTIONAL);
+ if (ib_dma_mapping_error(dev, *dma_addr)) {
+ kfree(hdr);
+ return NULL;
+ }
+
+ return hdr;
+}
+
+/* Free the DMA memory used to store struct rds_header.
+ *
+ * @dev: the RDS IB device
+ * @hdrs: pointer to the array storing DMA memory pointers
+ * @dma_addrs: pointer to the array storing DMA addresses
+ * @num_hdars: number of headers to free.
+ */
+static void rds_dma_hdrs_free(struct rds_ib_device *dev,
+ struct rds_header **hdrs, dma_addr_t *dma_addrs, u32 num_hdrs,
+ enum dma_data_direction dir)
+{
+ u32 i;
+
+ for (i = 0; i < num_hdrs; i++)
+ rds_dma_hdr_free(dev->dev, hdrs[i], dma_addrs[i], dir);
+ kvfree(hdrs);
+ kvfree(dma_addrs);
+}
+
+
/* Allocate DMA coherent memory to be used to store struct rds_header for
* sending/receiving packets. The pointers to the DMA memory and the
* associated DMA addresses are stored in two arrays.
*
- * @ibdev: the IB device
- * @pool: the DMA memory pool
+ * @dev: the RDS IB device
* @dma_addrs: pointer to the array for storing DMA addresses
* @num_hdrs: number of headers to allocate
*
* It returns the pointer to the array storing the DMA memory pointers. On
* error, NULL pointer is returned.
*/
-struct rds_header **rds_dma_hdrs_alloc(struct ib_device *ibdev,
- struct dma_pool *pool,
- dma_addr_t **dma_addrs, u32 num_hdrs)
+static struct rds_header **rds_dma_hdrs_alloc(struct rds_ib_device *dev,
+ dma_addr_t **dma_addrs, u32 num_hdrs,
+ enum dma_data_direction dir)
{
struct rds_header **hdrs;
dma_addr_t *hdr_daddrs;
u32 i;

hdrs = kvmalloc_node(sizeof(*hdrs) * num_hdrs, GFP_KERNEL,
- ibdev_to_node(ibdev));
+ ibdev_to_node(dev->dev));
if (!hdrs)
return NULL;

hdr_daddrs = kvmalloc_node(sizeof(*hdr_daddrs) * num_hdrs, GFP_KERNEL,
- ibdev_to_node(ibdev));
+ ibdev_to_node(dev->dev));
if (!hdr_daddrs) {
kvfree(hdrs);
return NULL;
}

for (i = 0; i < num_hdrs; i++) {
- hdrs[i] = dma_pool_zalloc(pool, GFP_KERNEL, &hdr_daddrs[i]);
+ hdrs[i] = rds_dma_hdr_alloc(dev->dev, &hdr_daddrs[i], dir);
if (!hdrs[i]) {
- rds_dma_hdrs_free(pool, hdrs, hdr_daddrs, i);
+ rds_dma_hdrs_free(dev, hdrs, hdr_daddrs, i, dir);
return NULL;
}
}
@@ -485,24 +529,6 @@ struct rds_header **rds_dma_hdrs_alloc(struct ib_device *ibdev,
return hdrs;
}

-/* Free the DMA memory used to store struct rds_header.
- *
- * @pool: the DMA memory pool
- * @hdrs: pointer to the array storing DMA memory pointers
- * @dma_addrs: pointer to the array storing DMA addresses
- * @num_hdars: number of headers to free.
- */
-void rds_dma_hdrs_free(struct dma_pool *pool, struct rds_header **hdrs,
- dma_addr_t *dma_addrs, u32 num_hdrs)
-{
- u32 i;
-
- for (i = 0; i < num_hdrs; i++)
- dma_pool_free(pool, hdrs[i], dma_addrs[i]);
- kvfree(hdrs);
- kvfree(dma_addrs);
-}
-
/*
* This needs to be very careful to not leave IS_ERR pointers around for
* cleanup to trip over.
@@ -516,7 +542,6 @@ static int rds_ib_setup_qp(struct rds_connection *conn)
struct rds_ib_device *rds_ibdev;
unsigned long max_wrs;
int ret, fr_queue_space;
- struct dma_pool *pool;

/*
* It's normal to see a null device if an incoming connection races
@@ -612,25 +637,26 @@ static int rds_ib_setup_qp(struct rds_connection *conn)
goto recv_cq_out;
}

- pool = rds_ibdev->rid_hdrs_pool;
- ic->i_send_hdrs = rds_dma_hdrs_alloc(dev, pool, &ic->i_send_hdrs_dma,
- ic->i_send_ring.w_nr);
+ ic->i_send_hdrs = rds_dma_hdrs_alloc(rds_ibdev, &ic->i_send_hdrs_dma,
+ ic->i_send_ring.w_nr,
+ DMA_TO_DEVICE);
if (!ic->i_send_hdrs) {
ret = -ENOMEM;
rdsdebug("DMA send hdrs alloc failed\n");
goto qp_out;
}

- ic->i_recv_hdrs = rds_dma_hdrs_alloc(dev, pool, &ic->i_recv_hdrs_dma,
- ic->i_recv_ring.w_nr);
+ ic->i_recv_hdrs = rds_dma_hdrs_alloc(rds_ibdev, &ic->i_recv_hdrs_dma,
+ ic->i_recv_ring.w_nr,
+ DMA_FROM_DEVICE);
if (!ic->i_recv_hdrs) {
ret = -ENOMEM;
rdsdebug("DMA recv hdrs alloc failed\n");
goto send_hdrs_dma_out;
}

- ic->i_ack = dma_pool_zalloc(pool, GFP_KERNEL,
- &ic->i_ack_dma);
+ ic->i_ack = rds_dma_hdr_alloc(rds_ibdev->dev, &ic->i_ack_dma,
+ DMA_TO_DEVICE);
if (!ic->i_ack) {
ret = -ENOMEM;
rdsdebug("DMA ack header alloc failed\n");
@@ -666,18 +692,19 @@ static int rds_ib_setup_qp(struct rds_connection *conn)
vfree(ic->i_sends);

ack_dma_out:
- dma_pool_free(pool, ic->i_ack, ic->i_ack_dma);
+ rds_dma_hdr_free(rds_ibdev->dev, ic->i_ack, ic->i_ack_dma,
+ DMA_TO_DEVICE);
ic->i_ack = NULL;

recv_hdrs_dma_out:
- rds_dma_hdrs_free(pool, ic->i_recv_hdrs, ic->i_recv_hdrs_dma,
- ic->i_recv_ring.w_nr);
+ rds_dma_hdrs_free(rds_ibdev, ic->i_recv_hdrs, ic->i_recv_hdrs_dma,
+ ic->i_recv_ring.w_nr, DMA_FROM_DEVICE);
ic->i_recv_hdrs = NULL;
ic->i_recv_hdrs_dma = NULL;

send_hdrs_dma_out:
- rds_dma_hdrs_free(pool, ic->i_send_hdrs, ic->i_send_hdrs_dma,
- ic->i_send_ring.w_nr);
+ rds_dma_hdrs_free(rds_ibdev, ic->i_send_hdrs, ic->i_send_hdrs_dma,
+ ic->i_send_ring.w_nr, DMA_TO_DEVICE);
ic->i_send_hdrs = NULL;
ic->i_send_hdrs_dma = NULL;

@@ -1110,29 +1137,30 @@ void rds_ib_conn_path_shutdown(struct rds_conn_path *cp)
}

if (ic->rds_ibdev) {
- struct dma_pool *pool;
-
- pool = ic->rds_ibdev->rid_hdrs_pool;
-
/* then free the resources that ib callbacks use */
if (ic->i_send_hdrs) {
- rds_dma_hdrs_free(pool, ic->i_send_hdrs,
+ rds_dma_hdrs_free(ic->rds_ibdev,
+ ic->i_send_hdrs,
ic->i_send_hdrs_dma,
- ic->i_send_ring.w_nr);
+ ic->i_send_ring.w_nr,
+ DMA_TO_DEVICE);
ic->i_send_hdrs = NULL;
ic->i_send_hdrs_dma = NULL;
}

if (ic->i_recv_hdrs) {
- rds_dma_hdrs_free(pool, ic->i_recv_hdrs,
+ rds_dma_hdrs_free(ic->rds_ibdev,
+ ic->i_recv_hdrs,
ic->i_recv_hdrs_dma,
- ic->i_recv_ring.w_nr);
+ ic->i_recv_ring.w_nr,
+ DMA_FROM_DEVICE);
ic->i_recv_hdrs = NULL;
ic->i_recv_hdrs_dma = NULL;
}

if (ic->i_ack) {
- dma_pool_free(pool, ic->i_ack, ic->i_ack_dma);
+ rds_dma_hdr_free(ic->rds_ibdev->dev, ic->i_ack,
+ ic->i_ack_dma, DMA_TO_DEVICE);
ic->i_ack = NULL;
}
} else {
diff --git a/net/rds/ib_recv.c b/net/rds/ib_recv.c
index 3cffcec5fb371b..6fdedd9dbbc28f 100644
--- a/net/rds/ib_recv.c
+++ b/net/rds/ib_recv.c
@@ -662,10 +662,16 @@ static void rds_ib_send_ack(struct rds_ib_connection *ic, unsigned int adv_credi
seq = rds_ib_get_ack(ic);

rdsdebug("send_ack: ic %p ack %llu\n", ic, (unsigned long long) seq);
+
+ ib_dma_sync_single_for_cpu(ic->rds_ibdev->dev, ic->i_ack_dma,
+ sizeof(*hdr), DMA_TO_DEVICE);
rds_message_populate_header(hdr, 0, 0, 0);
hdr->h_ack = cpu_to_be64(seq);
hdr->h_credit = adv_credits;
rds_message_make_checksum(hdr);
+ ib_dma_sync_single_for_device(ic->rds_ibdev->dev, ic->i_ack_dma,
+ sizeof(*hdr), DMA_TO_DEVICE);
+
ic->i_ack_queued = jiffies;

ret = ib_post_send(ic->i_cm_id->qp, &ic->i_ack_wr, NULL);
@@ -845,6 +851,7 @@ static void rds_ib_process_recv(struct rds_connection *conn,
struct rds_ib_connection *ic = conn->c_transport_data;
struct rds_ib_incoming *ibinc = ic->i_ibinc;
struct rds_header *ihdr, *hdr;
+ dma_addr_t dma_addr = ic->i_recv_hdrs_dma[recv - ic->i_recvs];

/* XXX shut down the connection if port 0,0 are seen? */

@@ -863,6 +870,8 @@ static void rds_ib_process_recv(struct rds_connection *conn,

ihdr = ic->i_recv_hdrs[recv - ic->i_recvs];

+ ib_dma_sync_single_for_cpu(ic->rds_ibdev->dev, dma_addr,
+ sizeof(*ihdr), DMA_FROM_DEVICE);
/* Validate the checksum. */
if (!rds_message_verify_checksum(ihdr)) {
rds_ib_conn_error(conn, "incoming message "
@@ -870,7 +879,7 @@ static void rds_ib_process_recv(struct rds_connection *conn,
"forcing a reconnect\n",
&conn->c_faddr);
rds_stats_inc(s_recv_drop_bad_checksum);
- return;
+ goto done;
}

/* Process the ACK sequence which comes with every packet */
@@ -899,7 +908,7 @@ static void rds_ib_process_recv(struct rds_connection *conn,
*/
rds_ib_frag_free(ic, recv->r_frag);
recv->r_frag = NULL;
- return;
+ goto done;
}

/*
@@ -933,7 +942,7 @@ static void rds_ib_process_recv(struct rds_connection *conn,
hdr->h_dport != ihdr->h_dport) {
rds_ib_conn_error(conn,
"fragment header mismatch; forcing reconnect\n");
- return;
+ goto done;
}
}

@@ -965,6 +974,9 @@ static void rds_ib_process_recv(struct rds_connection *conn,

rds_inc_put(&ibinc->ii_inc);
}
+done:
+ ib_dma_sync_single_for_device(ic->rds_ibdev->dev, dma_addr,
+ sizeof(*ihdr), DMA_FROM_DEVICE);
}

void rds_ib_recv_cqe_handler(struct rds_ib_connection *ic,
diff --git a/net/rds/ib_send.c b/net/rds/ib_send.c
index dfe778220657af..92b4a8689aae7a 100644
--- a/net/rds/ib_send.c
+++ b/net/rds/ib_send.c
@@ -638,6 +638,10 @@ int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm,
send->s_sge[0].length = sizeof(struct rds_header);
send->s_sge[0].lkey = ic->i_pd->local_dma_lkey;

+ ib_dma_sync_single_for_cpu(ic->rds_ibdev->dev,
+ ic->i_send_hdrs_dma[pos],
+ sizeof(struct rds_header),
+ DMA_TO_DEVICE);
memcpy(ic->i_send_hdrs[pos], &rm->m_inc.i_hdr,
sizeof(struct rds_header));

@@ -688,6 +692,10 @@ int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm,
adv_credits = 0;
rds_ib_stats_inc(s_ib_tx_credit_updates);
}
+ ib_dma_sync_single_for_device(ic->rds_ibdev->dev,
+ ic->i_send_hdrs_dma[pos],
+ sizeof(struct rds_header),
+ DMA_TO_DEVICE);

if (prev)
prev->s_wr.next = &send->s_wr;
--
2.28.0