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smc: remote memory buffers (RMBs) 

* allocate data RMB memory for sending and receiving
* size depends on the maximum socket send and receive buffers
* allocated RMBs are kept during life time of the owning link group
* map the allocated RMBs to DMA

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ursula Braun 2017-01-09 16:55:18 +01:00 committed by David S. Miller
parent 0cfdd8f92c
commit cd6851f303
7 changed files with 342 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
net/smc/af_smc.c
View File

@ -249,6 +249,8 @@ static void smc_conn_save_peer_info(struct smc_sock *smc,
struct smc_clc_msg_accept_confirm *clc)
{
smc->conn.peer_conn_idx = clc->conn_idx;
smc->conn.peer_rmbe_size = smc_uncompress_bufsize(clc->rmbe_size);
atomic_set(&smc->conn.peer_rmbe_space, smc->conn.peer_rmbe_size);
}
static void smc_link_save_peer_info(struct smc_link *link,
@ -323,6 +325,18 @@ static int smc_connect_rdma(struct smc_sock *smc)
link = &smc->conn.lgr->lnk[SMC_SINGLE_LINK];
smc_conn_save_peer_info(smc, &aclc);
rc = smc_sndbuf_create(smc);
if (rc) {
reason_code = SMC_CLC_DECL_MEM;
goto decline_rdma_unlock;
}
rc = smc_rmb_create(smc);
if (rc) {
reason_code = SMC_CLC_DECL_MEM;
goto decline_rdma_unlock;
}
if (local_contact == SMC_FIRST_CONTACT)
smc_link_save_peer_info(link, &aclc);
/* tbd in follow-on patch: more steps to setup RDMA communcication,
@ -598,9 +612,16 @@ static void smc_listen_work(struct work_struct *work)
}
link = &new_smc->conn.lgr->lnk[SMC_SINGLE_LINK];
/* tbd in follow-on patch: more steps to setup RDMA communcication,
* create rmbs, map rmbs
*/
rc = smc_sndbuf_create(new_smc);
if (rc) {
reason_code = SMC_CLC_DECL_MEM;
goto decline_rdma;
}
rc = smc_rmb_create(new_smc);
if (rc) {
reason_code = SMC_CLC_DECL_MEM;
goto decline_rdma;
}
rc = smc_clc_send_accept(new_smc, local_contact);
if (rc)
@ -1047,6 +1068,8 @@ static int smc_create(struct net *net, struct socket *sock, int protocol,
IPPROTO_TCP, &smc->clcsock);
if (rc)
sk_common_release(sk);
smc->sk.sk_sndbuf = max(smc->clcsock->sk->sk_sndbuf, SMC_BUF_MIN_SIZE);
smc->sk.sk_rcvbuf = max(smc->clcsock->sk->sk_rcvbuf, SMC_BUF_MIN_SIZE);
out:
return rc;

45
net/smc/smc.h
View File

@ -34,6 +34,16 @@ struct smc_connection {
struct smc_link_group *lgr; /* link group of connection */
u32 alert_token_local; /* unique conn. id */
u8 peer_conn_idx; /* from tcp handshake */
int peer_rmbe_size; /* size of peer rx buffer */
atomic_t peer_rmbe_space;/* remaining free bytes in peer
* rmbe
*/
struct smc_buf_desc *sndbuf_desc; /* send buffer descriptor */
int sndbuf_size; /* sndbuf size <== sock wmem */
struct smc_buf_desc *rmb_desc; /* RMBE descriptor */
int rmbe_size; /* RMBE size <== sock rmem */
int rmbe_size_short;/* compressed notation */
};
struct smc_sock { /* smc sock container */
@ -76,6 +86,41 @@ static inline u32 ntoh24(u8 *net)
return be32_to_cpu(t);
}
#define SMC_BUF_MIN_SIZE 16384 /* minimum size of an RMB */
#define SMC_RMBE_SIZES 16 /* number of distinct sizes for an RMBE */
/* theoretically, the RFC states that largest size would be 512K,
* i.e. compressed 5 and thus 6 sizes (0..5), despite
* struct smc_clc_msg_accept_confirm.rmbe_size being a 4 bit value (0..15)
*/
/* convert the RMB size into the compressed notation - minimum 16K.
* In contrast to plain ilog2, this rounds towards the next power of 2,
* so the socket application gets at least its desired sndbuf / rcvbuf size.
*/
static inline u8 smc_compress_bufsize(int size)
{
u8 compressed;
if (size <= SMC_BUF_MIN_SIZE)
return 0;
size = (size - 1) >> 14;
compressed = ilog2(size) + 1;
if (compressed >= SMC_RMBE_SIZES)
compressed = SMC_RMBE_SIZES - 1;
return compressed;
}
/* convert the RMB size from compressed notation into integer */
static inline int smc_uncompress_bufsize(u8 compressed)
{
u32 size;
size = 0x00000001 << (((int)compressed) + 14);
return (int)size;
}
#ifdef CONFIG_XFRM
static inline bool using_ipsec(struct smc_sock *smc)
{

6
net/smc/smc_clc.c
View File

@ -252,13 +252,13 @@ int smc_clc_send_accept(struct smc_sock *new_smc, int srv_first_contact)
SMC_GID_SIZE);
memcpy(&aclc.lcl.mac, link->smcibdev->mac[link->ibport - 1],
sizeof(link->smcibdev->mac[link->ibport - 1]));
/* tbd in follow-on patch: fill in rmb-related values */
hton24(aclc.qpn, link->roce_qp->qp_num);
aclc.conn_idx = 1; /* as long as 1 RMB = 1 RMBE */
aclc.rmbe_alert_token = htonl(conn->alert_token_local);
aclc.qp_mtu = link->path_mtu;
aclc.rmbe_size = conn->rmbe_size_short,
aclc.rmb_dma_addr =
cpu_to_be64((u64)conn->rmb_desc->dma_addr[SMC_SINGLE_LINK]);
hton24(aclc.psn, link->psn_initial);
memcpy(aclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));

224
net/smc/smc_core.c
View File

@ -133,6 +133,7 @@ static int smc_lgr_create(struct smc_sock *smc, __be32 peer_in_addr,
struct smc_link *lnk;
u8 rndvec[3];
int rc = 0;
int i;
lgr = kzalloc(sizeof(*lgr), GFP_KERNEL);
if (!lgr) {
@ -144,6 +145,12 @@ static int smc_lgr_create(struct smc_sock *smc, __be32 peer_in_addr,
lgr->daddr = peer_in_addr;
memcpy(lgr->peer_systemid, peer_systemid, SMC_SYSTEMID_LEN);
lgr->vlan_id = vlan_id;
rwlock_init(&lgr->sndbufs_lock);
rwlock_init(&lgr->rmbs_lock);
for (i = 0; i < SMC_RMBE_SIZES; i++) {
INIT_LIST_HEAD(&lgr->sndbufs[i]);
INIT_LIST_HEAD(&lgr->rmbs[i]);
}
INIT_DELAYED_WORK(&lgr->free_work, smc_lgr_free_work);
lgr->conns_all = RB_ROOT;
@ -164,6 +171,22 @@ out:
return rc;
}
static void smc_sndbuf_unuse(struct smc_connection *conn)
{
if (conn->sndbuf_desc) {
conn->sndbuf_desc->used = 0;
conn->sndbuf_size = 0;
}
}
static void smc_rmb_unuse(struct smc_connection *conn)
{
if (conn->rmb_desc) {
conn->rmb_desc->used = 0;
conn->rmbe_size = 0;
}
}
/* remove a finished connection from its link group */
void smc_conn_free(struct smc_connection *conn)
{
@ -172,6 +195,8 @@ void smc_conn_free(struct smc_connection *conn)
if (!lgr)
return;
smc_lgr_unregister_conn(conn);
smc_rmb_unuse(conn);
smc_sndbuf_unuse(conn);
}
static void smc_link_clear(struct smc_link *lnk)
@ -179,9 +204,39 @@ static void smc_link_clear(struct smc_link *lnk)
lnk->peer_qpn = 0;
}
static void smc_lgr_free_sndbufs(struct smc_link_group *lgr)
{
struct smc_buf_desc *sndbuf_desc, *bf_desc;
int i;
for (i = 0; i < SMC_RMBE_SIZES; i++) {
list_for_each_entry_safe(sndbuf_desc, bf_desc, &lgr->sndbufs[i],
list) {
kfree(sndbuf_desc->cpu_addr);
kfree(sndbuf_desc);
}
}
}
static void smc_lgr_free_rmbs(struct smc_link_group *lgr)
{
struct smc_buf_desc *rmb_desc, *bf_desc;
int i;
for (i = 0; i < SMC_RMBE_SIZES; i++) {
list_for_each_entry_safe(rmb_desc, bf_desc, &lgr->rmbs[i],
list) {
kfree(rmb_desc->cpu_addr);
kfree(rmb_desc);
}
}
}
/* remove a link group */
void smc_lgr_free(struct smc_link_group *lgr)
{
smc_lgr_free_rmbs(lgr);
smc_lgr_free_sndbufs(lgr);
smc_link_clear(&lgr->lnk[SMC_SINGLE_LINK]);
kfree(lgr);
}
@ -300,7 +355,9 @@ int smc_conn_create(struct smc_sock *smc, __be32 peer_in_addr,
sizeof(lcl->mac)) &&
!lgr->sync_err &&
(lgr->role == role) &&
(lgr->vlan_id == vlan_id)) {
(lgr->vlan_id == vlan_id) &&
((role == SMC_CLNT) ||
(lgr->conns_num < SMC_RMBS_PER_LGR_MAX))) {
/* link group found */
local_contact = SMC_REUSE_CONTACT;
conn->lgr = lgr;
@ -334,3 +391,168 @@ create:
out:
return rc ? rc : local_contact;
}
/* try to reuse a sndbuf description slot of the sndbufs list for a certain
* buf_size; if not available, return NULL
*/
static inline
struct smc_buf_desc *smc_sndbuf_get_slot(struct smc_link_group *lgr,
int compressed_bufsize)
{
struct smc_buf_desc *sndbuf_slot;
read_lock_bh(&lgr->sndbufs_lock);
list_for_each_entry(sndbuf_slot, &lgr->sndbufs[compressed_bufsize],
list) {
if (cmpxchg(&sndbuf_slot->used, 0, 1) == 0) {
read_unlock_bh(&lgr->sndbufs_lock);
return sndbuf_slot;
}
}
read_unlock_bh(&lgr->sndbufs_lock);
return NULL;
}
/* try to reuse an rmb description slot of the rmbs list for a certain
* rmbe_size; if not available, return NULL
*/
static inline
struct smc_buf_desc *smc_rmb_get_slot(struct smc_link_group *lgr,
int compressed_bufsize)
{
struct smc_buf_desc *rmb_slot;
read_lock_bh(&lgr->rmbs_lock);
list_for_each_entry(rmb_slot, &lgr->rmbs[compressed_bufsize],
list) {
if (cmpxchg(&rmb_slot->used, 0, 1) == 0) {
read_unlock_bh(&lgr->rmbs_lock);
return rmb_slot;
}
}
read_unlock_bh(&lgr->rmbs_lock);
return NULL;
}
/* create the tx buffer for an SMC socket */
int smc_sndbuf_create(struct smc_sock *smc)
{
struct smc_connection *conn = &smc->conn;
struct smc_link_group *lgr = conn->lgr;
int tmp_bufsize, tmp_bufsize_short;
struct smc_buf_desc *sndbuf_desc;
int rc;
/* use socket send buffer size (w/o overhead) as start value */
for (tmp_bufsize_short = smc_compress_bufsize(smc->sk.sk_sndbuf / 2);
tmp_bufsize_short >= 0; tmp_bufsize_short--) {
tmp_bufsize = smc_uncompress_bufsize(tmp_bufsize_short);
/* check for reusable sndbuf_slot in the link group */
sndbuf_desc = smc_sndbuf_get_slot(lgr, tmp_bufsize_short);
if (sndbuf_desc) {
memset(sndbuf_desc->cpu_addr, 0, tmp_bufsize);
break; /* found reusable slot */
}
/* try to alloc a new send buffer */
sndbuf_desc = kzalloc(sizeof(*sndbuf_desc), GFP_KERNEL);
if (!sndbuf_desc)
break; /* give up with -ENOMEM */
sndbuf_desc->cpu_addr = kzalloc(tmp_bufsize,
GFP_KERNEL | __GFP_NOWARN |
__GFP_NOMEMALLOC |
__GFP_NORETRY);
if (!sndbuf_desc->cpu_addr) {
kfree(sndbuf_desc);
/* if send buffer allocation has failed,
* try a smaller one
*/
continue;
}
rc = smc_ib_buf_map(lgr->lnk[SMC_SINGLE_LINK].smcibdev,
tmp_bufsize, sndbuf_desc,
DMA_TO_DEVICE);
if (rc) {
kfree(sndbuf_desc->cpu_addr);
kfree(sndbuf_desc);
continue; /* if mapping failed, try smaller one */
}
sndbuf_desc->used = 1;
write_lock_bh(&lgr->sndbufs_lock);
list_add(&sndbuf_desc->list,
&lgr->sndbufs[tmp_bufsize_short]);
write_unlock_bh(&lgr->sndbufs_lock);
break;
}
if (sndbuf_desc && sndbuf_desc->cpu_addr) {
conn->sndbuf_desc = sndbuf_desc;
conn->sndbuf_size = tmp_bufsize;
smc->sk.sk_sndbuf = tmp_bufsize * 2;
return 0;
} else {
return -ENOMEM;
}
}
/* create the RMB for an SMC socket (even though the SMC protocol
* allows more than one RMB-element per RMB, the Linux implementation
* uses just one RMB-element per RMB, i.e. uses an extra RMB for every
* connection in a link group
*/
int smc_rmb_create(struct smc_sock *smc)
{
struct smc_connection *conn = &smc->conn;
struct smc_link_group *lgr = conn->lgr;
int tmp_bufsize, tmp_bufsize_short;
struct smc_buf_desc *rmb_desc;
int rc;
/* use socket recv buffer size (w/o overhead) as start value */
for (tmp_bufsize_short = smc_compress_bufsize(smc->sk.sk_rcvbuf / 2);
tmp_bufsize_short >= 0; tmp_bufsize_short--) {
tmp_bufsize = smc_uncompress_bufsize(tmp_bufsize_short);
/* check for reusable rmb_slot in the link group */
rmb_desc = smc_rmb_get_slot(lgr, tmp_bufsize_short);
if (rmb_desc) {
memset(rmb_desc->cpu_addr, 0, tmp_bufsize);
break; /* found reusable slot */
}
/* try to alloc a new RMB */
rmb_desc = kzalloc(sizeof(*rmb_desc), GFP_KERNEL);
if (!rmb_desc)
break; /* give up with -ENOMEM */
rmb_desc->cpu_addr = kzalloc(tmp_bufsize,
GFP_KERNEL | __GFP_NOWARN |
__GFP_NOMEMALLOC |
__GFP_NORETRY);
if (!rmb_desc->cpu_addr) {
kfree(rmb_desc);
/* if RMB allocation has failed,
* try a smaller one
*/
continue;
}
rc = smc_ib_buf_map(lgr->lnk[SMC_SINGLE_LINK].smcibdev,
tmp_bufsize, rmb_desc,
DMA_FROM_DEVICE);
if (rc) {
kfree(rmb_desc->cpu_addr);
kfree(rmb_desc);
continue; /* if mapping failed, try smaller one */
}
rmb_desc->used = 1;
write_lock_bh(&lgr->rmbs_lock);
list_add(&rmb_desc->list,
&lgr->rmbs[tmp_bufsize_short]);
write_unlock_bh(&lgr->rmbs_lock);
break;
}
if (rmb_desc && rmb_desc->cpu_addr) {
conn->rmb_desc = rmb_desc;
conn->rmbe_size = tmp_bufsize;
conn->rmbe_size_short = tmp_bufsize_short;
smc->sk.sk_rcvbuf = tmp_bufsize * 2;
return 0;
} else {
return -ENOMEM;
}
}

21
net/smc/smc_core.h
View File

@ -16,6 +16,8 @@
#include "smc.h"
#include "smc_ib.h"
#define SMC_RMBS_PER_LGR_MAX 255 /* max. # of RMBs per link group */
struct smc_lgr_list { /* list of link group definition */
struct list_head list;
spinlock_t lock; /* protects list of link groups */
@ -52,6 +54,15 @@ struct smc_link {
#define SMC_FIRST_CONTACT 1 /* first contact to a peer */
#define SMC_REUSE_CONTACT 0 /* follow-on contact to a peer*/
/* tx/rx buffer list element for sndbufs list and rmbs list of a lgr */
struct smc_buf_desc {
struct list_head list;
u64 dma_addr[SMC_LINKS_PER_LGR_MAX];
/* mapped address of buffer */
void *cpu_addr; /* virtual address of buffer */
u32 used; /* currently used / unused */
};
struct smc_link_group {
struct list_head list;
enum smc_lgr_role role; /* client or server */
@ -63,6 +74,11 @@ struct smc_link_group {
rwlock_t conns_lock; /* protects conns_all */
unsigned int conns_num; /* current # of connections */
unsigned short vlan_id; /* vlan id of link group */
struct list_head sndbufs[SMC_RMBE_SIZES];/* tx buffers */
rwlock_t sndbufs_lock; /* protects tx buffers */
struct list_head rmbs[SMC_RMBE_SIZES]; /* rx buffers */
rwlock_t rmbs_lock; /* protects rx buffers */
struct delayed_work free_work; /* delayed freeing of an lgr */
bool sync_err; /* lgr no longer fits to peer */
};
@ -100,7 +116,12 @@ static inline struct smc_connection *smc_lgr_find_conn(
return res;
}
struct smc_sock;
struct smc_clc_msg_accept_confirm;
void smc_lgr_free(struct smc_link_group *lgr);
void smc_lgr_terminate(struct smc_link_group *lgr);
int smc_sndbuf_create(struct smc_sock *smc);
int smc_rmb_create(struct smc_sock *smc);
#endif

19
net/smc/smc_ib.c
View File

@ -16,6 +16,7 @@
#include "smc_pnet.h"
#include "smc_ib.h"
#include "smc_core.h"
#include "smc.h"
struct smc_ib_devices smc_ib_devices = { /* smc-registered ib devices */
@ -29,6 +30,24 @@ u8 local_systemid[SMC_SYSTEMID_LEN] = SMC_LOCAL_SYSTEMID_RESET; /* unique system
* identifier
*/
/* map a new TX or RX buffer to DMA */
int smc_ib_buf_map(struct smc_ib_device *smcibdev, int buf_size,
struct smc_buf_desc *buf_slot,
enum dma_data_direction data_direction)
{
int rc = 0;
if (buf_slot->dma_addr[SMC_SINGLE_LINK])
return rc; /* already mapped */
buf_slot->dma_addr[SMC_SINGLE_LINK] =
ib_dma_map_single(smcibdev->ibdev, buf_slot->cpu_addr,
buf_size, data_direction);
if (ib_dma_mapping_error(smcibdev->ibdev,
buf_slot->dma_addr[SMC_SINGLE_LINK]))
rc = -EIO;
return rc;
}
static int smc_ib_fill_gid_and_mac(struct smc_ib_device *smcibdev, u8 ibport)
{
struct net_device *ndev;

5
net/smc/smc_ib.h
View File

@ -32,9 +32,14 @@ struct smc_ib_device { /* ib-device infos for smc */
u8 initialized : 1; /* ib dev CQ, evthdl done */
};
struct smc_buf_desc;
int smc_ib_register_client(void) __init;
void smc_ib_unregister_client(void);
bool smc_ib_port_active(struct smc_ib_device *smcibdev, u8 ibport);
int smc_ib_remember_port_attr(struct smc_ib_device *smcibdev, u8 ibport);
int smc_ib_buf_map(struct smc_ib_device *smcibdev, int buf_size,
struct smc_buf_desc *buf_slot,
enum dma_data_direction data_direction);
#endif