* [PATCH net 1/4] net/smc: preallocated memory for rdma work requests
2019-02-04 12:44 [PATCH net 0/4] net/smc: fixes 2019-02-04 Ursula Braun
@ 2019-02-04 12:44 ` Ursula Braun
2019-02-04 12:44 ` [PATCH net 2/4] net/smc: fix sender_free computation Ursula Braun
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Ursula Braun @ 2019-02-04 12:44 UTC (permalink / raw)
To: davem
Cc: netdev, linux-s390, linux-rdma, schwidefsky, heiko.carstens,
raspl, ubraun
The work requests for rdma writes are built in local variables within
function smc_tx_rdma_write(). This violates the rule that the work
request storage has to stay till the work request is confirmed by
a completion queue response.
This patch introduces preallocated memory for these work requests.
The storage is allocated, once a link (and thus a queue pair) is
established.
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
---
net/smc/smc_cdc.c | 11 +++--------
net/smc/smc_cdc.h | 8 +++++++-
net/smc/smc_core.h | 20 ++++++++++++++++++++
net/smc/smc_llc.c | 3 ++-
net/smc/smc_tx.c | 44 ++++++++++++++++++++++----------------------
net/smc/smc_wr.c | 38 +++++++++++++++++++++++++++++++++++++-
net/smc/smc_wr.h | 1 +
7 files changed, 92 insertions(+), 33 deletions(-)
diff --git a/net/smc/smc_cdc.c b/net/smc/smc_cdc.c
index 1c5333d494e9..b80ef104ab4e 100644
--- a/net/smc/smc_cdc.c
+++ b/net/smc/smc_cdc.c
@@ -21,13 +21,6 @@
/********************************** send *************************************/
-struct smc_cdc_tx_pend {
- struct smc_connection *conn; /* socket connection */
- union smc_host_cursor cursor; /* tx sndbuf cursor sent */
- union smc_host_cursor p_cursor; /* rx RMBE cursor produced */
- u16 ctrl_seq; /* conn. tx sequence # */
-};
-
/* handler for send/transmission completion of a CDC msg */
static void smc_cdc_tx_handler(struct smc_wr_tx_pend_priv *pnd_snd,
struct smc_link *link,
@@ -61,12 +54,14 @@ static void smc_cdc_tx_handler(struct smc_wr_tx_pend_priv *pnd_snd,
int smc_cdc_get_free_slot(struct smc_connection *conn,
struct smc_wr_buf **wr_buf,
+ struct smc_rdma_wr **wr_rdma_buf,
struct smc_cdc_tx_pend **pend)
{
struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
int rc;
rc = smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf,
+ wr_rdma_buf,
(struct smc_wr_tx_pend_priv **)pend);
if (!conn->alert_token_local)
/* abnormal termination */
@@ -121,7 +116,7 @@ static int smcr_cdc_get_slot_and_msg_send(struct smc_connection *conn)
struct smc_wr_buf *wr_buf;
int rc;
- rc = smc_cdc_get_free_slot(conn, &wr_buf, &pend);
+ rc = smc_cdc_get_free_slot(conn, &wr_buf, NULL, &pend);
if (rc)
return rc;
diff --git a/net/smc/smc_cdc.h b/net/smc/smc_cdc.h
index b5bfe38c7f9b..2148da7a26b1 100644
--- a/net/smc/smc_cdc.h
+++ b/net/smc/smc_cdc.h
@@ -270,10 +270,16 @@ static inline void smc_cdc_msg_to_host(struct smc_host_cdc_msg *local,
smcr_cdc_msg_to_host(local, peer, conn);
}
-struct smc_cdc_tx_pend;
+struct smc_cdc_tx_pend {
+ struct smc_connection *conn; /* socket connection */
+ union smc_host_cursor cursor; /* tx sndbuf cursor sent */
+ union smc_host_cursor p_cursor; /* rx RMBE cursor produced */
+ u16 ctrl_seq; /* conn. tx sequence # */
+};
int smc_cdc_get_free_slot(struct smc_connection *conn,
struct smc_wr_buf **wr_buf,
+ struct smc_rdma_wr **wr_rdma_buf,
struct smc_cdc_tx_pend **pend);
void smc_cdc_tx_dismiss_slots(struct smc_connection *conn);
int smc_cdc_msg_send(struct smc_connection *conn, struct smc_wr_buf *wr_buf,
diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index b00287989a3d..8806d2afa6ed 100644
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -52,6 +52,24 @@ enum smc_wr_reg_state {
FAILED /* ib_wr_reg_mr response: failure */
};
+struct smc_rdma_sge { /* sges for RDMA writes */
+ struct ib_sge wr_tx_rdma_sge[SMC_IB_MAX_SEND_SGE];
+};
+
+#define SMC_MAX_RDMA_WRITES 2 /* max. # of RDMA writes per
+ * message send
+ */
+
+struct smc_rdma_sges { /* sges per message send */
+ struct smc_rdma_sge tx_rdma_sge[SMC_MAX_RDMA_WRITES];
+};
+
+struct smc_rdma_wr { /* work requests per message
+ * send
+ */
+ struct ib_rdma_wr wr_tx_rdma[SMC_MAX_RDMA_WRITES];
+};
+
struct smc_link {
struct smc_ib_device *smcibdev; /* ib-device */
u8 ibport; /* port - values 1 | 2 */
@@ -64,6 +82,8 @@ struct smc_link {
struct smc_wr_buf *wr_tx_bufs; /* WR send payload buffers */
struct ib_send_wr *wr_tx_ibs; /* WR send meta data */
struct ib_sge *wr_tx_sges; /* WR send gather meta data */
+ struct smc_rdma_sges *wr_tx_rdma_sges;/*RDMA WRITE gather meta data*/
+ struct smc_rdma_wr *wr_tx_rdmas; /* WR RDMA WRITE */
struct smc_wr_tx_pend *wr_tx_pends; /* WR send waiting for CQE */
/* above four vectors have wr_tx_cnt elements and use the same index */
dma_addr_t wr_tx_dma_addr; /* DMA address of wr_tx_bufs */
diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
index a6d3623d06f4..4fd60c522802 100644
--- a/net/smc/smc_llc.c
+++ b/net/smc/smc_llc.c
@@ -166,7 +166,8 @@ static int smc_llc_add_pending_send(struct smc_link *link,
{
int rc;
- rc = smc_wr_tx_get_free_slot(link, smc_llc_tx_handler, wr_buf, pend);
+ rc = smc_wr_tx_get_free_slot(link, smc_llc_tx_handler, wr_buf, NULL,
+ pend);
if (rc < 0)
return rc;
BUILD_BUG_ON_MSG(
diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c
index 36af3de731b9..2fdfaff60cf9 100644
--- a/net/smc/smc_tx.c
+++ b/net/smc/smc_tx.c
@@ -266,27 +266,23 @@ int smcd_tx_ism_write(struct smc_connection *conn, void *data, size_t len,
/* sndbuf consumer: actual data transfer of one target chunk with RDMA write */
static int smc_tx_rdma_write(struct smc_connection *conn, int peer_rmbe_offset,
- int num_sges, struct ib_sge sges[])
+ int num_sges, struct ib_rdma_wr *rdma_wr)
{
struct smc_link_group *lgr = conn->lgr;
- struct ib_rdma_wr rdma_wr;
struct smc_link *link;
int rc;
- memset(&rdma_wr, 0, sizeof(rdma_wr));
link = &lgr->lnk[SMC_SINGLE_LINK];
- rdma_wr.wr.wr_id = smc_wr_tx_get_next_wr_id(link);
- rdma_wr.wr.sg_list = sges;
- rdma_wr.wr.num_sge = num_sges;
- rdma_wr.wr.opcode = IB_WR_RDMA_WRITE;
- rdma_wr.remote_addr =
+ rdma_wr->wr.wr_id = smc_wr_tx_get_next_wr_id(link);
+ rdma_wr->wr.num_sge = num_sges;
+ rdma_wr->remote_addr =
lgr->rtokens[conn->rtoken_idx][SMC_SINGLE_LINK].dma_addr +
/* RMBE within RMB */
conn->tx_off +
/* offset within RMBE */
peer_rmbe_offset;
- rdma_wr.rkey = lgr->rtokens[conn->rtoken_idx][SMC_SINGLE_LINK].rkey;
- rc = ib_post_send(link->roce_qp, &rdma_wr.wr, NULL);
+ rdma_wr->rkey = lgr->rtokens[conn->rtoken_idx][SMC_SINGLE_LINK].rkey;
+ rc = ib_post_send(link->roce_qp, &rdma_wr->wr, NULL);
if (rc) {
conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
smc_lgr_terminate(lgr);
@@ -313,24 +309,25 @@ static inline void smc_tx_advance_cursors(struct smc_connection *conn,
/* SMC-R helper for smc_tx_rdma_writes() */
static int smcr_tx_rdma_writes(struct smc_connection *conn, size_t len,
size_t src_off, size_t src_len,
- size_t dst_off, size_t dst_len)
+ size_t dst_off, size_t dst_len,
+ struct smc_rdma_wr *wr_rdma_buf)
{
dma_addr_t dma_addr =
sg_dma_address(conn->sndbuf_desc->sgt[SMC_SINGLE_LINK].sgl);
- struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
int src_len_sum = src_len, dst_len_sum = dst_len;
- struct ib_sge sges[SMC_IB_MAX_SEND_SGE];
int sent_count = src_off;
int srcchunk, dstchunk;
int num_sges;
int rc;
for (dstchunk = 0; dstchunk < 2; dstchunk++) {
+ struct ib_sge *sge =
+ wr_rdma_buf->wr_tx_rdma[dstchunk].wr.sg_list;
+
num_sges = 0;
for (srcchunk = 0; srcchunk < 2; srcchunk++) {
- sges[srcchunk].addr = dma_addr + src_off;
- sges[srcchunk].length = src_len;
- sges[srcchunk].lkey = link->roce_pd->local_dma_lkey;
+ sge[srcchunk].addr = dma_addr + src_off;
+ sge[srcchunk].length = src_len;
num_sges++;
src_off += src_len;
@@ -343,7 +340,8 @@ static int smcr_tx_rdma_writes(struct smc_connection *conn, size_t len,
src_len = dst_len - src_len; /* remainder */
src_len_sum += src_len;
}
- rc = smc_tx_rdma_write(conn, dst_off, num_sges, sges);
+ rc = smc_tx_rdma_write(conn, dst_off, num_sges,
+ &wr_rdma_buf->wr_tx_rdma[dstchunk]);
if (rc)
return rc;
if (dst_len_sum == len)
@@ -402,7 +400,8 @@ static int smcd_tx_rdma_writes(struct smc_connection *conn, size_t len,
/* sndbuf consumer: prepare all necessary (src&dst) chunks of data transmit;
* usable snd_wnd as max transmit
*/
-static int smc_tx_rdma_writes(struct smc_connection *conn)
+static int smc_tx_rdma_writes(struct smc_connection *conn,
+ struct smc_rdma_wr *wr_rdma_buf)
{
size_t len, src_len, dst_off, dst_len; /* current chunk values */
union smc_host_cursor sent, prep, prod, cons;
@@ -463,7 +462,7 @@ static int smc_tx_rdma_writes(struct smc_connection *conn)
dst_off, dst_len);
else
rc = smcr_tx_rdma_writes(conn, len, sent.count, src_len,
- dst_off, dst_len);
+ dst_off, dst_len, wr_rdma_buf);
if (rc)
return rc;
@@ -484,11 +483,12 @@ static int smc_tx_rdma_writes(struct smc_connection *conn)
static int smcr_tx_sndbuf_nonempty(struct smc_connection *conn)
{
struct smc_cdc_producer_flags *pflags;
+ struct smc_rdma_wr *wr_rdma_buf;
struct smc_cdc_tx_pend *pend;
struct smc_wr_buf *wr_buf;
int rc;
- rc = smc_cdc_get_free_slot(conn, &wr_buf, &pend);
+ rc = smc_cdc_get_free_slot(conn, &wr_buf, &wr_rdma_buf, &pend);
if (rc < 0) {
if (rc == -EBUSY) {
struct smc_sock *smc =
@@ -506,7 +506,7 @@ static int smcr_tx_sndbuf_nonempty(struct smc_connection *conn)
spin_lock_bh(&conn->send_lock);
if (!conn->local_tx_ctrl.prod_flags.urg_data_present) {
- rc = smc_tx_rdma_writes(conn);
+ rc = smc_tx_rdma_writes(conn, wr_rdma_buf);
if (rc) {
smc_wr_tx_put_slot(&conn->lgr->lnk[SMC_SINGLE_LINK],
(struct smc_wr_tx_pend_priv *)pend);
@@ -533,7 +533,7 @@ static int smcd_tx_sndbuf_nonempty(struct smc_connection *conn)
spin_lock_bh(&conn->send_lock);
if (!pflags->urg_data_present)
- rc = smc_tx_rdma_writes(conn);
+ rc = smc_tx_rdma_writes(conn, NULL);
if (!rc)
rc = smcd_cdc_msg_send(conn);
diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c
index 1dc88c32d6bb..253aa75dc2b6 100644
--- a/net/smc/smc_wr.c
+++ b/net/smc/smc_wr.c
@@ -160,6 +160,7 @@ static inline int smc_wr_tx_get_free_slot_index(struct smc_link *link, u32 *idx)
* @link: Pointer to smc_link used to later send the message.
* @handler: Send completion handler function pointer.
* @wr_buf: Out value returns pointer to message buffer.
+ * @wr_rdma_buf: Out value returns pointer to rdma work request.
* @wr_pend_priv: Out value returns pointer serving as handler context.
*
* Return: 0 on success, or -errno on error.
@@ -167,6 +168,7 @@ static inline int smc_wr_tx_get_free_slot_index(struct smc_link *link, u32 *idx)
int smc_wr_tx_get_free_slot(struct smc_link *link,
smc_wr_tx_handler handler,
struct smc_wr_buf **wr_buf,
+ struct smc_rdma_wr **wr_rdma_buf,
struct smc_wr_tx_pend_priv **wr_pend_priv)
{
struct smc_wr_tx_pend *wr_pend;
@@ -204,6 +206,8 @@ int smc_wr_tx_get_free_slot(struct smc_link *link,
wr_ib = &link->wr_tx_ibs[idx];
wr_ib->wr_id = wr_id;
*wr_buf = &link->wr_tx_bufs[idx];
+ if (wr_rdma_buf)
+ *wr_rdma_buf = &link->wr_tx_rdmas[idx];
*wr_pend_priv = &wr_pend->priv;
return 0;
}
@@ -465,12 +469,26 @@ static void smc_wr_init_sge(struct smc_link *lnk)
lnk->wr_tx_dma_addr + i * SMC_WR_BUF_SIZE;
lnk->wr_tx_sges[i].length = SMC_WR_TX_SIZE;
lnk->wr_tx_sges[i].lkey = lnk->roce_pd->local_dma_lkey;
+ lnk->wr_tx_rdma_sges[i].tx_rdma_sge[0].wr_tx_rdma_sge[0].lkey =
+ lnk->roce_pd->local_dma_lkey;
+ lnk->wr_tx_rdma_sges[i].tx_rdma_sge[0].wr_tx_rdma_sge[1].lkey =
+ lnk->roce_pd->local_dma_lkey;
+ lnk->wr_tx_rdma_sges[i].tx_rdma_sge[1].wr_tx_rdma_sge[0].lkey =
+ lnk->roce_pd->local_dma_lkey;
+ lnk->wr_tx_rdma_sges[i].tx_rdma_sge[1].wr_tx_rdma_sge[1].lkey =
+ lnk->roce_pd->local_dma_lkey;
lnk->wr_tx_ibs[i].next = NULL;
lnk->wr_tx_ibs[i].sg_list = &lnk->wr_tx_sges[i];
lnk->wr_tx_ibs[i].num_sge = 1;
lnk->wr_tx_ibs[i].opcode = IB_WR_SEND;
lnk->wr_tx_ibs[i].send_flags =
IB_SEND_SIGNALED | IB_SEND_SOLICITED;
+ lnk->wr_tx_rdmas[i].wr_tx_rdma[0].wr.opcode = IB_WR_RDMA_WRITE;
+ lnk->wr_tx_rdmas[i].wr_tx_rdma[1].wr.opcode = IB_WR_RDMA_WRITE;
+ lnk->wr_tx_rdmas[i].wr_tx_rdma[0].wr.sg_list =
+ lnk->wr_tx_rdma_sges[i].tx_rdma_sge[0].wr_tx_rdma_sge;
+ lnk->wr_tx_rdmas[i].wr_tx_rdma[1].wr.sg_list =
+ lnk->wr_tx_rdma_sges[i].tx_rdma_sge[1].wr_tx_rdma_sge;
}
for (i = 0; i < lnk->wr_rx_cnt; i++) {
lnk->wr_rx_sges[i].addr =
@@ -521,8 +539,12 @@ void smc_wr_free_link_mem(struct smc_link *lnk)
lnk->wr_tx_mask = NULL;
kfree(lnk->wr_tx_sges);
lnk->wr_tx_sges = NULL;
+ kfree(lnk->wr_tx_rdma_sges);
+ lnk->wr_tx_rdma_sges = NULL;
kfree(lnk->wr_rx_sges);
lnk->wr_rx_sges = NULL;
+ kfree(lnk->wr_tx_rdmas);
+ lnk->wr_tx_rdmas = NULL;
kfree(lnk->wr_rx_ibs);
lnk->wr_rx_ibs = NULL;
kfree(lnk->wr_tx_ibs);
@@ -552,10 +574,20 @@ int smc_wr_alloc_link_mem(struct smc_link *link)
GFP_KERNEL);
if (!link->wr_rx_ibs)
goto no_mem_wr_tx_ibs;
+ link->wr_tx_rdmas = kcalloc(SMC_WR_BUF_CNT,
+ sizeof(link->wr_tx_rdmas[0]),
+ GFP_KERNEL);
+ if (!link->wr_tx_rdmas)
+ goto no_mem_wr_rx_ibs;
+ link->wr_tx_rdma_sges = kcalloc(SMC_WR_BUF_CNT,
+ sizeof(link->wr_tx_rdma_sges[0]),
+ GFP_KERNEL);
+ if (!link->wr_tx_rdma_sges)
+ goto no_mem_wr_tx_rdmas;
link->wr_tx_sges = kcalloc(SMC_WR_BUF_CNT, sizeof(link->wr_tx_sges[0]),
GFP_KERNEL);
if (!link->wr_tx_sges)
- goto no_mem_wr_rx_ibs;
+ goto no_mem_wr_tx_rdma_sges;
link->wr_rx_sges = kcalloc(SMC_WR_BUF_CNT * 3,
sizeof(link->wr_rx_sges[0]),
GFP_KERNEL);
@@ -579,6 +611,10 @@ int smc_wr_alloc_link_mem(struct smc_link *link)
kfree(link->wr_rx_sges);
no_mem_wr_tx_sges:
kfree(link->wr_tx_sges);
+no_mem_wr_tx_rdma_sges:
+ kfree(link->wr_tx_rdma_sges);
+no_mem_wr_tx_rdmas:
+ kfree(link->wr_tx_rdmas);
no_mem_wr_rx_ibs:
kfree(link->wr_rx_ibs);
no_mem_wr_tx_ibs:
diff --git a/net/smc/smc_wr.h b/net/smc/smc_wr.h
index 1d85bb14fd6f..09bf32fd3959 100644
--- a/net/smc/smc_wr.h
+++ b/net/smc/smc_wr.h
@@ -85,6 +85,7 @@ void smc_wr_add_dev(struct smc_ib_device *smcibdev);
int smc_wr_tx_get_free_slot(struct smc_link *link, smc_wr_tx_handler handler,
struct smc_wr_buf **wr_buf,
+ struct smc_rdma_wr **wrs,
struct smc_wr_tx_pend_priv **wr_pend_priv);
int smc_wr_tx_put_slot(struct smc_link *link,
struct smc_wr_tx_pend_priv *wr_pend_priv);
--
2.16.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH net 2/4] net/smc: fix sender_free computation
2019-02-04 12:44 [PATCH net 0/4] net/smc: fixes 2019-02-04 Ursula Braun
2019-02-04 12:44 ` [PATCH net 1/4] net/smc: preallocated memory for rdma work requests Ursula Braun
@ 2019-02-04 12:44 ` Ursula Braun
2019-02-04 12:44 ` [PATCH net 3/4] net/smc: delete rkey first before switching to unused Ursula Braun
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Ursula Braun @ 2019-02-04 12:44 UTC (permalink / raw)
To: davem
Cc: netdev, linux-s390, linux-rdma, schwidefsky, heiko.carstens,
raspl, ubraun
In some scenarios a separate consumer cursor update is necessary.
The decision is made in smc_tx_consumer_cursor_update(). The
sender_free computation could be wrong:
The rx confirmed cursor is always smaller than or equal to the
rx producer cursor. The parameters in the smc_curs_diff() call
have to be exchanged, otherwise sender_free might even be negative.
And if more data arrives local_rx_ctrl.prod might be updated, enabling
a cursor difference between local_rx_ctrl.prod and rx confirmed cursor
larger than the RMB size. This case is not covered by smc_curs_diff().
Thus function smc_curs_diff_large() is introduced here.
If a recvmsg() is processed in parallel, local_tx_ctrl.cons might
change during smc_cdc_msg_send. Make sure rx_curs_confirmed is updated
with the actually sent local_tx_ctrl.cons value.
Fixes: e82f2e31f559 ("net/smc: optimize consumer cursor updates")
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
---
net/smc/smc_cdc.c | 5 +++--
net/smc/smc_cdc.h | 26 +++++++++++++++++++++++++-
net/smc/smc_tx.c | 3 ++-
3 files changed, 30 insertions(+), 4 deletions(-)
diff --git a/net/smc/smc_cdc.c b/net/smc/smc_cdc.c
index b80ef104ab4e..a712c9f8699b 100644
--- a/net/smc/smc_cdc.c
+++ b/net/smc/smc_cdc.c
@@ -91,6 +91,7 @@ int smc_cdc_msg_send(struct smc_connection *conn,
struct smc_wr_buf *wr_buf,
struct smc_cdc_tx_pend *pend)
{
+ union smc_host_cursor cfed;
struct smc_link *link;
int rc;
@@ -102,10 +103,10 @@ int smc_cdc_msg_send(struct smc_connection *conn,
conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf,
&conn->local_tx_ctrl, conn);
+ smc_curs_copy(&cfed, &((struct smc_host_cdc_msg *)wr_buf)->cons, conn);
rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
if (!rc)
- smc_curs_copy(&conn->rx_curs_confirmed,
- &conn->local_tx_ctrl.cons, conn);
+ smc_curs_copy(&conn->rx_curs_confirmed, &cfed, conn);
return rc;
}
diff --git a/net/smc/smc_cdc.h b/net/smc/smc_cdc.h
index 2148da7a26b1..271e2524dc8f 100644
--- a/net/smc/smc_cdc.h
+++ b/net/smc/smc_cdc.h
@@ -160,7 +160,9 @@ static inline void smcd_curs_copy(union smcd_cdc_cursor *tgt,
#endif
}
-/* calculate cursor difference between old and new, where old <= new */
+/* calculate cursor difference between old and new, where old <= new and
+ * difference cannot exceed size
+ */
static inline int smc_curs_diff(unsigned int size,
union smc_host_cursor *old,
union smc_host_cursor *new)
@@ -185,6 +187,28 @@ static inline int smc_curs_comp(unsigned int size,
return smc_curs_diff(size, old, new);
}
+/* calculate cursor difference between old and new, where old <= new and
+ * difference may exceed size
+ */
+static inline int smc_curs_diff_large(unsigned int size,
+ union smc_host_cursor *old,
+ union smc_host_cursor *new)
+{
+ if (old->wrap < new->wrap)
+ return min_t(int,
+ (size - old->count) + new->count +
+ (new->wrap - old->wrap - 1) * size,
+ size);
+
+ if (old->wrap > new->wrap) /* wrap has switched from 0xffff to 0x0000 */
+ return min_t(int,
+ (size - old->count) + new->count +
+ (new->wrap + 0xffff - old->wrap) * size,
+ size);
+
+ return max_t(int, 0, (new->count - old->count));
+}
+
static inline void smc_host_cursor_to_cdc(union smc_cdc_cursor *peer,
union smc_host_cursor *local,
struct smc_connection *conn)
diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c
index 2fdfaff60cf9..f93f3580c100 100644
--- a/net/smc/smc_tx.c
+++ b/net/smc/smc_tx.c
@@ -595,7 +595,8 @@ void smc_tx_consumer_update(struct smc_connection *conn, bool force)
if (to_confirm > conn->rmbe_update_limit) {
smc_curs_copy(&prod, &conn->local_rx_ctrl.prod, conn);
sender_free = conn->rmb_desc->len -
- smc_curs_diff(conn->rmb_desc->len, &prod, &cfed);
+ smc_curs_diff_large(conn->rmb_desc->len,
+ &cfed, &prod);
}
if (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
--
2.16.4
^ permalink raw reply related [flat|nested] 6+ messages in thread