[PATCH net-next 05/12] net/smc: wait for departure of an IB message

Karsten Graul
2020-05-04T12:19:15Z

Introduce smc_wr_tx_send_wait() to send an IB message and wait for the
tx completion event of the message. This makes sure that the message is
no longer in-flight when the function returns.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
---
net/smc/smc_core.h | 1 +
net/smc/smc_wr.c | 39 +++++++++++++++++++++++++++++++++++++++
net/smc/smc_wr.h | 2 ++
3 files changed, 42 insertions(+)

diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index 584f11230c4f..86eebbadc8f6 100644
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -85,6 +85,7 @@ struct smc_link {
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 */
+ struct completion *wr_tx_compl; /* WR send CQE completion */
/* 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 */
atomic_long_t wr_tx_id; /* seq # of last sent WR */
diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c
index 3fd27bea4f7a..7239ba9b99dc 100644
--- a/net/smc/smc_wr.c
+++ b/net/smc/smc_wr.c
@@ -44,6 +44,7 @@ struct smc_wr_tx_pend { /* control data for a pending send request */
struct smc_link *link;
u32 idx;
struct smc_wr_tx_pend_priv priv;
+ u8 compl_requested;
};

/******************************** send queue *********************************/
@@ -103,6 +104,8 @@ static inline void smc_wr_tx_process_cqe(struct ib_wc *wc)
if (pnd_snd_idx == link->wr_tx_cnt)
return;
link->wr_tx_pends[pnd_snd_idx].wc_status = wc->status;
+ if (link->wr_tx_pends[pnd_snd_idx].compl_requested)
+ complete(&link->wr_tx_compl[pnd_snd_idx]);
memcpy(&pnd_snd, &link->wr_tx_pends[pnd_snd_idx], sizeof(pnd_snd));
/* clear the full struct smc_wr_tx_pend including .priv */
memset(&link->wr_tx_pends[pnd_snd_idx], 0,
@@ -275,6 +278,33 @@ int smc_wr_tx_send(struct smc_link *link, struct smc_wr_tx_pend_priv *priv)
return rc;
}

+/* Send prepared WR slot via ib_post_send and wait for send completion
+ * notification.
+ * @priv: pointer to smc_wr_tx_pend_priv identifying prepared message buffer
+ */
+int smc_wr_tx_send_wait(struct smc_link *link, struct smc_wr_tx_pend_priv *priv,
+ unsigned long timeout)
+{
+ struct smc_wr_tx_pend *pend;
+ int rc;
+
+ pend = container_of(priv, struct smc_wr_tx_pend, priv);
+ pend->compl_requested = 1;
+ init_completion(&link->wr_tx_compl[pend->idx]);
+
+ rc = smc_wr_tx_send(link, priv);
+ if (rc)
+ return rc;
+ /* wait for completion by smc_wr_tx_process_cqe() */
+ rc = wait_for_completion_interruptible_timeout(
+ &link->wr_tx_compl[pend->idx], timeout);
+ if (rc <= 0)
+ rc = -ENODATA;
+ if (rc > 0)
+ rc = 0;
+ return rc;
+}
+
/* Register a memory region and wait for result. */
int smc_wr_reg_send(struct smc_link *link, struct ib_mr *mr)
{
@@ -555,6 +585,8 @@ void smc_wr_free_link(struct smc_link *lnk)

void smc_wr_free_link_mem(struct smc_link *lnk)
{
+ kfree(lnk->wr_tx_compl);
+ lnk->wr_tx_compl = NULL;
kfree(lnk->wr_tx_pends);
lnk->wr_tx_pends = NULL;
kfree(lnk->wr_tx_mask);
@@ -625,8 +657,15 @@ int smc_wr_alloc_link_mem(struct smc_link *link)
GFP_KERNEL);
if (!link->wr_tx_pends)
goto no_mem_wr_tx_mask;
+ link->wr_tx_compl = kcalloc(SMC_WR_BUF_CNT,
+ sizeof(link->wr_tx_compl[0]),
+ GFP_KERNEL);
+ if (!link->wr_tx_compl)
+ goto no_mem_wr_tx_pends;
return 0;

+no_mem_wr_tx_pends:
+ kfree(link->wr_tx_pends);
no_mem_wr_tx_mask:
kfree(link->wr_tx_mask);
no_mem_wr_rx_sges:
diff --git a/net/smc/smc_wr.h b/net/smc/smc_wr.h
index f7eaeb3391f3..423b8709f1c9 100644
--- a/net/smc/smc_wr.h
+++ b/net/smc/smc_wr.h
@@ -101,6 +101,8 @@ int smc_wr_tx_put_slot(struct smc_link *link,
struct smc_wr_tx_pend_priv *wr_pend_priv);
int smc_wr_tx_send(struct smc_link *link,
struct smc_wr_tx_pend_priv *wr_pend_priv);
+int smc_wr_tx_send_wait(struct smc_link *link, struct smc_wr_tx_pend_priv *priv,
+ unsigned long timeout);
void smc_wr_tx_cq_handler(struct ib_cq *ib_cq, void *cq_context);
void smc_wr_tx_dismiss_slots(struct smc_link *lnk, u8 wr_rx_hdr_type,
smc_wr_tx_filter filter,
--
2.17.1