Commit 28a20817 authored by Wen Gu's avatar Wen Gu Committed by Zhengchao Shao
Browse files

net/smc: adapt cursor update when sndbuf and peer DMB are merged 

mainline inclusion
from mainline-v6.10-rc1
commit cc0ab806fc52e77f961b275ebb58024bd0e7adf2
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/IACM52

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cc0ab806fc52e77f961b275ebb58024bd0e7adf2



--------------------------------

If the local sndbuf shares the same physical memory with peer DMB,
the cursor update processing needs to be adapted to ensure that the
data to be consumed won't be overwritten.

So in this case, the fin_curs and sndbuf_space that were originally
updated after sending the CDC message should be modified to not be
update until the peer updates cons_curs.

Signed-off-by: default avatarWen Gu <guwen@linux.alibaba.com>
Reviewed-by: default avatarWenjia Zhang <wenjia@linux.ibm.com>
Reviewed-and-tested-by: default avatarJan Karcher <jaka@linux.ibm.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarZhengchao Shao <shaozhengchao@huawei.com>
parent 7f99bfda

net/smc/smc_cdc.c

+34 −2
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include "smc_tx.h"

#include "smc_rx.h"

#include "smc_close.h"

#include "smc_ism.h"



/********************************** send *************************************/
@@ -255,6 +256,14 @@ int smcd_cdc_msg_send(struct smc_connection *conn) 
		return rc;

	smc_curs_copy(&conn->rx_curs_confirmed, &curs, conn);

	conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;



	if (smc_ism_support_dmb_nocopy(conn->lgr->smcd))

		/* if local sndbuf shares the same memory region with

		 * peer DMB, then don't update the tx_curs_fin

		 * and sndbuf_space until peer has consumed the data.

		 */

		return 0;



	/* Calculate transmitted data and increment free send buffer space */

	diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin,

			     &conn->tx_curs_sent);
@@ -266,7 +275,7 @@ int smcd_cdc_msg_send(struct smc_connection *conn) 
	smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn);



	smc_tx_sndbuf_nonfull(smc);

	return rc;

	return 0;

}



/********************************* receive ***********************************/
@@ -323,7 +332,7 @@ static void smc_cdc_msg_recv_action(struct smc_sock *smc, 
{

	union smc_host_cursor cons_old, prod_old;

	struct smc_connection *conn = &smc->conn;

	int diff_cons, diff_prod;

	int diff_cons, diff_prod, diff_tx;



	smc_curs_copy(&prod_old, &conn->local_rx_ctrl.prod, conn);

	smc_curs_copy(&cons_old, &conn->local_rx_ctrl.cons, conn);
@@ -339,6 +348,29 @@ static void smc_cdc_msg_recv_action(struct smc_sock *smc, 
		atomic_add(diff_cons, &conn->peer_rmbe_space);

		/* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */

		smp_mb__after_atomic();



		/* if local sndbuf shares the same memory region with

		 * peer RMB, then update tx_curs_fin and sndbuf_space

		 * here since peer has already consumed the data.

		 */

		if (conn->lgr->is_smcd &&

		    smc_ism_support_dmb_nocopy(conn->lgr->smcd)) {

			/* Calculate consumed data and

			 * increment free send buffer space.

			 */

			diff_tx = smc_curs_diff(conn->sndbuf_desc->len,

						&conn->tx_curs_fin,

						&conn->local_rx_ctrl.cons);

			/* increase local sndbuf space and fin_curs */

			smp_mb__before_atomic();

			atomic_add(diff_tx, &conn->sndbuf_space);

			/* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */

			smp_mb__after_atomic();

			smc_curs_copy(&conn->tx_curs_fin,

				      &conn->local_rx_ctrl.cons, conn);



			smc_tx_sndbuf_nonfull(smc);

		}

	}



	diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old,