On 10/12/23 4:37 AM, Wenjia Zhang wrote:
On 11.10.23 09:33, D. Wythe wrote:From: "D. Wythe" <alibuda@xxxxxxxxxxxxxxxxx> This patch re-fix the issues memtianed by commit 22a825c541d7 ("net/smc: fix NULL sndbuf_desc in smc_cdc_tx_handler()"). Blocking sending message do solve the issues though, but it also prevents the peer to receive the final message. Besides, in logic, whether the sndbuf_desc is NULL or not have no impact on the processing of cdc message sending.Agree.Hence that, this patch allow the cdc message sending but to check the sndbuf_desc with care in smc_cdc_tx_handler().Fixes: 22a825c541d7 ("net/smc: fix NULL sndbuf_desc in smc_cdc_tx_handler()")Signed-off-by: D. Wythe <alibuda@xxxxxxxxxxxxxxxxx> --- net/smc/smc_cdc.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/net/smc/smc_cdc.c b/net/smc/smc_cdc.c index 01bdb79..3c06625 100644 --- a/net/smc/smc_cdc.c +++ b/net/smc/smc_cdc.c@@ -28,13 +28,15 @@ static void smc_cdc_tx_handler(struct smc_wr_tx_pend_priv *pnd_snd,{struct smc_cdc_tx_pend *cdcpend = (struct smc_cdc_tx_pend *)pnd_snd;struct smc_connection *conn = cdcpend->conn; + struct smc_buf_desc *sndbuf_desc; struct smc_sock *smc; int diff; + sndbuf_desc = conn->sndbuf_desc; smc = container_of(conn, struct smc_sock, conn); bh_lock_sock(&smc->sk); - if (!wc_status) { - diff = smc_curs_diff(cdcpend->conn->sndbuf_desc->len, + if (!wc_status && sndbuf_desc) { + diff = smc_curs_diff(sndbuf_desc->len,How could this guarantee that the sndbuf_desc would not be NULL?
It can not guarantee he sndbuf_desc would not be NULL, but it will prevents
the smc_cdc_tx_handler() to access a NULL sndbuf_desc. So that we
can avoid the panic descried in commit 22a825c541d7
("net/smc: fix NULL sndbuf_desc in smc_cdc_tx_handler()").
&cdcpend->conn->tx_curs_fin, &cdcpend->cursor); /* sndbuf_space is decreased in smc_sendmsg */ @@ -114,9 +116,6 @@ int smc_cdc_msg_send(struct smc_connection *conn, union smc_host_cursor cfed; int rc; - if (unlikely(!READ_ONCE(conn->sndbuf_desc))) - return -ENOBUFS; - smc_cdc_add_pending_send(conn, pend); conn->tx_cdc_seq++;
