diff mbox series

[net,3/5] net/smc: allow cdc msg send rather than drop it with NULL sndbuf_desc

Message ID 1697009600-22367-4-git-send-email-alibuda@linux.alibaba.com (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series net/smc: bugfixs for smc-r | expand

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netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1363 this patch: 1363
netdev/cc_maintainers fail 1 blamed authors not CCed: tonylu@linux.alibaba.com; 4 maintainers not CCed: tonylu@linux.alibaba.com pabeni@redhat.com edumazet@google.com guwen@linux.alibaba.com
netdev/build_clang success Errors and warnings before: 1387 this patch: 1387
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netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 1387 this patch: 1387
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 26 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

D. Wythe Oct. 11, 2023, 7:33 a.m. UTC 
From: "D. Wythe" <alibuda@linux.alibaba.com>

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.

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@linux.alibaba.com>
---
 net/smc/smc_cdc.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

Comments

Wenjia Zhang Oct. 11, 2023, 8:37 p.m. UTC | #1 
On 11.10.23 09:33, D. Wythe wrote:
> From: "D. Wythe" <alibuda@linux.alibaba.com>
> 
> 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@linux.alibaba.com>
> ---
>   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?

>   				     &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++;
D. Wythe Oct. 12, 2023, 2:49 a.m. UTC | #2 
On 10/12/23 4:37 AM, Wenjia Zhang wrote:
>
>
> On 11.10.23 09:33, D. Wythe wrote:
>> From: "D. Wythe" <alibuda@linux.alibaba.com>
>>
>> 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@linux.alibaba.com>
>> ---
>>   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++;
Wenjia Zhang Oct. 12, 2023, 3:15 p.m. UTC | #3 
On 12.10.23 04:49, D. Wythe wrote:
> 
> 
> On 10/12/23 4:37 AM, Wenjia Zhang wrote:
>>
>>
>> On 11.10.23 09:33, D. Wythe wrote:
>>> From: "D. Wythe" <alibuda@linux.alibaba.com>
>>>
>>> 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@linux.alibaba.com>
>>> ---
>>>   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()").
> 
got it, thanks!

Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>

>>> &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++;
>
diff mbox series

Patch

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,
 				     &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++;