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[2a03:2880:30ff:71::face:b00c]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a8d25c72eb0sm458917466b.132.2024.09.10.03.04.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Sep 2024 03:04:37 -0700 (PDT) From: Breno Leitao To: kuba@kernel.org, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com Cc: thepacketgeek@gmail.com, horms@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, davej@codemonkey.org.uk, vlad.wing@gmail.com, max@kutsevol.com Subject: [PATCH net-next v3 09/10] net: netconsole: split send_msg_fragmented Date: Tue, 10 Sep 2024 03:04:04 -0700 Message-ID: <20240910100410.2690012-10-leitao@debian.org> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20240910100410.2690012-1-leitao@debian.org> References: <20240910100410.2690012-1-leitao@debian.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org Refactor the send_msg_fragmented() function by extracting the logic for sending the message body into a new function called send_fragmented_body(). Now, send_msg_fragmented() handles appending the release and header, and then delegates the task of breaking up the body and sending the fragments to send_fragmented_body(). This is the final flow now: When send_ext_msg_udp() is called to send a message, it will: - call send_msg_no_fragmentation() if no fragmentation is needed or - call send_msg_fragmented() if fragmentation is needed * send_msg_fragmented() appends the header to the buffer, which is be persisted until the function returns * call send_fragmented_body() to iterate and populate the body of the message. It will not touch the header, and it will only replace the body, writing the msgbody and/or userdata. Also add some comment to make the code easier to review. Signed-off-by: Breno Leitao Reviewed-by: Simon Horman --- drivers/net/netconsole.c | 82 +++++++++++++++++++++++++--------------- 1 file changed, 51 insertions(+), 31 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 1de547b1deb7..86473dc2963f 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -1096,45 +1096,30 @@ static void append_release(char *buf) scnprintf(buf, MAX_PRINT_CHUNK, "%s,", release); } -static void send_msg_fragmented(struct netconsole_target *nt, - const char *msg, - int msg_len, - int release_len) +static void send_fragmented_body(struct netconsole_target *nt, char *buf, + const char *msgbody, int header_len, + int msgbody_len) { - const char *header, *msgbody, *userdata; - int header_len, msgbody_len, body_len; - static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */ - int offset = 0, userdata_len = 0; + const char *userdata = NULL; + int body_len, offset = 0; + int userdata_len = 0; #ifdef CONFIG_NETCONSOLE_DYNAMIC userdata = nt->userdata_complete; userdata_len = nt->userdata_length; #endif - /* need to insert extra header fields, detect header and msgbody */ - header = msg; - msgbody = memchr(msg, ';', msg_len); - if (WARN_ON_ONCE(!msgbody)) - return; - - header_len = msgbody - header; - msgbody_len = msg_len - header_len - 1; - msgbody++; - - /* - * Transfer multiple chunks with the following extra header. - * "ncfrag=/" + /* body_len represents the number of bytes that will be sent. This is + * bigger than MAX_PRINT_CHUNK, thus, it will be split in multiple + * packets */ - if (release_len) - append_release(buf); - - /* Copy the header into the buffer */ - memcpy(buf + release_len, header, header_len); - header_len += release_len; - body_len = msgbody_len + userdata_len; - /* for now on, the header will be persisted, and the msgbody - * will be replaced + + /* In each iteration of the while loop below, we send a packet + * containing the header and a portion of the body. The body is + * composed of two parts: msgbody and userdata. We keep track of how + * many bytes have been sent so far using the offset variable, which + * ranges from 0 to the total length of the body. */ while (offset < body_len) { int this_header = header_len; @@ -1143,7 +1128,7 @@ static void send_msg_fragmented(struct netconsole_target *nt, int this_chunk = 0; this_header += scnprintf(buf + this_header, - sizeof(buf) - this_header, + MAX_PRINT_CHUNK - this_header, ",ncfrag=%d/%d;", offset, body_len); @@ -1193,6 +1178,41 @@ static void send_msg_fragmented(struct netconsole_target *nt, } } +static void send_msg_fragmented(struct netconsole_target *nt, + const char *msg, + int msg_len, + int release_len) +{ + static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */ + int header_len, msgbody_len; + const char *msgbody; + + /* need to insert extra header fields, detect header and msgbody */ + msgbody = memchr(msg, ';', msg_len); + if (WARN_ON_ONCE(!msgbody)) + return; + + header_len = msgbody - msg; + msgbody_len = msg_len - header_len - 1; + msgbody++; + + /* + * Transfer multiple chunks with the following extra header. + * "ncfrag=/" + */ + if (release_len) + append_release(buf); + + /* Copy the header into the buffer */ + memcpy(buf + release_len, msg, header_len); + header_len += release_len; + + /* for now on, the header will be persisted, and the msgbody + * will be replaced + */ + send_fragmented_body(nt, buf, msgbody, header_len, msgbody_len); +} + /** * send_ext_msg_udp - send extended log message to target * @nt: target to send message to