From ab49de0f7a08c442ebdc097f6701e8bc4db6b432 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 17 Oct 2024 02:50:16 -0700 Subject: [PATCH 1/9] net: netconsole: remove msg_ready variable Variable msg_ready is useless, since it does not represent anything. Get rid of it, using buf directly instead. Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: Paolo Abeni --- drivers/net/netconsole.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index de20928f74021..a006507c92c6f 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -1075,7 +1075,6 @@ static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg, const char *header, *body; int offset = 0; int header_len, body_len; - const char *msg_ready = msg; const char *release; int release_len = 0; int userdata_len = 0; @@ -1105,8 +1104,7 @@ static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg, MAX_PRINT_CHUNK - msg_len, "%s", userdata); - msg_ready = buf; - netpoll_send_udp(&nt->np, msg_ready, msg_len); + netpoll_send_udp(&nt->np, buf, msg_len); return; } From e7650d8d475c4706a1841fbaab652e1fc8a7313c Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 17 Oct 2024 02:50:17 -0700 Subject: [PATCH 2/9] net: netconsole: split send_ext_msg_udp() function MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The send_ext_msg_udp() function has become quite large, currently spanning 102 lines. Its complexity, along with extensive pointer and offset manipulation, makes it difficult to read and error-prone. The function has evolved over time, and it’s now due for a refactor. To improve readability and maintainability, isolate the case where no message fragmentation occurs into a separate function, into a new send_msg_no_fragmentation() function. This scenario covers about 95% of the messages. Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: Paolo Abeni --- drivers/net/netconsole.c | 46 +++++++++++++++++++++++++--------------- 1 file changed, 29 insertions(+), 17 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index a006507c92c6f..23fe9edff26ed 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -1058,6 +1058,32 @@ static struct notifier_block netconsole_netdev_notifier = { .notifier_call = netconsole_netdev_event, }; +static void send_msg_no_fragmentation(struct netconsole_target *nt, + const char *msg, + const char *userdata, + int msg_len, + int release_len) +{ + static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */ + const char *release; + + if (release_len) { + release = init_utsname()->release; + + scnprintf(buf, MAX_PRINT_CHUNK, "%s,%s", release, msg); + msg_len += release_len; + } else { + memcpy(buf, msg, msg_len); + } + + if (userdata) + msg_len += scnprintf(&buf[msg_len], + MAX_PRINT_CHUNK - msg_len, + "%s", userdata); + + netpoll_send_udp(&nt->np, buf, msg_len); +} + /** * send_ext_msg_udp - send extended log message to target * @nt: target to send message to @@ -1090,23 +1116,9 @@ static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg, release_len = strlen(release) + 1; } - if (msg_len + release_len + userdata_len <= MAX_PRINT_CHUNK) { - /* No fragmentation needed */ - if (nt->release) { - scnprintf(buf, MAX_PRINT_CHUNK, "%s,%s", release, msg); - msg_len += release_len; - } else { - memcpy(buf, msg, msg_len); - } - - if (userdata) - msg_len += scnprintf(&buf[msg_len], - MAX_PRINT_CHUNK - msg_len, - "%s", userdata); - - netpoll_send_udp(&nt->np, buf, msg_len); - return; - } + if (msg_len + release_len + userdata_len <= MAX_PRINT_CHUNK) + return send_msg_no_fragmentation(nt, msg, userdata, msg_len, + release_len); /* need to insert extra header fields, detect header and body */ header = msg; From e1e1ea2e78e8a7f326866b136b820d3ba73a8ba2 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 17 Oct 2024 02:50:18 -0700 Subject: [PATCH 3/9] net: netconsole: separate fragmented message handling in send_ext_msg Following the previous change, where the non-fragmented case was moved to its own function, this update introduces a new function called send_msg_fragmented to specifically manage scenarios where message fragmentation is required. Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: Paolo Abeni --- drivers/net/netconsole.c | 76 +++++++++++++++++++++++++--------------- 1 file changed, 48 insertions(+), 28 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 23fe9edff26ed..6e916131c061a 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -1084,42 +1084,23 @@ static void send_msg_no_fragmentation(struct netconsole_target *nt, netpoll_send_udp(&nt->np, buf, msg_len); } -/** - * send_ext_msg_udp - send extended log message to target - * @nt: target to send message to - * @msg: extended log message to send - * @msg_len: length of message - * - * Transfer extended log @msg to @nt. If @msg is longer than - * MAX_PRINT_CHUNK, it'll be split and transmitted in multiple chunks with - * ncfrag header field added to identify them. - */ -static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg, - int msg_len) +static void send_msg_fragmented(struct netconsole_target *nt, + const char *msg, + const char *userdata, + int msg_len, + int release_len) { static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */ + int offset = 0, userdata_len = 0; const char *header, *body; - int offset = 0; int header_len, body_len; const char *release; - int release_len = 0; - int userdata_len = 0; - char *userdata = NULL; #ifdef CONFIG_NETCONSOLE_DYNAMIC - userdata = nt->userdata_complete; - userdata_len = nt->userdata_length; + if (userdata) + userdata_len = nt->userdata_length; #endif - if (nt->release) { - release = init_utsname()->release; - release_len = strlen(release) + 1; - } - - if (msg_len + release_len + userdata_len <= MAX_PRINT_CHUNK) - return send_msg_no_fragmentation(nt, msg, userdata, msg_len, - release_len); - /* need to insert extra header fields, detect header and body */ header = msg; body = memchr(msg, ';', msg_len); @@ -1134,11 +1115,18 @@ static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg, * Transfer multiple chunks with the following extra header. * "ncfrag=/" */ - if (nt->release) + if (release_len) { + release = init_utsname()->release; scnprintf(buf, MAX_PRINT_CHUNK, "%s,", release); + } + + /* Copy the header into the buffer */ memcpy(buf + release_len, header, header_len); header_len += release_len; + /* for now on, the header will be persisted, and the body + * will be replaced + */ while (offset < body_len + userdata_len) { int this_header = header_len; int this_offset = 0; @@ -1190,6 +1178,38 @@ static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg, } } +/** + * send_ext_msg_udp - send extended log message to target + * @nt: target to send message to + * @msg: extended log message to send + * @msg_len: length of message + * + * Transfer extended log @msg to @nt. If @msg is longer than + * MAX_PRINT_CHUNK, it'll be split and transmitted in multiple chunks with + * ncfrag header field added to identify them. + */ +static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg, + int msg_len) +{ + char *userdata = NULL; + int userdata_len = 0; + int release_len = 0; + +#ifdef CONFIG_NETCONSOLE_DYNAMIC + userdata = nt->userdata_complete; + userdata_len = nt->userdata_length; +#endif + + if (nt->release) + release_len = strlen(init_utsname()->release) + 1; + + if (msg_len + release_len + userdata_len <= MAX_PRINT_CHUNK) + return send_msg_no_fragmentation(nt, msg, userdata, msg_len, + release_len); + + return send_msg_fragmented(nt, msg, userdata, msg_len, release_len); +} + static void write_ext_msg(struct console *con, const char *msg, unsigned int len) { From e1fa5d23b2c02f265f3111f4aa0a6b6b47da80a0 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 17 Oct 2024 02:50:19 -0700 Subject: [PATCH 4/9] net: netconsole: rename body to msg_body With the introduction of the userdata concept, the term body has become ambiguous and less intuitive. To improve clarity, body is renamed to msg_body, making it clear that the body is not the only content following the header. In an upcoming patch, the term body_len will also be revised for further clarity. The current packet structure is as follows: release, header, body, [msg_body + userdata] Here, [msg_body + userdata] collectively forms what is currently referred to as "body." This renaming helps to distinguish and better understand each component of the packet. Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: Paolo Abeni --- drivers/net/netconsole.c | 41 ++++++++++++++++++++-------------------- 1 file changed, 21 insertions(+), 20 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 6e916131c061a..3f59b841d659c 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -1092,8 +1092,8 @@ static void send_msg_fragmented(struct netconsole_target *nt, { static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */ int offset = 0, userdata_len = 0; - const char *header, *body; - int header_len, body_len; + const char *header, *msgbody; + int header_len, msgbody_len; const char *release; #ifdef CONFIG_NETCONSOLE_DYNAMIC @@ -1101,15 +1101,15 @@ static void send_msg_fragmented(struct netconsole_target *nt, userdata_len = nt->userdata_length; #endif - /* need to insert extra header fields, detect header and body */ + /* need to insert extra header fields, detect header and msgbody */ header = msg; - body = memchr(msg, ';', msg_len); - if (WARN_ON_ONCE(!body)) + msgbody = memchr(msg, ';', msg_len); + if (WARN_ON_ONCE(!msgbody)) return; - header_len = body - header; - body_len = msg_len - header_len - 1; - body++; + header_len = msgbody - header; + msgbody_len = msg_len - header_len - 1; + msgbody++; /* * Transfer multiple chunks with the following extra header. @@ -1124,10 +1124,10 @@ static void send_msg_fragmented(struct netconsole_target *nt, memcpy(buf + release_len, header, header_len); header_len += release_len; - /* for now on, the header will be persisted, and the body + /* for now on, the header will be persisted, and the msgbody * will be replaced */ - while (offset < body_len + userdata_len) { + while (offset < msgbody_len + userdata_len) { int this_header = header_len; int this_offset = 0; int this_chunk = 0; @@ -1135,23 +1135,24 @@ static void send_msg_fragmented(struct netconsole_target *nt, this_header += scnprintf(buf + this_header, sizeof(buf) - this_header, ",ncfrag=%d/%d;", offset, - body_len + userdata_len); + msgbody_len + userdata_len); - /* Not all body data has been written yet */ - if (offset < body_len) { - this_chunk = min(body_len - offset, + /* Not all msgbody data has been written yet */ + if (offset < msgbody_len) { + this_chunk = min(msgbody_len - offset, MAX_PRINT_CHUNK - this_header); if (WARN_ON_ONCE(this_chunk <= 0)) return; - memcpy(buf + this_header, body + offset, this_chunk); + memcpy(buf + this_header, msgbody + offset, this_chunk); this_offset += this_chunk; } - /* Body is fully written and there is pending userdata to write, - * append userdata in this chunk + + /* Msg body is fully written and there is pending userdata to + * write, append userdata in this chunk */ - if (offset + this_offset >= body_len && - offset + this_offset < userdata_len + body_len) { - int sent_userdata = (offset + this_offset) - body_len; + if (offset + this_offset >= msgbody_len && + offset + this_offset < userdata_len + msgbody_len) { + int sent_userdata = (offset + this_offset) - msgbody_len; int preceding_bytes = this_chunk + this_header; if (WARN_ON_ONCE(sent_userdata < 0)) From 606994ad2695ca3ffcab3494d7782c45d964c6f7 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 17 Oct 2024 02:50:20 -0700 Subject: [PATCH 5/9] net: netconsole: introduce variable to track body length This new variable tracks the total length of the data to be sent, encompassing both the message body (msgbody) and userdata, which is collectively called body. By explicitly defining body_len, the code becomes clearer and easier to reason about, simplifying offset calculations and improving overall readability of the function. Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: Paolo Abeni --- drivers/net/netconsole.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 3f59b841d659c..6a6806eeb0c65 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -1090,10 +1090,10 @@ static void send_msg_fragmented(struct netconsole_target *nt, int msg_len, int release_len) { + 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 *header, *msgbody; - int header_len, msgbody_len; const char *release; #ifdef CONFIG_NETCONSOLE_DYNAMIC @@ -1124,10 +1124,11 @@ static void send_msg_fragmented(struct netconsole_target *nt, 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 */ - while (offset < msgbody_len + userdata_len) { + while (offset < body_len) { int this_header = header_len; int this_offset = 0; int this_chunk = 0; @@ -1135,7 +1136,7 @@ static void send_msg_fragmented(struct netconsole_target *nt, this_header += scnprintf(buf + this_header, sizeof(buf) - this_header, ",ncfrag=%d/%d;", offset, - msgbody_len + userdata_len); + body_len); /* Not all msgbody data has been written yet */ if (offset < msgbody_len) { @@ -1151,7 +1152,7 @@ static void send_msg_fragmented(struct netconsole_target *nt, * write, append userdata in this chunk */ if (offset + this_offset >= msgbody_len && - offset + this_offset < userdata_len + msgbody_len) { + offset + this_offset < body_len) { int sent_userdata = (offset + this_offset) - msgbody_len; int preceding_bytes = this_chunk + this_header; From b8dee8ed13b83b701b715dac993582d57c76e31a Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 17 Oct 2024 02:50:21 -0700 Subject: [PATCH 6/9] net: netconsole: track explicitly if msgbody was written to buffer The current check to determine if the message body was fully sent is difficult to follow. To improve clarity, introduce a variable that explicitly tracks whether the message body (msgbody) has been completely sent, indicating when it's time to begin sending userdata. Additionally, add comments to make the code more understandable for others who may work with it. Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: Paolo Abeni --- drivers/net/netconsole.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 6a6806eeb0c65..9a5cca4ee8b8b 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -1130,6 +1130,7 @@ static void send_msg_fragmented(struct netconsole_target *nt, */ while (offset < body_len) { int this_header = header_len; + bool msgbody_written = false; int this_offset = 0; int this_chunk = 0; @@ -1148,12 +1149,21 @@ static void send_msg_fragmented(struct netconsole_target *nt, this_offset += this_chunk; } + /* msgbody was finally written, either in the previous + * messages and/or in the current buf. Time to write + * the userdata. + */ + msgbody_written |= offset + this_offset >= msgbody_len; + /* Msg body is fully written and there is pending userdata to * write, append userdata in this chunk */ - if (offset + this_offset >= msgbody_len && - offset + this_offset < body_len) { + if (msgbody_written && offset + this_offset < body_len) { + /* Track how much user data was already sent. First + * time here, sent_userdata is zero + */ int sent_userdata = (offset + this_offset) - msgbody_len; + /* offset of bytes used in current buf */ int preceding_bytes = this_chunk + this_header; if (WARN_ON_ONCE(sent_userdata < 0)) From 684dce1f9984f749f109407fb24e4d435b6de829 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 17 Oct 2024 02:50:22 -0700 Subject: [PATCH 7/9] net: netconsole: extract release appending into separate function Refactor the code by extracting the logic for appending the release into the buffer into a separate function. The goal is to reduce the size of send_msg_fragmented() and improve code readability. Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: Paolo Abeni --- drivers/net/netconsole.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 9a5cca4ee8b8b..e86a857bc166a 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -1084,6 +1084,14 @@ static void send_msg_no_fragmentation(struct netconsole_target *nt, netpoll_send_udp(&nt->np, buf, msg_len); } +static void append_release(char *buf) +{ + const char *release; + + release = init_utsname()->release; + scnprintf(buf, MAX_PRINT_CHUNK, "%s,", release); +} + static void send_msg_fragmented(struct netconsole_target *nt, const char *msg, const char *userdata, @@ -1094,7 +1102,6 @@ static void send_msg_fragmented(struct netconsole_target *nt, static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */ int offset = 0, userdata_len = 0; const char *header, *msgbody; - const char *release; #ifdef CONFIG_NETCONSOLE_DYNAMIC if (userdata) @@ -1115,10 +1122,8 @@ static void send_msg_fragmented(struct netconsole_target *nt, * Transfer multiple chunks with the following extra header. * "ncfrag=/" */ - if (release_len) { - release = init_utsname()->release; - scnprintf(buf, MAX_PRINT_CHUNK, "%s,", release); - } + if (release_len) + append_release(buf); /* Copy the header into the buffer */ memcpy(buf + release_len, header, header_len); From 144d57360f5e9af7a836dcc33d12560de90a7d9d Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 17 Oct 2024 02:50:23 -0700 Subject: [PATCH 8/9] net: netconsole: do not pass userdata up to the tail Do not pass userdata to send_msg_fragmented, since we can get it later. This will be more useful in the next patch, where send_msg_fragmented() will be split even more, and userdata is only necessary in the last function. Suggested-by: Simon Horman Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: Paolo Abeni --- drivers/net/netconsole.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index e86a857bc166a..b04d86fcea8ff 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -1060,13 +1060,17 @@ static struct notifier_block netconsole_netdev_notifier = { static void send_msg_no_fragmentation(struct netconsole_target *nt, const char *msg, - const char *userdata, int msg_len, int release_len) { static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */ + const char *userdata = NULL; const char *release; +#ifdef CONFIG_NETCONSOLE_DYNAMIC + userdata = nt->userdata_complete; +#endif + if (release_len) { release = init_utsname()->release; @@ -1094,7 +1098,6 @@ static void append_release(char *buf) static void send_msg_fragmented(struct netconsole_target *nt, const char *msg, - const char *userdata, int msg_len, int release_len) { @@ -1102,10 +1105,11 @@ static void send_msg_fragmented(struct netconsole_target *nt, static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */ int offset = 0, userdata_len = 0; const char *header, *msgbody; + const char *userdata = NULL; #ifdef CONFIG_NETCONSOLE_DYNAMIC - if (userdata) - userdata_len = nt->userdata_length; + userdata = nt->userdata_complete; + userdata_len = nt->userdata_length; #endif /* need to insert extra header fields, detect header and msgbody */ @@ -1208,12 +1212,10 @@ static void send_msg_fragmented(struct netconsole_target *nt, static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg, int msg_len) { - char *userdata = NULL; int userdata_len = 0; int release_len = 0; #ifdef CONFIG_NETCONSOLE_DYNAMIC - userdata = nt->userdata_complete; userdata_len = nt->userdata_length; #endif @@ -1221,10 +1223,9 @@ static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg, release_len = strlen(init_utsname()->release) + 1; if (msg_len + release_len + userdata_len <= MAX_PRINT_CHUNK) - return send_msg_no_fragmentation(nt, msg, userdata, msg_len, - release_len); + return send_msg_no_fragmentation(nt, msg, msg_len, release_len); - return send_msg_fragmented(nt, msg, userdata, msg_len, release_len); + return send_msg_fragmented(nt, msg, msg_len, release_len); } static void write_ext_msg(struct console *con, const char *msg, From 60be416c6380c2098126b126ef918237b40815f7 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 17 Oct 2024 02:50:24 -0700 Subject: [PATCH 9/9] net: netconsole: split send_msg_fragmented 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 Signed-off-by: Paolo Abeni --- drivers/net/netconsole.c | 81 +++++++++++++++++++++++++--------------- 1 file changed, 50 insertions(+), 31 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index b04d86fcea8ff..4ea44a2f48f7b 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -1096,46 +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) { - 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 *header, *msgbody; 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; @@ -1144,7 +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); @@ -1199,6 +1183,41 @@ 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