From e2dbd601346aeb64b1b387168b217fd5c301644e Mon Sep 17 00:00:00 2001 From: Erik Hugne Date: Fri, 29 Jun 2012 00:50:22 -0400 Subject: tipc: simplify print buffer handling in tipc_printf tipc_printf was previously used both to construct debug traces and to append data to buffers that should be sent over netlink to the tipc-config application. A global print_buffer was used to format the string before it was copied to the actual output buffer. This could lead to concurrent access of the global print_buffer, which then had to be lock protected. This is simplified by changing tipc_printf to append data directly to the output buffer using vscnprintf. With the new implementation of tipc_printf, there is no longer any risk of concurrent access to the internal log buffer, so the lock (and the comments describing it) are no longer strictly necessary. However, there are still a few functions that do grab this lock before resizing/dumping the log buffer. We leave the lock, and these functions untouched since they will be removed with a subsequent commit that drops the deprecated log buffer handling code Signed-off-by: Erik Hugne Signed-off-by: Jon Maloy Signed-off-by: Paul Gortmaker --- net/tipc/log.c | 52 ++++++++++------------------------------------------ 1 file changed, 10 insertions(+), 42 deletions(-) (limited to 'net/tipc/log.c') diff --git a/net/tipc/log.c b/net/tipc/log.c index 026733f24919..d01e37a61b93 100644 --- a/net/tipc/log.c +++ b/net/tipc/log.c @@ -71,21 +71,11 @@ struct print_buf *const TIPC_LOG = &log_buf; * on the caller to prevent simultaneous use of the print buffer(s) being * manipulated. */ -static char print_string[TIPC_PB_MAX_STR]; static DEFINE_SPINLOCK(print_lock); static void tipc_printbuf_move(struct print_buf *pb_to, struct print_buf *pb_from); -#define FORMAT(PTR, LEN, FMT) \ -{\ - va_list args;\ - va_start(args, FMT);\ - LEN = vsprintf(PTR, FMT, args);\ - va_end(args);\ - *(PTR + LEN) = '\0';\ -} - /** * tipc_printbuf_init - initialize print buffer to empty * @pb: pointer to print buffer structure @@ -220,39 +210,17 @@ static void tipc_printbuf_move(struct print_buf *pb_to, */ void tipc_printf(struct print_buf *pb, const char *fmt, ...) { - int chars_to_add; - int chars_left; - char save_char; - - spin_lock_bh(&print_lock); - - FORMAT(print_string, chars_to_add, fmt); - if (chars_to_add >= TIPC_PB_MAX_STR) - strcpy(print_string, "*** PRINT BUFFER STRING TOO LONG ***"); - - if (pb->buf) { - chars_left = pb->buf + pb->size - pb->crs - 1; - if (chars_to_add <= chars_left) { - strcpy(pb->crs, print_string); - pb->crs += chars_to_add; - } else if (chars_to_add >= (pb->size - 1)) { - strcpy(pb->buf, print_string + chars_to_add + 1 - - pb->size); - pb->crs = pb->buf + pb->size - 1; - } else { - strcpy(pb->buf, print_string + chars_left); - save_char = print_string[chars_left]; - print_string[chars_left] = 0; - strcpy(pb->crs, print_string); - print_string[chars_left] = save_char; - pb->crs = pb->buf + chars_to_add - chars_left; - } - } - - if (pb->echo) - printk("%s", print_string); + int i; + va_list args; + char *buf; + int len; - spin_unlock_bh(&print_lock); + buf = pb->crs; + len = pb->buf + pb->size - pb->crs; + va_start(args, fmt); + i = vscnprintf(buf, len, fmt, args); + va_end(args); + pb->crs += i; } /** -- cgit From dc1aed37d17b4fe4f28a74d804c065b877bc7bed Mon Sep 17 00:00:00 2001 From: Erik Hugne Date: Fri, 29 Jun 2012 00:50:23 -0400 Subject: tipc: phase out most of the struct print_buf usage The tipc_printf is renamed to tipc_snprintf, as the new name describes more what the function actually does. It is also changed to take a buffer and length parameter and return number of characters written to the buffer. All callers of this function that used to pass a print_buf are updated. Final removal of the struct print_buf itself will be done synchronously with the pending removal of the deprecated logging code that also was using it. Functions that build up a response message with a list of ports, nametable contents etc. are changed to return the number of characters written to the output buffer. This information was previously hidden in a field of the print_buf struct, and the number of chars written was fetched with a call to tipc_printbuf_validate. This function is removed since it is no longer referenced nor needed. A generic max size ULTRA_STRING_MAX_LEN is defined, named in keeping with the existing TIPC_TLV_ULTRA_STRING, and the various definitions in port, link and nametable code that largely duplicated this information are removed. This means that amount of link statistics that can be returned is now increased from 2k to 32k. The buffer overflow check is now done just before the reply message is passed over netlink or TIPC to a remote node and the message indicating a truncated buffer is changed to a less dramatic one (less CAPS), placed at the end of the message. Signed-off-by: Erik Hugne Signed-off-by: Jon Maloy Signed-off-by: Paul Gortmaker --- net/tipc/log.c | 47 +++++------------------------------------------ 1 file changed, 5 insertions(+), 42 deletions(-) (limited to 'net/tipc/log.c') diff --git a/net/tipc/log.c b/net/tipc/log.c index d01e37a61b93..fa7ce927fda5 100644 --- a/net/tipc/log.c +++ b/net/tipc/log.c @@ -124,40 +124,6 @@ static int tipc_printbuf_empty(struct print_buf *pb) return !pb->buf || (pb->crs == pb->buf); } -/** - * tipc_printbuf_validate - check for print buffer overflow - * @pb: pointer to print buffer structure - * - * Verifies that a print buffer has captured all data written to it. - * If data has been lost, linearize buffer and prepend an error message - * - * Returns length of print buffer data string (including trailing NUL) - */ -int tipc_printbuf_validate(struct print_buf *pb) -{ - char *err = "\n\n*** PRINT BUFFER OVERFLOW ***\n\n"; - char *cp_buf; - struct print_buf cb; - - if (!pb->buf) - return 0; - - if (pb->buf[pb->size - 1] == 0) { - cp_buf = kmalloc(pb->size, GFP_ATOMIC); - if (cp_buf) { - tipc_printbuf_init(&cb, cp_buf, pb->size); - tipc_printbuf_move(&cb, pb); - tipc_printbuf_move(pb, &cb); - kfree(cp_buf); - memcpy(pb->buf, err, strlen(err)); - } else { - tipc_printbuf_reset(pb); - tipc_printf(pb, err); - } - } - return pb->crs - pb->buf + 1; -} - /** * tipc_printbuf_move - move print buffer contents to another print buffer * @pb_to: pointer to destination print buffer structure @@ -204,23 +170,20 @@ static void tipc_printbuf_move(struct print_buf *pb_to, } /** - * tipc_printf - append formatted output to print buffer - * @pb: pointer to print buffer + * tipc_snprintf - append formatted output to print buffer + * @buf: pointer to print buffer + * @len: buffer length * @fmt: formatted info to be printed */ -void tipc_printf(struct print_buf *pb, const char *fmt, ...) +int tipc_snprintf(char *buf, int len, const char *fmt, ...) { int i; va_list args; - char *buf; - int len; - buf = pb->crs; - len = pb->buf + pb->size - pb->crs; va_start(args, fmt); i = vscnprintf(buf, len, fmt, args); va_end(args); - pb->crs += i; + return i; } /** -- cgit From 869dd4662f90514cb92b44a389e85c737b464e25 Mon Sep 17 00:00:00 2001 From: Erik Hugne Date: Fri, 29 Jun 2012 00:50:24 -0400 Subject: tipc: remove print_buf and deprecated log buffer code The internal log buffer handling functions can now safely be removed since there is no code using it anymore. Requests to interact with the internal tipc log buffer over netlink (in config.c) will report 'obsolete command'. This represents the final removal of any references to a struct print_buf, and the removal of the struct itself. We also get rid of a TIPC specific Kconfig in the process. Finally, log.h is removed since it is not needed anymore. Signed-off-by: Erik Hugne Signed-off-by: Jon Maloy Signed-off-by: Paul Gortmaker --- net/tipc/log.c | 213 --------------------------------------------------------- 1 file changed, 213 deletions(-) (limited to 'net/tipc/log.c') diff --git a/net/tipc/log.c b/net/tipc/log.c index fa7ce927fda5..abef644f27d8 100644 --- a/net/tipc/log.c +++ b/net/tipc/log.c @@ -36,138 +36,6 @@ #include "core.h" #include "config.h" -#include "log.h" - -/* - * TIPC pre-defines the following print buffers: - * - * TIPC_NULL : null buffer (i.e. print nowhere) - * TIPC_CONS : system console - * TIPC_LOG : TIPC log buffer - * - * Additional user-defined print buffers are also permitted. - */ -static struct print_buf null_buf = { NULL, 0, NULL, 0 }; -struct print_buf *const TIPC_NULL = &null_buf; - -static struct print_buf cons_buf = { NULL, 0, NULL, 1 }; -struct print_buf *const TIPC_CONS = &cons_buf; - -static struct print_buf log_buf = { NULL, 0, NULL, 1 }; -struct print_buf *const TIPC_LOG = &log_buf; - -/* - * Locking policy when using print buffers. - * - * 1) tipc_printf() uses 'print_lock' to protect against concurrent access to - * 'print_string' when writing to a print buffer. This also protects against - * concurrent writes to the print buffer being written to. - * - * 2) tipc_log_XXX() leverages the aforementioned use of 'print_lock' to - * protect against all types of concurrent operations on their associated - * print buffer (not just write operations). - * - * Note: All routines of the form tipc_printbuf_XXX() are lock-free, and rely - * on the caller to prevent simultaneous use of the print buffer(s) being - * manipulated. - */ -static DEFINE_SPINLOCK(print_lock); - -static void tipc_printbuf_move(struct print_buf *pb_to, - struct print_buf *pb_from); - -/** - * tipc_printbuf_init - initialize print buffer to empty - * @pb: pointer to print buffer structure - * @raw: pointer to character array used by print buffer - * @size: size of character array - * - * Note: If the character array is too small (or absent), the print buffer - * becomes a null device that discards anything written to it. - */ -void tipc_printbuf_init(struct print_buf *pb, char *raw, u32 size) -{ - pb->buf = raw; - pb->crs = raw; - pb->size = size; - pb->echo = 0; - - if (size < TIPC_PB_MIN_SIZE) { - pb->buf = NULL; - } else if (raw) { - pb->buf[0] = 0; - pb->buf[size - 1] = ~0; - } -} - -/** - * tipc_printbuf_reset - reinitialize print buffer to empty state - * @pb: pointer to print buffer structure - */ -static void tipc_printbuf_reset(struct print_buf *pb) -{ - if (pb->buf) { - pb->crs = pb->buf; - pb->buf[0] = 0; - pb->buf[pb->size - 1] = ~0; - } -} - -/** - * tipc_printbuf_empty - test if print buffer is in empty state - * @pb: pointer to print buffer structure - * - * Returns non-zero if print buffer is empty. - */ -static int tipc_printbuf_empty(struct print_buf *pb) -{ - return !pb->buf || (pb->crs == pb->buf); -} - -/** - * tipc_printbuf_move - move print buffer contents to another print buffer - * @pb_to: pointer to destination print buffer structure - * @pb_from: pointer to source print buffer structure - * - * Current contents of destination print buffer (if any) are discarded. - * Source print buffer becomes empty if a successful move occurs. - */ -static void tipc_printbuf_move(struct print_buf *pb_to, - struct print_buf *pb_from) -{ - int len; - - /* Handle the cases where contents can't be moved */ - if (!pb_to->buf) - return; - - if (!pb_from->buf) { - tipc_printbuf_reset(pb_to); - return; - } - - if (pb_to->size < pb_from->size) { - strcpy(pb_to->buf, "*** PRINT BUFFER MOVE ERROR ***"); - pb_to->buf[pb_to->size - 1] = ~0; - pb_to->crs = strchr(pb_to->buf, 0); - return; - } - - /* Copy data from char after cursor to end (if used) */ - len = pb_from->buf + pb_from->size - pb_from->crs - 2; - if ((pb_from->buf[pb_from->size - 1] == 0) && (len > 0)) { - strcpy(pb_to->buf, pb_from->crs + 1); - pb_to->crs = pb_to->buf + len; - } else - pb_to->crs = pb_to->buf; - - /* Copy data from start to cursor (always) */ - len = pb_from->crs - pb_from->buf; - strcpy(pb_to->crs, pb_from->buf); - pb_to->crs += len; - - tipc_printbuf_reset(pb_from); -} /** * tipc_snprintf - append formatted output to print buffer @@ -185,84 +53,3 @@ int tipc_snprintf(char *buf, int len, const char *fmt, ...) va_end(args); return i; } - -/** - * tipc_log_resize - change the size of the TIPC log buffer - * @log_size: print buffer size to use - */ -int tipc_log_resize(int log_size) -{ - int res = 0; - - spin_lock_bh(&print_lock); - kfree(TIPC_LOG->buf); - TIPC_LOG->buf = NULL; - if (log_size) { - if (log_size < TIPC_PB_MIN_SIZE) - log_size = TIPC_PB_MIN_SIZE; - res = TIPC_LOG->echo; - tipc_printbuf_init(TIPC_LOG, kmalloc(log_size, GFP_ATOMIC), - log_size); - TIPC_LOG->echo = res; - res = !TIPC_LOG->buf; - } - spin_unlock_bh(&print_lock); - - return res; -} - -/** - * tipc_log_resize_cmd - reconfigure size of TIPC log buffer - */ -struct sk_buff *tipc_log_resize_cmd(const void *req_tlv_area, int req_tlv_space) -{ - u32 value; - - if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_UNSIGNED)) - return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR); - - value = ntohl(*(__be32 *)TLV_DATA(req_tlv_area)); - if (value > 32768) - return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE - " (log size must be 0-32768)"); - if (tipc_log_resize(value)) - return tipc_cfg_reply_error_string( - "unable to create specified log (log size is now 0)"); - return tipc_cfg_reply_none(); -} - -/** - * tipc_log_dump - capture TIPC log buffer contents in configuration message - */ -struct sk_buff *tipc_log_dump(void) -{ - struct sk_buff *reply; - - spin_lock_bh(&print_lock); - if (!TIPC_LOG->buf) { - spin_unlock_bh(&print_lock); - reply = tipc_cfg_reply_ultra_string("log not activated\n"); - } else if (tipc_printbuf_empty(TIPC_LOG)) { - spin_unlock_bh(&print_lock); - reply = tipc_cfg_reply_ultra_string("log is empty\n"); - } else { - struct tlv_desc *rep_tlv; - struct print_buf pb; - int str_len; - - str_len = min(TIPC_LOG->size, 32768u); - spin_unlock_bh(&print_lock); - reply = tipc_cfg_reply_alloc(TLV_SPACE(str_len)); - if (reply) { - rep_tlv = (struct tlv_desc *)reply->data; - tipc_printbuf_init(&pb, TLV_DATA(rep_tlv), str_len); - spin_lock_bh(&print_lock); - tipc_printbuf_move(&pb, TIPC_LOG); - spin_unlock_bh(&print_lock); - str_len = strlen(TLV_DATA(rep_tlv)) + 1; - skb_put(reply, TLV_SPACE(str_len)); - TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len); - } - } - return reply; -} -- cgit