From e2dbd601346aeb64b1b387168b217fd5c301644e Mon Sep 17 00:00:00 2001 From: Erik Hugne Date: Fri, 29 Jun 2012 00:50:22 -0400 Subject: [PATCH] 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(-) 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; + int i; + va_list args; + char *buf; + int len; - 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); - - 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; } /**