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Message-Id: <1406037717-9670-2-git-send-email-elder@linaro.org> Date: Tue, 22 Jul 2014 09:01:56 -0500 From: Alex Elder <elder@...aro.org> To: akpm@...ux-foundation.org Cc: kay@...y.org, pmladek@...e.cz, bp@...e.de, john.stultz@...aro.org, jack@...e.cz, linux-kernel@...r.kernel.org Subject: [PATCH v2 1/2] printk: kill LOG_CONT The LOG_CONT and LOG_NEWLINE flags are mutually exclusive, i.e., the presence of LOG_NEWLINE implies the absense of LOG_CONT, and vice-versa. As a result, wherever LOG_CONT is used, we can equivalently substitute !LOG_NEWLINE; and we can use LOG_NEWLINE wherever !LOG_CONT is used. Switch to using LOG_NEWLINE only, and get rid of LOG_CONT. Make some refinements on a nearby block of comments. Signed-off-by: Alex Elder <elder@...aro.org> --- kernel/printk/printk.c | 42 +++++++++++++++++++++--------------------- 1 file changed, 21 insertions(+), 21 deletions(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 6848e7d..49c9238 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -211,7 +211,6 @@ enum log_flags { LOG_NOCONS = 1, /* already flushed, do not print to console */ LOG_NEWLINE = 2, /* text ended with a newline */ LOG_PREFIX = 4, /* text started with a prefix */ - LOG_CONT = 8, /* text is a fragment of a continuation line */ }; struct printk_log { @@ -613,22 +612,25 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf, do_div(ts_usec, 1000); /* - * If we couldn't merge continuation line fragments during the print, - * export the stored flags to allow an optional external merge of the - * records. Merging the records isn't always necessarily correct, like - * when we hit a race during printing. In most cases though, it produces - * better readable output. 'c' in the record flags mark the first - * fragment of a line, '+' the following. + * Sometimes it's necessary to flush an incomplete record to the log. + * When this happens, consecutive records should be merged to produce + * a logically complete message. + * + * Indicate this to user space with a flag character. A 'c' indicates + * the first of a series of incomplete log records. A '+' indicates + * a record that should be merged with one or more earlier records. + * And a '-' indicates a "normal" self-contained single record. */ - if ((user->prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)) + if (!(user->prev & LOG_NEWLINE) && !(msg->flags & LOG_PREFIX)) cont = '+'; - else if (msg->flags & LOG_CONT) + else if (!(msg->flags & LOG_NEWLINE)) cont = 'c'; else cont = '-'; /* Insert a newline if the previous line was not terminated properly */ - insert_newline = (user->prev & LOG_CONT) && (msg->flags & LOG_PREFIX); + insert_newline = !(user->prev & LOG_NEWLINE) && + (msg->flags & LOG_PREFIX); len = sprintf(user->buf, "%s%u,%llu,%llu,%c;", insert_newline ? "\n" : "", (msg->facility << 3) | msg->level, @@ -1007,13 +1009,13 @@ static size_t msg_print_text(const struct printk_log *msg, enum log_flags prev, bool newline = true; size_t len = 0; - if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)) + if (!(prev & LOG_NEWLINE) && !(msg->flags & LOG_PREFIX)) prefix = false; - if (msg->flags & LOG_CONT) + if (!(msg->flags & LOG_NEWLINE)) newline = false; - if ((prev & LOG_CONT) && (msg->flags & LOG_PREFIX) && len < size) { + if (!(prev & LOG_NEWLINE) && (msg->flags & LOG_PREFIX) && len < size) { if (buf) buf[len++] = '\n'; else @@ -1081,7 +1083,7 @@ static int syslog_print(char __user *buf, int size) */ syslog_seq = log_first_seq; syslog_idx = log_first_idx; - syslog_prev &= LOG_NEWLINE|LOG_CONT; + syslog_prev &= LOG_NEWLINE; syslog_partial = 0; } if (syslog_seq == log_next_seq) { @@ -1210,7 +1212,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear) */ seq = log_first_seq; idx = log_first_idx; - prev &= LOG_NEWLINE|LOG_CONT; + prev &= LOG_NEWLINE; } } } @@ -1319,7 +1321,7 @@ int do_syslog(int type, char __user *buf, int len, bool from_file) */ syslog_seq = log_first_seq; syslog_idx = log_first_idx; - syslog_prev &= LOG_NEWLINE|LOG_CONT; + syslog_prev &= LOG_NEWLINE; syslog_partial = 0; } if (from_file) { @@ -1534,7 +1536,7 @@ static bool cont_add(int facility, int level, const char *text, size_t len) if (cont.len + len > sizeof(cont.buf)) { /* the line gets too long, split it up in separate records */ - cont_flush(LOG_CONT); + cont_flush(0); return false; } @@ -1552,7 +1554,7 @@ static bool cont_add(int facility, int level, const char *text, size_t len) cont.len += len; if (cont.len > (sizeof(cont.buf) * 80) / 100) - cont_flush(LOG_CONT); + cont_flush(0); return true; } @@ -1665,8 +1667,6 @@ asmlinkage int vprintk_emit(int facility, int level, if (text_len && text[text_len-1] == '\n') { text_len--; lflags = LOG_NEWLINE; - } else { - lflags = LOG_CONT; } /* strip kernel syslog prefix and extract log level or control flags */ @@ -2167,7 +2167,7 @@ again: if (console_seq < log_first_seq) { len = sprintf(text, "%s** %u printk messages dropped **\n", - (console_prev & LOG_CONT) ? "\n" : "", + (console_prev & LOG_NEWLINE) ? "" : "\n", (unsigned)(log_first_seq - console_seq)); /* Messages are gone, move to first one. */ console_seq = log_first_seq; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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