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McKenney" , Daniel Vetter , Greg Kroah-Hartman , Helge Deller , Jason Wessel , Daniel Thompson Subject: [patch RFC 16/29] printk: Use struct cons_text_buf References: <20220910221947.171557773@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Date: Sun, 11 Sep 2022 00:27:56 +0200 (CEST) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Replace the seperately allocated output buffers with a single instance of struct cons_text_buf. Signed-off-by: Thomas Gleixner --- kernel/printk/printk.c | 50 ++++++++++++++++++++----------------------------- 1 file changed, 21 insertions(+), 29 deletions(-) --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -666,11 +666,9 @@ struct devkmsg_user { atomic64_t seq; struct ratelimit_state rs; struct mutex lock; - char buf[CONSOLE_EXT_LOG_MAX]; - struct printk_info info; - char text_buf[CONSOLE_EXT_LOG_MAX]; struct printk_record record; + struct cons_text_buf txtbuf; }; static __printf(3, 4) __cold @@ -753,6 +751,8 @@ static ssize_t devkmsg_read(struct file { struct devkmsg_user *user = file->private_data; struct printk_record *r = &user->record; + char *outbuf = user->txtbuf.ext_text; + const int maxlen = sizeof(user->txtbuf.ext_text); size_t len; ssize_t ret; @@ -793,8 +793,8 @@ static ssize_t devkmsg_read(struct file goto out; } - len = info_print_ext_header(user->buf, sizeof(user->buf), r->info); - len += msg_print_ext_body(user->buf + len, sizeof(user->buf) - len, + len = info_print_ext_header(outbuf, maxlen, r->info); + len += msg_print_ext_body(outbuf + len, maxlen - len, &r->text_buf[0], r->info->text_len, &r->info->dev_info); @@ -805,7 +805,7 @@ static ssize_t devkmsg_read(struct file goto out; } - if (copy_to_user(buf, user->buf, len)) { + if (copy_to_user(buf, outbuf, len)) { ret = -EFAULT; goto out; } @@ -904,7 +904,8 @@ static int devkmsg_open(struct inode *in mutex_init(&user->lock); prb_rec_init_rd(&user->record, &user->info, - &user->text_buf[0], sizeof(user->text_buf)); + user->txtbuf.text, + sizeof(user->txtbuf.text)); atomic64_set(&user->seq, prb_first_valid_seq(prb)); @@ -2704,8 +2705,8 @@ static void __console_unlock(void) * * Requires the console_lock. */ -static bool console_emit_next_record(struct console *con, char *text, char *ext_text, - char *dropped_text, bool *handover) +static bool console_emit_next_record(struct console *con, struct cons_text_buf *txtbuf, + bool *handover, bool extmsg) { static int panic_console_dropped; struct printk_info info; @@ -2714,7 +2715,7 @@ static bool console_emit_next_record(str char *write_text; size_t len; - prb_rec_init_rd(&r, &info, text, CONSOLE_LOG_MAX); + prb_rec_init_rd(&r, &info, txtbuf->text, CONSOLE_LOG_MAX); *handover = false; @@ -2736,13 +2737,13 @@ static bool console_emit_next_record(str goto skip; } - if (ext_text) { - write_text = ext_text; - len = info_print_ext_header(ext_text, CONSOLE_EXT_LOG_MAX, r.info); - len += msg_print_ext_body(ext_text + len, CONSOLE_EXT_LOG_MAX - len, + if (extmsg) { + write_text = txtbuf->ext_text; + len = info_print_ext_header(write_text, CONSOLE_EXT_LOG_MAX, r.info); + len += msg_print_ext_body(write_text + len, CONSOLE_EXT_LOG_MAX - len, &r.text_buf[0], r.info->text_len, &r.info->dev_info); } else { - write_text = text; + write_text = txtbuf->text; len = record_print_text(&r, console_msg_format & MSG_FORMAT_SYSLOG, printk_time); } @@ -2760,7 +2761,7 @@ static bool console_emit_next_record(str console_lock_spinning_enable(); stop_critical_timings(); /* don't trace print latency */ - call_console_driver(con, write_text, len, dropped_text); + call_console_driver(con, write_text, len, extmsg ? NULL : txtbuf->dropped_text); start_critical_timings(); con->seq++; @@ -2796,9 +2797,7 @@ static bool console_emit_next_record(str */ static bool console_flush_all(bool do_cond_resched, u64 *next_seq, bool *handover) { - static char dropped_text[DROPPED_TEXT_MAX]; - static char ext_text[CONSOLE_EXT_LOG_MAX]; - static char text[CONSOLE_LOG_MAX]; + static struct cons_text_buf txtbuf; bool any_usable = false; struct console *con; bool any_progress; @@ -2816,16 +2815,9 @@ static bool console_flush_all(bool do_co continue; any_usable = true; - if (con->flags & CON_EXTENDED) { - /* Extended consoles do not print "dropped messages". */ - progress = console_emit_next_record(con, &text[0], - &ext_text[0], NULL, - handover); - } else { - progress = console_emit_next_record(con, &text[0], - NULL, &dropped_text[0], - handover); - } + progress = console_emit_next_record(con, &txtbuf, handover, + con->flags & CON_EXTENDED); + if (*handover) return false;