From 63842c21347ecf4685d6ec008e667e61b0ead6e5 Mon Sep 17 00:00:00 2001 From: Namit Gupta Date: Wed, 20 Jun 2018 19:26:19 +0530 Subject: [PATCH] printk: Remove unnecessary kmalloc() from syslog during clear When the request is only for clearing logs, there is no need for allocation/deallocation. Only the indexes need to be reset and returned. Rest of the patch is mostly made up of changes because of indention. Link: http://lkml.kernel.org/r/20180620135951epcas5p3bd2a8f25ec689ca333bce861b527dba2~54wyKcT0_3155531555epcas5p3y@epcas5p3.samsung.com Cc: linux-kernel@vger.kernel.org Cc: pankaj.m@samsung.com Cc: a.sahrawat@samsung.com Signed-off-by: Namit Gupta Signed-off-by: Himanshu Maithani Reviewed-by: Steven Rostedt (VMware) Reviewed-by: Sergey Senozhatsky Signed-off-by: Petr Mladek --- kernel/printk/printk.c | 115 ++++++++++++++++++++++------------------- 1 file changed, 61 insertions(+), 54 deletions(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 3999c295d6f7..16b02cc51a14 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1352,71 +1352,78 @@ static int syslog_print_all(char __user *buf, int size, bool clear) { char *text; int len = 0; + u64 next_seq; + u64 seq; + u32 idx; + + if (!buf) { + if (clear) { + logbuf_lock_irq(); + clear_seq = log_next_seq; + clear_idx = log_next_idx; + logbuf_unlock_irq(); + } + return 0; + } text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); if (!text) return -ENOMEM; logbuf_lock_irq(); - if (buf) { - u64 next_seq; - u64 seq; - u32 idx; + /* + * Find first record that fits, including all following records, + * into the user-provided buffer for this dump. + */ + seq = clear_seq; + idx = clear_idx; + while (seq < log_next_seq) { + struct printk_log *msg = log_from_idx(idx); - /* - * Find first record that fits, including all following records, - * into the user-provided buffer for this dump. - */ - seq = clear_seq; - idx = clear_idx; - while (seq < log_next_seq) { - struct printk_log *msg = log_from_idx(idx); + len += msg_print_text(msg, true, NULL, 0); + idx = log_next(idx); + seq++; + } - len += msg_print_text(msg, true, NULL, 0); - idx = log_next(idx); - seq++; + /* move first record forward until length fits into the buffer */ + seq = clear_seq; + idx = clear_idx; + while (len > size && seq < log_next_seq) { + struct printk_log *msg = log_from_idx(idx); + + len -= msg_print_text(msg, true, NULL, 0); + idx = log_next(idx); + seq++; + } + + /* last message fitting into this dump */ + next_seq = log_next_seq; + + len = 0; + while (len >= 0 && seq < next_seq) { + struct printk_log *msg = log_from_idx(idx); + int textlen; + + textlen = msg_print_text(msg, true, text, + LOG_LINE_MAX + PREFIX_MAX); + if (textlen < 0) { + len = textlen; + break; } + idx = log_next(idx); + seq++; - /* move first record forward until length fits into the buffer */ - seq = clear_seq; - idx = clear_idx; - while (len > size && seq < log_next_seq) { - struct printk_log *msg = log_from_idx(idx); + logbuf_unlock_irq(); + if (copy_to_user(buf + len, text, textlen)) + len = -EFAULT; + else + len += textlen; + logbuf_lock_irq(); - len -= msg_print_text(msg, true, NULL, 0); - idx = log_next(idx); - seq++; - } - - /* last message fitting into this dump */ - next_seq = log_next_seq; - - len = 0; - while (len >= 0 && seq < next_seq) { - struct printk_log *msg = log_from_idx(idx); - int textlen; - - textlen = msg_print_text(msg, true, text, - LOG_LINE_MAX + PREFIX_MAX); - if (textlen < 0) { - len = textlen; - break; - } - idx = log_next(idx); - seq++; - - logbuf_unlock_irq(); - if (copy_to_user(buf + len, text, textlen)) - len = -EFAULT; - else - len += textlen; - logbuf_lock_irq(); - - if (seq < log_first_seq) { - /* messages are gone, move to next one */ - seq = log_first_seq; - idx = log_first_idx; - } + if (seq < log_first_seq) { + /* messages are gone, move to next one */ + seq = log_first_seq; + idx = log_first_idx; } }