On (02/03/17 12:18), Petr Mladek wrote:
[..]
> > by "the new approved variant" do you mean resend of the entire
> > patch set (v8) or just 0004 patch?
>
> I depends on how many and how complicated are possible conflicts
> with the followup patches.
>
> It is perfectly fine to send just 0004 if there are no conflicts
> or if they are trivial to resolve.
so there are no conflicts at all. 0004 can be replaced with the patch below.
but the thing is - I want to keep printk_safe_flush_line() around.
we call
static void printk_safe_flush_line(const char *text, int len)
{
/*
* Avoid any console drivers calls from here, because we may be
* in NMI or printk_safe context (when in panic). The messages
* must go only into the ring buffer at this stage. Consoles will
* get explicitly called later when a crashdump is not generated.
*/
printk_deferred("%.*s", len, text);
}
from many places:
4x printk_safe_flush_buffer()
1x __printk_safe_flush()
replacing printk_safe_flush_line() with printk_deferred() produces things
like these
printk_deferred("%.*s", end - start, start);
printk_deferred("%.*s", strlen(newline), newline);
which, I think, makes the code worse. any objections?
just in case, the patch (which I prefer to be ignored)
===8<======8<===
>From daa9bd8c2659a91036c00e22bb218be6871a371d Mon Sep 17 00:00:00 2001
From: Sergey Senozhatsky <sergey.senozhat...@gmail.com>
Date: Tue, 27 Dec 2016 23:16:07 +0900
Subject: [PATCH] printk: always use deferred printk when flush printk_safe
lines
Always use printk_deferred() in printk_safe_flush_line().
Flushing can be done from NMI or printk_safe contexts (when
we are in panic), so we can't call console drivers, yet still
want to store the messages in the logbuf buffer. Therefore we
use a deferred printk version.
Signed-off-by: Sergey Senozhatsky <sergey.senozhat...@gmail.com>
Suggested-by: Petr Mladek <pmla...@suse.com>
---
kernel/printk/printk_safe.c | 30 ++++++++++++------------------
1 file changed, 12 insertions(+), 18 deletions(-)
diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
index efc89a4e9df5..801f0f1c7547 100644
--- a/kernel/printk/printk_safe.c
+++ b/kernel/printk/printk_safe.c
@@ -110,19 +110,6 @@ static int printk_safe_log_store(struct
printk_safe_seq_buf *s,
return add;
}
-static void printk_safe_flush_line(const char *text, int len)
-{
- /*
- * The buffers are flushed in NMI only on panic. The messages must
- * go only into the ring buffer at this stage. Consoles will get
- * explicitly called later when a crashdump is not generated.
- */
- if (in_nmi())
- printk_deferred("%.*s", len, text);
- else
- printk("%.*s", len, text);
-}
-
/* printk part of the temporary buffer line by line */
static int printk_safe_flush_buffer(const char *start, size_t len)
{
@@ -136,7 +123,14 @@ static int printk_safe_flush_buffer(const char *start,
size_t len)
/* Print line by line. */
while (c < end) {
if (*c == '\n') {
- printk_safe_flush_line(start, c - start + 1);
+ /*
+ * Avoid any console drivers calls from here, because
+ * we may be in NMI or printk_safe context (when in
+ * panic). The messages must go only into the ring
+ * buffer at this stage. Consoles will get explicitly
+ * called later when a crashdump is not generated.
+ */
+ printk_deferred("%.*s", c - start + 1, start);
start = ++c;
header = true;
continue;
@@ -149,7 +143,7 @@ static int printk_safe_flush_buffer(const char *start,
size_t len)
continue;
}
- printk_safe_flush_line(start, c - start);
+ printk_deferred("%.*s", c - start, start);
start = c++;
header = true;
continue;
@@ -163,8 +157,8 @@ static int printk_safe_flush_buffer(const char *start,
size_t len)
if (start < end && !header) {
static const char newline[] = KERN_CONT "\n";
- printk_safe_flush_line(start, end - start);
- printk_safe_flush_line(newline, strlen(newline));
+ printk_deferred("%.*s", end - start, start);
+ printk_deferred("%.*s", strlen(newline), newline);
}
return len;
@@ -206,7 +200,7 @@ static void __printk_safe_flush(struct irq_work *work)
if ((i && i >= len) || len > sizeof(s->buffer)) {
const char *msg = "printk_safe_flush: internal error\n";
- printk_safe_flush_line(msg, strlen(msg));
+ printk_deferred("%.*s", strlen(msg), msg);
len = 0;
}
--
2.11.1
