From: Steven Rostedt <rostedt@goodmis.org>
To: Petr Mladek <pmladek@suse.cz>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Jiri Kosina <jkosina@suse.cz>, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC][PATCH 03/12 v3] tracing: Create seq_buf layer in trace_seq
Date: Wed, 5 Nov 2014 15:00:07 -0500 [thread overview]
Message-ID: <20141105150007.1c543b9e@gandalf.local.home> (raw)
In-Reply-To: <20141105134147.226a23ef@gandalf.local.home>
On Wed, 5 Nov 2014 13:41:47 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > > + */
> > > +int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
> > > + int nmaskbits)
> > > +{
> > > + unsigned int len = SEQ_BUF_LEFT(s);
> > >
> > > + int ret;
> > > +
> > > + WARN_ON(s->size == 0);
> > > +
> > > + if (s->len < s->size) {
> > > + ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits);
> >
> > It writes to the beginning of the buffer. It should be
> >
> > ret = bitmap_scnprintf(s->buffer + s->len, len,
> > maskp, nmaskbits);
> >
>
> Yep thanks. Luckily its only user didn't care.
>
> Will fix.
>
> >
> > > + if (s->len + ret < s->size) {
> >
> > This will always happen because bitmap_scnprintf() is limited by SEQ_BUF_LEFT(s)
> > and it currently returns the remaining size - len - 1.
>
> Hmm, that's correct, as bitmap_scnprintf() returns the amount written
> instead of the amount that it would write like snprintf() would.
>
>
> >
> > You might want to use "s->size - s->len" instead of SEQ_BUF_LEFT(s).
>
> That wont help when we make overflow len > size.
>
> Probably should see if ret == the amount of bits required for the
> bitmask.
Here's the new version:
int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
int nmaskbits)
{
unsigned int len = seq_buf_buffer_left(s);
int size;
int ret;
WARN_ON(s->size == 0);
if (s->len < s->size) {
/*
* Calculate to see if we have enough room to fit
* @nmaskbits as a string
*/
size = (nmaskbits + 3) / 4;
/* Add the commas that are used for groups of 8 hex digits */
size += size / 8;
if (len >= size) {
ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits);
WARN_ON_ONCE(s->len + ret >= s->size);
s->len += ret;
return 0;
}
}
seq_buf_set_overflow(s);
return -1;
}
>
> >
> >
> > > + s->len += ret;
> > > + return 0;
> > > + }
> > > + }
> > > + seq_buf_set_overflow(s);
> > > + return -1;
> > > +}
> > > +/**
> > > + * seq_buf_putmem_hex - write raw memory into the buffer in ASCII hex
> > > + * @s: seq_buf descriptor
> > > + * @mem: The raw memory to write its hex ASCII representation of
> > > + * @len: The length of the raw memory to copy (in bytes)
> > > + *
> > > + * This is similar to seq_buf_putmem() except instead of just copying the
> > > + * raw memory into the buffer it writes its ASCII representation of it
> > > + * in hex characters.
> > > + *
> > > + * Returns zero on success, -1 on overflow
> > > + */
> > > +int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
> > > + unsigned int len)
> > > +{
> > > + unsigned char hex[HEX_CHARS];
> > > + const unsigned char *data = mem;
> > > + unsigned int start_len;
> > > + int i, j;
> > > +
> > > + WARN_ON(s->size == 0);
> > > +
> > > + while (len) {
> > > + start_len = min(len, HEX_CHARS - 1);
> > > +#ifdef __BIG_ENDIAN
> > > + for (i = 0, j = 0; i < start_len; i++) {
> > > +#else
> > > + for (i = start_len-1, j = 0; i >= 0; i--) {
> > > +#endif
> > > + hex[j++] = hex_asc_hi(data[i]);
> > > + hex[j++] = hex_asc_lo(data[i]);
> > > + }
> > > + if (WARN_ON_ONCE(j == 0 || j/2 > len))
> > > + break;
> > > +
> > > + /* j increments twice per loop */
> > > + len -= j / 2;
> > > + hex[j++] = ' ';
> > > +
> > > + seq_buf_putmem(s, hex, j);
> > > + if (seq_buf_has_overflowed(s))
> >
> > We might want to use the seq_buf_putmem() return value here.
>
> We could do that.
Actually, no we can't. As I stated before, the return values of most
of the seq_*() functions (for seq_file and seq_buf) will be turning
into void functions.
I'm avoiding checking return values here.
-- Steve
>
> >
> > > + return -1;
> > > + }
> > > + return 0;
> > > +}
> > > +
> >
next prev parent reply other threads:[~2014-11-05 20:00 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-04 15:52 [RFC][PATCH 00/12 v3] seq-buf/x86/printk: Print all stacks from NMI safely Steven Rostedt
2014-11-04 15:52 ` [RFC][PATCH 01/12 v3] x86/kvm/tracing: Use helper function trace_seq_buffer_ptr() Steven Rostedt
2014-11-04 16:27 ` Paolo Bonzini
2014-11-04 17:17 ` Rustad, Mark D
2014-11-04 19:09 ` Steven Rostedt
2014-11-04 19:35 ` Steven Rostedt
2014-11-04 20:09 ` Rustad, Mark D
2014-11-05 10:28 ` Petr Mladek
2014-11-04 15:52 ` [RFC][PATCH 02/12 v3] RAS/tracing: Use trace_seq_buffer_ptr() helper instead of open coded Steven Rostedt
2014-11-04 19:59 ` Borislav Petkov
2014-11-05 10:29 ` Petr Mladek
2014-11-04 15:52 ` [RFC][PATCH 03/12 v3] tracing: Create seq_buf layer in trace_seq Steven Rostedt
2014-11-05 14:22 ` Petr Mladek
2014-11-05 18:41 ` Steven Rostedt
2014-11-05 20:00 ` Steven Rostedt [this message]
2014-11-05 21:17 ` Steven Rostedt
2014-11-05 21:21 ` Steven Rostedt
2014-11-06 16:33 ` Petr Mladek
2014-11-07 18:30 ` Steven Rostedt
2014-11-07 18:59 ` Joe Perches
2014-11-07 19:10 ` Steven Rostedt
2014-11-10 13:53 ` Petr Mladek
2014-11-10 17:37 ` Steven Rostedt
2014-11-10 19:02 ` Petr Mladek
2014-11-06 16:13 ` Petr Mladek
2014-11-05 14:26 ` Petr Mladek
2014-11-05 18:42 ` Steven Rostedt
2014-11-04 15:52 ` [RFC][PATCH 04/12 v3] tracing: Convert seq_buf_path() to be like seq_path() Steven Rostedt
2014-11-05 14:45 ` Petr Mladek
2014-11-05 20:10 ` Steven Rostedt
2014-11-06 14:18 ` Petr Mladek
2014-11-06 21:09 ` Steven Rostedt
2014-11-06 15:01 ` Petr Mladek
2014-11-07 18:34 ` Steven Rostedt
2014-11-10 14:03 ` Petr Mladek
2014-11-10 17:38 ` Steven Rostedt
2014-11-04 15:52 ` [RFC][PATCH 05/12 v3] tracing: Convert seq_buf fields to be like seq_file fields Steven Rostedt
2014-11-05 15:57 ` Petr Mladek
2014-11-05 20:14 ` Steven Rostedt
2014-11-06 14:24 ` Petr Mladek
2014-11-04 15:52 ` [RFC][PATCH 06/12 v3] tracing: Add a seq_buf_clear() helper and clear len and readpos in init Steven Rostedt
2014-11-05 16:00 ` Petr Mladek
2014-11-04 15:52 ` [RFC][PATCH 07/12 v3] tracing: Have seq_buf use full buffer Steven Rostedt
2014-11-05 16:31 ` Petr Mladek
2014-11-05 20:21 ` Steven Rostedt
2014-11-05 21:06 ` Steven Rostedt
2014-11-06 15:31 ` Petr Mladek
2014-11-06 19:24 ` Steven Rostedt
2014-11-07 9:11 ` Petr Mladek
2014-11-07 18:37 ` Steven Rostedt
2014-11-10 18:11 ` Petr Mladek
2014-11-06 15:13 ` Petr Mladek
2014-11-04 15:52 ` [RFC][PATCH 08/12 v3] tracing: Add seq_buf_get_buf() and seq_buf_commit() helper functions Steven Rostedt
2014-11-05 16:51 ` Petr Mladek
2014-11-05 20:26 ` Steven Rostedt
2014-11-07 18:39 ` Steven Rostedt
2014-11-10 18:33 ` Petr Mladek
2014-11-10 19:23 ` Steven Rostedt
2014-11-04 15:52 ` [RFC][PATCH 09/12 v3] seq_buf: Move the seq_buf code to lib/ Steven Rostedt
2014-11-05 16:57 ` Petr Mladek
2014-11-05 20:32 ` Steven Rostedt
2014-11-04 15:52 ` [RFC][PATCH 10/12 v3] seq-buf: Make seq_buf_bprintf() conditional on CONFIG_BINARY_PRINTF Steven Rostedt
2014-11-05 17:06 ` Petr Mladek
2014-11-05 20:33 ` Steven Rostedt
2014-11-05 20:42 ` Steven Rostedt
2014-11-06 14:39 ` Petr Mladek
2014-11-07 20:36 ` Junio C Hamano
2014-11-07 21:49 ` Steven Rostedt
2014-11-10 18:43 ` Petr Mladek
2014-11-04 15:52 ` [RFC][PATCH 11/12 v3] printk: Add per_cpu printk func to allow printk to be diverted Steven Rostedt
2014-11-06 16:56 ` Petr Mladek
2014-11-04 15:52 ` [RFC][PATCH 12/12 v3] x86/nmi: Perform a safe NMI stack trace on all CPUs Steven Rostedt
2014-11-04 23:05 ` Jiri Kosina
2014-11-04 23:41 ` Steven Rostedt
2014-11-06 18:41 ` Petr Mladek
2014-11-07 18:56 ` Steven Rostedt
2014-11-10 18:58 ` Petr Mladek
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