Messages in this thread | | | Date | Wed, 5 Nov 2014 16:17:20 -0500 | From | Steven Rostedt <> | Subject | Re: [RFC][PATCH 03/12 v3] tracing: Create seq_buf layer in trace_seq |
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On Wed, 5 Nov 2014 15:00:07 -0500 Steven Rostedt <rostedt@goodmis.org> wrote:
> 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: >
Take 2:
int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp, int nmaskbits) { unsigned int len = seq_buf_buffer_left(s); int ret;
WARN_ON(s->size == 0);
if (s->len < s->size) { ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits); /* * Note, because bitmap_scnprintf() only returns the * number of bytes written and not the number that * would be written, we use the last byte of the buffer * to let us know if we overflowed. There's a small * chance that the bitmap could have fit exactly inside * the buffer, but it's not that critical if that does * happen. */ if (s->len + ret < s->size) { s->len += ret; return 0; } } seq_buf_set_overflow(s); return -1; }
-- Steve
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