Messages in this thread | | | Date | Wed, 5 Nov 2014 15:45:53 +0100 | From | Petr Mladek <> | Subject | Re: [RFC][PATCH 04/12 v3] tracing: Convert seq_buf_path() to be like seq_path() |
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On Tue 2014-11-04 10:52:41, Steven Rostedt wrote: > From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org> > > Rewrite seq_buf_path() like it is done in seq_path() and allow > it to accept any escape character instead of just "\n". > > Making seq_buf_path() like seq_path() will help prevent problems > when converting seq_file to use the seq_buf logic. > > Signed-off-by: Steven Rostedt <rostedt@goodmis.org> > --- > include/linux/seq_buf.h | 2 +- > kernel/trace/seq_buf.c | 30 ++++++++++++++++-------------- > kernel/trace/trace_seq.c | 2 +- > 3 files changed, 18 insertions(+), 16 deletions(-) > > diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h > index 97872154d51c..6d1c57d6073f 100644 > --- a/include/linux/seq_buf.h > +++ b/include/linux/seq_buf.h > @@ -64,7 +64,7 @@ extern int seq_buf_putc(struct seq_buf *s, unsigned char c); > extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len); > extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem, > unsigned int len); > -extern int seq_buf_path(struct seq_buf *s, const struct path *path); > +extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc); > > extern int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp, > int nmaskbits); > diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c > index 2bf582753902..243123b12d16 100644 > --- a/kernel/trace/seq_buf.c > +++ b/kernel/trace/seq_buf.c > @@ -272,28 +272,30 @@ int seq_buf_putmem_hex(struct seq_buf *s, const void *mem, > * seq_buf_path - copy a path into the sequence buffer > * @s: seq_buf descriptor > * @path: path to write into the sequence buffer. > + * @esc: set of characters to escape in the output > * > * Write a path name into the sequence buffer. > * > * Returns zero on success, -1 on overflow > > */ > -int seq_buf_path(struct seq_buf *s, const struct path *path) > +int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc) > { > - unsigned int len = SEQ_BUF_LEFT(s); > - unsigned char *p; > - > - WARN_ON(s->size == 0);
I would keep this check.
> - p = d_path(path, s->buffer + s->len, len); > - if (!IS_ERR(p)) { > - p = mangle_path(s->buffer + s->len, p, "\n"); > - if (p) { > - s->len = p - s->buffer; > - return 0; > + char *buf = s->buffer + s->len; > + size_t size = SEQ_BUF_LEFT(s);
I would use the variable name "len" to make it consistent with the other fucntions in seq_buf.c.
> + int res = -1; > + > + if (size) { > + char *p = d_path(path, buf, size); > + if (!IS_ERR(p)) { > + char *end = mangle_path(buf, p, esc); > + if (end) > + res = end - buf; > } > } > - seq_buf_set_overflow(s);
We still should set overflow on failure.
> - return -1; > + if (res > 0) > + s->len += res; > + > + return res;
It returns -1 on failure and the number of written characters on success. This is incompatible with the other seq_buf functions and with the comment above this function. Also it changes the return value from trace_seq_path().
I do not mind about the used scheme but I think that we should make it consistent.
Best Regards, Petr
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