Messages in this thread | | | Date | Mon, 9 Feb 2009 13:43:04 -0500 (EST) | From | Steven Rostedt <> | Subject | Re: [PATCH 3/3] tracing: clean up splice code |
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On Mon, 9 Feb 2009, Eduard - Gabriel Munteanu wrote:
> On Mon, Feb 09, 2009 at 08:26:20PM +0200, Pekka Enberg wrote: > > Eduard - Gabriel Munteanu wrote: > >>> @@ -2573,45 +2607,25 @@ static ssize_t tracing_splice_read_pipe(struct > >>> file *filp, > >>> ret = iter->trace->splice_read(iter, filp, > >>> ppos, pipe, len, flags); > >>> if (ret) > >>> - goto out; > >>> + goto out_err; > >>> } > >>> ret = tracing_wait_pipe(filp); > >>> if (ret <= 0) > >>> - goto out; > >>> + goto out_err; > >>> if (!iter->ent && !find_next_entry_inc(iter)) { > >>> ret = -EFAULT; > >>> - goto out; > >>> + goto out_err; > >>> } > >>> /* Fill as many pages as possible. */ > >>> for (i = 0, rem = len; i < PIPE_BUFFERS && rem; i++) { > >>> pages[i] = alloc_page(GFP_KERNEL); > >>> + if (!pages[i]) > >>> + break; > >> I believe you should decrement 'i' before breaking, since we fill > >> spd.nr_pages just after the loop. In case the current page couldn't be > >> allocated, spd.nr_pages will be one too many (that is, 'i'). > > > > But, but, if we fail for i == 1, for example, we want ->nr_pages == 1, no? > > > > Pekka > > Sure, my bad. I even made the same assumption myself about the outer > 'for' loop when I wrote it ('i' would end up last page + 1). The patch is > okay. :-)
Heh, I was just about to say, if this is wrong then so is the if below it ;-)
pages[i] = alloc_page(GFP_KERNEL); if (!pages[i]) break;
rem = tracing_fill_pipe_page(pages[i], rem, iter);
/* Copy the data into the page, so we can start over. */ ret = trace_seq_to_buffer(&iter->seq, page_address(pages[i]), iter->seq.len); if (ret < 0) { __free_page(pages[i]);
Same 'i'. break; }
Thanks Eduard!
-- Steve
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