On Tue, 22 Apr 2025 00:28:50 +0900
Jeongjun Park <[email protected]> wrote:
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -6784,7 +6784,7 @@ static ssize_t tracing_splice_read_pipe(struct file
> *filp,
> };
> ssize_t ret;
> size_t rem;
> - unsigned int i;
> + unsigned int i, copy_len;
FYI, I don't care for variables to be on the same line unless they are
related. As "i" and "copy_len" are not related, the should be separate
declarations.
unsigned int copy_len;
unsigned int i;
>
> if (splice_grow_spd(pipe, &spd))
> return -ENOMEM;
> @@ -6818,16 +6818,18 @@ static ssize_t tracing_splice_read_pipe(struct file
> *filp,
>
> rem = tracing_fill_pipe_page(rem, iter);
>
> + copy_len = trace_seq_used(&iter->seq);
Why not have the min here?
copy_len = min(trace_seq_used(&iter->seq), PAGE_SIZE);
??
> +
> /* Copy the data into the page, so we can start over. */
> ret = trace_seq_to_buffer(&iter->seq,
> page_address(spd.pages[i]),
> - trace_seq_used(&iter->seq));
> + min(copy_len, PAGE_SIZE));
> if (ret < 0) {
> __free_page(spd.pages[i]);
> break;
> }
> spd.partial[i].offset = 0;
> - spd.partial[i].len = trace_seq_used(&iter->seq);
> + spd.partial[i].len = min(copy_len, PAGE_SIZE);
And actually, len should equal ret as that's how much was copied.
-- Steve
>
> trace_seq_init(&iter->seq);
> }
> --
