ping.
On Tue, Aug 10, 2021 at 05:26:22PM +0200, Christoph Hellwig wrote:
> Factor out a helper to deal with a single blkcg_gq to make the code a
> little bit easier to follow.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> block/blk-cgroup.c | 148 ++++++++++++++++++++++-----------------------
> 1 file changed, 74 insertions(+), 74 deletions(-)
>
> diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
> index db034e35ae20..52aa0540ccaf 100644
> --- a/block/blk-cgroup.c
> +++ b/block/blk-cgroup.c
> @@ -870,97 +870,97 @@ static void blkcg_fill_root_iostats(void)
> }
> }
>
> -static int blkcg_print_stat(struct seq_file *sf, void *v)
> +static void blkcg_print_one_stat(struct blkcg_gq *blkg, struct seq_file *s)
> {
> - struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
> - struct blkcg_gq *blkg;
> -
> - if (!seq_css(sf)->parent)
> - blkcg_fill_root_iostats();
> - else
> - cgroup_rstat_flush(blkcg->css.cgroup);
> -
> - rcu_read_lock();
> + struct blkg_iostat_set *bis = &blkg->iostat;
> + u64 rbytes, wbytes, rios, wios, dbytes, dios;
> + bool has_stats = false;
> + const char *dname;
> + unsigned seq;
> + char *buf;
> + size_t size = seq_get_buf(s, &buf), off = 0;
> + int i;
>
> - hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
> - struct blkg_iostat_set *bis = &blkg->iostat;
> - const char *dname;
> - char *buf;
> - u64 rbytes, wbytes, rios, wios, dbytes, dios;
> - size_t size = seq_get_buf(sf, &buf), off = 0;
> - int i;
> - bool has_stats = false;
> - unsigned seq;
> + if (!blkg->online)
> + return;
>
> - spin_lock_irq(&blkg->q->queue_lock);
> + dname = blkg_dev_name(blkg);
> + if (!dname)
> + return;
>
> - if (!blkg->online)
> - goto skip;
> + /*
> + * Hooray string manipulation, count is the size written NOT
> + * INCLUDING THE \0, so size is now count+1 less than what we
> + * had before, but we want to start writing the next bit from
> + * the \0 so we only add count to buf.
> + */
> + off += scnprintf(buf+off, size-off, "%s ", dname);
>
> - dname = blkg_dev_name(blkg);
> - if (!dname)
> - goto skip;
> + do {
> + seq = u64_stats_fetch_begin(&bis->sync);
> +
> + rbytes = bis->cur.bytes[BLKG_IOSTAT_READ];
> + wbytes = bis->cur.bytes[BLKG_IOSTAT_WRITE];
> + dbytes = bis->cur.bytes[BLKG_IOSTAT_DISCARD];
> + rios = bis->cur.ios[BLKG_IOSTAT_READ];
> + wios = bis->cur.ios[BLKG_IOSTAT_WRITE];
> + dios = bis->cur.ios[BLKG_IOSTAT_DISCARD];
> + } while (u64_stats_fetch_retry(&bis->sync, seq));
> +
> + if (rbytes || wbytes || rios || wios) {
> + has_stats = true;
> + off += scnprintf(buf+off, size-off,
> + "rbytes=%llu wbytes=%llu rios=%llu wios=%llu dbytes=%llu dios=%llu",
> + rbytes, wbytes, rios, wios,
> + dbytes, dios);
> + }
>
> - /*
> - * Hooray string manipulation, count is the size written NOT
> - * INCLUDING THE \0, so size is now count+1 less than what we
> - * had before, but we want to start writing the next bit from
> - * the \0 so we only add count to buf.
> - */
> - off += scnprintf(buf+off, size-off, "%s ", dname);
> + if (blkcg_debug_stats && atomic_read(&blkg->use_delay)) {
> + has_stats = true;
> + off += scnprintf(buf+off, size-off, " use_delay=%d delay_nsec=%llu",
> + atomic_read(&blkg->use_delay),
> + atomic64_read(&blkg->delay_nsec));
> + }
>
> - do {
> - seq = u64_stats_fetch_begin(&bis->sync);
> + for (i = 0; i < BLKCG_MAX_POLS; i++) {
> + struct blkcg_policy *pol = blkcg_policy[i];
> + size_t written;
>
> - rbytes = bis->cur.bytes[BLKG_IOSTAT_READ];
> - wbytes = bis->cur.bytes[BLKG_IOSTAT_WRITE];
> - dbytes = bis->cur.bytes[BLKG_IOSTAT_DISCARD];
> - rios = bis->cur.ios[BLKG_IOSTAT_READ];
> - wios = bis->cur.ios[BLKG_IOSTAT_WRITE];
> - dios = bis->cur.ios[BLKG_IOSTAT_DISCARD];
> - } while (u64_stats_fetch_retry(&bis->sync, seq));
> + if (!blkg->pd[i] || !pol->pd_stat_fn)
> + continue;
>
> - if (rbytes || wbytes || rios || wios) {
> + written = pol->pd_stat_fn(blkg->pd[i], buf+off, size-off);
> + if (written)
> has_stats = true;
> - off += scnprintf(buf+off, size-off,
> - "rbytes=%llu wbytes=%llu rios=%llu wios=%llu dbytes=%llu dios=%llu",
> - rbytes, wbytes, rios, wios,
> - dbytes, dios);
> - }
> + off += written;
> + }
>
> - if (blkcg_debug_stats && atomic_read(&blkg->use_delay)) {
> - has_stats = true;
> - off += scnprintf(buf+off, size-off,
> - " use_delay=%d delay_nsec=%llu",
> - atomic_read(&blkg->use_delay),
> - (unsigned long long)atomic64_read(&blkg->delay_nsec));
> + if (has_stats) {
> + if (off < size - 1) {
> + off += scnprintf(buf+off, size-off, "\n");
> + seq_commit(s, off);
> + } else {
> + seq_commit(s, -1);
> }
> + }
> +}
>
> - for (i = 0; i < BLKCG_MAX_POLS; i++) {
> - struct blkcg_policy *pol = blkcg_policy[i];
> - size_t written;
> -
> - if (!blkg->pd[i] || !pol->pd_stat_fn)
> - continue;
> +static int blkcg_print_stat(struct seq_file *sf, void *v)
> +{
> + struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
> + struct blkcg_gq *blkg;
>
> - written = pol->pd_stat_fn(blkg->pd[i], buf+off, size-off);
> - if (written)
> - has_stats = true;
> - off += written;
> - }
> + if (!seq_css(sf)->parent)
> + blkcg_fill_root_iostats();
> + else
> + cgroup_rstat_flush(blkcg->css.cgroup);
>
> - if (has_stats) {
> - if (off < size - 1) {
> - off += scnprintf(buf+off, size-off, "\n");
> - seq_commit(sf, off);
> - } else {
> - seq_commit(sf, -1);
> - }
> - }
> - skip:
> + rcu_read_lock();
> + hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
> + spin_lock_irq(&blkg->q->queue_lock);
> + blkcg_print_one_stat(blkg, sf);
> spin_unlock_irq(&blkg->q->queue_lock);
> }
> -
> rcu_read_unlock();
> return 0;
> }
> --
> 2.30.2
---end quoted text---
