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[207.226.244.124]) by smtp.gmail.com with ESMTPSA id h130sm4479717pfc.98.2018.04.25.03.59.49 (version=TLS1_2 cipher=AES128-SHA bits=128/128); Wed, 25 Apr 2018 03:59:50 -0700 (PDT) From: Ganesh Mahendran To: rjw@rjwysocki.net, pavel@ucw.cz, len.brown@intel.com, rafael@kernel.org, gregkh@linuxfoundation.org, geert@linux-m68k.org Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Ganesh Mahendran Subject: [PATCH v3] PM / wakeup: use seq_open() to show wakeup stats Date: Wed, 25 Apr 2018 18:59:31 +0800 Message-Id: <1524653971-10425-1-git-send-email-opensource.ganesh@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP single_open() interface requires that the whole output must fit into a single buffer. This will lead to timeout when system memory is not in a good situation. This patch use seq_open() to show wakeup stats. This method need only one page, so timeout will not be observed. Signed-off-by: Ganesh Mahendran ---- v3: simplify wakeup_sources_stats_seq_start v2: use srcu_read_lock instead of rcu_read_lock --- drivers/base/power/wakeup.c | 75 +++++++++++++++++++++++++++++++++++---------- 1 file changed, 59 insertions(+), 16 deletions(-) diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c index ea01621..5872705 100644 --- a/drivers/base/power/wakeup.c +++ b/drivers/base/power/wakeup.c @@ -1029,32 +1029,75 @@ static int print_wakeup_source_stats(struct seq_file *m, return 0; } -/** - * wakeup_sources_stats_show - Print wakeup sources statistics information. - * @m: seq_file to print the statistics into. - */ -static int wakeup_sources_stats_show(struct seq_file *m, void *unused) +static void *wakeup_sources_stats_seq_start(struct seq_file *m, + loff_t *pos) { struct wakeup_source *ws; - int srcuidx; + loff_t n = *pos; + int *srcuidx = m->private; - seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t" - "expire_count\tactive_since\ttotal_time\tmax_time\t" - "last_change\tprevent_suspend_time\n"); + if (n == 0) { + seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t" + "expire_count\tactive_since\ttotal_time\tmax_time\t" + "last_change\tprevent_suspend_time\n"); + } - srcuidx = srcu_read_lock(&wakeup_srcu); - list_for_each_entry_rcu(ws, &wakeup_sources, entry) - print_wakeup_source_stats(m, ws); - srcu_read_unlock(&wakeup_srcu, srcuidx); + *srcuidx = srcu_read_lock(&wakeup_srcu); + list_for_each_entry_rcu(ws, &wakeup_sources, entry) { + if (n-- <= 0) + return ws; + } + + return NULL; +} + +static void *wakeup_sources_stats_seq_next(struct seq_file *m, + void *v, loff_t *pos) +{ + struct wakeup_source *ws = v; + struct wakeup_source *next_ws = NULL; + + ++(*pos); - print_wakeup_source_stats(m, &deleted_ws); + list_for_each_entry_continue_rcu(ws, &wakeup_sources, entry) { + next_ws = ws; + break; + } + + return next_ws; +} + +static void wakeup_sources_stats_seq_stop(struct seq_file *m, void *v) +{ + int *srcuidx = m->private; + + srcu_read_unlock(&wakeup_srcu, *srcuidx); +} + +/** + * wakeup_sources_stats_seq_show - Print wakeup sources statistics information. + * @m: seq_file to print the statistics into. + * @v: wakeup_source of each iteration + */ +static int wakeup_sources_stats_seq_show(struct seq_file *m, void *v) +{ + struct wakeup_source *ws = v; + + print_wakeup_source_stats(m, ws); return 0; } +static const struct seq_operations wakeup_sources_stats_seq_ops = { + .start = wakeup_sources_stats_seq_start, + .next = wakeup_sources_stats_seq_next, + .stop = wakeup_sources_stats_seq_stop, + .show = wakeup_sources_stats_seq_show, +}; + static int wakeup_sources_stats_open(struct inode *inode, struct file *file) { - return single_open(file, wakeup_sources_stats_show, NULL); + return seq_open_private(file, &wakeup_sources_stats_seq_ops, sizeof(int)); } static const struct file_operations wakeup_sources_stats_fops = { @@ -1062,7 +1105,7 @@ static int wakeup_sources_stats_open(struct inode *inode, struct file *file) .open = wakeup_sources_stats_open, .read = seq_read, .llseek = seq_lseek, - .release = single_release, + .release = seq_release_private, }; static int __init wakeup_sources_debugfs_init(void)