[PATCH AUTOSEL 5.10 20/25] PM: wakeup: simplify the output logic of pm_show_wakelocks()

Sasha Levin
2022-02-03T20:38:00Z

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit c9d967b2ce40d71e968eb839f36c936b8a9cf1ea ]

The buffer handling in pm_show_wakelocks() is tricky, and hopefully
correct. Ensure it really is correct by using sysfs_emit_at() which
handles all of the tricky string handling logic in a PAGE_SIZE buffer
for us automatically as this is a sysfs file being read from.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/power/wakelock.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/kernel/power/wakelock.c b/kernel/power/wakelock.c
index 105df4dfc7839..52571dcad768b 100644
--- a/kernel/power/wakelock.c
+++ b/kernel/power/wakelock.c
@@ -39,23 +39,20 @@ ssize_t pm_show_wakelocks(char *buf, bool show_active)
{
struct rb_node *node;
struct wakelock *wl;
- char *str = buf;
- char *end = buf + PAGE_SIZE;
+ int len = 0;

mutex_lock(&wakelocks_lock);

for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) {
wl = rb_entry(node, struct wakelock, node);
if (wl->ws->active == show_active)
- str += scnprintf(str, end - str, "%s ", wl->name);
+ len += sysfs_emit_at(buf, len, "%s ", wl->name);
}
- if (str > buf)
- str--;

- str += scnprintf(str, end - str, "\n");
+ len += sysfs_emit_at(buf, len, "\n");

mutex_unlock(&wakelocks_lock);
- return (str - buf);
+ return len;
}

#if CONFIG_PM_WAKELOCKS_LIMIT > 0
--
2.34.1