From: Douglas Anderson <diand...@chromium.org>
[ Upstream commit 299632e54b2e692d2830af84be51172480dc1e26 ]
If a regmap has "fast_io" set then its lock function uses a spinlock.
That doesn't work so well with the functions:
* regmap_cache_only_write_file()
* regmap_cache_bypass_write_file()
Both of the above functions have the pattern:
1. Lock the regmap.
2. Call:
debugfs_write_file_bool()
copy_from_user()
__might_fault()
__might_sleep()
Let's reorder things a bit so that we do all of our sleepable
functions before we grab the lock.
Fixes: d3dc5430d68f ("regmap: debugfs: Allow writes to cache state settings")
Signed-off-by: Douglas Anderson <diand...@chromium.org>
Link:
https://lore.kernel.org/r/20200715164611.1.I35b3533e8a80efde0cec1cc70f71e1e74b2fa0da@changeid
Signed-off-by: Mark Brown <broo...@kernel.org>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
drivers/base/regmap/regmap-debugfs.c | 52 ++++++++++++++++------------
1 file changed, 29 insertions(+), 23 deletions(-)
diff --git a/drivers/base/regmap/regmap-debugfs.c
b/drivers/base/regmap/regmap-debugfs.c
index c9687c8b23478..056e34ce1eddd 100644
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -453,29 +453,31 @@ static ssize_t regmap_cache_only_write_file(struct file
*file,
{
struct regmap *map = container_of(file->private_data,
struct regmap, cache_only);
- ssize_t result;
- bool was_enabled, require_sync = false;
+ bool new_val, require_sync = false;
int err;
- map->lock(map->lock_arg);
+ err = kstrtobool_from_user(user_buf, count, &new_val);
+ /* Ignore malforned data like debugfs_write_file_bool() */
+ if (err)
+ return count;
- was_enabled = map->cache_only;
+ err = debugfs_file_get(file->f_path.dentry);
+ if (err)
+ return err;
- result = debugfs_write_file_bool(file, user_buf, count, ppos);
- if (result < 0) {
- map->unlock(map->lock_arg);
- return result;
- }
+ map->lock(map->lock_arg);
- if (map->cache_only && !was_enabled) {
+ if (new_val && !map->cache_only) {
dev_warn(map->dev, "debugfs cache_only=Y forced\n");
add_taint(TAINT_USER, LOCKDEP_STILL_OK);
- } else if (!map->cache_only && was_enabled) {
+ } else if (!new_val && map->cache_only) {
dev_warn(map->dev, "debugfs cache_only=N forced: syncing
cache\n");
require_sync = true;
}
+ map->cache_only = new_val;
map->unlock(map->lock_arg);
+ debugfs_file_put(file->f_path.dentry);
if (require_sync) {
err = regcache_sync(map);
@@ -483,7 +485,7 @@ static ssize_t regmap_cache_only_write_file(struct file
*file,
dev_err(map->dev, "Failed to sync cache %d\n", err);
}
- return result;
+ return count;
}
static const struct file_operations regmap_cache_only_fops = {
@@ -498,28 +500,32 @@ static ssize_t regmap_cache_bypass_write_file(struct file
*file,
{
struct regmap *map = container_of(file->private_data,
struct regmap, cache_bypass);
- ssize_t result;
- bool was_enabled;
+ bool new_val;
+ int err;
- map->lock(map->lock_arg);
+ err = kstrtobool_from_user(user_buf, count, &new_val);
+ /* Ignore malforned data like debugfs_write_file_bool() */
+ if (err)
+ return count;
- was_enabled = map->cache_bypass;
+ err = debugfs_file_get(file->f_path.dentry);
+ if (err)
+ return err;
- result = debugfs_write_file_bool(file, user_buf, count, ppos);
- if (result < 0)
- goto out;
+ map->lock(map->lock_arg);
- if (map->cache_bypass && !was_enabled) {
+ if (new_val && !map->cache_bypass) {
dev_warn(map->dev, "debugfs cache_bypass=Y forced\n");
add_taint(TAINT_USER, LOCKDEP_STILL_OK);
- } else if (!map->cache_bypass && was_enabled) {
+ } else if (!new_val && map->cache_bypass) {
dev_warn(map->dev, "debugfs cache_bypass=N forced\n");
}
+ map->cache_bypass = new_val;
-out:
map->unlock(map->lock_arg);
+ debugfs_file_put(file->f_path.dentry);
- return result;
+ return count;
}
static const struct file_operations regmap_cache_bypass_fops = {
--
2.25.1
