Messages in this thread | | | From | Andy Shevchenko <> | Date | Tue, 12 Dec 2017 13:12:05 +0200 | Subject | Re: [PATCH] regmap: allow to disable all locking mechanisms |
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On Sun, Dec 10, 2017 at 5:14 PM, Bartosz Golaszewski <brgl@bgdev.pl> wrote: > 2017-12-10 14:10 GMT+01:00 Andy Shevchenko <andy.shevchenko@gmail.com>: >> On Wed, Dec 6, 2017 at 4:26 PM, Bartosz Golaszewski <brgl@bgdev.pl> wrote: >>> We have a use case in the at24 EEPROM driver (recently converted to >>> using regmap instead of raw i2c/smbus calls) where we read from/write >>> to the regmap in a loop, while protecting the entire loop with >>> a mutex. >>> >>> Currently this implicitly makes us use two mutexes - one in the driver >>> and one in regmap. While browsing the code for similar use cases I >>> noticed a significant number of places where locking *seems* redundant. >>> >>> Allow users to completely disable any locking mechanisms in regmap >>> config. >> >>> +static void regmap_lock_unlock_empty(void *__map) >> >> ..._none()? >> > > Too late, Mark already applied it.
Ah, Mark always works at speed of light!
>> Why not to introduce positive switch, namely >> bool mutex_lock; // choose better name >> and assign ..._none() by default? > > Because we don't want to break all the existing regmaps, if map->lock > or map->unlock is empty, regmap core decides internally whether to use > a mutex or a spinlock.
Good point. So, it means the options like: nomutex (false — mutex is in use) or nolock (true — disable locking). From those the latter looks better to me and IIUC you went that way.
-- With Best Regards, Andy Shevchenko
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