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5c34c0aef1
bq27xxx_battery_update() assumes / requires that it is only run once,
not multiple times at the same time. But there are 3 possible callers:
1. bq27xxx_battery_poll() delayed_work item handler
2. bq27xxx_battery_irq_handler_thread() I2C IRQ handler
3. bq27xxx_battery_setup()
And there is no protection against these racing with each other,
fix this race condition by making all callers take di->lock:
- Rename bq27xxx_battery_update() to bq27xxx_battery_update_unlocked()
- Add new bq27xxx_battery_update() which takes di->lock and then calls
bq27xxx_battery_update_unlocked()
- Make stale cache check code in bq27xxx_battery_get_property(), which
already takes di->lock directly to check the jiffies, call
bq27xxx_battery_update_unlocked() instead of messing with
the delayed_work item
- Make bq27xxx_battery_update_unlocked() mod the delayed-work item
so that the next poll is delayed to poll_interval milliseconds after
the last update independent of the source of the update
Fixes: 740b755a3b ("bq27x00: Poll battery state")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.