From 50d6b9d56e69563d3b261ee25bc644c59c5bff58 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Mon, 12 Feb 2024 19:01:36 +0200 Subject: auxdisplay: linedisp: Use unique number for id The absence of decrementation of linedisp_id is incorrect in two ways, i.e. it may cause: - an ID exhaustion - (and if the above is addressed) a duplicate id number may be allocated next time a device is added Replace above mentioned approach by using IDA framework. Reviewed-by: Geert Uytterhoeven Tested-by: Geert Uytterhoeven Signed-off-by: Andy Shevchenko --- drivers/auxdisplay/line-display.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'drivers/auxdisplay/line-display.c') diff --git a/drivers/auxdisplay/line-display.c b/drivers/auxdisplay/line-display.c index 310e9bfb41ae..c4dbb13293d1 100644 --- a/drivers/auxdisplay/line-display.c +++ b/drivers/auxdisplay/line-display.c @@ -11,6 +11,7 @@ #include #include +#include #include #include #include @@ -188,11 +189,14 @@ static struct attribute *linedisp_attrs[] = { }; ATTRIBUTE_GROUPS(linedisp); +static DEFINE_IDA(linedisp_id); + static void linedisp_release(struct device *dev) { struct linedisp *linedisp = container_of(dev, struct linedisp, dev); kfree(linedisp->message); + ida_free(&linedisp_id, linedisp->id); } static const struct device_type linedisp_type = { @@ -214,7 +218,6 @@ int linedisp_register(struct linedisp *linedisp, struct device *parent, unsigned int num_chars, char *buf, void (*update)(struct linedisp *linedisp)) { - static atomic_t linedisp_id = ATOMIC_INIT(-1); int err; memset(linedisp, 0, sizeof(*linedisp)); @@ -225,9 +228,13 @@ int linedisp_register(struct linedisp *linedisp, struct device *parent, linedisp->num_chars = num_chars; linedisp->scroll_rate = DEFAULT_SCROLL_RATE; + err = ida_alloc(&linedisp_id, GFP_KERNEL); + if (err < 0) + return err; + linedisp->id = err; + device_initialize(&linedisp->dev); - dev_set_name(&linedisp->dev, "linedisp.%lu", - (unsigned long)atomic_inc_return(&linedisp_id)); + dev_set_name(&linedisp->dev, "linedisp.%u", linedisp->id); /* initialise a timer for scrolling the message */ timer_setup(&linedisp->timer, linedisp_scroll, 0); -- cgit v1.2.3