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| author | Andy Shevchenko <andriy.shevchenko@linux.intel.com> | 2024-02-12 20:01:36 +0300 |
|---|---|---|
| committer | Andy Shevchenko <andriy.shevchenko@linux.intel.com> | 2024-02-15 14:31:12 +0300 |
| commit | 50d6b9d56e69563d3b261ee25bc644c59c5bff58 (patch) | |
| tree | 9bf0f919315adb02c61dca792cebc7c6582a6b03 | |
| parent | 2327960f0c5ecd7a285e69284b6ec3fdbd2757be (diff) | |
| download | linux-50d6b9d56e69563d3b261ee25bc644c59c5bff58.tar.xz | |
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 <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
| -rw-r--r-- | drivers/auxdisplay/line-display.c | 13 | ||||
| -rw-r--r-- | drivers/auxdisplay/line-display.h | 2 |
2 files changed, 12 insertions, 3 deletions
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 <generated/utsrelease.h> #include <linux/device.h> +#include <linux/idr.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/string.h> @@ -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); diff --git a/drivers/auxdisplay/line-display.h b/drivers/auxdisplay/line-display.h index 0f5891d34c48..5068e3445e4f 100644 --- a/drivers/auxdisplay/line-display.h +++ b/drivers/auxdisplay/line-display.h @@ -22,6 +22,7 @@ * @message_len: the length of the @message string * @scroll_pos: index of the first character of @message currently displayed * @scroll_rate: scroll interval in jiffies + * @id: instance id of this display */ struct linedisp { struct device dev; @@ -33,6 +34,7 @@ struct linedisp { unsigned int message_len; unsigned int scroll_pos; unsigned int scroll_rate; + unsigned int id; }; int linedisp_register(struct linedisp *linedisp, struct device *parent, |