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authorAndy Shevchenko <andriy.shevchenko@linux.intel.com>2024-02-12 20:01:36 +0300
committerAndy Shevchenko <andriy.shevchenko@linux.intel.com>2024-02-15 14:31:12 +0300
commit50d6b9d56e69563d3b261ee25bc644c59c5bff58 (patch)
tree9bf0f919315adb02c61dca792cebc7c6582a6b03 /drivers/auxdisplay
parent2327960f0c5ecd7a285e69284b6ec3fdbd2757be (diff)
downloadlinux-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>
Diffstat (limited to 'drivers/auxdisplay')
-rw-r--r--drivers/auxdisplay/line-display.c13
-rw-r--r--drivers/auxdisplay/line-display.h2
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,