[PATCH] staging: greybus: uart: replace IDR with XArray

[PATCH] staging: greybus: uart: replace IDR with XArray

[Jack Lee]

DEFINE_IDR is deprecated in favor of XArray. Convert tty_minors
from IDR to XArray, replacing idr_alloc, idr_find, idr_remove and
idr_destroy with their xa_alloc, xa_load, xa_erase and xa_destroy
equivalents.

Signed-off-by: Jack Lee <skunkolee@gmail.com>
---
 drivers/staging/greybus/uart.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/drivers/staging/greybus/uart.c b/drivers/staging/greybus/uart.c
index 7d060b4cd33d..30afcd0caa14 100644
--- a/drivers/staging/greybus/uart.c
+++ b/drivers/staging/greybus/uart.c
@@ -22,13 +22,13 @@
 #include <linux/serial.h>
 #include <linux/tty_driver.h>
 #include <linux/tty_flip.h>
-#include <linux/idr.h>
 #include <linux/fs.h>
 #include <linux/kdev_t.h>
 #include <linux/kfifo.h>
 #include <linux/workqueue.h>
 #include <linux/completion.h>
 #include <linux/greybus.h>
+#include <linux/xarray.h>
 
 #include "gbphy.h"
 
@@ -67,7 +67,7 @@ struct gb_tty {
 };
 
 static struct tty_driver *gb_tty_driver;
-static DEFINE_IDR(tty_minors);
+static DEFINE_XARRAY_ALLOC(tty_minors);
 static DEFINE_MUTEX(table_lock);
 
 static int gb_uart_receive_data_handler(struct gb_operation *op)
@@ -342,7 +342,7 @@ static struct gb_tty *get_gb_by_minor(unsigned int minor)
 	struct gb_tty *gb_tty;
 
 	mutex_lock(&table_lock);
-	gb_tty = idr_find(&tty_minors, minor);
+	gb_tty = xa_load(&tty_minors, minor);
 	if (gb_tty) {
 		mutex_lock(&gb_tty->mutex);
 		if (gb_tty->disconnected) {
@@ -359,14 +359,13 @@ static struct gb_tty *get_gb_by_minor(unsigned int minor)
 
 static int alloc_minor(struct gb_tty *gb_tty)
 {
-	int minor;
+	int ret;
 
-	mutex_lock(&table_lock);
-	minor = idr_alloc(&tty_minors, gb_tty, 0, GB_NUM_MINORS, GFP_KERNEL);
-	mutex_unlock(&table_lock);
-	if (minor >= 0)
-		gb_tty->minor = minor;
-	return minor;
+	ret = xa_alloc(&tty_minors, &gb_tty->minor, gb_tty,
+		       XA_LIMIT(0, GB_NUM_MINORS - 1), GFP_KERNEL);
+	if (ret)
+		return ret;
+	return gb_tty->minor;
 }
 
 static void release_minor(struct gb_tty *gb_tty)
@@ -375,7 +374,7 @@ static void release_minor(struct gb_tty *gb_tty)
 
 	gb_tty->minor = 0;	/* Maybe should use an invalid value instead */
 	mutex_lock(&table_lock);
-	idr_remove(&tty_minors, minor);
+	xa_erase(&tty_minors, minor);
 	mutex_unlock(&table_lock);
 }
 
@@ -984,7 +983,7 @@ static void gb_tty_exit(void)
 {
 	tty_unregister_driver(gb_tty_driver);
 	tty_driver_kref_put(gb_tty_driver);
-	idr_destroy(&tty_minors);
+	xa_destroy(&tty_minors);
 }
 
 static const struct gbphy_device_id gb_uart_id_table[] = {
-- 
2.54.0

Re: [PATCH] staging: greybus: uart: replace IDR with XArray

[Greg KH]

On Tue, Jun 16, 2026 at 12:07:03PM -0700, Jack Lee wrote:
> DEFINE_IDR is deprecated in favor of XArray. Convert tty_minors
> from IDR to XArray, replacing idr_alloc, idr_find, idr_remove and
> idr_destroy with their xa_alloc, xa_load, xa_erase and xa_destroy
> equivalents.
> 
> Signed-off-by: Jack Lee <skunkolee@gmail.com>
> ---
>  drivers/staging/greybus/uart.c | 23 +++++++++++------------
>  1 file changed, 11 insertions(+), 12 deletions(-)
> 

This "cleanup" has come up in the past, and shot down each time as it's
not really needed or necessary.  idr is just fine to use here and xarray
is overkill.

thanks,

greg k-h