[PATCH] ax25: use GFP_KERNEL over GFP_ATOMIC where possible

* [PATCH] ax25: use GFP_KERNEL over GFP_ATOMIC where possible
@ 2022-06-02 11:21 Peter Lafreniere
  2022-06-03  2:47 ` Jakub Kicinski
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Peter Lafreniere @ 2022-06-02 11:21 UTC (permalink / raw)
  To: linux-hams; +Cc: ralf, netdev, Peter Lafreniere

There are a few functions that can sleep that use GFP_ATOMIC.
Here we change allocations to use the more reliable GFP_KERNEL
flag.

ax25_dev_device_up() is only called during device setup, which is
done in user context. In addition, ax25_dev_device_up()
unconditionally calls ax25_register_dev_sysctl(), which already
allocates with GFP_KERNEL.

ax25_rt_add() is a static function that is only called from
ax25_rt_ioctl(), which must run in user context already due to
copy_from_user() usage.

Since it is allowed to sleep in both of these functions, here we
change the functions to use GFP_KERNEL to reduce unnecessary
out-of-memory errors.

Signed-off-by: Peter Lafreniere <pjlafren@mtu.edu>
---
 net/ax25/ax25_dev.c   | 4 ++--
 net/ax25/ax25_route.c | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c
index d2a244e1c260..b264904980a8 100644
--- a/net/ax25/ax25_dev.c
+++ b/net/ax25/ax25_dev.c
@@ -52,7 +52,7 @@ void ax25_dev_device_up(struct net_device *dev)
 {
 	ax25_dev *ax25_dev;
 
-	if ((ax25_dev = kzalloc(sizeof(*ax25_dev), GFP_ATOMIC)) == NULL) {
+	if ((ax25_dev = kzalloc(sizeof(*ax25_dev), GFP_KERNEL)) == NULL) {
 		printk(KERN_ERR "AX.25: ax25_dev_device_up - out of memory\n");
 		return;
 	}
@@ -60,7 +60,7 @@ void ax25_dev_device_up(struct net_device *dev)
 	refcount_set(&ax25_dev->refcount, 1);
 	dev->ax25_ptr     = ax25_dev;
 	ax25_dev->dev     = dev;
-	dev_hold_track(dev, &ax25_dev->dev_tracker, GFP_ATOMIC);
+	dev_hold_track(dev, &ax25_dev->dev_tracker, GFP_KERNEL);
 	ax25_dev->forward = NULL;
 
 	ax25_dev->values[AX25_VALUES_IPDEFMODE] = AX25_DEF_IPDEFMODE;
diff --git a/net/ax25/ax25_route.c b/net/ax25/ax25_route.c
index b7c4d656a94b..c77b848ccfc7 100644
--- a/net/ax25/ax25_route.c
+++ b/net/ax25/ax25_route.c
@@ -91,7 +91,7 @@ static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
 			kfree(ax25_rt->digipeat);
 			ax25_rt->digipeat = NULL;
 			if (route->digi_count != 0) {
-				if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
+				if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_KERNEL)) == NULL) {
 					write_unlock_bh(&ax25_route_lock);
 					ax25_dev_put(ax25_dev);
 					return -ENOMEM;
@@ -110,7 +110,7 @@ static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
 		ax25_rt = ax25_rt->next;
 	}
 
-	if ((ax25_rt = kmalloc(sizeof(ax25_route), GFP_ATOMIC)) == NULL) {
+	if ((ax25_rt = kmalloc(sizeof(ax25_route), GFP_KERNEL)) == NULL) {
 		write_unlock_bh(&ax25_route_lock);
 		ax25_dev_put(ax25_dev);
 		return -ENOMEM;
-- 
2.36.1


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