On 06.07.24 10:38, Ronald Wahl wrote:
On 06.07.24 02:39, Jakub Kicinski wrote:
On Thu, 4 Jul 2024 19:47:56 +0200 Ronald Wahl wrote:
--- a/drivers/net/ethernet/micrel/ks8851_spi.c
+++ b/drivers/net/ethernet/micrel/ks8851_spi.c
@@ -385,7 +385,7 @@ static netdev_tx_t ks8851_start_xmit_spi(struct
sk_buff *skb,
netif_dbg(ks, tx_queued, ks->netdev,
"%s: skb %p, %d@%p\n", __func__, skb, skb->len, skb->data);
- spin_lock(&ks->statelock);
+ spin_lock_bh(&ks->statelock);
if (ks->queued_len + needed > ks->tx_space) {
netif_stop_queue(dev);
@@ -395,7 +395,7 @@ static netdev_tx_t ks8851_start_xmit_spi(struct
sk_buff *skb,
skb_queue_tail(&ks->txq, skb);
}
- spin_unlock(&ks->statelock);
+ spin_unlock_bh(&ks->statelock);
this one probably can stay as spin_lock() since networking stack only
calls xmit in BH context.
I already suspected this it was more a mental hint here. I will remove it.
But I see 2 other spin_lock(statelock) in the
driver which I'm not as sure about. Any taking of this lock has to be
_bh() unless you're sure the caller is already in BH.
The other two instances are not in BH context as far as I know but also
do not interfere with BH. The one in ks8861_tx_work protects only
variable assignments used only inside the driver and the one in
ks8851_set_rx_mode also only does some driver local variable stuff and a
schedule_work which as far as I know has nothing to do with BH because
workqueues are running in process context. Am I wrong here?
I guess I found a misunderstanding on my side: I was assuming that a
softirq cannot asynchronously interrupt a spin lock protected section. Maybe
this is wrong. In the one place where I'm waking the queue again the
spin_lock_bh avoids synchronously triggering the BH processing while still
holding a spinlock.
I will use the _bh variants on the two other places.
- ron
________________________________
Ce message, ainsi que tous les fichiers joints à ce message, peuvent contenir des informations sensibles et/ ou confidentielles ne devant pas être divulguées. Si vous n'êtes pas le destinataire de ce message (ou que vous recevez ce message par erreur), nous vous remercions de le notifier immédiatement à son expéditeur, et de détruire ce message. Toute copie, divulgation, modification, utilisation ou diffusion, non autorisée, directe ou indirecte, de tout ou partie de ce message, est strictement interdite.
This e-mail, and any document attached hereby, may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized, direct or indirect, copying, disclosure, distribution or other use of the material or parts thereof is strictly forbidden.
