Re: [PATCH net-next] xsk: Return -EINVAL instead of -EBUSY after xsk_get_pool_from_qid() fails

From: wanghai (M)
Date: Wed Jun 02 2021 - 05:27:30 EST

Sorry, I misunderstood here, this is a faulty patch and no changes are needed here. Please ignore this patch

在 2021/6/2 16:29, Magnus Karlsson 写道:
On Wed, Jun 2, 2021 at 6:02 AM Wang Hai <wanghai38@xxxxxxxxxx> wrote:
xsk_get_pool_from_qid() fails not because the device's queues are busy,
but because the queue_id exceeds the current number of queues.
So when it fails, it is better to return -EINVAL instead of -EBUSY.

Signed-off-by: Wang Hai <wanghai38@xxxxxxxxxx>
net/xdp/xsk_buff_pool.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
index 8de01aaac4a0..30ece117117a 100644
--- a/net/xdp/xsk_buff_pool.c
+++ b/net/xdp/xsk_buff_pool.c
@@ -135,7 +135,7 @@ int xp_assign_dev(struct xsk_buff_pool *pool,
return -EINVAL;

if (xsk_get_pool_from_qid(netdev, queue_id))
- return -EBUSY;
+ return -EINVAL;
I guess your intent here is to return -EINVAL only when the queue_id
is larger than the number of active queues.

Yes, I just confirmed that this has been implemented in xp_assign_dev().

int xp_assign_dev()



    err = xsk_reg_pool_at_qid(netdev, pool, queue_id);

    if (err)

        return err;     //return -EINVAL;



But this patch also
changes the return code when the queue id is already in use and in
that case we should continue to return -EBUSY. As this function is
used by a number of drivers, the easiest way to accomplish this is to
introduce a test for queue_id out of bounds before this if-statement
and return -EINVAL there.

pool->netdev = netdev;
pool->queue_id = queue_id;