Hi,
On Wed, Feb 16, 2022 at 02:29:34PM +0100, Tobias Waldekranz wrote:
> +static int mv88e6xxx_sid_new(struct mv88e6xxx_chip *chip, u8 *sid)
> +{
> + DECLARE_BITMAP(busy, MV88E6XXX_N_SID) = { 0 };
> + struct mv88e6xxx_mst *mst;
> +
> + set_bit(0, busy);
> +
> + list_for_each_entry(mst, &chip->msts, node) {
> + set_bit(mst->stu.sid, busy);
> + }
Do you need these set_bit() operations to be atomic? Would __set_bit()
produce better code?
> +
> + *sid = find_first_zero_bit(busy, MV88E6XXX_N_SID);
> +
> + return (*sid >= mv88e6xxx_max_sid(chip)) ? -ENOSPC : 0;
Hmm. Let's hope that mv88e6xxx_max_sid() never returns a value larger
than MV88E6XXX_N_SID.
> +}
> +
...
> +static int mv88e6xxx_sid_get(struct mv88e6xxx_chip *chip, struct net_device *br,
> + u16 mstid, u8 *sid)
> +{
> + struct mv88e6xxx_mst *mst;
> + int err;
> +
> + if (!br)
> + return 0;
> +
> + if (!mv88e6xxx_has_stu(chip))
> + return -EOPNOTSUPP;
> +
> + list_for_each_entry(mst, &chip->msts, node) {
> + if (mst->br == br && mst->mstid == mstid) {
> + refcount_inc(&mst->refcnt);
> + *sid = mst->stu.sid;
> + return 0;
> + }
> + }
> +
> + err = mv88e6xxx_sid_new(chip, sid);
> + if (err)
> + return err;
> +
> + mst = kzalloc(sizeof(*mst), GFP_KERNEL);
> + if (!mst)
> + return -ENOMEM;
> +
> + INIT_LIST_HEAD(&mst->node);
There is no need to initialise the node if you're then going to be
adding it to the list.
> + refcount_set(&mst->refcnt, 1);
> + mst->br = br;
> + mst->mstid = mstid;
> + mst->stu.valid = true;
> + mst->stu.sid = *sid;
> + list_add_tail(&mst->node, &chip->msts);
> + return mv88e6xxx_stu_loadpurge(chip, &mst->stu);
I haven't checked what the locking is here - I hope it's not possible
for two of these to run concurrently.
Thanks.
--
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