Le 04/09/2023 à 14:31, Alexandra Diupina a écrit :
> Process the result of hdlc_open() and call uhdlc_close()
> in case of an error. It is necessary to pass the error
> code up the control flow, similar to a possible
> error in request_irq().
> Also add a hdlc_close() call to the uhdlc_close()
> because the comment to hdlc_close() says it must be called
> by the hardware driver when the HDLC device is being closed
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: c19b6d246a35 ("drivers/net: support hdlc function for QE-UCC")
> Signed-off-by: Alexandra Diupina <adiup...@astralinux.ru>
> ---
> v4: undo all the things done prior to hdlc_open() as
> Jakub Kicinski <k...@kernel.org> suggested,
> add hdlc_close() call to the uhdlc_close() to match the function comment,
> add uhdlc_close() declaration to the top of the file not to put the
> uhdlc_close() function definition before uhdlc_open()
> v3: Fix the commits tree
> v2: Remove the 'rc' variable (stores the return value of the
> hdlc_open()) as Christophe Leroy <christophe.le...@csgroup.eu> suggested
> drivers/net/wan/fsl_ucc_hdlc.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/wan/fsl_ucc_hdlc.c b/drivers/net/wan/fsl_ucc_hdlc.c
> index 47c2ad7a3e42..fd999dabdd39 100644
> --- a/drivers/net/wan/fsl_ucc_hdlc.c
> +++ b/drivers/net/wan/fsl_ucc_hdlc.c
> @@ -34,6 +34,8 @@
> #define TDM_PPPOHT_SLIC_MAXIN
> #define RX_BD_ERRORS (R_CD_S | R_OV_S | R_CR_S | R_AB_S | R_NO_S | R_LG_S)
>
> +static int uhdlc_close(struct net_device *dev);
> +
> static struct ucc_tdm_info utdm_primary_info = {
> .uf_info = {
> .tsa = 0,
> @@ -731,7 +733,9 @@ static int uhdlc_open(struct net_device *dev)
> napi_enable(&priv->napi);
> netdev_reset_queue(dev);
> netif_start_queue(dev);
> - hdlc_open(dev);
> +
> + int rc = hdlc_open(dev);
Do not mix declarations and code. Please put all declaration at the top
of the block.
> + return rc == 0 ? 0 : (uhdlc_close(dev), rc);
> }
That's not easy to read.
I know that's more changes, but I'd prefer something like:
static int uhdlc_open(struct net_device *dev)
{
u32 cecr_subblock;
hdlc_device *hdlc = dev_to_hdlc(dev);
struct ucc_hdlc_private *priv = hdlc->priv;
struct ucc_tdm *utdm = priv->utdm;
int rc;
if (priv->hdlc_busy != 1)
return 0;
if (request_irq(priv->ut_info->uf_info.irq,
ucc_hdlc_irq_handler, 0, "hdlc", priv))
return -ENODEV;
cecr_subblock = ucc_fast_get_qe_cr_subblock(
priv->ut_info->uf_info.ucc_num);
qe_issue_cmd(QE_INIT_TX_RX, cecr_subblock,
QE_CR_PROTOCOL_UNSPECIFIED, 0);
ucc_fast_enable(priv->uccf, COMM_DIR_RX | COMM_DIR_TX);
/* Enable the TDM port */
if (priv->tsa)
qe_setbits_8(&utdm->si_regs->siglmr1_h, 0x1 << utdm->tdm_port);
priv->hdlc_busy = 1;
netif_device_attach(priv->ndev);
napi_enable(&priv->napi);
netdev_reset_queue(dev);
netif_start_queue(dev);
rc = hdlc_open(dev);
if (rc)
uhdlc_close(dev);
return rc;
}
>
> return 0;
> @@ -824,6 +828,8 @@ static int uhdlc_close(struct net_device *dev)
> netdev_reset_queue(dev);
> priv->hdlc_busy = 0;
>
> + hdlc_close(dev);
> +
> return 0;
> }
>
And while you are looking at the correctness of this code, is it sure
that uhdlc_open() cannot be called twice in parallele ?
If it can be called in parallèle I think the "if (priv->hdlc_busy != 1)"
should be replaced by something using cmpxchg()
