Re: [PATCH net] forcedeth: Fix an error handling path in nv_probe()

[Christophe JAILLET]

Le 22/05/2023 à 13:10, Simon Horman a écrit :
> On Mon, May 22, 2023 at 01:35:38PM +0300, Dan Carpenter wrote:
> > On Mon, May 22, 2023 at 12:12:48PM +0200, Simon Horman wrote:
> > > On Sat, May 20, 2023 at 10:30:17AM +0200, Christophe JAILLET wrote:
> > > > If an error occures after calling nv_mgmt_acquire_sema(), it should be
> > > > undone with a corresponding nv_mgmt_release_sema() call.
> > >
> > > nit: s/occures/occurs/
> > >
> > > > Add it in the error handling path of the probe as already done in the
> > > > remove function.
> > >
> > > I was going to ask what happens if nv_mgmt_acquire_sema() fails.
> > > Then I realised that it always returns 0.
> > >
> > > Perhaps it would be worth changing it's return type to void at some point.
> >
> > What? No?  It returns true on success and false on failure.
> >
> > drivers/net/ethernet/nvidia/forcedeth.c
> >    5377  static int nv_mgmt_acquire_sema(struct net_device *dev)
> >    5378  {
> >    5379          struct fe_priv *np = netdev_priv(dev);
> >    5380          u8 __iomem *base = get_hwbase(dev);
> >    5381          int i;
> >    5382          u32 tx_ctrl, mgmt_sema;
> >    5383
> >    5384          for (i = 0; i < 10; i++) {
> >    5385                  mgmt_sema = readl(base + NvRegTransmitterControl) & NVREG_XMITCTL_MGMT_SEMA_MASK;
> >    5386                  if (mgmt_sema == NVREG_XMITCTL_MGMT_SEMA_FREE)
> >    5387                          break;
> >    5388                  msleep(500);
> >    5389          }
> >    5390
> >    5391          if (mgmt_sema != NVREG_XMITCTL_MGMT_SEMA_FREE)
> >    5392                  return 0;
> >    5393
> >    5394          for (i = 0; i < 2; i++) {
> >    5395                  tx_ctrl = readl(base + NvRegTransmitterControl);
> >    5396                  tx_ctrl |= NVREG_XMITCTL_HOST_SEMA_ACQ;
> >    5397                  writel(tx_ctrl, base + NvRegTransmitterControl);
> >    5398
> >    5399                  /* verify that semaphore was acquired */
> >    5400                  tx_ctrl = readl(base + NvRegTransmitterControl);
> >    5401                  if (((tx_ctrl & NVREG_XMITCTL_HOST_SEMA_MASK) == NVREG_XMITCTL_HOST_SEMA_ACQ) &&
> >    5402                      ((tx_ctrl & NVREG_XMITCTL_MGMT_SEMA_MASK) == NVREG_XMITCTL_MGMT_SEMA_FREE)) {
> >    5403                          np->mgmt_sema = 1;
> >    5404                          return 1;
> >                                  ^^^^^^^^^
> > Success path.
> >
> >    5405                  } else
> >    5406                          udelay(50);
> >    5407          }
> >    5408
> >    5409          return 0;
> >    5410  }
>
> Thanks Dan,
>
> my eyes deceived me.
>
> In that case, my question is: what if nv_mgmt_acquire_sema() fails?
> But I think the answer is that nv_mgmt_release_sema() will do
> nothing because mgmt_sema is not set.

At least, it is my understanding.

Can you fix the typo s/occures/occurs/ when applying the patch, or do 
you really need a v2 only for that?

CJ.

> So I think we are good.