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

Simon Horman
2023-05-23T08:41:36Z

On Mon, May 22, 2023 at 07:13:43PM +0200, Christophe JAILLET wrote:
> 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?

It's beyond my powers to fix things in that way.
But I'd say there is no need to respin just for a spelling error.

FWIIW,

Reviewed-by: Simon Horman <simon.horman@corigine.com>