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

Christophe JAILLET
2023-05-22T17:14:02Z

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.
>
>
>