linux-kernel - Re: [PATCH net] forcedeth: Fix an error handling path in nv

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Message-ID: <f4296d23-83ce-4147-894a-3e5640cdf87c@kili.mountain>
Date:   Mon, 22 May 2023 13:35:38 +0300
From:   Dan Carpenter <dan.carpenter@...aro.org>
To:     Simon Horman <simon.horman@...igine.com>
Cc:     Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        Rain River <rain.1986.08.12@...il.com>,
        Zhu Yanjun <zyjzyj2000@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Ayaz Abdulla <aabdulla@...dia.com>,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        netdev@...r.kernel.org
Subject: Re: [PATCH net] forcedeth: Fix an error handling path in nv_probe()

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  }

regards,
dan carpenter