diff mbox series

[next,S89,7/8] i40e: stop using cmpxchg flow in i40e_set_priv_flags()

Message ID 20180316082637.49915-7-alice.michael@intel.com
State Accepted
Delegated to: Jeff Kirsher
Headers show
Series [next,S89,1/8] i40e: move I40E_FLAG_FILTER_SYNC to a state bit | expand

Commit Message

Michael, Alice March 16, 2018, 8:26 a.m. UTC 
From: Jacob Keller <jacob.e.keller@intel.com>

Now that the only places which modify flags are either (a) during
initialization prior to creating a netdevice, or (b) while holding the
rtnl lock, we no longer need the cmpxchg64 call in i40e_set_priv_flags.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
---
 drivers/net/ethernet/intel/i40e/i40e_ethtool.c | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

Comments

Bowers, AndrewX March 19, 2018, 9:16 p.m. UTC | #1 
> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces@osuosl.org] On
> Behalf Of Alice Michael
> Sent: Friday, March 16, 2018 1:27 AM
> To: Michael, Alice <alice.michael@intel.com>; intel-wired-
> lan@lists.osuosl.org
> Subject: [Intel-wired-lan] [next PATCH S89 7/8] i40e: stop using cmpxchg flow
> in i40e_set_priv_flags()
> 
> From: Jacob Keller <jacob.e.keller@intel.com>
> 
> Now that the only places which modify flags are either (a) during initialization
> prior to creating a netdevice, or (b) while holding the rtnl lock, we no longer
> need the cmpxchg64 call in i40e_set_priv_flags.
> 
> Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
> ---
>  drivers/net/ethernet/intel/i40e/i40e_ethtool.c | 19 +++++--------------
>  1 file changed, 5 insertions(+), 14 deletions(-)

Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
diff mbox series

Patch

diff --git a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
index 031bc7c..9a97f3f 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
@@ -4436,21 +4436,12 @@  static int i40e_set_priv_flags(struct net_device *dev, u32 flags)
 		}
 	}
 
-	/* Compare and exchange the new flags into place. If we failed, that
-	 * is if cmpxchg returns anything but the old value, this means that
-	 * something else has modified the flags variable since we copied it
-	 * originally. We'll just punt with an error and log something in the
-	 * message buffer.
-	 *
-	 * This is the point of no return for this function.  We need to have
-	 * checked any discrepancies or misconfigurations and returned
-	 * EOPNOTSUPP before updating pf->flags here.
+	/* Now that we've checked to ensure that the new flags are valid, load
+	 * them into place. Since we only modify flags either (a) during
+	 * initialization or (b) while holding the RTNL lock, we don't need
+	 * anything fancy here.
 	 */
-	if (cmpxchg64(&pf->flags, orig_flags, new_flags) != orig_flags) {
-		dev_warn(&pf->pdev->dev,
-			 "Unable to update pf->flags as it was modified by another thread...\n");
-		return -EAGAIN;
-	}
+	pf->flags = new_flags;
 
 	/* Process any additional changes needed as a result of flag changes.
 	 * The changed_flags value reflects the list of bits that were