From: Jacob Keller <jacob.e.keller@intel.com>
Date: Fri, 16 Mar 2018 01:26:36 -0700
Subject: i40e: stop using cmpxchg flow in i40e_set_priv_flags()
Patch-mainline: v4.17-rc1
Git-commit: 886ff146a73627c287262a7d92ddfb50baa29552
References: bsc#1101816 FATE#325147 FATE#325149
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>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/net/ethernet/intel/i40e/i40e_ethtool.c | 19 +++++--------------
1 file changed, 5 insertions(+), 14 deletions(-)
--- a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
@@ -4443,21 +4443,12 @@ flags_complete:
}
}
- /* 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