RE: [Intel-wired-lan] [PATCH 4/5] e1000e: Separate signaling for link check/link up

From	"Brown, Aaron F" <aaron.f.brown@intel.com>
Newsgroups	linux.kernel
Subject	RE: [Intel-wired-lan] [PATCH 4/5] e1000e: Separate signaling for link check/link up
Date	2017-09-15 02:30 +0200
Message-ID	<upMG5-3I4-7@gated-at.bofh.it> (permalink)
References	(1 earlier) <u5L0d-8jy-3@gated-at.bofh.it> <u5L0d-8jy-1@gated-at.bofh.it> <ua00G-KN-5@gated-at.bofh.it> <ua2Yx-2AD-7@gated-at.bofh.it> <ua3hT-2KU-1@gated-at.bofh.it>
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On 7/21/2017 21:36, Benjamin Poirier wrote:
> Lennart reported the following race condition:
>
> \ e1000_watchdog_task
>      \ e1000e_has_link
>          \ hw->mac.ops.check_for_link() === e1000e_check_for_copper_link
>              /* link is up */
>              mac->get_link_status = false;
>
>                              /* interrupt */
>                              \ e1000_msix_other
>                                  hw->mac.get_link_status = true;
>
>          link_active = !hw->mac.get_link_status
>          /* link_active is false, wrongly */
>
> This problem arises because the single flag get_link_status is used to
> signal two different states: link status needs checking and link status is
> down.
>
> Avoid the problem by using the return value of .check_for_link to signal
> the link status to e1000e_has_link().
>
> Reported-by: Lennart Sorensen <lsorense@csclub.uwaterloo.ca>
> Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
> ---
>   drivers/net/ethernet/intel/e1000e/mac.c    | 11 ++++++++---
>   drivers/net/ethernet/intel/e1000e/netdev.c |  2 +-
>   2 files changed, 9 insertions(+), 4 deletions(-)

Tested-by: Aaron Brown <aaron.f.brown@intel.com>

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RE: [Intel-wired-lan] [PATCH 4/5] e1000e: Separate signaling for  link check/link up "Brown, Aaron F" <aaron.f.brown@intel.com> - 2017-09-15 02:30 +0200

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