e1000e: Separate signaling for link check/link up

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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>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

...

This commit is contained in:

Benjamin Poirier 2017-07-21 11:36:26 -07:00 • committed by Jeff Kirsher

parent d3509f8bc7

commit 19110cfbb3

2 changed files with 9 additions and 4 deletions

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11

drivers/net/ethernet/intel/e1000e/mac.c

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2

drivers/net/ethernet/intel/e1000e/netdev.c

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