diff options
author | Eric Dumazet <edumazet@google.com> | 2014-10-10 04:48:15 -0700 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2014-10-10 15:37:28 -0400 |
commit | 00cd5adb0313f540aa58672d14e764d164586a43 (patch) | |
tree | bdeeb422a5a8627d6da8a42499aeec2340cef437 /drivers/net/ethernet/intel | |
parent | 42b0270b40e2ad692ef59e28233202ee6f293e1e (diff) |
igb: fix race accessing page->_count
This is illegal to use atomic_set(&page->_count, 2) even if we 'own'
the page. Other entities in the kernel need to use get_page_unless_zero()
to get a reference to the page before testing page properties, so we could
loose a refcount increment.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/intel')
-rw-r--r-- | drivers/net/ethernet/intel/igb/igb_main.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c index ae59c0b108c5..a21b14495ebd 100644 --- a/drivers/net/ethernet/intel/igb/igb_main.c +++ b/drivers/net/ethernet/intel/igb/igb_main.c @@ -6545,11 +6545,10 @@ static bool igb_can_reuse_rx_page(struct igb_rx_buffer *rx_buffer, /* flip page offset to other buffer */ rx_buffer->page_offset ^= IGB_RX_BUFSZ; - /* since we are the only owner of the page and we need to - * increment it, just set the value to 2 in order to avoid - * an unnecessary locked operation + /* Even if we own the page, we are not allowed to use atomic_set() + * This would break get_page_unless_zero() users. */ - atomic_set(&page->_count, 2); + atomic_inc(&page->_count); #else /* move offset up to the next cache line */ rx_buffer->page_offset += truesize; |