| From | Sasha Levin <> | Subject | [PATCH AUTOSEL 4.19 485/671] cxgb4: smt: Add lock for atomic_dec_and_test | Date | Thu, 16 Jan 2020 12:02:03 -0500 |
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From: Chuhong Yuan <hslester96@gmail.com>
[ Upstream commit 4a8937b83892cb69524291cae6cdabad4a8be033 ]
The atomic_dec_and_test() is not safe because it is outside of locks. Move the locks of t4_smte_free() to its caller, cxgb4_smt_release() to protect the atomic decrement.
Fixes: 3bdb376e6944 ("cxgb4: introduce SMT ops to prepare for SMAC rewrite support") Signed-off-by: Chuhong Yuan <hslester96@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/net/ethernet/chelsio/cxgb4/smt.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/chelsio/cxgb4/smt.c b/drivers/net/ethernet/chelsio/cxgb4/smt.c index 7b2207a2a130..9b3f4205cb4d 100644 --- a/drivers/net/ethernet/chelsio/cxgb4/smt.c +++ b/drivers/net/ethernet/chelsio/cxgb4/smt.c @@ -98,11 +98,9 @@ static struct smt_entry *find_or_alloc_smte(struct smt_data *s, u8 *smac) static void t4_smte_free(struct smt_entry *e) { - spin_lock_bh(&e->lock); if (atomic_read(&e->refcnt) == 0) { /* hasn't been recycled */ e->state = SMT_STATE_UNUSED; } - spin_unlock_bh(&e->lock); } /** @@ -112,8 +110,10 @@ static void t4_smte_free(struct smt_entry *e) */ void cxgb4_smt_release(struct smt_entry *e) { + spin_lock_bh(&e->lock); if (atomic_dec_and_test(&e->refcnt)) t4_smte_free(e); + spin_unlock_bh(&e->lock); } EXPORT_SYMBOL(cxgb4_smt_release); -- 2.20.1
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