diff options
| author | Edward Cree <ecree@solarflare.com> | 2016-06-15 17:43:43 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-06-15 22:26:25 -0700 |
| commit | dd98708cf6a7981ad5bc23b1e10c548689482ef7 (patch) | |
| tree | fcd520dc48e6eccc891ff98703a9fd0acb8248e6 | |
| parent | ebfcd0fd90b88088e4d3841c4be9a8c5753d3993 (diff) | |
| download | linux-dd98708cf6a7981ad5bc23b1e10c548689482ef7.tar.bz2 | |
sfc: Assert filter_sem write locked when required
Based on a patch by Andrew Rybchenko <Andrew.Rybchenko@oktetlabs.ru>
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/ethernet/sfc/ef10.c | 16 | ||||
| -rw-r--r-- | drivers/net/ethernet/sfc/efx.h | 9 |
2 files changed, 24 insertions, 1 deletions
diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c index ebe35496b294..66cc9637fd8f 100644 --- a/drivers/net/ethernet/sfc/ef10.c +++ b/drivers/net/ethernet/sfc/ef10.c @@ -3735,6 +3735,12 @@ static int efx_ef10_filter_table_probe(struct efx_nic *efx) size_t outlen; int rc; + if (!efx_rwsem_assert_write_locked(&efx->filter_sem)) + return -EINVAL; + + if (efx->filter_state) /* already probed */ + return 0; + table = kzalloc(sizeof(*table), GFP_KERNEL); if (!table) return -ENOMEM; @@ -3846,7 +3852,6 @@ static void efx_ef10_filter_table_restore(struct efx_nic *efx) nic_data->must_restore_filters = false; } -/* Caller must hold efx->filter_sem for write */ static void efx_ef10_filter_table_remove(struct efx_nic *efx) { struct efx_ef10_filter_table *table = efx->filter_state; @@ -3856,6 +3861,15 @@ static void efx_ef10_filter_table_remove(struct efx_nic *efx) int rc; efx->filter_state = NULL; + /* If we were called without locking, then it's not safe to free + * the table as others might be using it. So we just WARN, leak + * the memory, and potentially get an inconsistent filter table + * state. + * This should never actually happen. + */ + if (!efx_rwsem_assert_write_locked(&efx->filter_sem)) + return; + if (!table) return; diff --git a/drivers/net/ethernet/sfc/efx.h b/drivers/net/ethernet/sfc/efx.h index 5e3f93f04e62..c3ae739e9c7a 100644 --- a/drivers/net/ethernet/sfc/efx.h +++ b/drivers/net/ethernet/sfc/efx.h @@ -274,4 +274,13 @@ static inline void efx_device_detach_sync(struct efx_nic *efx) netif_tx_unlock_bh(dev); } +static inline bool efx_rwsem_assert_write_locked(struct rw_semaphore *sem) +{ + if (WARN_ON(down_read_trylock(sem))) { + up_read(sem); + return false; + } + return true; +} + #endif /* EFX_EFX_H */ |