From 0e2fc98f3d50d4ca0d0bfb2c10ca996d1bfb8346 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Sat, 4 Jan 2020 22:51:44 +0100 Subject: [PATCH] mlx5: work around high stack usage with gcc BugLink: https://bugs.launchpad.net/bugs/1864488 [ Upstream commit 42ae1a5c76691928ed217c7e40269db27f5225e9 ] In some configurations, gcc tries too hard to optimize this code: drivers/net/ethernet/mellanox/mlx5/core/en_stats.c: In function 'mlx5e_grp_sw_update_stats': drivers/net/ethernet/mellanox/mlx5/core/en_stats.c:302:1: error: the frame size of 1336 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] As was stated in the bug report, the reason is that gcc runs into a corner case in the register allocator that is rather hard to fix in a good way. As there is an easy way to work around it, just add a comment and the barrier that stops gcc from trying to overoptimize the function. Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92657 Cc: Adhemerval Zanella Signed-off-by: Arnd Bergmann Signed-off-by: Saeed Mahameed Signed-off-by: Sasha Levin Signed-off-by: Paolo Pisati --- drivers/net/ethernet/mellanox/mlx5/core/en_stats.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c index 9f09253f9f46..a05158472ed1 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c @@ -297,6 +297,9 @@ static void mlx5e_grp_sw_update_stats(struct mlx5e_priv *priv) s->tx_tls_drop_bypass_req += sq_stats->tls_drop_bypass_req; #endif s->tx_cqes += sq_stats->cqes; + + /* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92657 */ + barrier(); } } } -- 2.39.5