From: Arnd Bergmann Date: Tue, 10 Jun 2025 09:28:42 +0000 (+0200) Subject: RDMA/mlx5: reduce stack usage in mlx5_ib_ufile_hw_cleanup X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=b26852daaa83f535109253d114426d1fa674155d;p=users%2Fdwmw2%2Flinux.git RDMA/mlx5: reduce stack usage in mlx5_ib_ufile_hw_cleanup This function has an array of eight mlx5_async_cmd structures, which often fits on the stack, but depending on the configuration can end up blowing the stack frame warning limit: drivers/infiniband/hw/mlx5/devx.c:2670:6: error: stack frame size (1392) exceeds limit (1280) in 'mlx5_ib_ufile_hw_cleanup' [-Werror,-Wframe-larger-than] Change this to a dynamic allocation instead. While a kmalloc() can theoretically fail, a GFP_KERNEL allocation under a page will block until memory has been freed up, so in the worst case, this only adds extra time in an already constrained environment. Fixes: 7c891a4dbcc1 ("RDMA/mlx5: Add implementation for ufile_hw_cleanup device operation") Signed-off-by: Arnd Bergmann Link: https://patch.msgid.link/20250610092846.2642535-1-arnd@kernel.org Signed-off-by: Leon Romanovsky --- diff --git a/drivers/infiniband/hw/mlx5/devx.c b/drivers/infiniband/hw/mlx5/devx.c index 2479da8620ca9..bceae1c1f9801 100644 --- a/drivers/infiniband/hw/mlx5/devx.c +++ b/drivers/infiniband/hw/mlx5/devx.c @@ -2669,7 +2669,7 @@ static void devx_wait_async_destroy(struct mlx5_async_cmd *cmd) void mlx5_ib_ufile_hw_cleanup(struct ib_uverbs_file *ufile) { - struct mlx5_async_cmd async_cmd[MAX_ASYNC_CMDS]; + struct mlx5_async_cmd *async_cmd; struct ib_ucontext *ucontext = ufile->ucontext; struct ib_device *device = ucontext->device; struct mlx5_ib_dev *dev = to_mdev(device); @@ -2678,6 +2678,10 @@ void mlx5_ib_ufile_hw_cleanup(struct ib_uverbs_file *ufile) int head = 0; int tail = 0; + async_cmd = kcalloc(MAX_ASYNC_CMDS, sizeof(*async_cmd), GFP_KERNEL); + if (!async_cmd) + return; + list_for_each_entry(uobject, &ufile->uobjects, list) { WARN_ON(uverbs_try_lock_object(uobject, UVERBS_LOOKUP_WRITE)); @@ -2713,6 +2717,8 @@ void mlx5_ib_ufile_hw_cleanup(struct ib_uverbs_file *ufile) devx_wait_async_destroy(&async_cmd[head % MAX_ASYNC_CMDS]); head++; } + + kfree(async_cmd); } static ssize_t devx_async_cmd_event_read(struct file *filp, char __user *buf,