From 7a1fa8a4363b0cb3610a0808e98eb2d35f262398 Mon Sep 17 00:00:00 2001 From: =?utf8?q?J=C3=A9r=C3=B4me=20Pouiller?= Date: Thu, 13 Jan 2022 09:54:57 +0100 Subject: [PATCH] staging: wfx: fix comment correctness MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Using DMA with stack allocated buffers is not supported, whatever the value of CONFIG_VMAP_STACK. Signed-off-by: Jérôme Pouiller Link: https://lore.kernel.org/r/20220113085524.1110708-5-Jerome.Pouiller@silabs.com Signed-off-by: Greg Kroah-Hartman --- drivers/staging/wfx/hwio.c | 12 ------------ drivers/staging/wfx/hwio.h | 4 ++++ 2 files changed, 4 insertions(+), 12 deletions(-) diff --git a/drivers/staging/wfx/hwio.c b/drivers/staging/wfx/hwio.c index 30eb888830d28..393bcb1e2f4ec 100644 --- a/drivers/staging/wfx/hwio.c +++ b/drivers/staging/wfx/hwio.c @@ -14,18 +14,6 @@ #include "bus.h" #include "traces.h" -/* - * Internal helpers. - * - * About CONFIG_VMAP_STACK: - * When CONFIG_VMAP_STACK is enabled, it is not possible to run DMA on stack - * allocated data. Functions below that work with registers (aka functions - * ending with "32") automatically reallocate buffers with kmalloc. However, - * functions that work with arbitrary length buffers let's caller to handle - * memory location. In doubt, enable CONFIG_DEBUG_SG to detect badly located - * buffer. - */ - static int read32(struct wfx_dev *wdev, int reg, u32 *val) { int ret; diff --git a/drivers/staging/wfx/hwio.h b/drivers/staging/wfx/hwio.h index ff09575dd1aff..d34baae470174 100644 --- a/drivers/staging/wfx/hwio.h +++ b/drivers/staging/wfx/hwio.h @@ -12,6 +12,10 @@ struct wfx_dev; +/* Caution: in the functions below, 'buf' will used with a DMA. So, it must be + * kmalloc'd (do not use stack allocated buffers). In doubt, enable + * CONFIG_DEBUG_SG to detect badly located buffer. + */ int wfx_data_read(struct wfx_dev *wdev, void *buf, size_t buf_len); int wfx_data_write(struct wfx_dev *wdev, const void *buf, size_t buf_len); -- 2.30.2