[PATCH] drm/radeon: reduce stack frame size for radeon_cs_ioctl

[PATCH] drm/radeon: reduce stack frame size for radeon_cs_ioctl

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

Clang inlines radeon_cs_parser_relocs() into radeon_cs_ioctl(), and
since both of these use a lot of stack space, the sum of them can
make it exceed a limit of 1280 bytes:

drivers/gpu/drm/radeon/radeon_cs.c:669:5: error: stack frame size (1328) exceeds limit (1280) in 'radeon_cs_ioctl' [-Werror,-Wframe-larger-than]
  669 | int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
      |     ^

Mark radeon_cs_parser_relocs as noinline_for_stack, so clang and gcc
both behave in a consistent way. Calling into radeon_cs_parser_relocs()
still uses a lot of stack space here, but this is not any worse than it
already was, and the other code paths are better now.

Fixes: c9b76548899c ("drm/radeon: validate relocations in the order determined by userspace v3")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpu/drm/radeon/radeon_cs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/radeon/radeon_cs.c b/drivers/gpu/drm/radeon/radeon_cs.c
index b8e6202f1d5b..220a9b107b15 100644
--- a/drivers/gpu/drm/radeon/radeon_cs.c
+++ b/drivers/gpu/drm/radeon/radeon_cs.c
@@ -78,7 +78,7 @@ static void radeon_cs_buckets_get_list(struct radeon_cs_buckets *b,
 	}
 }
 
-static int radeon_cs_parser_relocs(struct radeon_cs_parser *p)
+static noinline_for_stack int radeon_cs_parser_relocs(struct radeon_cs_parser *p)
 {
 	struct radeon_cs_chunk *chunk;
 	struct radeon_cs_buckets buckets;
-- 
2.39.5