[PATCH 1/3] media: saa7146: avoid high stack usage with clang

From: Arnd Bergmann
Date: Tue Feb 19 2019 - 12:02:27 EST


Two saa7146/hexium files contain a construct that causes a warning
when built with clang:

drivers/media/pci/saa7146/hexium_orion.c:210:12: error: stack frame size of 2272 bytes in function 'hexium_probe'
[-Werror,-Wframe-larger-than=]
static int hexium_probe(struct saa7146_dev *dev)
^
drivers/media/pci/saa7146/hexium_gemini.c:257:12: error: stack frame size of 2304 bytes in function 'hexium_attach'
[-Werror,-Wframe-larger-than=]
static int hexium_attach(struct saa7146_dev *dev, struct saa7146_pci_extension_data *info)
^

This one happens regardless of KASAN, and the problem is that a
constructor to initalize a dynamically allocated structure leads
to a copy of that structure on the stack, whereas gcc initializes
it in place.

Link: https://bugs.llvm.org/show_bug.cgi?id=40776
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/media/pci/saa7146/hexium_gemini.c | 4 +---
drivers/media/pci/saa7146/hexium_orion.c | 4 +---
2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/media/pci/saa7146/hexium_gemini.c b/drivers/media/pci/saa7146/hexium_gemini.c
index 5817d9cde4d0..f7ce0e1770bf 100644
--- a/drivers/media/pci/saa7146/hexium_gemini.c
+++ b/drivers/media/pci/saa7146/hexium_gemini.c
@@ -270,9 +270,7 @@ static int hexium_attach(struct saa7146_dev *dev, struct saa7146_pci_extension_d
/* enable i2c-port pins */
saa7146_write(dev, MC1, (MASK_08 | MASK_24 | MASK_10 | MASK_26));

- hexium->i2c_adapter = (struct i2c_adapter) {
- .name = "hexium gemini",
- };
+ strscpy(hexium->i2c_adapter.name, "hexium gemini", sizeof(hexium->i2c_adapter.name));
saa7146_i2c_adapter_prepare(dev, &hexium->i2c_adapter, SAA7146_I2C_BUS_BIT_RATE_480);
if (i2c_add_adapter(&hexium->i2c_adapter) < 0) {
DEB_S("cannot register i2c-device. skipping.\n");
diff --git a/drivers/media/pci/saa7146/hexium_orion.c b/drivers/media/pci/saa7146/hexium_orion.c
index 0a05176c18ab..b9f4a09c744d 100644
--- a/drivers/media/pci/saa7146/hexium_orion.c
+++ b/drivers/media/pci/saa7146/hexium_orion.c
@@ -231,9 +231,7 @@ static int hexium_probe(struct saa7146_dev *dev)
saa7146_write(dev, DD1_STREAM_B, 0x00000000);
saa7146_write(dev, MC2, (MASK_09 | MASK_25 | MASK_10 | MASK_26));

- hexium->i2c_adapter = (struct i2c_adapter) {
- .name = "hexium orion",
- };
+ strscpy(hexium->i2c_adapter.name, "hexium orion", sizeof(hexium->i2c_adapter.name));
saa7146_i2c_adapter_prepare(dev, &hexium->i2c_adapter, SAA7146_I2C_BUS_BIT_RATE_480);
if (i2c_add_adapter(&hexium->i2c_adapter) < 0) {
DEB_S("cannot register i2c-device. skipping.\n");
--
2.20.0