| Message ID | 20230815-void-drivers-mtd-nand-raw-vf610_nfc-v1-1-7cc65314c56c@google.com |
|---|---|
| State | New |
| Headers | show |
| Series | mtd: rawnand: fix -Wvoid-pointer-to-enum-cast warning | expand |
Hi Justin, justinstitt@google.com wrote on Tue, 15 Aug 2023 20:58:47 +0000: > When building with clang 18 I see the following warning: > | drivers/mtd/nand/raw/vf610_nfc.c:853:17: warning: cast to smaller integer > | type 'enum vf610_nfc_variant' from 'const void *' [-Wvoid-pointer-to-enum-cast] > | 853 | nfc->variant = (enum vf610_nfc_variant)of_id->data; > > This is due to the fact that `of_id->data` is a void* while `enum > vf610_nfc_variant` has the size of an int. This leads to truncation and > possible data loss. Can you please update this commit log to what Krzysztof suggested in the "mtd: maps: fix -W<foo> warning" thread? > Link: https://github.com/ClangBuiltLinux/linux/issues/1910 > Reported-by: Nathan Chancellor <nathan@kernel.org> > Signed-off-by: Justin Stitt <justinstitt@google.com> > --- > Note: There is likely no data loss actually occurring here due to the > fact that `enum vf610_nfc_variant` only has a few fields which are not > nearly large enough to cause data loss. This patch helps towards the > goal of eventually enabling this warning. > > Also, should we use `unsigned long` here instead of `uintptr_t`? I've > seen maintainers request both and I'm flipping a coin here. I'm fine with uintptr_t. Thanks, Miquèl
diff --git a/drivers/mtd/nand/raw/vf610_nfc.c b/drivers/mtd/nand/raw/vf610_nfc.c index 86522048e271..11d996dc655d 100644 --- a/drivers/mtd/nand/raw/vf610_nfc.c +++ b/drivers/mtd/nand/raw/vf610_nfc.c @@ -850,7 +850,7 @@ static int vf610_nfc_probe(struct platform_device *pdev) goto err_disable_clk; } - nfc->variant = (enum vf610_nfc_variant)of_id->data; + nfc->variant = (uintptr_t)of_id->data; for_each_available_child_of_node(nfc->dev->of_node, child) { if (of_device_is_compatible(child, "fsl,vf610-nfc-nandcs")) {
When building with clang 18 I see the following warning: | drivers/mtd/nand/raw/vf610_nfc.c:853:17: warning: cast to smaller integer | type 'enum vf610_nfc_variant' from 'const void *' [-Wvoid-pointer-to-enum-cast] | 853 | nfc->variant = (enum vf610_nfc_variant)of_id->data; This is due to the fact that `of_id->data` is a void* while `enum vf610_nfc_variant` has the size of an int. This leads to truncation and possible data loss. Link: https://github.com/ClangBuiltLinux/linux/issues/1910 Reported-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Justin Stitt <justinstitt@google.com> --- Note: There is likely no data loss actually occurring here due to the fact that `enum vf610_nfc_variant` only has a few fields which are not nearly large enough to cause data loss. This patch helps towards the goal of eventually enabling this warning. Also, should we use `unsigned long` here instead of `uintptr_t`? I've seen maintainers request both and I'm flipping a coin here. --- drivers/mtd/nand/raw/vf610_nfc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- base-commit: 2ccdd1b13c591d306f0401d98dedc4bdcd02b421 change-id: 20230815-void-drivers-mtd-nand-raw-vf610_nfc-6c358f424b8a Best regards, -- Justin Stitt <justinstitt@google.com>