Re: linux-next: build warning after merge of the nand tree

Miquel Raynal
2019-04-03T07:49:58Z

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Hi Stephen,

Stephen Rothwell <sfr@canb.auug.org.au> wrote on Wed, 3 Apr 2019
10:22:39 +1100:

> Hi all,
>
> After merging the nand tree, today's linux-next build (x86_64
> allmodconfig) produced this warning:
>
> drivers/mtd/nand/raw/ingenic/jz4725b_bch.c: In function 'jz4725b_bch_read_parity':
> drivers/mtd/nand/raw/ingenic/jz4725b_bch.c:147:12: warning: this statement may fall through [-Wimplicit-fallthrough=]
> dest8[2] = (val >> 16) & 0xff;
> ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
> drivers/mtd/nand/raw/ingenic/jz4725b_bch.c:148:2: note: here
> case 2: /* fall-through */
> ^~~~
> drivers/mtd/nand/raw/ingenic/jz4725b_bch.c:149:12: warning: this statement may fall through [-Wimplicit-fallthrough=]
> dest8[1] = (val >> 8) & 0xff;
> ~~~~~~~~~^~~~~~~~~~~~~~~~~~~
> drivers/mtd/nand/raw/ingenic/jz4725b_bch.c:150:2: note: here
> case 1: /* fall-through */
> ^~~~
>
> Introduced by commit
>
> acb29396f956 ("mtd: rawnand: ingenic: Add support for the JZ4725B")
>
> I get this warning because I am building with -Wimplicit-fallthrough
> in attempt to catch new additions early. The gcc warning can be turned
> off by adding a /* fall through */ comment at the point the fall through
> happens (i.e. before the next case label).
>

Thanks for the warnings, I moved the fall-through comments so the
warnings are gone.

I also added -Wextra in my "mtd-builds" setup to catch these earlier.

Thanks,
Miquèl