diff mbox series

[RESEND,v3,05/11] mtd: rawnand: vf610_nfc: add initializer to avoid -Wmaybe-uninitialized

Message ID 20190423034959.13525-6-yamada.masahiro@socionext.com
State New
Headers show
Series compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING | expand

Commit Message

Masahiro Yamada April 23, 2019, 3:49 a.m. UTC 
This prepares to move CONFIG_OPTIMIZE_INLINING from x86 to a common
place. We need to eliminate potential issues beforehand.

Kbuild test robot has never reported -Wmaybe-uninitialized warning
for this probably because vf610_nfc_run() is inlined by the x86
compiler's inlining heuristic.

If CONFIG_OPTIMIZE_INLINING is enabled for a different architecture
and vf610_nfc_run() is not inlined, the following warning is reported:

drivers/mtd/nand/raw/vf610_nfc.c: In function ‘vf610_nfc_cmd’:
drivers/mtd/nand/raw/vf610_nfc.c:455:3: warning: ‘offset’ may be used uninitialized in this function [-Wmaybe-uninitialized]
   vf610_nfc_rd_from_sram(instr->ctx.data.buf.in + offset,
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            nfc->regs + NFC_MAIN_AREA(0) + offset,
            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            trfr_sz, !nfc->data_access);
            ~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

Changes in v3: None
Changes in v2:
  - split into a separate patch

 drivers/mtd/nand/raw/vf610_nfc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Miquel Raynal May 2, 2019, 2:13 p.m. UTC | #1 
Hi Masahiro,

Masahiro Yamada <yamada.masahiro@socionext.com> wrote on Tue, 23 Apr
2019 12:49:53 +0900:

> This prepares to move CONFIG_OPTIMIZE_INLINING from x86 to a common
> place. We need to eliminate potential issues beforehand.
> 
> Kbuild test robot has never reported -Wmaybe-uninitialized warning
> for this probably because vf610_nfc_run() is inlined by the x86
> compiler's inlining heuristic.
> 
> If CONFIG_OPTIMIZE_INLINING is enabled for a different architecture
> and vf610_nfc_run() is not inlined, the following warning is reported:
> 
> drivers/mtd/nand/raw/vf610_nfc.c: In function ‘vf610_nfc_cmd’:
> drivers/mtd/nand/raw/vf610_nfc.c:455:3: warning: ‘offset’ may be used uninitialized in this function [-Wmaybe-uninitialized]
>    vf610_nfc_rd_from_sram(instr->ctx.data.buf.in + offset,
>    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>             nfc->regs + NFC_MAIN_AREA(0) + offset,
>             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>             trfr_sz, !nfc->data_access);
>             ~~~~~~~~~~~~~~~~~~~~~~~~~~~

IMHO this patch has no dependencies with this series.
Would you mind sending it alone with the proper Fixes tag?

> 
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> ---
> 
> Changes in v3: None
> Changes in v2:
>   - split into a separate patch
> 
>  drivers/mtd/nand/raw/vf610_nfc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/nand/raw/vf610_nfc.c b/drivers/mtd/nand/raw/vf610_nfc.c
> index a662ca1970e5..19792d725ec2 100644
> --- a/drivers/mtd/nand/raw/vf610_nfc.c
> +++ b/drivers/mtd/nand/raw/vf610_nfc.c
> @@ -364,7 +364,7 @@ static int vf610_nfc_cmd(struct nand_chip *chip,
>  {
>  	const struct nand_op_instr *instr;
>  	struct vf610_nfc *nfc = chip_to_nfc(chip);
> -	int op_id = -1, trfr_sz = 0, offset;
> +	int op_id = -1, trfr_sz = 0, offset = 0;
>  	u32 col = 0, row = 0, cmd1 = 0, cmd2 = 0, code = 0;
>  	bool force8bit = false;
>  

Thanks,
Miquèl
Masahiro Yamada May 3, 2019, 10:36 a.m. UTC | #2 
Hi Miquel,

On Thu, May 2, 2019 at 11:14 PM Miquel Raynal <miquel.raynal@bootlin.com> wrote:
>
> Hi Masahiro,
>
> Masahiro Yamada <yamada.masahiro@socionext.com> wrote on Tue, 23 Apr
> 2019 12:49:53 +0900:
>
> > This prepares to move CONFIG_OPTIMIZE_INLINING from x86 to a common
> > place. We need to eliminate potential issues beforehand.
> >
> > Kbuild test robot has never reported -Wmaybe-uninitialized warning
> > for this probably because vf610_nfc_run() is inlined by the x86
> > compiler's inlining heuristic.
> >
> > If CONFIG_OPTIMIZE_INLINING is enabled for a different architecture
> > and vf610_nfc_run() is not inlined, the following warning is reported:
> >
> > drivers/mtd/nand/raw/vf610_nfc.c: In function ‘vf610_nfc_cmd’:
> > drivers/mtd/nand/raw/vf610_nfc.c:455:3: warning: ‘offset’ may be used uninitialized in this function [-Wmaybe-uninitialized]
> >    vf610_nfc_rd_from_sram(instr->ctx.data.buf.in + offset,
> >    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >             nfc->regs + NFC_MAIN_AREA(0) + offset,
> >             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >             trfr_sz, !nfc->data_access);
> >             ~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> IMHO this patch has no dependencies with this series.


This patch is the prerequisite for 11/11.
https://lore.kernel.org/patchwork/patch/1064959/


Without the correct patch order,
the kbuild test robot reports the warning.


> Would you mind sending it alone with the proper Fixes tag?


I do not think Fixes is necessary.

Nobody has noticed this potential issue before.
Without 11/11, probably we cannot reproduce this warning.


BTW, this series has been for a while in linux-next.


>
> >
> > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> > ---
> >
> > Changes in v3: None
> > Changes in v2:
> >   - split into a separate patch
> >
> >  drivers/mtd/nand/raw/vf610_nfc.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/mtd/nand/raw/vf610_nfc.c b/drivers/mtd/nand/raw/vf610_nfc.c
> > index a662ca1970e5..19792d725ec2 100644
> > --- a/drivers/mtd/nand/raw/vf610_nfc.c
> > +++ b/drivers/mtd/nand/raw/vf610_nfc.c
> > @@ -364,7 +364,7 @@ static int vf610_nfc_cmd(struct nand_chip *chip,
> >  {
> >       const struct nand_op_instr *instr;
> >       struct vf610_nfc *nfc = chip_to_nfc(chip);
> > -     int op_id = -1, trfr_sz = 0, offset;
> > +     int op_id = -1, trfr_sz = 0, offset = 0;
> >       u32 col = 0, row = 0, cmd1 = 0, cmd2 = 0, code = 0;
> >       bool force8bit = false;
> >
>
> Thanks,
> Miquèl
>
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/



--
Best Regards

Masahiro Yamada
Miquel Raynal May 3, 2019, 11:11 a.m. UTC | #3 
Hi Masahiro,

Masahiro Yamada <yamada.masahiro@socionext.com> wrote on Fri, 3 May
2019 19:36:35 +0900:

> Hi Miquel,
> 
> On Thu, May 2, 2019 at 11:14 PM Miquel Raynal <miquel.raynal@bootlin.com> wrote:
> >
> > Hi Masahiro,
> >
> > Masahiro Yamada <yamada.masahiro@socionext.com> wrote on Tue, 23 Apr
> > 2019 12:49:53 +0900:
> >  
> > > This prepares to move CONFIG_OPTIMIZE_INLINING from x86 to a common
> > > place. We need to eliminate potential issues beforehand.
> > >
> > > Kbuild test robot has never reported -Wmaybe-uninitialized warning
> > > for this probably because vf610_nfc_run() is inlined by the x86
> > > compiler's inlining heuristic.
> > >
> > > If CONFIG_OPTIMIZE_INLINING is enabled for a different architecture
> > > and vf610_nfc_run() is not inlined, the following warning is reported:
> > >
> > > drivers/mtd/nand/raw/vf610_nfc.c: In function ‘vf610_nfc_cmd’:
> > > drivers/mtd/nand/raw/vf610_nfc.c:455:3: warning: ‘offset’ may be used uninitialized in this function [-Wmaybe-uninitialized]
> > >    vf610_nfc_rd_from_sram(instr->ctx.data.buf.in + offset,
> > >    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > >             nfc->regs + NFC_MAIN_AREA(0) + offset,
> > >             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > >             trfr_sz, !nfc->data_access);
> > >             ~~~~~~~~~~~~~~~~~~~~~~~~~~~  
> >
> > IMHO this patch has no dependencies with this series.  
> 
> 
> This patch is the prerequisite for 11/11.
> https://lore.kernel.org/patchwork/patch/1064959/
> 
> 
> Without the correct patch order,
> the kbuild test robot reports the warning.
> 
> 
> > Would you mind sending it alone with the proper Fixes tag?  
> 
> 
> I do not think Fixes is necessary.

IMHO it is. Even if today the warning does not spawn, there is a
real C error which might already be an issue.

> 
> Nobody has noticed this potential issue before.
> Without 11/11, probably we cannot reproduce this warning.
> 
> 
> BTW, this series has been for a while in linux-next.

Missed that. Ok, nevermind.


Thanks,
Miquèl
diff mbox series

Patch

diff --git a/drivers/mtd/nand/raw/vf610_nfc.c b/drivers/mtd/nand/raw/vf610_nfc.c
index a662ca1970e5..19792d725ec2 100644
--- a/drivers/mtd/nand/raw/vf610_nfc.c
+++ b/drivers/mtd/nand/raw/vf610_nfc.c
@@ -364,7 +364,7 @@  static int vf610_nfc_cmd(struct nand_chip *chip,
 {
 	const struct nand_op_instr *instr;
 	struct vf610_nfc *nfc = chip_to_nfc(chip);
-	int op_id = -1, trfr_sz = 0, offset;
+	int op_id = -1, trfr_sz = 0, offset = 0;
 	u32 col = 0, row = 0, cmd1 = 0, cmd2 = 0, code = 0;
 	bool force8bit = false;