[PATCH] drivers/ata/sata_via.c - Eliminate "may be used uninitialized" warning

[PATCH] drivers/ata/sata_via.c - Eliminate "may be used uninitialized" warning

[Joe Perches]

Called by svia_init_one with a temporary,
so there's no effective code change.

Signed-off-by: Joe Perches <joe@perches.com>

 drivers/ata/sata_via.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/ata/sata_via.c b/drivers/ata/sata_via.c
index 0d03f44..e01d2b1 100644
--- a/drivers/ata/sata_via.c
+++ b/drivers/ata/sata_via.c
@@ -406,10 +406,9 @@ static int vt6420_prepare_host(struct pci_dev *pdev, struct ata_host **r_host)
 	struct ata_host *host;
 	int rc;
 
-	rc = ata_pci_prepare_sff_host(pdev, ppi, &host);
+	rc = ata_pci_prepare_sff_host(pdev, ppi, r_host);
 	if (rc)
 		return rc;
-	*r_host = host;
 
 	rc = pcim_iomap_regions(pdev, 1 << 5, DRV_NAME);
 	if (rc) {
@@ -417,6 +416,7 @@ static int vt6420_prepare_host(struct pci_dev *pdev, struct ata_host **r_host)
 		return rc;
 	}
 
+	host = *r_host;
 	host->ports[0]->ioaddr.scr_addr = svia_scr_addr(host->iomap[5], 0);
 	host->ports[1]->ioaddr.scr_addr = svia_scr_addr(host->iomap[5], 1);
 

Re: [PATCH] drivers/ata/sata_via.c - Eliminate "may be used uninitialized" warning

[Adrian Bunk]

On Sun, Apr 06, 2008 at 02:45:20PM -0700, Joe Perches wrote:
> Called by svia_init_one with a temporary,
> so there's no effective code change.
>...

I'm not getting any warning here.

Are you using an older gcc?

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

Re: [PATCH] drivers/ata/sata_via.c - Eliminate "may be used uninitialized" warning

[Joe Perches]

On Mon, 2008-04-07 at 00:50 +0300, Adrian Bunk wrote:
> On Sun, Apr 06, 2008 at 02:45:20PM -0700, Joe Perches wrote:
> > Called by svia_init_one with a temporary,
> > so there's no effective code change.
> I'm not getting any warning here.
> Are you using an older gcc?

Yes.  Slightly less than 4.3.0

$ gcc --version
gcc (GCC) 4.2.2 20071128 (prerelease) (4.2.2-3.1mdv2008.0)

$ git-show
commit 6fdf5e67fe8d3c83500dad9acae985132c2459a3
Merge: abd24df... e64a3cf...
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Fri Apr 4 15:09:44 2008 -0700

    Merge branch 'upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/ralf/upstream-linus
    
    * 'upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/ralf/upstream-linus:
      [MIPS] Make KGDB compile on UP
      [MIPS] Pb1200: Fix header breakage

$ make defconfig
[]
$ make clean
[]
$ make drivers/ata/sata_via.o
[]
  CC      drivers/ata/sata_via.o
drivers/ata/sata_via.c: In function ‘svia_init_one’:
drivers/ata/sata_via.c:504: warning: ‘host’ may be used uninitialized in this function

Re: [PATCH] drivers/ata/sata_via.c - Eliminate "may be used uninitialized" warning

[Adrian Bunk]

On Sun, Apr 06, 2008 at 03:00:07PM -0700, Joe Perches wrote:
> On Mon, 2008-04-07 at 00:50 +0300, Adrian Bunk wrote:
> > On Sun, Apr 06, 2008 at 02:45:20PM -0700, Joe Perches wrote:
> > > Called by svia_init_one with a temporary,
> > > so there's no effective code change.
> > I'm not getting any warning here.
> > Are you using an older gcc?
> 
> Yes.  Slightly less than 4.3.0
> 
> $ gcc --version
> gcc (GCC) 4.2.2 20071128 (prerelease) (4.2.2-3.1mdv2008.0)
>...

I've reproduced the warning with 4.2 but not with the 4.3 in Debian 
unstable.

Jeff is the one to decide about this specific patch.

Independent from this specific patch my opinion is that considering that 
we support 7 different release series of gcc aiming for a warning free 
compilation with the latest gcc is a good goal, but aiming for a warning 
free compilation with all supported gcc release series is not worth it
(especially considering that patches that fix such warnings might even 
introduce new bugs).

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed