| Message ID | 1359057478-3920-1-git-send-email-sque@chromium.org |
|---|---|
| State | Not Applicable |
| Delegated to: | David Miller |
| Headers | show |
Hello. On 24-01-2013 23:57, Simon Que wrote: > Eliminates a compiler warning about uninitialized variable. > "warning: 'native_sectors' may be used uninitialized in this function" > Signed-off-by: Simon Que <sque@chromium.org> > --- > drivers/ata/libata-core.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c > index d2b18ea..b185db1 100644 > --- a/drivers/ata/libata-core.c > +++ b/drivers/ata/libata-core.c > @@ -1324,7 +1324,7 @@ static int ata_hpa_resize(struct ata_device *dev) > int print_info = ehc->i.flags & ATA_EHI_PRINTINFO; > bool unlock_hpa = ata_ignore_hpa || dev->flags & ATA_DFLAG_UNLOCK_HPA; > u64 sectors = ata_id_n_sectors(dev->id); > - u64 native_sectors; > + u64 native_sectors = 0; Isn't it wiser to set it to 'sectors'? And frankly speaking I don't see how this variable may indeed be used unitialized. What version of gcc are you using? MBR, Sergei -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
I'm using a ChromeOS / ChromiumOS gcc. Technically it won't be used uninitialized since there's a check for the return value. But this isn't always obvious to the compiler -- it'd have to be smart enough to look at ata_read_native_max_address() to see that if '*max_sectors' is not set, then there is a nonzero return value, which would cause ata_hpa_resize() to return early. This patch is really meant to satisfy the compiler, rather than to catch some corner case where 'native_sectors' gets used uninitialized. Setting it to 0 makes more sense because its "true initialization" is in a later call. On Fri, Jan 25, 2013 at 3:21 AM, Sergei Shtylyov <sshtylyov@mvista.com> wrote: > Hello. > > > On 24-01-2013 23:57, Simon Que wrote: > >> Eliminates a compiler warning about uninitialized variable. >> "warning: 'native_sectors' may be used uninitialized in this function" > > >> Signed-off-by: Simon Que <sque@chromium.org> >> --- >> drivers/ata/libata-core.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) > > >> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c >> index d2b18ea..b185db1 100644 >> --- a/drivers/ata/libata-core.c >> +++ b/drivers/ata/libata-core.c >> @@ -1324,7 +1324,7 @@ static int ata_hpa_resize(struct ata_device *dev) >> int print_info = ehc->i.flags & ATA_EHI_PRINTINFO; >> bool unlock_hpa = ata_ignore_hpa || dev->flags & >> ATA_DFLAG_UNLOCK_HPA; >> u64 sectors = ata_id_n_sectors(dev->id); >> - u64 native_sectors; >> + u64 native_sectors = 0; > > > Isn't it wiser to set it to 'sectors'? And frankly speaking I don't see > how this variable may indeed be used unitialized. What version of gcc are > you using? > > MBR, Sergei > -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
More specifically... I have gcc 4.7.1. On Fri, Jan 25, 2013 at 3:31 PM, Simon Que <sque@chromium.org> wrote: > I'm using a ChromeOS / ChromiumOS gcc. > > Technically it won't be used uninitialized since there's a check for > the return value. But this isn't always obvious to the compiler -- > it'd have to be smart enough to look at ata_read_native_max_address() > to see that if '*max_sectors' is not set, then there is a nonzero > return value, which would cause ata_hpa_resize() to return early. > > This patch is really meant to satisfy the compiler, rather than to > catch some corner case where 'native_sectors' gets used uninitialized. > Setting it to 0 makes more sense because its "true initialization" is > in a later call. > > On Fri, Jan 25, 2013 at 3:21 AM, Sergei Shtylyov <sshtylyov@mvista.com> wrote: >> Hello. >> >> >> On 24-01-2013 23:57, Simon Que wrote: >> >>> Eliminates a compiler warning about uninitialized variable. >>> "warning: 'native_sectors' may be used uninitialized in this function" >> >> >>> Signed-off-by: Simon Que <sque@chromium.org> >>> --- >>> drivers/ata/libata-core.c | 2 +- >>> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> >>> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c >>> index d2b18ea..b185db1 100644 >>> --- a/drivers/ata/libata-core.c >>> +++ b/drivers/ata/libata-core.c >>> @@ -1324,7 +1324,7 @@ static int ata_hpa_resize(struct ata_device *dev) >>> int print_info = ehc->i.flags & ATA_EHI_PRINTINFO; >>> bool unlock_hpa = ata_ignore_hpa || dev->flags & >>> ATA_DFLAG_UNLOCK_HPA; >>> u64 sectors = ata_id_n_sectors(dev->id); >>> - u64 native_sectors; >>> + u64 native_sectors = 0; >> >> >> Isn't it wiser to set it to 'sectors'? And frankly speaking I don't see >> how this variable may indeed be used unitialized. What version of gcc are >> you using? >> >> MBR, Sergei >> -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index d2b18ea..b185db1 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -1324,7 +1324,7 @@ static int ata_hpa_resize(struct ata_device *dev) int print_info = ehc->i.flags & ATA_EHI_PRINTINFO; bool unlock_hpa = ata_ignore_hpa || dev->flags & ATA_DFLAG_UNLOCK_HPA; u64 sectors = ata_id_n_sectors(dev->id); - u64 native_sectors; + u64 native_sectors = 0; int rc; /* do we need to do it? */
Eliminates a compiler warning about uninitialized variable. "warning: 'native_sectors' may be used uninitialized in this function" Signed-off-by: Simon Que <sque@chromium.org> --- drivers/ata/libata-core.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)