Re: [edk2-devel] [PATCH v2 2/2] MdeModulePkg/Bus/Ata/AtaAtapiPassThru: Fix UNUSED_VALUE Coverity issue

["Ard Biesheuvel" <ardb@kernel.org>]

On Wed, 12 Jul 2023 at 09:06, Wu, Hao A <hao.a.wu@intel.com> wrote:
>
> It works for me, better to override by:
>
>   Status = EFI_SUCCESS;
>
>

So now we're adding unnecessary assignments just to please coverity? I
don't think this is a good idea.

If Coverity does not understand that the source references Status
after the assignment (which it does but only in DEBUG mode), fix
coverity, not the code.




>
> From: Ranbir Singh <rsingh@ventanamicro.com>
> Sent: Wednesday, July 12, 2023 3:01 PM
> To: Wu, Hao A <hao.a.wu@intel.com>
> Cc: devel@edk2.groups.io; Ni, Ray <ray.ni@intel.com>
> Subject: Re: [PATCH v2 2/2] MdeModulePkg/Bus/Ata/AtaAtapiPassThru: Fix UNUSED_VALUE Coverity issue
>
>
>
> Thanks Hao for digging deeper into this.
>
>
>
> The if block itself might get knocked off in Release mode when there is only a DEBUG statement inside it and hence Coverity might still complain. So, we can override the Status value in this scenario inside the if block and then proceed normally - let me know if this is acceptable and I will update the patch as below then
>
>       if (EFI_ERROR (Status)) {
>         DEBUG ((DEBUG_WARN, "Set Drive Parameters Fail, Status = %r\n", Status));
>
>         /* Ignore Warning and proceed normally */
>
>         Status = 0;
>       }
>
>
>
> Best Regards,
>
> Ranbir Singh
>
>
>
> On Wed, Jul 12, 2023 at 10:08 AM Wu, Hao A <hao.a.wu@intel.com> wrote:
>
> Really sorry,
>
> After referring to the Information Technology - AT Attachment with Packet Interface (ATA/ATAPI) Specification,
> It seems to me that the commands being executed in function SetDriveParameters() are not mandatory during device initialization.
>
> 1. INITIALIZE DEVICE PARAMETERS command (ID 0x91h):
> This command got obsoleted since ATA/ATAPI-6 spec version.
> Also, the return status of SetDriveParameters() is irrelevant with the execution result of this command.
>
> 2. SET MULTIPLE MODE command (ID 0xC6h):
> My take is that this command is necessary if there is subsequent usage of command READ MULTIPLE, READ MULTIPLE EXT, WRITE MULTIPLE, or WRITE MULTIPLE EXT.
> I do not find usage of the above 4 commands within edk2, so I think the successful execution of SET MULTIPLE MODE command is not mandatory for detecting hard disk device.
>
> Based on the above findings, could you help to update the patch to:
>       Status = SetDriveParameters (Instance, IdeChannel, IdeDevice, &DriveParameters, NULL);
>
>       if (EFI_ERROR (Status)) {
>         DEBUG ((DEBUG_WARN, "Set Drive Parameters Fail, Status = %r\n", Status));
>       }
>
> Will doing so still please Coverity?
>
> Best Regards,
> Hao Wu
>
> > -----Original Message-----
> > From: Ranbir Singh <rsingh@ventanamicro.com>
> > Sent: Friday, June 9, 2023 8:33 PM
> > To: devel@edk2.groups.io; rsingh@ventanamicro.com
> > Cc: Wu, Hao A <hao.a.wu@intel.com>; Ni, Ray <ray.ni@intel.com>
> > Subject: [PATCH v2 2/2] MdeModulePkg/Bus/Ata/AtaAtapiPassThru: Fix
> > UNUSED_VALUE Coverity issue
> >
> > From: Ranbir Singh <Ranbir.Singh3@Dell.com>
> >
> > The return value stored in Status after call to SetDriveParameters
> > is not made of any use thereafter and hence it remains as UNUSED.
> >
> > Add error check as is done after calls to SetDeviceTransferMode.
> >
> > Cc: Hao A Wu <hao.a.wu@intel.com>
> > Cc: Ray Ni <ray.ni@intel.com>
> > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4204
> > Signed-off-by: Ranbir Singh <Ranbir.Singh3@Dell.com>
> > Signed-off-by: Ranbir Singh <rsingh@ventanamicro.com>
> > ---
> >
> > Notes:
> >     Add error check instead of Status storage removal
> >
> >  MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c | 7 ++++++-
> >  1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c
> > b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c
> > index 75403886e44a..d04b1d95a7f5 100644
> > --- a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c
> > +++ b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c
> > @@ -2549,13 +2549,18 @@ DetectAndConfigIdeDevice (
> >      //
> >
> >      if (DeviceType == EfiIdeHarddisk) {
> >
> >        //
> >
> > -      // Init driver parameters
> >
> > +      // Init drive parameters
> >
> >        //
> >
> >        DriveParameters.Sector         = (UINT8)((ATA5_IDENTIFY_DATA
> > *)(&Buffer.AtaData))->sectors_per_track;
> >
> >        DriveParameters.Heads          = (UINT8)(((ATA5_IDENTIFY_DATA
> > *)(&Buffer.AtaData))->heads - 1);
> >
> >        DriveParameters.MultipleSector = (UINT8)((ATA5_IDENTIFY_DATA
> > *)(&Buffer.AtaData))->multi_sector_cmd_max_sct_cnt;
> >
> >
> >
> >        Status = SetDriveParameters (Instance, IdeChannel, IdeDevice,
> > &DriveParameters, NULL);
> >
> > +
> >
> > +      if (EFI_ERROR (Status)) {
> >
> > +        DEBUG ((DEBUG_ERROR, "Set Drive Parameters Fail, Status = %r\n",
> > Status));
> >
> > +        continue;
> >
> > +      }
> >
> >      }
> >
> >
> >
> >      //
> >
> > --
> > 2.34.1
>
>