Re: [edk2-devel] [PATCH v3 1/2] Ext4Pkg: Improve Ext4IsBindingSupported() behavior

["Pedro Falcato" <pedro.falcato@gmail.com>]

On BY_DRIVER, Jeff reached the conclusion that we can't open the
BLOCK_IO protocol with BY_DRIVER since it's already owned by
DiskIoDxe. The finding makes sense and is consistent
with FatPkg's behaviour.
As for the GET_PROTOCOL issue, feel free to send a patch ;)

On Sun, Sep 12, 2021 at 11:40 AM Marvin Häuser <mhaeuser@posteo.de> wrote:
>
> On 11/09/2021 00:11, Jeff Brasen via groups.io wrote:
> > A couple of improvements to improve performance.
> > Add check to return ACCESS_DENIED if already connected
> > Add check to verify superblock magic during supported to reduce start calls
> >
> > Signed-off-by: Jeff Brasen <jbrasen@nvidia.com>
> > ---
> >   Features/Ext4Pkg/Ext4Dxe/Ext4Dxe.h    | 14 +++++++
> >   Features/Ext4Pkg/Ext4Dxe/Ext4Dxe.c    | 54 +++++++++++++++++++++------
> >   Features/Ext4Pkg/Ext4Dxe/Superblock.c | 35 +++++++++++++++++
> >   3 files changed, 92 insertions(+), 11 deletions(-)
> >
> > diff --git a/Features/Ext4Pkg/Ext4Dxe/Ext4Dxe.h b/Features/Ext4Pkg/Ext4Dxe/Ext4Dxe.h
> > index 64eab455db..a9b932ed52 100644
> > --- a/Features/Ext4Pkg/Ext4Dxe/Ext4Dxe.h
> > +++ b/Features/Ext4Pkg/Ext4Dxe/Ext4Dxe.h
> > @@ -1117,4 +1117,18 @@ Ext4GetVolumeName (
> >     OUT UINTN          *VolNameLen
> >     );
> >
> > +/**
> > +   Checks the superblock's magic value.
> > +
> > +   @param[in] DiskIo      Pointer to the DiskIo.
> > +   @param[in] BlockIo     Pointer to the BlockIo.
> > +
> > +   @returns Whether the partition has a valid EXT4 superblock magic value.
> > +**/
> > +BOOLEAN
> > +Ext4SuperblockCheckMagic (
> > +  IN EFI_DISK_IO_PROTOCOL   *DiskIo,
> > +  IN EFI_BLOCK_IO_PROTOCOL  *BlockIo
> > +  );
> > +
> >   #endif
> > diff --git a/Features/Ext4Pkg/Ext4Dxe/Ext4Dxe.c b/Features/Ext4Pkg/Ext4Dxe/Ext4Dxe.c
> > index ea2e048d77..d9fbe9ea78 100644
> > --- a/Features/Ext4Pkg/Ext4Dxe/Ext4Dxe.c
> > +++ b/Features/Ext4Pkg/Ext4Dxe/Ext4Dxe.c
> > @@ -631,7 +631,6 @@ Ext4Unload (
> >     @retval EFI_ACCESS_DENIED        The device specified by ControllerHandle and
> >                                      RemainingDevicePath is already being managed by a different
> >                                      driver or an application that requires exclusive access.
> > -                                   Currently not implemented.
> >     @retval EFI_UNSUPPORTED          The device specified by ControllerHandle and
> >                                      RemainingDevicePath is not supported by the driver specified by This.
> >   **/
> > @@ -643,32 +642,65 @@ Ext4IsBindingSupported (
> >     IN EFI_DEVICE_PATH *RemainingDevicePath  OPTIONAL
> >     )
> >   {
> > -  // Note to self: EFI_OPEN_PROTOCOL_TEST_PROTOCOL lets us not close the
> > -  // protocol and ignore the output argument entirely
> > +  EFI_STATUS            Status;
> > +  EFI_DISK_IO_PROTOCOL  *DiskIo;
> > +  EFI_BLOCK_IO_PROTOCOL *BlockIo;
> >
> > -  EFI_STATUS  Status;
> > +  DiskIo = NULL;
> > +  BlockIo = NULL;
> >
> > +  //
> > +  // Open the IO Abstraction(s) needed to perform the supported test
> > +  //
> >     Status = gBS->OpenProtocol (
> >                     ControllerHandle,
> >                     &gEfiDiskIoProtocolGuid,
> > -                  NULL,
> > -                  BindingProtocol->ImageHandle,
> > +                  (VOID **) &DiskIo,
> > +                  BindingProtocol->DriverBindingHandle,
> >                     ControllerHandle,
> > -                  EFI_OPEN_PROTOCOL_TEST_PROTOCOL
> > +                  EFI_OPEN_PROTOCOL_BY_DRIVER
> >                     );
> >
> >     if (EFI_ERROR (Status)) {
> >       return Status;
> >     }
> > -
> > +  //
> > +  // Open the IO Abstraction(s) needed to perform the supported test
> > +  //
> >     Status = gBS->OpenProtocol (
> >                     ControllerHandle,
> >                     &gEfiBlockIoProtocolGuid,
> > -                  NULL,
> > -                  BindingProtocol->ImageHandle,
> > +                  (VOID **) &BlockIo,
> > +                  BindingProtocol->DriverBindingHandle,
> >                     ControllerHandle,
> > -                  EFI_OPEN_PROTOCOL_TEST_PROTOCOL
> > +                  EFI_OPEN_PROTOCOL_GET_PROTOCOL
> >                     );
> > +
> > +  if (!EFI_ERROR (Status)) {
> > +    if (!Ext4SuperblockCheckMagic (DiskIo, BlockIo)) {
> > +      Status = EFI_UNSUPPORTED;
> > +    }
> > +  }
> > +
> > +  //
> > +  // Close the I/O Abstraction(s) used to perform the supported test
> > +  //
> > +  if (DiskIo != NULL) {
> > +    gBS->CloseProtocol (
> > +          ControllerHandle,
> > +          &gEfiDiskIoProtocolGuid,
> > +          BindingProtocol->DriverBindingHandle,
> > +          ControllerHandle
> > +          );
> > +  }
> > +  if (BlockIo != NULL) {
> > +    gBS->CloseProtocol (
> > +          ControllerHandle,
> > +          &gEfiBlockIoProtocolGuid,
> > +          BindingProtocol->DriverBindingHandle,
> > +          ControllerHandle
> > +          );
> > +  }
>
> GET_PROTOCOL protocols are not to be closed, I guess this was missed
> when there was still the question whether to use BY_DRIVER for BlockIo.
>
> Best regards,
> Marvin
>
> >     return Status;
> >   }
> >
> > diff --git a/Features/Ext4Pkg/Ext4Dxe/Superblock.c b/Features/Ext4Pkg/Ext4Dxe/Superblock.c
> > index c321d8c3d8..0c965415c5 100644
> > --- a/Features/Ext4Pkg/Ext4Dxe/Superblock.c
> > +++ b/Features/Ext4Pkg/Ext4Dxe/Superblock.c
> > @@ -34,6 +34,41 @@ STATIC CONST UINT32  gSupportedIncompatFeat =
> >   // this is desired, it's fairly trivial to look for EFI_VOLUME_CORRUPTED
> >   // references and add some Ext4SignalCorruption function + function call.
> >
> > +/**
> > +   Checks the superblock's magic value.
> > +
> > +   @param[in] DiskIo      Pointer to the DiskIo.
> > +   @param[in] BlockIo     Pointer to the BlockIo.
> > +
> > +   @returns Whether the partition has a valid EXT4 superblock magic value.
> > +**/
> > +BOOLEAN
> > +Ext4SuperblockCheckMagic (
> > +  IN EFI_DISK_IO_PROTOCOL   *DiskIo,
> > +  IN EFI_BLOCK_IO_PROTOCOL  *BlockIo
> > +  )
> > +{
> > +  UINT16      Magic;
> > +  EFI_STATUS  Status;
> > +
> > +  Status = DiskIo->ReadDisk (
> > +                     DiskIo,
> > +                     BlockIo->Media->MediaId,
> > +                     EXT4_SUPERBLOCK_OFFSET + OFFSET_OF (EXT4_SUPERBLOCK, s_magic),
> > +                     sizeof (Magic),
> > +                     &Magic
> > +                     );
> > +  if (EFI_ERROR (Status)) {
> > +    return FALSE;
> > +  }
> > +
> > +  if (Magic != EXT4_SIGNATURE) {
> > +    return FALSE;
> > +  }
> > +
> > +  return TRUE;
> > +}
> > +
> >   /**
> >      Does brief validation of the ext4 superblock.
> >
>


-- 
Pedro Falcato