Re: [PATCH v2 1/2] Ext4Pkg: Improve Ext4IsBindingSupported() behavior

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

Like Marvin raised in v1, it's a good idea to change the first
OpenProtocol's EFI_OPEN_PROTOCOL_BY_DRIVER
into EFI_OPEN_PROTOCOL_GET_PROTOCOL, for consistency's sake.
Since we're not keeping these protocols open, using BY_DRIVER makes no
difference.

You didn't update Ext4SuperblockCheckMagic's comment in Superblock.c
when you changed it in the header.
Just a nitpick, but if you could quickly align the
Ext4SuperblockCheckMagic's parameters' descriptions like

   @param[in] DiskIo      Pointer to the DiskIo.
   @param[in] BlockIo     Pointer to the BlockIo.

it would be excellent.

Apart from that, looks great to me and the patch series will get my RB
after that quick change.

Best regards,

Pedro

On Fri, Sep 10, 2021 at 4:58 PM Jeff Brasen <jbrasen@nvidia.com> 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    | 58 +++++++++++++++++++++------
>  Features/Ext4Pkg/Ext4Dxe/Superblock.c | 35 ++++++++++++++++
>  3 files changed, 95 insertions(+), 12 deletions(-)
>
> diff --git a/Features/Ext4Pkg/Ext4Dxe/Ext4Dxe.h b/Features/Ext4Pkg/Ext4Dxe/Ext4Dxe.h
> index 64eab455db..5c60860894 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.
> +
> +   @return TRUE if a valid ext4 superblock, else FALSE.
> +**/
> +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..5ae93d0484 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 +642,67 @@ 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;
> +    goto Exit;
>    }
> -
> +  //
> +  // 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)) {
> +    goto Exit;
> +  }
> +
> +  if (!Ext4SuperblockCheckMagic (DiskIo, BlockIo)) {
> +    Status = EFI_UNSUPPORTED;
> +  }
> +
> +Exit:
> +  //
> +  // 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
> +          );
> +  }
>    return Status;
>  }
>
> diff --git a/Features/Ext4Pkg/Ext4Dxe/Superblock.c b/Features/Ext4Pkg/Ext4Dxe/Superblock.c
> index c321d8c3d8..1ceb0d5cbb 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 only superblock magic value.
> +
> +   @param[in] DiskIo     Pointer to the DiskIo.
> +   @param[in] BlockIo     Pointer to the BlockIo.
> +
> +   @return TRUE if a valid ext4 superblock, else FALSE.
> +**/
> +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.
>
> --
> 2.17.1
>


-- 
Pedro Falcato