On Tue, Oct 11, 2022 at 01:08:26PM +0200, Heinrich Schuchardt wrote: > > > On 10/11/22 09:35, AKASHI Takahiro wrote: > > On Tue, Oct 11, 2022 at 07:58:11AM +0200, Heinrich Schuchardt wrote: > > > > > > > > > On 10/11/22 02:49, AKASHI Takahiro wrote: > > > > The commit message is not accurate. > > > > > > > > On Fri, Oct 07, 2022 at 04:06:23PM +0200, Heinrich Schuchardt wrote: > > > > > The CloseProtocol() boot service requires a handle as first argument. > > > > > Passing the protocol interface is incorrect. > > > > > > > > Correct, but > > > > > > > > > CloseProtocol() only has an effect if called with a non-zero value for > > > > > agent_handle. HandleProtocol() uses an opaque agent_handle when > > > > > invoking > > > > > OpenProtocol() (currently NULL). > > > > > > > > No. OpenProtocol() is called with efi_root as an agent handle. > > > > So, calling CloseProtocol() is a right thing at the end. > > > > > > Typically an agent handle is used to relate to a driver exposing the > > > driver > > > binding protocol. > > > > Why can't we, other than a driver, call HandleProtocol() > > as a convenient way of accessing an interface? > > The description of HandleProtocol() clearly says that it is deprecated. > > The assumption that the UEFI specification makes in it is example code that > you never be able to close a protocol opened with HandleProtocol.
I don't understand this statement. I never find any description of "you never be able to close a protocol opened with HandleProtocol" in the spec. > After the first usage of handle protocol the open protocol information with > the opaque agent handle will block the protocol interface from ever being > removed by the driver exposing it. > > > > > > The root node does not expose the driver binding protocol. > > > > So do you mean the current implementation of HandleProtocol() is wrong? > > Yes. If you ever install a boot time driver, it might remove a protocol > interface which is actually still in use. Again, what about efi_load_image_from_path() that I gave in another example? I think that you have something to do *before* you submit this patch. Anyhow, your commit message is not accurate. -Takahiro Akashi > > > > > Why would you want to create an open protocol information entry here? > > > > To access get_image_info() quickly. > > This is not related to an open protocol information (see the UEFI spec > description of OpenProtocolInformation()). > > Best regards > > Heinrich > > > > > > Do you think anything with the code after the patch is wrong? > > > > No reason to replace handle_protocol(). > > > > Another example is here: > > efi_load_image_from_path() > > efi_handle_protocol(device, guid, (void **)&load_file_protocol)); > > ... > > efi_close_protocol(device, guid, efi_root, NULL); > > > > I believe that this function is anything but a driver. > > I think using HandleProtocol() (or preferably OpenProtocol()) and > > CloseProtocol() > > in pair seems totally sane. > > > > -Takahiro Akashi > > > > > > > > > Best regards > > > > > > Heinrich > > > > > > > > > > > > Therefore HandleProtocol() should be > > > > > avoided. > > > > > > > > > > * Replace the LocateHandle() call by efi_search_protocol(). > > > > > > > > LocateHandle() -> efi_handle_protocol() > > > > > > > > So you could have fixed this way: > > > > EFI_CALL(efi_close_protocol(handle, ..., &efi_root, NULL); > > > > > > > > I preferred to use EFI_CALL() over this file as you can see. > > > > > > > > -Takahiro Akashi > > > > > > > > > * Remove the CloseProtocol() call. > > > > > > > > > > Fixes: 8d99026f0697 ("efi_loader: capsule: support firmware update") > > > > > Signed-off-by: Heinrich Schuchardt <heinrich.schucha...@canonical.com> > > > > > --- > > > > > lib/efi_loader/efi_capsule.c | 14 ++++++-------- > > > > > 1 file changed, 6 insertions(+), 8 deletions(-) > > > > > > > > > > diff --git a/lib/efi_loader/efi_capsule.c > > > > > b/lib/efi_loader/efi_capsule.c > > > > > index b6bd2d6af8..397e393a18 100644 > > > > > --- a/lib/efi_loader/efi_capsule.c > > > > > +++ b/lib/efi_loader/efi_capsule.c > > > > > @@ -159,12 +159,14 @@ efi_fmp_find(efi_guid_t *image_type, u8 > > > > > image_index, u64 instance, > > > > > efi_status_t ret; > > > > > for (i = 0, handle = handles; i < no_handles; i++, handle++) { > > > > > - ret = EFI_CALL(efi_handle_protocol( > > > > > - *handle, > > > > > - &efi_guid_firmware_management_protocol, > > > > > - (void **)&fmp)); > > > > > + struct efi_handler *fmp_handler; > > > > > + > > > > > + ret = efi_search_protocol( > > > > > + *handle, > > > > > &efi_guid_firmware_management_protocol, > > > > > + &fmp_handler); > > > > > if (ret != EFI_SUCCESS) > > > > > continue; > > > > > + fmp = fmp_handler->protocol_interface; > > > > > /* get device's image info */ > > > > > info_size = 0; > > > > > @@ -215,10 +217,6 @@ efi_fmp_find(efi_guid_t *image_type, u8 > > > > > image_index, u64 instance, > > > > > skip: > > > > > efi_free_pool(package_version_name); > > > > > free(image_info); > > > > > - EFI_CALL(efi_close_protocol( > > > > > - (efi_handle_t)fmp, > > > > > - &efi_guid_firmware_management_protocol, > > > > > - NULL, NULL)); > > > > > if (found) > > > > > return fmp; > > > > > } > > > > > -- > > > > > 2.37.2 > > > > >