Are you saying in an application: OpenProtocol(Handle, &gEfiDiskIoProtocolGuid, (void**) &DiskIO, ImageHandle, NULL, EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL)
is not safe - it will still invalidate the pointers in DiskIO when removed and won't wait until CloseProtocol is used? On Tue, Feb 12, 2013 at 12:19 PM, Andrew Fish <af...@apple.com> wrote: > > On Feb 12, 2013, at 10:48 AM, David F. <df7...@gmail.com> wrote: > >> I mean the device itself may be removed, USB hard drive, 1394, etc.. >> I presume it would still be safe and attempts to access it would >> simply fail? >> > > The bus driver (USB Bus Driver for example) does a > gBS->DisconnectController() and causes the Block IO driver to stop. Stop > means uninstall your protocols. This works fine for the EFI driver model as > the leaf gets stopped first. So the file system driver first, then the > partition driver, and then the Block IO driver get stopped. The problem we > run into is the EFI application may do a HandleProtocol() and in this case it > will not be notified when the stack gets torn down. > > In my other mail where I attached a patch, there was a library that wraps > Block IO and makes it safe to use by following the driver model. Basically > you just call library functions and if you application is in the middle of a > block IO call you fail the stop. This library implements the BY_DRIVER > attribute of OpenProtocol() and produces a driver binding protocol instance > so a surprise removal request can be detected or deferred. > > This model is a side effect of some of the other rules we have. For example > device paths must be unique, only one instance of a protocol per handle, and > how the DXE core tracks all the drivers and their parent child relationships. > > Thanks, > > Andrew Fish > >> On Tue, Feb 12, 2013 at 8:44 AM, Andrew Fish <af...@apple.com> wrote: >>> What do you mean by device being removed? Media being removed from a device >>> is a different case than unplugging an USB disk. >>> >>> Andrew Fish >>> >>> >>> On Feb 11, 2013, at 7:38 PM, "David F." <df7...@gmail.com> wrote: >>> >>>> Hi, >>>> >>>> I'd like to open the DISK_IO protocol and leave it open for quite a >>>> while (hours). In the mean time the device may be removed. I would >>>> assume that I can continue to try using the protocol to read/write and >>>> there would simply be a failure (as long as its detached - if >>>> something else in its place may fail due to media-id difference, but >>>> that is understood). Once I close the protocol, then the item is >>>> cleaned up. >>>> >>>> Is the assumption good? >>>> >>>> TIA!! >>>> >>>> ------------------------------------------------------------------------------ >>>> Free Next-Gen Firewall Hardware Offer >>>> Buy your Sophos next-gen firewall before the end March 2013 >>>> and get the hardware for free! Learn more. >>>> http://p.sf.net/sfu/sophos-d2d-feb >>>> _______________________________________________ >>>> edk2-devel mailing list >>>> edk2-devel@lists.sourceforge.net >>>> https://lists.sourceforge.net/lists/listinfo/edk2-devel >>> >>> >>> ------------------------------------------------------------------------------ >>> Free Next-Gen Firewall Hardware Offer >>> Buy your Sophos next-gen firewall before the end March 2013 >>> and get the hardware for free! Learn more. >>> http://p.sf.net/sfu/sophos-d2d-feb >>> _______________________________________________ >>> edk2-devel mailing list >>> edk2-devel@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/edk2-devel >> >> ------------------------------------------------------------------------------ >> Free Next-Gen Firewall Hardware Offer >> Buy your Sophos next-gen firewall before the end March 2013 >> and get the hardware for free! Learn more. >> http://p.sf.net/sfu/sophos-d2d-feb >> _______________________________________________ >> edk2-devel mailing list >> edk2-devel@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/edk2-devel > > > ------------------------------------------------------------------------------ > Free Next-Gen Firewall Hardware Offer > Buy your Sophos next-gen firewall before the end March 2013 > and get the hardware for free! Learn more. > http://p.sf.net/sfu/sophos-d2d-feb > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/edk2-devel ------------------------------------------------------------------------------ Free Next-Gen Firewall Hardware Offer Buy your Sophos next-gen firewall before the end March 2013 and get the hardware for free! Learn more. http://p.sf.net/sfu/sophos-d2d-feb _______________________________________________ edk2-devel mailing list edk2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/edk2-devel
