Messages in this thread | | | Subject | Re: PROBLEM: Firmware loader fallback mechanism no longer works with sendfile | From | Siddharth Gupta <> | Date | Tue, 5 Jan 2021 17:00:58 -0800 |
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On 1/4/2021 10:36 PM, Greg KH wrote: > On Mon, Jan 04, 2021 at 02:43:45PM -0800, Siddharth Gupta wrote: >> Hi all, >> >> With the introduction of the filesystem change "fs: don't allow splice >> read/write without explicit ops"[1] the fallback mechanism of the firmware >> loader[2] no longer works when using sendfile[3] from the userspace. > What userspace program are you using to load firmware? The userspace program is in the android userspace which listens to a uevent from the firmware loader and then loads the firmware using sendfile[1]. > Are you not using the in-kernel firmware loader for some reason? We have certain non-standard firmware paths that should not be added to the linux kernel, and the firmware_class.path only supports a single path. > >> Since the binary attributes don't support splice_{read,write} functions the >> calls to splice_{read,write} used the default kernel_{read,write} functions. >> With the above change this results in an -EINVAL return from >> do_splice_from[4]. >> >> This essentially means that sendfile will not work for any binary attribute >> in the sysfs. > Have you tried fixing this with a patch much like what we did for the > proc files that needed this? If not, can you? I am not aware of this fix, could you provide me a link for reference? I will try it out. > >> [1]: https://github.com/torvalds/linux/commit/36e2c7421f02a22f71c9283e55fdb672a9eb58e7#diff-70c49af2ed5805fc1406ed6e6532d6a029ada1abd90cca6442711b9cecd4d523 >> [2]: https://github.com/torvalds/linux/blob/master/drivers/base/firmware_loader/main.c#L831 >> [3]: https://github.com/torvalds/linux/blob/master/fs/read_write.c#L1257 >> [4]: https://github.com/torvalds/linux/blob/master/fs/splice.c#L753 > kernel development is on git.kernel.org, not github :) I use it because it is easier on the eyes when looking at diffs :D But I'll be sure to use git.kernel.org from now on if that is what is preferred! > > thanks, > > greg k-h Thanks, Sid
[1]: https://android.googlesource.com/platform/system/core/+/refs/heads/master/init/firmware_handler.cpp#55
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