On 1/8/2021 6:44 AM, Greg KH wrote:
On Thu, Jan 07, 2021 at 02:03:47PM -0800, Siddharth Gupta wrote:
On 1/6/2021 2:33 AM, Greg KH wrote:
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.
Look at the series of commits starting at fe33850ff798 ("proc: wire up
generic_file_splice_read for iter ops") for how this was fixed in procfs
as an example of what also needs to be done for binary sysfs files.
I tried to follow these fixes, but I am unfamiliar with fs code. I don't see
the generic_file_splice_write function anymore on newer kernels, also AFAICT
kernfs_ops does not define {read,write}_iter operations. If the solution is
simple and someone could provide the patches I would be happy to test them
out. If not, some more information about how to proceed would be nice.
Can you try this tiny patch out below?
Sorry for the delay, I tried out the patch, but I am still seeing the
error. Please take a look at these logs with
android running in the userspace[1]:
[ 62.295056][ T249] remoteproc remoteproc1: powering up
xxxxxxxx.remoteproc-cdsp
[ 62.304138][ T249] remoteproc remoteproc1: Direct firmware load for
cdsp.mdt failed with error -2
[ 62.312976][ T249] remoteproc remoteproc1: Falling back to sysfs
fallback for: cdsp.mdt
[ 62.469748][ T394] ueventd: firmware: loading 'cdsp.mdt' for
'/devices/platform/soc/xxxxxxxx.remoteproc-cdsp/remoteproc/remoteproc1/cdsp.mdt'
[ 62.498700][ T394] ueventd: firmware: sendfile failed {
'/sys/devices/platform/soc/xxxxxxxx.remoteproc-cdsp/remoteproc/remoteproc1/cdsp.mdt',
'cdsp.mdt' }: Invalid argument
Thanks,
Sid
[1]:
https://android.googlesource.com/platform/system/core/+/refs/heads/master/init/firmware_handler.cpp#57
thanks,
greg k-h
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index f277d023ebcd..113bc816d430 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -968,6 +968,8 @@ const struct file_operations kernfs_file_fops = {
.release = kernfs_fop_release,
.poll = kernfs_fop_poll,
.fsync = noop_fsync,
+ .splice_read = generic_file_splice_read,
+ .splice_write = iter_file_splice_write,
};
/**
