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Subjectdid vfs_read or something related to it get broken?
Hi,

I have a driver that reads data from a file that has worked from
kernel 3.x up to 4.9.13. I haven't tried all the other 4.9's or 4.10,
or 4.11.6 or earlier, but in 4.11.7 it's now broken and an error is
returned. It's based on
http://krishnamohanlinux.blogspot.com/2013/12/how-to-write-to-file-from-kernel-module.html

Is there a new requirement of some sort or did it get broken?

int driver_file_read(struct file *file, unsigned char *data, unsigned int size)
{
int ret;
mm_segment_t oldfs;

// get file pointer
loff_t pos = file->f_pos;

oldfs = get_fs();
set_fs(get_ds());

ret=vfs_read(file, data, size, &pos);

set_fs(oldfs);

// update file pointer
file->f_pos=pos;

return (ret);
}


struct file *driver_file_open(const char *path, int flags, int mode, int *err)
{
int ec=0;
struct file *filp = NULL;
filp=filp_open(path, flags, mode);
if (IS_ERR(filp)) {
ec=PTR_ERR(filp);
filp=NULL;
}
// update callers error code
if (err) {
*err=ec;
}
// return pointer to file
return (filp);
}

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