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spm_addr_dev0 and spm_addr_dev1. Reading MINOR(mdevice->cdevice.dev) before > cdev_add() therefore always sees an uninitialized dev_t. As a result, both > coherent devices select the same physical range, and adding the second > device fails due to the overlapping dev_pagemap range. > > Use mdevice->device.devt instead. It is initialized in > dmirror_device_init() before dmirror_allocate_chunk() is called and is the > same dev_t later passed to cdev_device_add(). > > Fixes: af69016dab96 ("lib: test_hmm: implement a device release method") > Signed-off-by: Stanislav Kinsburskii > --- > lib/test_hmm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/lib/test_hmm.c b/lib/test_hmm.c > index 9c59d1ceb5b5..c4adbf98fac7 100644 > --- a/lib/test_hmm.c > +++ b/lib/test_hmm.c > @@ -581,7 +581,7 @@ static int dmirror_allocate_chunk(struct dmirror_device *mdevice, > devmem->pagemap.type = MEMORY_DEVICE_PRIVATE; > break; > case HMM_DMIRROR_MEMORY_DEVICE_COHERENT: > - devmem->pagemap.range.start = (MINOR(mdevice->cdevice.dev) - 2) ? > + devmem->pagemap.range.start = (MINOR(mdevice->device.devt) - 2) ? Makes sense to me. As Andrew mentioned we should cc: stable, but I assume he will add that so: Reviewed-by: Alistair Popple > spm_addr_dev0 : > spm_addr_dev1; > devmem->pagemap.range.end = devmem->pagemap.range.start + > > >