Hi Luiz,
> > > This patch adds functionality to perform flush from guest to host > > over VIRTIO. We are registering a callback based on 'nd_region' type. > > As virtio_pmem driver requires this special flush interface, for rest > > of the region types we are registering existing flush function. > > Also report the error returned by virtio flush interface. > > This patch doesn't apply against latest upstream. A few more comments > below. My bad, I tested it with 4.17-rc1. Will rebase it. > > > > > Signed-off-by: Pankaj Gupta <pagu...@redhat.com> > > --- > > drivers/nvdimm/nd.h | 1 + > > drivers/nvdimm/pmem.c | 4 ++-- > > drivers/nvdimm/region_devs.c | 24 ++++++++++++++++++------ > > include/linux/libnvdimm.h | 5 ++++- > > 4 files changed, 25 insertions(+), 9 deletions(-) > > > > diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h > > index 32e0364..1b62f79 100644 > > --- a/drivers/nvdimm/nd.h > > +++ b/drivers/nvdimm/nd.h > > @@ -159,6 +159,7 @@ struct nd_region { > > struct badblocks bb; > > struct nd_interleave_set *nd_set; > > struct nd_percpu_lane __percpu *lane; > > + int (*flush)(struct device *dev); > > struct nd_mapping mapping[0]; > > }; > > > > diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c > > index 9d71492..29fd2cd 100644 > > --- a/drivers/nvdimm/pmem.c > > +++ b/drivers/nvdimm/pmem.c > > @@ -180,7 +180,7 @@ static blk_qc_t pmem_make_request(struct request_queue > > *q, struct bio *bio) > > struct nd_region *nd_region = to_region(pmem); > > > > if (bio->bi_opf & REQ_FLUSH) > > - nvdimm_flush(nd_region); > > + bio->bi_status = nvdimm_flush(nd_region); > > > > do_acct = nd_iostat_start(bio, &start); > > bio_for_each_segment(bvec, bio, iter) { > > @@ -196,7 +196,7 @@ static blk_qc_t pmem_make_request(struct request_queue > > *q, struct bio *bio) > > nd_iostat_end(bio, start); > > > > if (bio->bi_opf & REQ_FUA) > > - nvdimm_flush(nd_region); > > + bio->bi_status = nvdimm_flush(nd_region); > > > > bio_endio(bio); > > return BLK_QC_T_NONE; > > diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c > > index a612be6..124aae7 100644 > > --- a/drivers/nvdimm/region_devs.c > > +++ b/drivers/nvdimm/region_devs.c > > @@ -1025,6 +1025,7 @@ static struct nd_region *nd_region_create(struct > > nvdimm_bus *nvdimm_bus, > > dev->of_node = ndr_desc->of_node; > > nd_region->ndr_size = resource_size(ndr_desc->res); > > nd_region->ndr_start = ndr_desc->res->start; > > + nd_region->flush = ndr_desc->flush; > > nd_device_register(dev); > > > > return nd_region; > > @@ -1065,13 +1066,10 @@ struct nd_region > > *nvdimm_volatile_region_create(struct nvdimm_bus *nvdimm_bus, > > } > > EXPORT_SYMBOL_GPL(nvdimm_volatile_region_create); > > > > -/** > > - * nvdimm_flush - flush any posted write queues between the cpu and pmem > > media > > - * @nd_region: blk or interleaved pmem region > > - */ > > -void nvdimm_flush(struct nd_region *nd_region) > > +void pmem_flush(struct device *dev) > > { > > - struct nd_region_data *ndrd = dev_get_drvdata(&nd_region->dev); > > + struct nd_region_data *ndrd = dev_get_drvdata(dev); > > + struct nd_region *nd_region = to_nd_region(dev); > > int i, idx; > > > > /* > > @@ -1094,6 +1092,20 @@ void nvdimm_flush(struct nd_region *nd_region) > > writeq(1, ndrd_get_flush_wpq(ndrd, i, idx)); > > wmb(); > > } > > + > > +/** > > + * nvdimm_flush - flush any posted write queues between the cpu and pmem > > media > > + * @nd_region: blk or interleaved pmem region > > + */ > > +int nvdimm_flush(struct nd_region *nd_region) > > +{ > > + if (nd_region->flush) > > + return(nd_region->flush(&nd_region->dev)); > > + > > + pmem_flush(&nd_region->dev); > > IMHO, a better way of doing this would be to allow nvdimm_flush() to > be overridden. That is, in nd_region_create() you set nd_region->flush > to the original nvdimm_flush() if ndr_desc->flush is NULL. And then > always call nd_region->flush() where nvdimm_flush() is called today. I wanted to do minimal changes for actual 'nvdimm_flush' function because it does not return an error or return status for fsync. So, I needed to differentiate between 'fake DAX' & 'NVDIMM' at the time of calling 'flush', otherwise I need to change 'nvdimm_flush' to return zero for all the calls. Looks like I am already doing this, will change as suggested. > > > + > > + return 0; > > +} > > EXPORT_SYMBOL_GPL(nvdimm_flush); > > > > /** > > diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h > > index 097072c..33b617f 100644 > > --- a/include/linux/libnvdimm.h > > +++ b/include/linux/libnvdimm.h > > @@ -126,6 +126,7 @@ struct nd_region_desc { > > int numa_node; > > unsigned long flags; > > struct device_node *of_node; > > + int (*flush)(struct device *dev); > > }; > > > > struct device; > > @@ -201,7 +202,9 @@ unsigned long nd_blk_memremap_flags(struct > > nd_blk_region *ndbr); > > unsigned int nd_region_acquire_lane(struct nd_region *nd_region); > > void nd_region_release_lane(struct nd_region *nd_region, unsigned int > > lane); > > u64 nd_fletcher64(void *addr, size_t len, bool le); > > -void nvdimm_flush(struct nd_region *nd_region); > > +int nvdimm_flush(struct nd_region *nd_region); > > +void pmem_set_flush(struct nd_region *nd_region, void (*flush) > > + (struct device *)); > > It seems pmem_set_flush() doesn't exist. Sorry! will remove it. > > > int nvdimm_has_flush(struct nd_region *nd_region); > > int nvdimm_has_cache(struct nd_region *nd_region); > > > > Thanks, Pankaj