From mboxrd@z Thu Jan 1 00:00:00 1970 From: Luiz Capitulino Subject: Re: [RFC v3 1/2] libnvdimm: Add flush callback for virtio pmem Date: Fri, 13 Jul 2018 16:35:59 -0400 Message-ID: <20180713163559.692aca30@doriath> References: <20180713075232.9575-1-pagupta@redhat.com> <20180713075232.9575-2-pagupta@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180713075232.9575-2-pagupta@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: Pankaj Gupta Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, qemu-devel@nongnu.org, linux-nvdimm@ml01.01.org, jack@suse.cz, stefanha@redhat.com, dan.j.williams@intel.com, riel@surriel.com, haozhong.zhang@intel.com, nilal@redhat.com, kwolf@redhat.com, pbonzini@redhat.com, ross.zwisler@intel.com, david@redhat.com, xiaoguangrong.eric@gmail.com, hch@infradead.org, mst@redhat.com, niteshnarayanlal@hotmail.com, imammedo@redhat.com, eblake@redhat.com List-Id: linux-nvdimm@lists.01.org On Fri, 13 Jul 2018 13:22:30 +0530 Pankaj Gupta wrote: > 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. > > Signed-off-by: Pankaj Gupta > --- > 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. > + > + 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. > int nvdimm_has_flush(struct nd_region *nd_region); > int nvdimm_has_cache(struct nd_region *nd_region); >