Re: [Qemu-devel] [RFC v3 1/2] libnvdimm: Add flush callback for virtio pmem
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
> > ---
> > 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, );
> > 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(_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(_region->dev));
> > +
> > + pmem_flush(_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
Re: [Qemu-devel] [RFC v3 1/2] libnvdimm: Add flush callback for virtio pmem
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, );
> 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(_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(_region->dev));
> +
> + pmem_flush(_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
[Qemu-devel] [RFC v3 1/2] libnvdimm: Add flush callback for virtio pmem
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.
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, );
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(_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(_region->dev));
+
+ pmem_flush(_region->dev);
+
+ 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 *));
int nvdimm_has_flush(struct nd_region *nd_region);
int nvdimm_has_cache(struct nd_region *nd_region);
--
2.9.3
