[Qemu-devel] [PATCH v9 1/7] libnvdimm: nd_region flush callback support

[Pankaj Gupta]

This patch adds functionality to perform flush from guest
to host over VIRTIO. We are registering a callback based
on 'nd_region' type. virtio_pmem driver requires this special
flush function. For rest of the region types we are registering
existing flush function. Report error returned by host fsync
failure to userspace.

Signed-off-by: Pankaj Gupta <address@hidden>
---
 drivers/acpi/nfit/core.c     |  4 ++--
 drivers/nvdimm/claim.c       |  6 ++++--
 drivers/nvdimm/nd.h          |  1 +
 drivers/nvdimm/pmem.c        | 13 ++++++++-----
 drivers/nvdimm/region_devs.c | 26 ++++++++++++++++++++++++--
 include/linux/libnvdimm.h    |  8 +++++++-
 6 files changed, 46 insertions(+), 12 deletions(-)

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 5a389a4f4f65..08dde76cf459 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -2434,7 +2434,7 @@ static void write_blk_ctl(struct nfit_blk *nfit_blk, 
unsigned int bw,
                offset = to_interleave_offset(offset, mmio);
 
        writeq(cmd, mmio->addr.base + offset);
-       nvdimm_flush(nfit_blk->nd_region);
+       nvdimm_flush(nfit_blk->nd_region, NULL);
 
        if (nfit_blk->dimm_flags & NFIT_BLK_DCR_LATCH)
                readq(mmio->addr.base + offset);
@@ -2483,7 +2483,7 @@ static int acpi_nfit_blk_single_io(struct nfit_blk 
*nfit_blk,
        }
 
        if (rw)
-               nvdimm_flush(nfit_blk->nd_region);
+               nvdimm_flush(nfit_blk->nd_region, NULL);
 
        rc = read_blk_stat(nfit_blk, lane) ? -EIO : 0;
        return rc;
diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c
index fb667bf469c7..13510bae1e6f 100644
--- a/drivers/nvdimm/claim.c
+++ b/drivers/nvdimm/claim.c
@@ -263,7 +263,7 @@ static int nsio_rw_bytes(struct nd_namespace_common *ndns,
        struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
        unsigned int sz_align = ALIGN(size + (offset & (512 - 1)), 512);
        sector_t sector = offset >> 9;
-       int rc = 0;
+       int rc = 0, ret = 0;
 
        if (unlikely(!size))
                return 0;
@@ -301,7 +301,9 @@ static int nsio_rw_bytes(struct nd_namespace_common *ndns,
        }
 
        memcpy_flushcache(nsio->addr + offset, buf, size);
-       nvdimm_flush(to_nd_region(ndns->dev.parent));
+       ret = nvdimm_flush(to_nd_region(ndns->dev.parent), NULL);
+       if (ret)
+               rc = ret;
 
        return rc;
 }
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index a5ac3b240293..0c74d2428bd7 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 nd_region *nd_region, struct bio *bio);
        struct nd_mapping mapping[0];
 };
 
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index bc2f700feef8..f719245da170 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -192,6 +192,7 @@ static blk_status_t pmem_do_bvec(struct pmem_device *pmem, 
struct page *page,
 
 static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio)
 {
+       int ret = 0;
        blk_status_t rc = 0;
        bool do_acct;
        unsigned long start;
@@ -201,7 +202,7 @@ 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_PREFLUSH)
-               nvdimm_flush(nd_region);
+               ret = nvdimm_flush(nd_region, bio);
 
        do_acct = nd_iostat_start(bio, &start);
        bio_for_each_segment(bvec, bio, iter) {
@@ -216,7 +217,10 @@ 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);
+               ret = nvdimm_flush(nd_region, bio);
+
+       if (ret)
+               bio->bi_status = errno_to_blk_status(ret);
 
        bio_endio(bio);
        return BLK_QC_T_NONE;
@@ -469,7 +473,6 @@ static int pmem_attach_disk(struct device *dev,
        }
        dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
        pmem->dax_dev = dax_dev;
-
        gendev = disk_to_dev(disk);
        gendev->groups = pmem_attribute_groups;
 
@@ -527,14 +530,14 @@ static int nd_pmem_remove(struct device *dev)
                sysfs_put(pmem->bb_state);
                pmem->bb_state = NULL;
        }
-       nvdimm_flush(to_nd_region(dev->parent));
+       nvdimm_flush(to_nd_region(dev->parent), NULL);
 
        return 0;
 }
 
 static void nd_pmem_shutdown(struct device *dev)
 {
-       nvdimm_flush(to_nd_region(dev->parent));
+       nvdimm_flush(to_nd_region(dev->parent), NULL);
 }
 
 static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index b4ef7d9ff22e..e5b59708865e 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -295,7 +295,9 @@ static ssize_t deep_flush_store(struct device *dev, struct 
device_attribute *att
                return rc;
        if (!flush)
                return -EINVAL;
-       nvdimm_flush(nd_region);
+       rc = nvdimm_flush(nd_region, NULL);
+       if (rc)
+               return rc;
 
        return len;
 }
@@ -1085,6 +1087,11 @@ 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;
+       if (ndr_desc->flush)
+               nd_region->flush = ndr_desc->flush;
+       else
+               nd_region->flush = NULL;
+
        nd_device_register(dev);
 
        return nd_region;
@@ -1125,11 +1132,24 @@ struct nd_region *nvdimm_volatile_region_create(struct 
nvdimm_bus *nvdimm_bus,
 }
 EXPORT_SYMBOL_GPL(nvdimm_volatile_region_create);
 
+int nvdimm_flush(struct nd_region *nd_region, struct bio *bio)
+{
+       int rc = 0;
+
+       if (!nd_region->flush)
+               rc = generic_nvdimm_flush(nd_region);
+       else {
+               if (nd_region->flush(nd_region, bio))
+                       rc = -EIO;
+       }
+
+       return rc;
+}
 /**
  * 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)
+int generic_nvdimm_flush(struct nd_region *nd_region)
 {
        struct nd_region_data *ndrd = dev_get_drvdata(&nd_region->dev);
        int i, idx;
@@ -1153,6 +1173,8 @@ void nvdimm_flush(struct nd_region *nd_region)
                if (ndrd_get_flush_wpq(ndrd, i, 0))
                        writeq(1, ndrd_get_flush_wpq(ndrd, i, idx));
        wmb();
+
+       return 0;
 }
 EXPORT_SYMBOL_GPL(nvdimm_flush);
 
diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index feb342d026f2..a5f369ec3726 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -65,6 +65,9 @@ enum {
         */
        ND_REGION_PERSIST_MEMCTRL = 2,
 
+       /* Platform provides asynchronous flush mechanism */
+       ND_REGION_ASYNC = 3,
+
        /* mark newly adjusted resources as requiring a label update */
        DPA_RESOURCE_ADJUSTED = 1 << 0,
 };
@@ -121,6 +124,7 @@ struct nd_mapping_desc {
        int position;
 };
 
+struct nd_region;
 struct nd_region_desc {
        struct resource *res;
        struct nd_mapping_desc *mapping;
@@ -133,6 +137,7 @@ struct nd_region_desc {
        int target_node;
        unsigned long flags;
        struct device_node *of_node;
+       int (*flush)(struct nd_region *nd_region, struct bio *bio);
 };
 
 struct device;
@@ -260,7 +265,8 @@ 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, struct bio *bio);
+int generic_nvdimm_flush(struct nd_region *nd_region);
 int nvdimm_has_flush(struct nd_region *nd_region);
 int nvdimm_has_cache(struct nd_region *nd_region);
 int nvdimm_in_overwrite(struct nvdimm *nvdimm);
-- 
2.20.1