libnvdimm, pmem: clear poison on write

If a write is directed at a known bad block perform the following:

1/ write the data

2/ send a clear poison command

3/ invalidate the poison out of the cache hierarchy

Cc: <x86@kernel.org>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/arch/x86/include/asm/pmem.h b/arch/x86/include/asm/pmem.h
index c57fd1e..bf8b35d 100644 (file)
--- a/arch/x86/include/asm/pmem.h
+++ b/arch/x86/include/asm/pmem.h
@@ -137,6 +137,11 @@ static inline void arch_clear_pmem(void __pmem *addr, size_t size)
        arch_wb_cache_pmem(addr, size);
 }
 
+static inline void arch_invalidate_pmem(void __pmem *addr, size_t size)
+{
+       clflush_cache_range((void __force *) addr, size);
+}
+
 static inline bool __arch_has_wmb_pmem(void)
 {
        /*

diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index cb6fd64..3355748 100644 (file)
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -159,6 +159,52 @@ void nvdimm_region_notify(struct nd_region *nd_region, enum nvdimm_event event)
 }
 EXPORT_SYMBOL_GPL(nvdimm_region_notify);
 
+long nvdimm_clear_poison(struct device *dev, phys_addr_t phys,
+               unsigned int len)
+{
+       struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
+       struct nvdimm_bus_descriptor *nd_desc;
+       struct nd_cmd_clear_error clear_err;
+       struct nd_cmd_ars_cap ars_cap;
+       u32 clear_err_unit, mask;
+       int cmd_rc, rc;
+
+       if (!nvdimm_bus)
+               return -ENXIO;
+
+       nd_desc = nvdimm_bus->nd_desc;
+       if (!nd_desc->ndctl)
+               return -ENXIO;
+
+       memset(&ars_cap, 0, sizeof(ars_cap));
+       ars_cap.address = phys;
+       ars_cap.length = len;
+       rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_CAP, &ars_cap,
+                       sizeof(ars_cap), &cmd_rc);
+       if (rc < 0)
+               return rc;
+       if (cmd_rc < 0)
+               return cmd_rc;
+       clear_err_unit = ars_cap.clear_err_unit;
+       if (!clear_err_unit || !is_power_of_2(clear_err_unit))
+               return -ENXIO;
+
+       mask = clear_err_unit - 1;
+       if ((phys | len) & mask)
+               return -ENXIO;
+       memset(&clear_err, 0, sizeof(clear_err));
+       clear_err.address = phys;
+       clear_err.length = len;
+       rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_CLEAR_ERROR, &clear_err,
+                       sizeof(clear_err), &cmd_rc);
+       if (rc < 0)
+               return rc;
+       if (cmd_rc < 0)
+               return cmd_rc;
+       return clear_err.cleared;
+}
+EXPORT_SYMBOL_GPL(nvdimm_clear_poison);
+
 static struct bus_type nvdimm_bus_type = {
        .name = "nd",
        .uevent = nvdimm_bus_uevent,

diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index 78b82f6..1799bd9 100644 (file)
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -186,6 +186,8 @@ int nvdimm_init_nsarea(struct nvdimm_drvdata *ndd);
 int nvdimm_init_config_data(struct nvdimm_drvdata *ndd);
 int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,
                void *buf, size_t len);
+long nvdimm_clear_poison(struct device *dev, phys_addr_t phys,
+               unsigned int len);
 struct nd_btt *to_nd_btt(struct device *dev);
 
 struct nd_gen_sb {

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index e7b86a7..adc3872 100644 (file)
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -62,17 +62,40 @@ static bool is_bad_pmem(struct badblocks *bb, sector_t sector, unsigned int len)
        return false;
 }
 
+static void pmem_clear_poison(struct pmem_device *pmem, phys_addr_t offset,
+               unsigned int len)
+{
+       struct device *dev = disk_to_dev(pmem->pmem_disk);
+       sector_t sector;
+       long cleared;
+
+       sector = (offset - pmem->data_offset) / 512;
+       cleared = nvdimm_clear_poison(dev, pmem->phys_addr + offset, len);
+
+       if (cleared > 0 && cleared / 512) {
+               dev_dbg(dev, "%s: %llx clear %ld sector%s\n",
+                               __func__, (unsigned long long) sector,
+                               cleared / 512, cleared / 512 > 1 ? "s" : "");
+               badblocks_clear(&pmem->bb, sector, cleared / 512);
+       }
+       invalidate_pmem(pmem->virt_addr + offset, len);
+}
+
 static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
                        unsigned int len, unsigned int off, int rw,
                        sector_t sector)
 {
        int rc = 0;
+       bool bad_pmem = false;
        void *mem = kmap_atomic(page);
        phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
        void __pmem *pmem_addr = pmem->virt_addr + pmem_off;
 
+       if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
+               bad_pmem = true;
+
        if (rw == READ) {
-               if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
+               if (unlikely(bad_pmem))
                        rc = -EIO;
                else {
                        memcpy_from_pmem(mem + off, pmem_addr, len);
@@ -81,6 +104,10 @@ static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
        } else {
                flush_dcache_page(page);
                memcpy_to_pmem(pmem_addr, mem + off, len);
+               if (unlikely(bad_pmem)) {
+                       pmem_clear_poison(pmem, pmem_off, len);
+                       memcpy_to_pmem(pmem_addr, mem + off, len);
+               }
        }
 
        kunmap_atomic(mem);

diff --git a/include/linux/pmem.h b/include/linux/pmem.h
index 7c3d11a..3ec5309 100644 (file)
--- a/include/linux/pmem.h
+++ b/include/linux/pmem.h
@@ -58,6 +58,11 @@ static inline void arch_wb_cache_pmem(void __pmem *addr, size_t size)
 {
        BUG();
 }
+
+static inline void arch_invalidate_pmem(void __pmem *addr, size_t size)
+{
+       BUG();
+}
 #endif
 
 /*
@@ -185,6 +190,20 @@ static inline void clear_pmem(void __pmem *addr, size_t size)
                default_clear_pmem(addr, size);
 }
 
+/**
+ * invalidate_pmem - flush a pmem range from the cache hierarchy
+ * @addr:      virtual start address
+ * @size:      bytes to invalidate (internally aligned to cache line size)
+ *
+ * For platforms that support clearing poison this flushes any poisoned
+ * ranges out of the cache
+ */
+static inline void invalidate_pmem(void __pmem *addr, size_t size)
+{
+       if (arch_has_pmem_api())
+               arch_invalidate_pmem(addr, size);
+}
+
 /**
  * wb_cache_pmem - write back processor cache for PMEM memory range
  * @addr:      virtual start address