libnvdimm/pfn: stop padding pmem namespaces to section alignment

Now that the mm core supports section-unaligned hotplug of ZONE_DEVICE
memory, we no longer need to add padding at pfn/dax device creation
time.  The kernel will still honor padding established by older kernels.

Link: http://lkml.kernel.org/r/156092356588.979959.6793371748950931916.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Jeff Moyer <jmoyer@redhat.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>	[ppc64]
Cc: David Hildenbrand <david@redhat.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/nvdimm/pfn.h b/drivers/nvdimm/pfn.h
index dfb2bcda8f5a43e570538373923684d4f7cd761a..7381673b7b70b9804b00ed982ddac2153d44f305 100644 (file)
--- a/drivers/nvdimm/pfn.h
+++ b/drivers/nvdimm/pfn.h
@@ -33,18 +33,4 @@ struct nd_pfn_sb {
        __le64 checksum;
 };
 
-#ifdef CONFIG_SPARSEMEM
-#define PFN_SECTION_ALIGN_DOWN(x) SECTION_ALIGN_DOWN(x)
-#define PFN_SECTION_ALIGN_UP(x) SECTION_ALIGN_UP(x)
-#else
-/*
- * In this case ZONE_DEVICE=n and we will disable 'pfn' device support,
- * but we still want pmem to compile.
- */
-#define PFN_SECTION_ALIGN_DOWN(x) (x)
-#define PFN_SECTION_ALIGN_UP(x) (x)
-#endif
-
-#define PHYS_SECTION_ALIGN_DOWN(x) PFN_PHYS(PFN_SECTION_ALIGN_DOWN(PHYS_PFN(x)))
-#define PHYS_SECTION_ALIGN_UP(x) PFN_PHYS(PFN_SECTION_ALIGN_UP(PHYS_PFN(x)))
 #endif /* __NVDIMM_PFN_H */

diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 06f465c0baf321a0715341c4c7555701607c490b..df2bdbd22450488af1c9c4d68a4a2569c64f143e 100644 (file)
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -587,14 +587,14 @@ static u32 info_block_reserve(void)
 }
 
 /*
- * We hotplug memory at section granularity, pad the reserved area from
- * the previous section base to the namespace base address.
+ * We hotplug memory at sub-section granularity, pad the reserved area
+ * from the previous section base to the namespace base address.
  */
 static unsigned long init_altmap_base(resource_size_t base)
 {
        unsigned long base_pfn = PHYS_PFN(base);
 
-       return PFN_SECTION_ALIGN_DOWN(base_pfn);
+       return SUBSECTION_ALIGN_DOWN(base_pfn);
 }
 
 static unsigned long init_altmap_reserve(resource_size_t base)
@@ -602,7 +602,7 @@ static unsigned long init_altmap_reserve(resource_size_t base)
        unsigned long reserve = info_block_reserve() >> PAGE_SHIFT;
        unsigned long base_pfn = PHYS_PFN(base);
 
-       reserve += base_pfn - PFN_SECTION_ALIGN_DOWN(base_pfn);
+       reserve += base_pfn - SUBSECTION_ALIGN_DOWN(base_pfn);
        return reserve;
 }
 
@@ -632,8 +632,7 @@ static int __nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
                        return -EINVAL;
                nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
        } else if (nd_pfn->mode == PFN_MODE_PMEM) {
-               nd_pfn->npfns = PFN_SECTION_ALIGN_UP((resource_size(res)
-                                       - offset) / PAGE_SIZE);
+               nd_pfn->npfns = PHYS_PFN((resource_size(res) - offset));
                if (le64_to_cpu(nd_pfn->pfn_sb->npfns) > nd_pfn->npfns)
                        dev_info(&nd_pfn->dev,
                                        "number of pfns truncated from %lld to %ld\n",
@@ -649,54 +648,14 @@ static int __nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
        return 0;
 }
 
-static u64 phys_pmem_align_down(struct nd_pfn *nd_pfn, u64 phys)
-{
-       return min_t(u64, PHYS_SECTION_ALIGN_DOWN(phys),
-                       ALIGN_DOWN(phys, nd_pfn->align));
-}
-
-/*
- * Check if pmem collides with 'System RAM', or other regions when
- * section aligned.  Trim it accordingly.
- */
-static void trim_pfn_device(struct nd_pfn *nd_pfn, u32 *start_pad, u32 *end_trunc)
-{
-       struct nd_namespace_common *ndns = nd_pfn->ndns;
-       struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
-       struct nd_region *nd_region = to_nd_region(nd_pfn->dev.parent);
-       const resource_size_t start = nsio->res.start;
-       const resource_size_t end = start + resource_size(&nsio->res);
-       resource_size_t adjust, size;
-
-       *start_pad = 0;
-       *end_trunc = 0;
-
-       adjust = start - PHYS_SECTION_ALIGN_DOWN(start);
-       size = resource_size(&nsio->res) + adjust;
-       if (region_intersects(start - adjust, size, IORESOURCE_SYSTEM_RAM,
-                               IORES_DESC_NONE) == REGION_MIXED
-                       || nd_region_conflict(nd_region, start - adjust, size))
-               *start_pad = PHYS_SECTION_ALIGN_UP(start) - start;
-
-       /* Now check that end of the range does not collide. */
-       adjust = PHYS_SECTION_ALIGN_UP(end) - end;
-       size = resource_size(&nsio->res) + adjust;
-       if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
-                               IORES_DESC_NONE) == REGION_MIXED
-                       || !IS_ALIGNED(end, nd_pfn->align)
-                       || nd_region_conflict(nd_region, start, size))
-               *end_trunc = end - phys_pmem_align_down(nd_pfn, end);
-}
-
 static int nd_pfn_init(struct nd_pfn *nd_pfn)
 {
        struct nd_namespace_common *ndns = nd_pfn->ndns;
        struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
-       u32 start_pad, end_trunc, reserve = info_block_reserve();
        resource_size_t start, size;
        struct nd_region *nd_region;
+       unsigned long npfns, align;
        struct nd_pfn_sb *pfn_sb;
-       unsigned long npfns;
        phys_addr_t offset;
        const char *sig;
        u64 checksum;
@@ -727,43 +686,35 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
                return -ENXIO;
        }
 
-       memset(pfn_sb, 0, sizeof(*pfn_sb));
-
-       trim_pfn_device(nd_pfn, &start_pad, &end_trunc);
-       if (start_pad + end_trunc)
-               dev_info(&nd_pfn->dev, "%s alignment collision, truncate %d bytes\n",
-                               dev_name(&ndns->dev), start_pad + end_trunc);
-
        /*
         * Note, we use 64 here for the standard size of struct page,
         * debugging options may cause it to be larger in which case the
         * implementation will limit the pfns advertised through
         * ->direct_access() to those that are included in the memmap.
         */
-       start = nsio->res.start + start_pad;
+       start = nsio->res.start;
        size = resource_size(&nsio->res);
-       npfns = PFN_SECTION_ALIGN_UP((size - start_pad - end_trunc - reserve)
-                       / PAGE_SIZE);
+       npfns = PHYS_PFN(size - SZ_8K);
+       align = max(nd_pfn->align, (1UL << SUBSECTION_SHIFT));
        if (nd_pfn->mode == PFN_MODE_PMEM) {
                /*
                 * The altmap should be padded out to the block size used
                 * when populating the vmemmap. This *should* be equal to
                 * PMD_SIZE for most architectures.
                 */
-               offset = ALIGN(start + reserve + 64 * npfns,
-                               max(nd_pfn->align, PMD_SIZE)) - start;
+               offset = ALIGN(start + SZ_8K + 64 * npfns, align) - start;
        } else if (nd_pfn->mode == PFN_MODE_RAM)
-               offset = ALIGN(start + reserve, nd_pfn->align) - start;
+               offset = ALIGN(start + SZ_8K, align) - start;
        else
                return -ENXIO;
 
-       if (offset + start_pad + end_trunc >= size) {
+       if (offset >= size) {
                dev_err(&nd_pfn->dev, "%s unable to satisfy requested alignment\n",
                                dev_name(&ndns->dev));
                return -ENXIO;
        }
 
-       npfns = (size - offset - start_pad - end_trunc) / SZ_4K;
+       npfns = PHYS_PFN(size - offset);
        pfn_sb->mode = cpu_to_le32(nd_pfn->mode);
        pfn_sb->dataoff = cpu_to_le64(offset);
        pfn_sb->npfns = cpu_to_le64(npfns);
@@ -772,8 +723,6 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
        memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16);
        pfn_sb->version_major = cpu_to_le16(1);
        pfn_sb->version_minor = cpu_to_le16(3);
-       pfn_sb->start_pad = cpu_to_le32(start_pad);
-       pfn_sb->end_trunc = cpu_to_le32(end_trunc);
        pfn_sb->align = cpu_to_le32(nd_pfn->align);
        checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
        pfn_sb->checksum = cpu_to_le64(checksum);

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 8331e76677c0428e9ad8218ec35de5be2a6bad55..d77d717c620cbe3362b5787086b546f08b938f46 100644 (file)
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -1160,6 +1160,9 @@ static inline unsigned long section_nr_to_pfn(unsigned long sec)
 #define SUBSECTIONS_PER_SECTION (1UL << (SECTION_SIZE_BITS - SUBSECTION_SHIFT))
 #endif
 
+#define SUBSECTION_ALIGN_UP(pfn) ALIGN((pfn), PAGES_PER_SUBSECTION)
+#define SUBSECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SUBSECTION_MASK)
+
 struct mem_section_usage {
        DECLARE_BITMAP(subsection_map, SUBSECTIONS_PER_SECTION);
        /* See declaration of similar field in struct zone */