memremap: replace the altmap_valid field with a PGMAP_ALTMAP_VALID flag

Add a flags field to struct dev_pagemap to replace the altmap_valid
boolean to be a little more extensible.  Also add a pgmap_altmap() helper
to find the optional altmap and clean up the code using the altmap using
it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 2540d3b2588c316dfea441f58c1f5d8bfb13eb65..a2923c5c1982e44e0a6998d8afa01b991134e4ac 100644 (file)
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -131,17 +131,9 @@ void __ref arch_remove_memory(int nid, u64 start, u64 size,
 {
        unsigned long start_pfn = start >> PAGE_SHIFT;
        unsigned long nr_pages = size >> PAGE_SHIFT;
-       struct page *page;
+       struct page *page = pfn_to_page(start_pfn) + vmem_altmap_offset(altmap);
        int ret;
 
-       /*
-        * If we have an altmap then we need to skip over any reserved PFNs
-        * when querying the zone.
-        */
-       page = pfn_to_page(start_pfn);
-       if (altmap)
-               page += vmem_altmap_offset(altmap);
-
        __remove_pages(page_zone(page), start_pfn, nr_pages, altmap);
 
        /* Remove htab bolted mappings for this section of memory */

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 0f01c7b1d2170673b7b0de01cae22c2a46359026..08bbf648827b24e211f2a7a3e08ebe29fdccbb5a 100644 (file)
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1213,13 +1213,9 @@ void __ref arch_remove_memory(int nid, u64 start, u64 size,
 {
        unsigned long start_pfn = start >> PAGE_SHIFT;
        unsigned long nr_pages = size >> PAGE_SHIFT;
-       struct page *page = pfn_to_page(start_pfn);
-       struct zone *zone;
+       struct page *page = pfn_to_page(start_pfn) + vmem_altmap_offset(altmap);
+       struct zone *zone = page_zone(page);
 
-       /* With altmap the first mapped page is offset from @start */
-       if (altmap)
-               page += vmem_altmap_offset(altmap);
-       zone = page_zone(page);
        __remove_pages(zone, start_pfn, nr_pages, altmap);
        kernel_physical_mapping_remove(start, start + size);
 }

diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 0f81fc56bbfde5089ea515344300fad79946c3fa..55fb6b7433ed2e7360c0f15502feab885c48fae1 100644 (file)
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -622,7 +622,6 @@ static int __nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
                if (offset < reserve)
                        return -EINVAL;
                nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
-               pgmap->altmap_valid = false;
        } else if (nd_pfn->mode == PFN_MODE_PMEM) {
                nd_pfn->npfns = PFN_SECTION_ALIGN_UP((resource_size(res)
                                        - offset) / PAGE_SIZE);
@@ -634,7 +633,7 @@ static int __nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
                memcpy(altmap, &__altmap, sizeof(*altmap));
                altmap->free = PHYS_PFN(offset - reserve);
                altmap->alloc = 0;
-               pgmap->altmap_valid = true;
+               pgmap->flags |= PGMAP_ALTMAP_VALID;
        } else
                return -ENXIO;
 

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 093408ce40ad91cfc47779c7725a86e43aef2081..e7d8cc9f41e8315740e9c365a76da1053a9b3162 100644 (file)
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -412,7 +412,6 @@ static int pmem_attach_disk(struct device *dev,
                bb_res.start += pmem->data_offset;
        } else if (pmem_should_map_pages(dev)) {
                memcpy(&pmem->pgmap.res, &nsio->res, sizeof(pmem->pgmap.res));
-               pmem->pgmap.altmap_valid = false;
                pmem->pgmap.type = MEMORY_DEVICE_FS_DAX;
                pmem->pgmap.ops = &fsdax_pagemap_ops;
                addr = devm_memremap_pages(dev, &pmem->pgmap);

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 336eca601dad0795505904ac29da70d035615084..e25685b878e96901123fe49b4fd15a48d028b562 100644 (file)
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -88,6 +88,8 @@ struct dev_pagemap_ops {
        vm_fault_t (*migrate_to_ram)(struct vm_fault *vmf);
 };
 
+#define PGMAP_ALTMAP_VALID     (1 << 0)
+
 /**
  * struct dev_pagemap - metadata for ZONE_DEVICE mappings
  * @altmap: pre-allocated/reserved memory for vmemmap allocations
@@ -96,19 +98,27 @@ struct dev_pagemap_ops {
  * @dev: host device of the mapping for debug
  * @data: private data pointer for page_free()
  * @type: memory type: see MEMORY_* in memory_hotplug.h
+ * @flags: PGMAP_* flags to specify defailed behavior
  * @ops: method table
  */
 struct dev_pagemap {
        struct vmem_altmap altmap;
-       bool altmap_valid;
        struct resource res;
        struct percpu_ref *ref;
        struct device *dev;
        enum memory_type type;
+       unsigned int flags;
        u64 pci_p2pdma_bus_offset;
        const struct dev_pagemap_ops *ops;
 };
 
+static inline struct vmem_altmap *pgmap_altmap(struct dev_pagemap *pgmap)
+{
+       if (pgmap->flags & PGMAP_ALTMAP_VALID)
+               return &pgmap->altmap;
+       return NULL;
+}
+
 #ifdef CONFIG_ZONE_DEVICE
 void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap);
 void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap);

diff --git a/kernel/memremap.c b/kernel/memremap.c
index 6c3dbb692037d7bacbc1e2d303cfac95ee1c30d4..eee490e7d7e1624fa55396c660688b903abf71c9 100644 (file)
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -54,14 +54,8 @@ static void pgmap_array_delete(struct resource *res)
 
 static unsigned long pfn_first(struct dev_pagemap *pgmap)
 {
-       const struct resource *res = &pgmap->res;
-       struct vmem_altmap *altmap = &pgmap->altmap;
-       unsigned long pfn;
-
-       pfn = res->start >> PAGE_SHIFT;
-       if (pgmap->altmap_valid)
-               pfn += vmem_altmap_offset(altmap);
-       return pfn;
+       return (pgmap->res.start >> PAGE_SHIFT) +
+               vmem_altmap_offset(pgmap_altmap(pgmap));
 }
 
 static unsigned long pfn_end(struct dev_pagemap *pgmap)
@@ -109,7 +103,7 @@ static void devm_memremap_pages_release(void *data)
                                align_size >> PAGE_SHIFT, NULL);
        } else {
                arch_remove_memory(nid, align_start, align_size,
-                               pgmap->altmap_valid ? &pgmap->altmap : NULL);
+                               pgmap_altmap(pgmap));
                kasan_remove_zero_shadow(__va(align_start), align_size);
        }
        mem_hotplug_done();
@@ -129,8 +123,8 @@ static void devm_memremap_pages_release(void *data)
  * 1/ At a minimum the res, ref and type and ops members of @pgmap must be
  *    initialized by the caller before passing it to this function
  *
- * 2/ The altmap field may optionally be initialized, in which case altmap_valid
- *    must be set to true
+ * 2/ The altmap field may optionally be initialized, in which case
+ *    PGMAP_ALTMAP_VALID must be set in pgmap->flags.
  *
  * 3/ pgmap->ref must be 'live' on entry and will be killed and reaped
  *    at devm_memremap_pages_release() time, or if this routine fails.
@@ -142,15 +136,13 @@ static void devm_memremap_pages_release(void *data)
 void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
 {
        resource_size_t align_start, align_size, align_end;
-       struct vmem_altmap *altmap = pgmap->altmap_valid ?
-                       &pgmap->altmap : NULL;
        struct resource *res = &pgmap->res;
        struct dev_pagemap *conflict_pgmap;
        struct mhp_restrictions restrictions = {
                /*
                 * We do not want any optional features only our own memmap
                */
-               .altmap = altmap,
+               .altmap = pgmap_altmap(pgmap),
        };
        pgprot_t pgprot = PAGE_KERNEL;
        int error, nid, is_ram;
@@ -274,7 +266,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
 
                zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
                move_pfn_range_to_zone(zone, align_start >> PAGE_SHIFT,
-                               align_size >> PAGE_SHIFT, altmap);
+                               align_size >> PAGE_SHIFT, pgmap_altmap(pgmap));
        }
 
        mem_hotplug_done();
@@ -319,7 +311,9 @@ EXPORT_SYMBOL_GPL(devm_memunmap_pages);
 unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
 {
        /* number of pfns from base where pfn_to_page() is valid */
-       return altmap->reserve + altmap->free;
+       if (altmap)
+               return altmap->reserve + altmap->free;
+       return 0;
 }
 
 void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns)

diff --git a/mm/hmm.c b/mm/hmm.c
index 36e25cdbdac11381bc39e63f378cb4a08a1d3033..e4470462298f059870ba781da599bdaf7d03b3c4 100644 (file)
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -1442,7 +1442,6 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
        devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
        devmem->pagemap.res = *devmem->resource;
        devmem->pagemap.ops = &hmm_pagemap_ops;
-       devmem->pagemap.altmap_valid = false;
        devmem->pagemap.ref = &devmem->ref;
 
        result = devm_memremap_pages(devmem->device, &devmem->pagemap);

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e096c987d261412ba0803aa29a34936a008b5ec5..6166ba5a15f3e533f66f3e6e1ef2be540cdb4c13 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -557,10 +557,8 @@ void __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
        int sections_to_remove;
 
        /* In the ZONE_DEVICE case device driver owns the memory region */
-       if (is_dev_zone(zone)) {
-               if (altmap)
-                       map_offset = vmem_altmap_offset(altmap);
-       }
+       if (is_dev_zone(zone))
+               map_offset = vmem_altmap_offset(altmap);
 
        clear_zone_contiguous(zone);
 

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d66bc8abe0afd214bd6db006c9a610d9d6a64240..17a39d40a5565ae7d6c0130bc1e9fa4f96d9559e 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5853,6 +5853,7 @@ void __ref memmap_init_zone_device(struct zone *zone,
 {
        unsigned long pfn, end_pfn = start_pfn + size;
        struct pglist_data *pgdat = zone->zone_pgdat;
+       struct vmem_altmap *altmap = pgmap_altmap(pgmap);
        unsigned long zone_idx = zone_idx(zone);
        unsigned long start = jiffies;
        int nid = pgdat->node_id;
@@ -5865,9 +5866,7 @@ void __ref memmap_init_zone_device(struct zone *zone,
         * of the pages reserved for the memmap, so we can just jump to
         * the end of that region and start processing the device pages.
         */
-       if (pgmap->altmap_valid) {
-               struct vmem_altmap *altmap = &pgmap->altmap;
-
+       if (altmap) {
                start_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
                size = end_pfn - start_pfn;
        }