diff options
| -rw-r--r-- | drivers/nvdimm/Kconfig | 19 | ||||
| -rw-r--r-- | drivers/nvdimm/nd.h | 2 | ||||
| -rw-r--r-- | drivers/nvdimm/pfn_devs.c | 42 |
3 files changed, 47 insertions, 16 deletions
diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig index 79d93126453d..77b06d54cc62 100644 --- a/drivers/nvdimm/Kconfig +++ b/drivers/nvdimm/Kconfig @@ -102,6 +102,25 @@ config NVDIMM_KEYS depends on ENCRYPTED_KEYS depends on (LIBNVDIMM=ENCRYPTED_KEYS) || LIBNVDIMM=m +config NVDIMM_KMSAN + bool + depends on KMSAN + help + KMSAN, and other memory debug facilities, increase the size of + 'struct page' to contain extra metadata. This collides with + the NVDIMM capability to store a potentially + larger-than-"System RAM" size 'struct page' array in a + reservation of persistent memory rather than limited / + precious DRAM. However, that reservation needs to persist for + the life of the given NVDIMM namespace. If you are using KMSAN + to debug an issue unrelated to NVDIMMs or DAX then say N to this + option. Otherwise, say Y but understand that any namespaces + (with the page array stored pmem) created with this build of + the kernel will permanently reserve and strand excess + capacity compared to the CONFIG_KMSAN=n case. + + Select N if unsure. + config NVDIMM_TEST_BUILD tristate "Build the unit test core" depends on m diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h index 85ca5b4da3cf..ec5219680092 100644 --- a/drivers/nvdimm/nd.h +++ b/drivers/nvdimm/nd.h @@ -652,7 +652,7 @@ void devm_namespace_disable(struct device *dev, struct nd_namespace_common *ndns); #if IS_ENABLED(CONFIG_ND_CLAIM) /* max struct page size independent of kernel config */ -#define MAX_STRUCT_PAGE_SIZE 128 +#define MAX_STRUCT_PAGE_SIZE 64 int nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap); #else static inline int nvdimm_setup_pfn(struct nd_pfn *nd_pfn, diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c index 61af072ac98f..af7d9301520c 100644 --- a/drivers/nvdimm/pfn_devs.c +++ b/drivers/nvdimm/pfn_devs.c @@ -13,6 +13,8 @@ #include "pfn.h" #include "nd.h" +static const bool page_struct_override = IS_ENABLED(CONFIG_NVDIMM_KMSAN); + static void nd_pfn_release(struct device *dev) { struct nd_region *nd_region = to_nd_region(dev->parent); @@ -758,12 +760,6 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn) return -ENXIO; } - /* - * 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; size = resource_size(&nsio->res); npfns = PHYS_PFN(size - SZ_8K); @@ -782,20 +778,33 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn) } end_trunc = start + size - ALIGN_DOWN(start + size, align); if (nd_pfn->mode == PFN_MODE_PMEM) { + unsigned long page_map_size = MAX_STRUCT_PAGE_SIZE * npfns; + /* * 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. * - * Also make sure size of struct page is less than 128. We - * want to make sure we use large enough size here so that - * we don't have a dynamic reserve space depending on - * struct page size. But we also want to make sure we notice - * when we end up adding new elements to struct page. + * Also make sure size of struct page is less than + * MAX_STRUCT_PAGE_SIZE. The goal here is compatibility in the + * face of production kernel configurations that reduce the + * 'struct page' size below MAX_STRUCT_PAGE_SIZE. For debug + * kernel configurations that increase the 'struct page' size + * above MAX_STRUCT_PAGE_SIZE, the page_struct_override allows + * for continuing with the capacity that will be wasted when + * reverting to a production kernel configuration. Otherwise, + * those configurations are blocked by default. */ - BUILD_BUG_ON(sizeof(struct page) > MAX_STRUCT_PAGE_SIZE); - offset = ALIGN(start + SZ_8K + MAX_STRUCT_PAGE_SIZE * npfns, align) - - start; + if (sizeof(struct page) > MAX_STRUCT_PAGE_SIZE) { + if (page_struct_override) + page_map_size = sizeof(struct page) * npfns; + else { + dev_err(&nd_pfn->dev, + "Memory debug options prevent using pmem for the page map\n"); + return -EINVAL; + } + } + offset = ALIGN(start + SZ_8K + page_map_size, align) - start; } else if (nd_pfn->mode == PFN_MODE_RAM) offset = ALIGN(start + SZ_8K, align) - start; else @@ -818,7 +827,10 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn) pfn_sb->version_minor = cpu_to_le16(4); pfn_sb->end_trunc = cpu_to_le32(end_trunc); pfn_sb->align = cpu_to_le32(nd_pfn->align); - pfn_sb->page_struct_size = cpu_to_le16(MAX_STRUCT_PAGE_SIZE); + if (sizeof(struct page) > MAX_STRUCT_PAGE_SIZE && page_struct_override) + pfn_sb->page_struct_size = cpu_to_le16(sizeof(struct page)); + else + pfn_sb->page_struct_size = cpu_to_le16(MAX_STRUCT_PAGE_SIZE); pfn_sb->page_size = cpu_to_le32(PAGE_SIZE); checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb); pfn_sb->checksum = cpu_to_le64(checksum); |