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| author | Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> | 2019-09-05 18:45:59 +0300 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2019-09-06 02:11:14 +0300 |
| commit | e96f0bf2ec92da2bc9c11b0d69e9086f076e7f0b (patch) | |
| tree | 2d14675286fa34ee7efe7f9b3d0480a5a4e7bc20 /drivers/nvdimm/pfn_devs.c | |
| parent | 1c97afa714098aab2ca588cc654f8ff67dd46dcb (diff) | |
| download | linux-e96f0bf2ec92da2bc9c11b0d69e9086f076e7f0b.tar.xz | |
libnvdimm/pfn_dev: Add a build check to make sure we notice when struct page size change
Namespaces created with PFN_MODE_PMEM mode stores struct page in the reserve
block area. We need to make sure we account for the right struct page
size while doing this. Instead of directly depending on sizeof(struct page)
which can change based on different kernel config option, use the max struct
page size (64) while calculating the reserve block area. This makes sure pmem
device can be used across kernels built with different configs.
If the above assumption of max struct page size change, we need to update the
reserve block allocation space for new namespaces created.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Link: https://lore.kernel.org/r/20190905154603.10349-4-aneesh.kumar@linux.ibm.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/nvdimm/pfn_devs.c')
| -rw-r--r-- | drivers/nvdimm/pfn_devs.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c index 3e7b11cf1aae..cd120feb9213 100644 --- a/drivers/nvdimm/pfn_devs.c +++ b/drivers/nvdimm/pfn_devs.c @@ -701,8 +701,16 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn) * 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 64. 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. */ - offset = ALIGN(start + SZ_8K + 64 * npfns, align) - start; + BUILD_BUG_ON(sizeof(struct page) > MAX_STRUCT_PAGE_SIZE); + offset = ALIGN(start + SZ_8K + MAX_STRUCT_PAGE_SIZE * npfns, align) + - start; } else if (nd_pfn->mode == PFN_MODE_RAM) offset = ALIGN(start + SZ_8K, align) - start; else |