Callers that expect PCI P2PDMA pages can now set FOLL_PCI_P2PDMA to allow obtaining P2PDMA pages. If a caller does not set this flag and tries to map P2PDMA pages it will fail. This is implemented by adding a flag and a check to get_dev_pagemap(). Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx> --- drivers/dax/super.c | 7 ++++--- include/linux/memremap.h | 4 ++-- include/linux/mm.h | 1 + mm/gup.c | 28 +++++++++++++++++----------- mm/huge_memory.c | 8 ++++---- mm/memory-failure.c | 4 ++-- mm/memory_hotplug.c | 2 +- mm/memremap.c | 14 ++++++++++---- 8 files changed, 41 insertions(+), 27 deletions(-) diff --git a/drivers/dax/super.c b/drivers/dax/super.c index fc89e91beea7..ffb6e57e65bb 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -180,9 +180,10 @@ bool generic_fsdax_supported(struct dax_device *dax_dev, } else if (pfn_t_devmap(pfn) && pfn_t_devmap(end_pfn)) { struct dev_pagemap *pgmap, *end_pgmap; - pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL); - end_pgmap = get_dev_pagemap(pfn_t_to_pfn(end_pfn), NULL); - if (pgmap && pgmap == end_pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX + pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL, false); + end_pgmap = get_dev_pagemap(pfn_t_to_pfn(end_pfn), NULL, false); + if (!IS_ERR_OR_NULL(pgmap) && pgmap == end_pgmap + && pgmap->type == MEMORY_DEVICE_FS_DAX && pfn_t_to_page(pfn)->pgmap == pgmap && pfn_t_to_page(end_pfn)->pgmap == pgmap && pfn_t_to_pfn(pfn) == PHYS_PFN(__pa(kaddr)) diff --git a/include/linux/memremap.h b/include/linux/memremap.h index c0e9d35889e8..f10c332dac8b 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -136,7 +136,7 @@ void memunmap_pages(struct dev_pagemap *pgmap); void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap); void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap); struct dev_pagemap *get_dev_pagemap(unsigned long pfn, - struct dev_pagemap *pgmap); + struct dev_pagemap *pgmap, bool allow_pci_p2pdma); bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn); unsigned long vmem_altmap_offset(struct vmem_altmap *altmap); @@ -161,7 +161,7 @@ static inline void devm_memunmap_pages(struct device *dev, } static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn, - struct dev_pagemap *pgmap) + struct dev_pagemap *pgmap, bool allow_pci_p2pdma) { return NULL; } diff --git a/include/linux/mm.h b/include/linux/mm.h index 73a52aba448f..6afdc09d0712 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2864,6 +2864,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address, #define FOLL_SPLIT_PMD 0x20000 /* split huge pmd before returning */ #define FOLL_PIN 0x40000 /* pages must be released via unpin_user_page */ #define FOLL_FAST_ONLY 0x80000 /* gup_fast: prevent fall-back to slow gup */ +#define FOLL_PCI_P2PDMA 0x100000 /* allow returning PCI P2PDMA pages */ /* * FOLL_PIN and FOLL_LONGTERM may be used in various combinations with each diff --git a/mm/gup.c b/mm/gup.c index 886d6148d3d0..1a03b9200cd9 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -522,11 +522,16 @@ static struct page *follow_page_pte(struct vm_area_struct *vma, * case since they are only valid while holding the pgmap * reference. */ - *pgmap = get_dev_pagemap(pte_pfn(pte), *pgmap); - if (*pgmap) + *pgmap = get_dev_pagemap(pte_pfn(pte), *pgmap, + flags & FOLL_PCI_P2PDMA); + if (IS_ERR(*pgmap)) { + page = ERR_CAST(*pgmap); + goto out; + } else if (*pgmap) { page = pte_page(pte); - else + } else { goto no_page; + } } else if (unlikely(!page)) { if (flags & FOLL_DUMP) { /* Avoid special (like zero) pages in core dumps */ @@ -846,7 +851,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address, return NULL; page = follow_page_mask(vma, address, foll_flags, &ctx); - if (ctx.pgmap) + if (!IS_ERR_OR_NULL(ctx.pgmap)) put_dev_pagemap(ctx.pgmap); return page; } @@ -1199,7 +1204,7 @@ static long __get_user_pages(struct mm_struct *mm, nr_pages -= page_increm; } while (nr_pages); out: - if (ctx.pgmap) + if (!IS_ERR_OR_NULL(ctx.pgmap)) put_dev_pagemap(ctx.pgmap); return i ? i : ret; } @@ -2149,8 +2154,9 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, if (unlikely(flags & FOLL_LONGTERM)) goto pte_unmap; - pgmap = get_dev_pagemap(pte_pfn(pte), pgmap); - if (unlikely(!pgmap)) { + pgmap = get_dev_pagemap(pte_pfn(pte), pgmap, + flags & FOLL_PCI_P2PDMA); + if (IS_ERR_OR_NULL(pgmap)) { undo_dev_pagemap(nr, nr_start, flags, pages); goto pte_unmap; } @@ -2198,7 +2204,7 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, ret = 1; pte_unmap: - if (pgmap) + if (!IS_ERR_OR_NULL(pgmap)) put_dev_pagemap(pgmap); pte_unmap(ptem); return ret; @@ -2233,8 +2239,8 @@ static int __gup_device_huge(unsigned long pfn, unsigned long addr, do { struct page *page = pfn_to_page(pfn); - pgmap = get_dev_pagemap(pfn, pgmap); - if (unlikely(!pgmap)) { + pgmap = get_dev_pagemap(pfn, pgmap, flags & FOLL_PCI_P2PDMA); + if (IS_ERR_OR_NULL(pgmap)) { undo_dev_pagemap(nr, nr_start, flags, pages); ret = 0; break; @@ -2708,7 +2714,7 @@ static int internal_get_user_pages_fast(unsigned long start, if (WARN_ON_ONCE(gup_flags & ~(FOLL_WRITE | FOLL_LONGTERM | FOLL_FORCE | FOLL_PIN | FOLL_GET | - FOLL_FAST_ONLY))) + FOLL_FAST_ONLY | FOLL_PCI_P2PDMA))) return -EINVAL; if (gup_flags & FOLL_PIN) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 5e9ef0fc261e..853157a84b00 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1014,8 +1014,8 @@ struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, return ERR_PTR(-EEXIST); pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT; - *pgmap = get_dev_pagemap(pfn, *pgmap); - if (!*pgmap) + *pgmap = get_dev_pagemap(pfn, *pgmap, flags & FOLL_PCI_P2PDMA); + if (IS_ERR_OR_NULL(*pgmap)) return ERR_PTR(-EFAULT); page = pfn_to_page(pfn); if (!try_grab_page(page, flags)) @@ -1181,8 +1181,8 @@ struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, return ERR_PTR(-EEXIST); pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT; - *pgmap = get_dev_pagemap(pfn, *pgmap); - if (!*pgmap) + *pgmap = get_dev_pagemap(pfn, *pgmap, flags & FOLL_PCI_P2PDMA); + if (IS_ERR_OR_NULL(*pgmap)) return ERR_PTR(-EFAULT); page = pfn_to_page(pfn); if (!try_grab_page(page, flags)) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 54879c339024..8f15ccce5aea 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1635,8 +1635,8 @@ int memory_failure(unsigned long pfn, int flags) p = pfn_to_online_page(pfn); if (!p) { if (pfn_valid(pfn)) { - pgmap = get_dev_pagemap(pfn, NULL); - if (pgmap) + pgmap = get_dev_pagemap(pfn, NULL, false); + if (!IS_ERR_OR_NULL(pgmap)) return memory_failure_dev_pagemap(pfn, flags, pgmap); } diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 9fd0be32a281..fa5cf8898b6b 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -285,7 +285,7 @@ struct page *pfn_to_online_page(unsigned long pfn) * the section may be 'offline' but 'valid'. Only * get_dev_pagemap() can determine sub-section online status. */ - pgmap = get_dev_pagemap(pfn, NULL); + pgmap = get_dev_pagemap(pfn, NULL, true); put_dev_pagemap(pgmap); /* The presence of a pgmap indicates ZONE_DEVICE offline pfn */ diff --git a/mm/memremap.c b/mm/memremap.c index ed593bf87109..ceebdb8a72bb 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -206,14 +206,14 @@ static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params, "altmap not supported for multiple ranges\n")) return -EINVAL; - conflict_pgmap = get_dev_pagemap(PHYS_PFN(range->start), NULL); + conflict_pgmap = get_dev_pagemap(PHYS_PFN(range->start), NULL, true); if (conflict_pgmap) { WARN(1, "Conflicting mapping in same section\n"); put_dev_pagemap(conflict_pgmap); return -ENOMEM; } - conflict_pgmap = get_dev_pagemap(PHYS_PFN(range->end), NULL); + conflict_pgmap = get_dev_pagemap(PHYS_PFN(range->end), NULL, true); if (conflict_pgmap) { WARN(1, "Conflicting mapping in same section\n"); put_dev_pagemap(conflict_pgmap); @@ -465,19 +465,20 @@ void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns) * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn * @pfn: page frame number to lookup page_map * @pgmap: optional known pgmap that already has a reference + * @allow_pci_p2pdma: allow getting a pgmap with the PCI P2PDMA type * * If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap * is non-NULL but does not cover @pfn the reference to it will be released. */ struct dev_pagemap *get_dev_pagemap(unsigned long pfn, - struct dev_pagemap *pgmap) + struct dev_pagemap *pgmap, bool allow_pci_p2pdma) { resource_size_t phys = PFN_PHYS(pfn); /* * In the cached case we're already holding a live reference. */ - if (pgmap) { + if (!IS_ERR_OR_NULL(pgmap)) { if (phys >= pgmap->range.start && phys <= pgmap->range.end) return pgmap; put_dev_pagemap(pgmap); @@ -490,6 +491,11 @@ struct dev_pagemap *get_dev_pagemap(unsigned long pfn, pgmap = NULL; rcu_read_unlock(); + if (!allow_pci_p2pdma && pgmap->type == MEMORY_DEVICE_PCI_P2PDMA) { + put_dev_pagemap(pgmap); + return ERR_PTR(-EREMOTEIO); + } + return pgmap; } EXPORT_SYMBOL_GPL(get_dev_pagemap); -- 2.30.2