diff options
author | Kumar Gala <galak@kernel.crashing.org> | 2007-02-12 23:57:21 -0600 |
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committer | Kumar Gala <galak@kernel.crashing.org> | 2007-02-12 23:57:21 -0600 |
commit | 54c66f6d781e03dc0b23956234963c4911e6d1c0 (patch) | |
tree | 40619a66ae6d8703a57bf681d087ffeabbffd346 /mm/mmap.c | |
parent | 8ce0a7df6e6117d8814e976d4b7ce6a6b2c9cf93 (diff) | |
parent | 17e0e27020d028a790d97699aff85a43af5be472 (diff) |
Merge branch 'master' into 85xx
Diffstat (limited to 'mm/mmap.c')
-rw-r--r-- | mm/mmap.c | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index cc3a2081945..eb509ae7655 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2101,3 +2101,75 @@ int may_expand_vm(struct mm_struct *mm, unsigned long npages) return 0; return 1; } + + +static struct page *special_mapping_nopage(struct vm_area_struct *vma, + unsigned long address, int *type) +{ + struct page **pages; + + BUG_ON(address < vma->vm_start || address >= vma->vm_end); + + address -= vma->vm_start; + for (pages = vma->vm_private_data; address > 0 && *pages; ++pages) + address -= PAGE_SIZE; + + if (*pages) { + struct page *page = *pages; + get_page(page); + return page; + } + + return NOPAGE_SIGBUS; +} + +/* + * Having a close hook prevents vma merging regardless of flags. + */ +static void special_mapping_close(struct vm_area_struct *vma) +{ +} + +static struct vm_operations_struct special_mapping_vmops = { + .close = special_mapping_close, + .nopage = special_mapping_nopage, +}; + +/* + * Called with mm->mmap_sem held for writing. + * Insert a new vma covering the given region, with the given flags. + * Its pages are supplied by the given array of struct page *. + * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. + * The region past the last page supplied will always produce SIGBUS. + * The array pointer and the pages it points to are assumed to stay alive + * for as long as this mapping might exist. + */ +int install_special_mapping(struct mm_struct *mm, + unsigned long addr, unsigned long len, + unsigned long vm_flags, struct page **pages) +{ + struct vm_area_struct *vma; + + vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); + if (unlikely(vma == NULL)) + return -ENOMEM; + + vma->vm_mm = mm; + vma->vm_start = addr; + vma->vm_end = addr + len; + + vma->vm_flags = vm_flags | mm->def_flags; + vma->vm_page_prot = protection_map[vma->vm_flags & 7]; + + vma->vm_ops = &special_mapping_vmops; + vma->vm_private_data = pages; + + if (unlikely(insert_vm_struct(mm, vma))) { + kmem_cache_free(vm_area_cachep, vma); + return -ENOMEM; + } + + mm->total_vm += len >> PAGE_SHIFT; + + return 0; +} |