From f67d9b1576c1c6e02100f8b27f4e9d66bbeb4d49 Mon Sep 17 00:00:00 2001 From: Bob Liu Date: Tue, 24 May 2011 17:12:56 -0700 Subject: [PATCH] nommu: add page alignment to mmap Currently on nommu arch mmap(),mremap() and munmap() doesn't do page_align() which isn't consist with mmu arch and cause some issues. First, some drivers' mmap() function depends on vma->vm_end - vma->start is page aligned which is true on mmu arch but not on nommu. eg: uvc camera driver. Second munmap() may return -EINVAL[split file] error in cases when end is not page aligned(passed into from userspace) but vma->vm_end is aligned dure to split or driver's mmap() ops. Add page alignment to fix those issues. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Bob Liu Cc: David Howells Cc: Paul Mundt Cc: Greg Ungerer Cc: Geert Uytterhoeven Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/nommu.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/mm/nommu.c b/mm/nommu.c index 92e1a47d1e52..1fd0c51b10a6 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1124,7 +1124,7 @@ static int do_mmap_private(struct vm_area_struct *vma, unsigned long capabilities) { struct page *pages; - unsigned long total, point, n, rlen; + unsigned long total, point, n; void *base; int ret, order; @@ -1148,13 +1148,12 @@ static int do_mmap_private(struct vm_area_struct *vma, * make a private copy of the data and map that instead */ } - rlen = PAGE_ALIGN(len); /* allocate some memory to hold the mapping * - note that this may not return a page-aligned address if the object * we're allocating is smaller than a page */ - order = get_order(rlen); + order = get_order(len); kdebug("alloc order %d for %lx", order, len); pages = alloc_pages(GFP_KERNEL, order); @@ -1164,7 +1163,7 @@ static int do_mmap_private(struct vm_area_struct *vma, total = 1 << order; atomic_long_add(total, &mmap_pages_allocated); - point = rlen >> PAGE_SHIFT; + point = len >> PAGE_SHIFT; /* we allocated a power-of-2 sized page set, so we may want to trim off * the excess */ @@ -1186,7 +1185,7 @@ static int do_mmap_private(struct vm_area_struct *vma, base = page_address(pages); region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY; region->vm_start = (unsigned long) base; - region->vm_end = region->vm_start + rlen; + region->vm_end = region->vm_start + len; region->vm_top = region->vm_start + (total << PAGE_SHIFT); vma->vm_start = region->vm_start; @@ -1202,15 +1201,15 @@ static int do_mmap_private(struct vm_area_struct *vma, old_fs = get_fs(); set_fs(KERNEL_DS); - ret = vma->vm_file->f_op->read(vma->vm_file, base, rlen, &fpos); + ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos); set_fs(old_fs); if (ret < 0) goto error_free; /* clear the last little bit */ - if (ret < rlen) - memset(base + ret, 0, rlen - ret); + if (ret < len) + memset(base + ret, 0, len - ret); } @@ -1259,6 +1258,7 @@ unsigned long do_mmap_pgoff(struct file *file, /* we ignore the address hint */ addr = 0; + len = PAGE_ALIGN(len); /* we've determined that we can make the mapping, now translate what we * now know into VMA flags */ @@ -1635,14 +1635,17 @@ static int shrink_vma(struct mm_struct *mm, int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) { struct vm_area_struct *vma; - unsigned long end = start + len; + unsigned long end; int ret; kenter(",%lx,%zx", start, len); + len = PAGE_ALIGN(len); if (len == 0) return -EINVAL; + end = start + len; + /* find the first potentially overlapping VMA */ vma = find_vma(mm, start); if (!vma) { @@ -1762,6 +1765,8 @@ unsigned long do_mremap(unsigned long addr, struct vm_area_struct *vma; /* insanity checks first */ + old_len = PAGE_ALIGN(old_len); + new_len = PAGE_ALIGN(new_len); if (old_len == 0 || new_len == 0) return (unsigned long) -EINVAL; -- 2.20.1