Messages in this thread Patch in this message | | | Date | Mon, 14 Oct 2002 14:20:45 -0700 | From | William Lee Irwin III <> | Subject | Re: [patch, feature] nonlinear mappings, prefaulting support, 2.5.42-F8 |
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On Mon, Oct 14, 2002 at 06:02:30PM +0200, Ingo Molnar wrote: >> if this is really an issue then we could force vma->vm_page_prot to >> PROT_NONE within remap_file_pages(), so at least all subsequent faults >> will be PROT_NONE and the user would have to explicitly re-mprotect() >> the vma again to change this. > i've added this to the -G1 patch at: > http://redhat.com/~mingo/remap-file-pages-patches/ > Ingo
Also, this may be relaxed when the file offsets match. Against unpatched -G1:
Bill
--- mpop-2.5.42/mm/fremap.c 2002-10-14 11:43:03.000000000 -0700 +++ wlipop-2.5.42/mm/fremap.c 2002-10-14 14:17:11.000000000 -0700 @@ -129,10 +129,16 @@ end > start && start >= vma->vm_start && end <= vma->vm_end) { /* - * Change the default protection to PROT_NONE: + * Change the default protection to PROT_NONE if + * the file offset doesn't coincide with the vma's: */ - if (pgprot_val(vma->vm_page_prot) != pgprot_val(__S000)) - vma->vm_page_prot = __S000; + if (pgprot_val(vma->vm_page_prot) != pgprot_val(__S000)) { + unsigned long offset; + offset = (start - vma->vm_start) >> PAGE_CACHE_SHIFT + + vma->vm_pgoff; + if (offset != pgoff) + vma->vm_page_prot = __S000; + } err = vma->vm_ops->populate(vma, start, size, prot, pgoff, flags & MAP_NONBLOCK); } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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