Messages in this thread | | | Date | Thu, 13 Nov 2008 00:23:12 +0100 | From | Nick Piggin <> | Subject | Re: [patch 2/8] x86 PAT: set VM_PFNMAP flag in vm_insert_pfn |
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You have to be careful of this, because it can be called with mmap_sem held for read only. Hmm, I guess vm_insert_page is doing the same thing. Probably mostly works because all other modifiers of vm_flags are holding mmap_sem.
However, in some cases, code can do vm_insert_pfn and vm_insert_page (actually hmm, no vm_insert_mixed actually should cover most of those cases).
Still, I'd be much happier if we could make these into BUG_ON, and then teach callers to set it in their .mmap routines.
On Wed, Nov 12, 2008 at 01:26:49PM -0800, Venkatesh Pallipadi wrote: > vm_insert_pfn() is not setting the VM_PFNMAP flag in vma. Fix that. > > Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> > Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> > > --- > mm/memory.c | 2 ++ > 1 file changed, 2 insertions(+) > > Index: tip/mm/memory.c > =================================================================== > --- tip.orig/mm/memory.c 2008-11-06 09:44:56.000000000 -0800 > +++ tip/mm/memory.c 2008-11-10 09:44:47.000000000 -0800 > @@ -1444,6 +1444,8 @@ int vm_insert_pfn(struct vm_area_struct > > if (addr < vma->vm_start || addr >= vma->vm_end) > return -EFAULT; > + > + vma->vm_flags |= VM_PFNMAP; > return insert_pfn(vma, addr, pfn, vma->vm_page_prot); > } > EXPORT_SYMBOL(vm_insert_pfn); > > --
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