Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | Date | Thu, 29 May 2003 19:38:26 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [RFC][PATCH] Avoid vmtruncate/mmap-page-fault race |
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On Thu, May 29, 2003 at 05:33:04PM +0100, Hugh Dickins wrote: > On Thu, 29 May 2003, Paul E. McKenney wrote: > > On Fri, May 23, 2003 at 11:42:02AM -0700, Paul E. McKenney wrote: > > > > > > Exactly -- allows a ->nopage() to drop some lock to avoid races > > > between pagefault and either vmtruncate() or invalidate_mmap_range(). > > > This race (from the cross-host mmap viewpoint) is described in: > > > > > > http://marc.theaimsgroup.com/?l=linux-kernel&m=105286345316249&w=2 > > > > Rediffed for 2.5.70-mm1. > > Me? I much preferred your original, much sparer, nopagedone patch > (labelled "uglyh as hell" by hch). I dislike passing lots of args > down a level so they can be passed up again to the library function. > > In particular, I feel queasy (fear loss of control) about passing a > pmd_t* down to a filesystem, which I'd prefer to have no access to > such. But I may be in a minority, and the decision won't be mine.
Fine by me either way. ;-) Here is the rediffed nopagedone patch for 2.5.70-mm1.
Thanx, Paul
diff -urN -X dontdiff linux-2.5.70-mm1/include/linux/mm.h linux-2.5.70-mm1.nopagedone/include/linux/mm.h --- linux-2.5.70-mm1/include/linux/mm.h 2003-05-28 20:16:04.000000000 -0700 +++ linux-2.5.70-mm1.nopagedone/include/linux/mm.h 2003-05-29 19:34:55.000000000 -0700 @@ -143,6 +143,7 @@ void (*open)(struct vm_area_struct * area); void (*close)(struct vm_area_struct * area); struct page * (*nopage)(struct vm_area_struct * area, unsigned long address, int unused); + void (*nopagedone)(struct vm_area_struct * area, unsigned long address, int status); int (*populate)(struct vm_area_struct * area, unsigned long address, unsigned long len, pgprot_t prot, unsigned long pgoff, int nonblock); }; diff -urN -X dontdiff linux-2.5.70-mm1/mm/memory.c linux-2.5.70-mm1.nopagedone/mm/memory.c --- linux-2.5.70-mm1/mm/memory.c 2003-05-28 20:16:04.000000000 -0700 +++ linux-2.5.70-mm1.nopagedone/mm/memory.c 2003-05-29 19:34:55.000000000 -0700 @@ -1468,6 +1468,9 @@ ret = VM_FAULT_OOM; out: pte_chain_free(pte_chain); + if (vma->vm_ops && vma->vm_ops->nopagedone) { + vma->vm_ops->nopagedone(vma, address & PAGE_MASK, ret); + } return ret; } - 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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