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authorPallipadi, Venkatesh <venkatesh.pallipadi@intel.com>2009-03-13 03:45:27 +0300
committerIngo Molnar <mingo@elte.hu>2009-03-13 06:28:50 +0300
commit4bb9c5c02153dfc89a6c73a6f32091413805ad7d (patch)
tree408dee350cab80fbe7884b6640d651ef8ec44601 /include/linux/mm.h
parent6a5c05f002c3e4f24887a5fe8e7df757d339d368 (diff)
downloadlinux-4bb9c5c02153dfc89a6c73a6f32091413805ad7d.tar.xz
VM, x86, PAT: Change is_linear_pfn_mapping to not use vm_pgoff
Impact: fix false positive PAT warnings - also fix VirtalBox hang Use of vma->vm_pgoff to identify the pfnmaps that are fully mapped at mmap time is broken. vm_pgoff is set by generic mmap code even for cases where drivers are setting up the mappings at the fault time. The problem was originally reported here: http://marc.info/?l=linux-kernel&m=123383810628583&w=2 Change is_linear_pfn_mapping logic to overload VM_INSERTPAGE flag along with VM_PFNMAP to mean full PFNMAP setup at mmap time. Problem also tracked at: http://bugzilla.kernel.org/show_bug.cgi?id=12800 Reported-by: Thomas Hellstrom <thellstrom@vmware.com> Tested-by: Frans Pop <elendil@planet.nl> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha>@intel.com> Cc: Nick Piggin <npiggin@suse.de> Cc: "ebiederm@xmission.com" <ebiederm@xmission.com> Cc: <stable@kernel.org> # only for 2.6.29.1, not .28 LKML-Reference: <20090313004527.GA7176@linux-os.sc.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux/mm.h')
-rw-r--r--include/linux/mm.h15
1 files changed, 13 insertions, 2 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 065cdf8c09fb..3daa05feed9f 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -98,7 +98,7 @@ extern unsigned int kobjsize(const void *objp);
#define VM_HUGETLB 0x00400000 /* Huge TLB Page VM */
#define VM_NONLINEAR 0x00800000 /* Is non-linear (remap_file_pages) */
#define VM_MAPPED_COPY 0x01000000 /* T if mapped copy of data (nommu mmap) */
-#define VM_INSERTPAGE 0x02000000 /* The vma has had "vm_insert_page()" done on it */
+#define VM_INSERTPAGE 0x02000000 /* The vma has had "vm_insert_page()" done on it. Refer note in VM_PFNMAP_AT_MMAP below */
#define VM_ALWAYSDUMP 0x04000000 /* Always include in core dumps */
#define VM_CAN_NONLINEAR 0x08000000 /* Has ->fault & does nonlinear pages */
@@ -127,6 +127,17 @@ extern unsigned int kobjsize(const void *objp);
#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
/*
+ * pfnmap vmas that are fully mapped at mmap time (not mapped on fault).
+ * Used by x86 PAT to identify such PFNMAP mappings and optimize their handling.
+ * Note VM_INSERTPAGE flag is overloaded here. i.e,
+ * VM_INSERTPAGE && !VM_PFNMAP implies
+ * The vma has had "vm_insert_page()" done on it
+ * VM_INSERTPAGE && VM_PFNMAP implies
+ * The vma is PFNMAP with full mapping at mmap time
+ */
+#define VM_PFNMAP_AT_MMAP (VM_INSERTPAGE | VM_PFNMAP)
+
+/*
* mapping from the currently active vm_flags protection bits (the
* low four bits) to a page protection mask..
*/
@@ -145,7 +156,7 @@ extern pgprot_t protection_map[16];
*/
static inline int is_linear_pfn_mapping(struct vm_area_struct *vma)
{
- return ((vma->vm_flags & VM_PFNMAP) && vma->vm_pgoff);
+ return ((vma->vm_flags & VM_PFNMAP_AT_MMAP) == VM_PFNMAP_AT_MMAP);
}
static inline int is_pfn_mapping(struct vm_area_struct *vma)