diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-01-27 21:03:39 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-01-27 21:03:39 -0800 |
commit | d12de1ef5eba3adb88f8e9dd81b6a60349466378 (patch) | |
tree | e7a82d5d797ba453ab16754a4750ec393773a2a1 | |
parent | ba635f8cd20ebc7bddf1eb8e1f4eae28a034e916 (diff) | |
parent | b3084f4db3aeb991c507ca774337c7e7893ed04f (diff) | |
download | linux-d12de1ef5eba3adb88f8e9dd81b6a60349466378.tar.gz linux-d12de1ef5eba3adb88f8e9dd81b6a60349466378.tar.bz2 linux-d12de1ef5eba3adb88f8e9dd81b6a60349466378.zip |
Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
Pull powerpc mremap fix from Ben Herrenschmidt:
"This is the patch that I had sent after -rc8 and which we decided to
wait before merging. It's based on a different tree than my -next
branch (it needs some pre-reqs that were in -rc4 or so while my -next
is based on -rc1) so I left it as a separate branch for your to pull.
It's identical to the request I did 2 or 3 weeks back.
This fixes crashes in mremap with THP on powerpc.
The fix however requires a small change in the generic code. It moves
a condition into a helper we can override from the arch which is
harmless, but it *also* slightly changes the order of the set_pmd and
the withdraw & deposit, which should be fine according to Kirill (who
wrote that code) but I agree -rc8 is a bit late...
It was acked by Kirill and Andrew told me to just merge it via powerpc"
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
powerpc/thp: Fix crash on mremap
-rw-r--r-- | arch/powerpc/include/asm/pgtable-ppc64.h | 14 | ||||
-rw-r--r-- | include/asm-generic/pgtable.h | 12 | ||||
-rw-r--r-- | mm/huge_memory.c | 14 |
3 files changed, 31 insertions, 9 deletions
diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h index 4a191c472867..d27960c89a71 100644 --- a/arch/powerpc/include/asm/pgtable-ppc64.h +++ b/arch/powerpc/include/asm/pgtable-ppc64.h @@ -558,5 +558,19 @@ extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp); #define __HAVE_ARCH_PMDP_INVALIDATE extern void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp); + +#define pmd_move_must_withdraw pmd_move_must_withdraw +typedef struct spinlock spinlock_t; +static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, + spinlock_t *old_pmd_ptl) +{ + /* + * Archs like ppc64 use pgtable to store per pmd + * specific information. So when we switch the pmd, + * we should also withdraw and deposit the pgtable + */ + return true; +} + #endif /* __ASSEMBLY__ */ #endif /* _ASM_POWERPC_PGTABLE_PPC64_H_ */ diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index db0923458940..8e4f41d9af4d 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -558,6 +558,18 @@ static inline pmd_t pmd_read_atomic(pmd_t *pmdp) } #endif +#ifndef pmd_move_must_withdraw +static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, + spinlock_t *old_pmd_ptl) +{ + /* + * With split pmd lock we also need to move preallocated + * PTE page table if new_pmd is on different PMD page table. + */ + return new_pmd_ptl != old_pmd_ptl; +} +#endif + /* * This function is meant to be used by sites walking pagetables with * the mmap_sem hold in read mode to protect against MADV_DONTNEED and diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 65c98eb5483c..82166bf974e1 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1508,19 +1508,15 @@ int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); VM_BUG_ON(!pmd_none(*new_pmd)); - set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); - if (new_ptl != old_ptl) { - pgtable_t pgtable; - /* - * Move preallocated PTE page table if new_pmd is on - * different PMD page table. - */ + if (pmd_move_must_withdraw(new_ptl, old_ptl)) { + pgtable_t pgtable; pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); pgtable_trans_huge_deposit(mm, new_pmd, pgtable); - - spin_unlock(new_ptl); } + set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); + if (new_ptl != old_ptl) + spin_unlock(new_ptl); spin_unlock(old_ptl); } out: |