remove double indirection on tlb parameter to free_pgd_range() & Co

The double indirection here is not needed anywhere and hence (at least) confusing.

Signed-off-by Jan Beulich <[email protected]>

---
 arch/ia64/mm/hugetlbpage.c    |    2 +-
 arch/powerpc/mm/hugetlbpage.c |    8 ++++----
 fs/exec.c                     |    4 ++--
 include/asm-ia64/hugetlb.h    |    2 +-
 include/asm-powerpc/hugetlb.h |    2 +-
 include/asm-sh/hugetlb.h      |    2 +-
 include/asm-sparc64/hugetlb.h |    2 +-
 include/asm-x86/hugetlb.h     |    2 +-
 include/linux/mm.h            |    4 +---
 mm/internal.h                 |    3 +++
 mm/memory.c                   |   10 ++++++----
 mm/mmap.c                     |    6 ++++--
 12 files changed, 26 insertions(+), 21 deletions(-)

arch/ia64/mm/hugetlbpage.c +1 -1

@@ -112,7 +112,7 @@ follow_huge_pmd(struct mm_struct *mm, un
 	return NULL;
 }
 
-void hugetlb_free_pgd_range(struct mmu_gather **tlb,
+void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 			unsigned long addr, unsigned long end,
 			unsigned long floor, unsigned long ceiling)
 {

arch/powerpc/mm/hugetlbpage.c +4 -4

@@ -255,7 +255,7 @@ static void hugetlb_free_pud_range(struc
  *
  * Must be called with pagetable lock held.
  */
-void hugetlb_free_pgd_range(struct mmu_gather **tlb,
+void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 			    unsigned long addr, unsigned long end,
 			    unsigned long floor, unsigned long ceiling)
 {

@@ -315,13 +315,13 @@ void hugetlb_free_pgd_range(struct mmu_g
 		return;
 
 	start = addr;
-	pgd = pgd_offset((*tlb)->mm, addr);
+	pgd = pgd_offset(tlb->mm, addr);
 	do {
-		BUG_ON(get_slice_psize((*tlb)->mm, addr) != mmu_huge_psize);
+		BUG_ON(get_slice_psize(tlb->mm, addr) != mmu_huge_psize);
 		next = pgd_addr_end(addr, end);
 		if (pgd_none_or_clear_bad(pgd))
 			continue;
-		hugetlb_free_pud_range(*tlb, pgd, addr, next, floor, ceiling);
+		hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
 	} while (pgd++, addr = next, addr != end);
 }
 

fs/exec.c +2 -2

@@ -537,7 +537,7 @@ static int shift_arg_pages(struct vm_are
 		/*
 		 * when the old and new regions overlap clear from new_end.
 		 */
-		free_pgd_range(&tlb, new_end, old_end, new_end,
+		free_pgd_range(tlb, new_end, old_end, new_end,
 			vma->vm_next ? vma->vm_next->vm_start : 0);
 	} else {
 		/*

@@ -546,7 +546,7 @@ static int shift_arg_pages(struct vm_are
 		 * have constraints on va-space that make this illegal (IA64) -
 		 * for the others its just a little faster.
 		 */
-		free_pgd_range(&tlb, old_start, old_end, new_end,
+		free_pgd_range(tlb, old_start, old_end, new_end,
 			vma->vm_next ? vma->vm_next->vm_start : 0);
 	}
 	tlb_finish_mmu(tlb, new_end, old_end);

include/asm-ia64/hugetlb.h +1 -1

@@ -4,7 +4,7 @@
 #include <asm/page.h>
 
 
-void hugetlb_free_pgd_range(struct mmu_gather **tlb, unsigned long addr,
+void hugetlb_free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
 			    unsigned long end, unsigned long floor,
 			    unsigned long ceiling);
 

include/asm-powerpc/hugetlb.h +1 -1

@@ -7,7 +7,7 @@
 int is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
 			   unsigned long len);
 
-void hugetlb_free_pgd_range(struct mmu_gather **tlb, unsigned long addr,
+void hugetlb_free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
 			    unsigned long end, unsigned long floor,
 			    unsigned long ceiling);
 

include/asm-sh/hugetlb.h +1 -1

@@ -26,7 +26,7 @@ static inline int prepare_hugepage_range
 static inline void hugetlb_prefault_arch_hook(struct mm_struct *mm) {
 }
 
-static inline void hugetlb_free_pgd_range(struct mmu_gather **tlb,
+static inline void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 					  unsigned long addr, unsigned long end,
 					  unsigned long floor,
 					  unsigned long ceiling)

include/asm-sparc64/hugetlb.h +1 -1

@@ -31,7 +31,7 @@ static inline int prepare_hugepage_range
 	return 0;
 }
 
-static inline void hugetlb_free_pgd_range(struct mmu_gather **tlb,
+static inline void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 					  unsigned long addr, unsigned long end,
 					  unsigned long floor,
 					  unsigned long ceiling)

include/asm-x86/hugetlb.h +1 -1

@@ -26,7 +26,7 @@ static inline int prepare_hugepage_range
 static inline void hugetlb_prefault_arch_hook(struct mm_struct *mm) {
 }
 
-static inline void hugetlb_free_pgd_range(struct mmu_gather **tlb,
+static inline void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 					  unsigned long addr, unsigned long end,
 					  unsigned long floor,
 					  unsigned long ceiling)

include/linux/mm.h +1 -3

@@ -770,10 +770,8 @@ struct mm_walk {
 int walk_page_range(const struct mm_struct *, unsigned long addr,
 		    unsigned long end, const struct mm_walk *walk,
 		    void *private);
-void free_pgd_range(struct mmu_gather **tlb, unsigned long addr,
+void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
 		unsigned long end, unsigned long floor, unsigned long ceiling);
-void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *start_vma,
-		unsigned long floor, unsigned long ceiling);
 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
 			struct vm_area_struct *vma);
 void unmap_mapping_range(struct address_space *mapping,

mm/internal.h +3 -0

@@ -13,6 +13,9 @@
 
 #include <linux/mm.h>
 
+void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
+		unsigned long floor, unsigned long ceiling);
+
 static inline void set_page_count(struct page *page, int v)
 {
 	atomic_set(&page->_count, v);

mm/memory.c +6 -4

@@ -61,6 +61,8 @@
 #include <linux/swapops.h>
 #include <linux/elf.h>
 
+#include "internal.h"
+
 #ifndef CONFIG_NEED_MULTIPLE_NODES
 /* use the per-pgdat data instead for discontigmem - mbligh */
 unsigned long max_mapnr;

@@ -211,7 +213,7 @@ static inline void free_pud_range(struct
  *
  * Must be called with pagetable lock held.
  */
-void free_pgd_range(struct mmu_gather **tlb,
+void free_pgd_range(struct mmu_gather *tlb,
 			unsigned long addr, unsigned long end,
 			unsigned long floor, unsigned long ceiling)
 {

@@ -262,16 +264,16 @@ void free_pgd_range(struct mmu_gather **
 		return;
 
 	start = addr;
-	pgd = pgd_offset((*tlb)->mm, addr);
+	pgd = pgd_offset(tlb->mm, addr);
 	do {
 		next = pgd_addr_end(addr, end);
 		if (pgd_none_or_clear_bad(pgd))
 			continue;
-		free_pud_range(*tlb, pgd, addr, next, floor, ceiling);
+		free_pud_range(tlb, pgd, addr, next, floor, ceiling);
 	} while (pgd++, addr = next, addr != end);
 }
 
-void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma,
+void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		unsigned long floor, unsigned long ceiling)
 {
 	while (vma) {

mm/mmap.c +4 -3

@@ -32,6 +32,8 @@
 #include <asm/tlb.h>
 #include <asm/mmu_context.h>
 
+#include "internal.h"
+
 #ifndef arch_mmap_check
 #define arch_mmap_check(addr, len, flags)	(0)
 #endif

@@ -1756,7 +1758,7 @@ static void unmap_region(struct mm_struc
 	update_hiwater_rss(mm);
 	unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL);
 	vm_unacct_memory(nr_accounted);
-	free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS,
+	free_pgtables(tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS,
 				 next? next->vm_start: 0);
 	tlb_finish_mmu(tlb, start, end);
 }

@@ -2056,7 +2058,7 @@ void exit_mmap(struct mm_struct *mm)
 	/* Use -1 here to ensure all VMAs in the mm are unmapped */
 	end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);
 	vm_unacct_memory(nr_accounted);
-	free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0);
+	free_pgtables(tlb, vma, FIRST_USER_ADDRESS, 0);
 	tlb_finish_mmu(tlb, 0, end);
 
 	/*
 
 
--

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The double indirection here is not needed anywhere and hence (at least) confusing.

Signed-off-by Jan Beulich <[email protected]>

Quoted 1 line

Quoted 1 line

Hugh Dickins <[email protected]> 16.05.08 16:39 >>>

Pass mmu_gather** in the
public interfaces, since we might want to add latency lockdrops later; but no attempt to do so yet, going by vma should itself reduce latency.
...
But, returning to the start, please let's hold yours back after all.

If you want to keep and actively use the double indirection, would you

guarantee current semantics like ->mm and ->fullmm to always be what was specified at the start of the operation?

Verifying this was what
made me go through that call tree in the first place, and obviously this is harder to verify when there is potential for the whole structure pointed to to be replaced by another one.

Quoted 6 lines

Quoted 1 line

Quoted 1 line

Hugh Dickins <[email protected]> 16.05.08 16:39 >>>

Pass mmu_gather** in the
public interfaces, since we might want to add latency lockdrops later; but no attempt to do so yet, going by vma should itself reduce latency.
...
But, returning to the start, please let's hold yours back after all.

If you want to keep and actively use the double indirection, would you guarantee current semantics like ->mm and ->fullmm to always be what was specified at the start of the operation? Verifying this was what made me go through that call tree in the first place, and obviously this is harder to verify when there is potential for the whole structure pointed to to be replaced by another one.

We'd several of us like to rework the mmu_gathering so as not to disable
preemption: I got stuck and BenH took over, a patch much like yours below
was a part of what I had - I too was glad to get rid of the **s.