[PATCH] mm: arches skip ptlock
Convert those few architectures which are calling pud_alloc, pmd_alloc,
pte_alloc_map on a user mm, not to take the page_table_lock first, nor drop it
after. Each of these can continue to use pte_alloc_map, no need to change
over to pte_alloc_map_lock, they're neither racy nor swappable.
In the sparc64 io_remap_pfn_range, flush_tlb_range then falls outside of the
page_table_lock: that's okay, on sparc64 it's like flush_tlb_mm, and that has
always been called from outside of page_table_lock in dup_mmap.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/arm/mm/mm-armv.c b/arch/arm/mm/mm-armv.c
index 61bc2fa..60f3e03 100644
--- a/arch/arm/mm/mm-armv.c
+++ b/arch/arm/mm/mm-armv.c
@@ -180,11 +180,6 @@
if (!vectors_high()) {
/*
- * This lock is here just to satisfy pmd_alloc and pte_lock
- */
- spin_lock(&mm->page_table_lock);
-
- /*
* On ARM, first page must always be allocated since it
* contains the machine vectors.
*/
@@ -201,23 +196,14 @@
set_pte(new_pte, *init_pte);
pte_unmap_nested(init_pte);
pte_unmap(new_pte);
-
- spin_unlock(&mm->page_table_lock);
}
return new_pgd;
no_pte:
- spin_unlock(&mm->page_table_lock);
pmd_free(new_pmd);
- free_pages((unsigned long)new_pgd, 2);
- return NULL;
-
no_pmd:
- spin_unlock(&mm->page_table_lock);
free_pages((unsigned long)new_pgd, 2);
- return NULL;
-
no_pgd:
return NULL;
}
diff --git a/arch/arm26/mm/memc.c b/arch/arm26/mm/memc.c
index d6b008b..34def63 100644
--- a/arch/arm26/mm/memc.c
+++ b/arch/arm26/mm/memc.c
@@ -79,12 +79,6 @@
goto no_pgd;
/*
- * This lock is here just to satisfy pmd_alloc and pte_lock
- * FIXME: I bet we could avoid taking it pretty much altogether
- */
- spin_lock(&mm->page_table_lock);
-
- /*
* On ARM, first page must always be allocated since it contains
* the machine vectors.
*/
@@ -113,23 +107,14 @@
memcpy(new_pgd + FIRST_KERNEL_PGD_NR, init_pgd + FIRST_KERNEL_PGD_NR,
(PTRS_PER_PGD - FIRST_KERNEL_PGD_NR) * sizeof(pgd_t));
- spin_unlock(&mm->page_table_lock);
-
/* update MEMC tables */
cpu_memc_update_all(new_pgd);
return new_pgd;
no_pte:
- spin_unlock(&mm->page_table_lock);
pmd_free(new_pmd);
- free_pgd_slow(new_pgd);
- return NULL;
-
no_pmd:
- spin_unlock(&mm->page_table_lock);
free_pgd_slow(new_pgd);
- return NULL;
-
no_pgd:
return NULL;
}
diff --git a/arch/sparc/mm/generic.c b/arch/sparc/mm/generic.c
index 659c9a7..9604893 100644
--- a/arch/sparc/mm/generic.c
+++ b/arch/sparc/mm/generic.c
@@ -81,9 +81,8 @@
dir = pgd_offset(mm, from);
flush_cache_range(vma, beg, end);
- spin_lock(&mm->page_table_lock);
while (from < end) {
- pmd_t *pmd = pmd_alloc(current->mm, dir, from);
+ pmd_t *pmd = pmd_alloc(mm, dir, from);
error = -ENOMEM;
if (!pmd)
break;
@@ -93,7 +92,6 @@
from = (from + PGDIR_SIZE) & PGDIR_MASK;
dir++;
}
- spin_unlock(&mm->page_table_lock);
flush_tlb_range(vma, beg, end);
return error;
diff --git a/arch/sparc64/mm/generic.c b/arch/sparc64/mm/generic.c
index afc01ce..112c316 100644
--- a/arch/sparc64/mm/generic.c
+++ b/arch/sparc64/mm/generic.c
@@ -135,9 +135,8 @@
dir = pgd_offset(mm, from);
flush_cache_range(vma, beg, end);
- spin_lock(&mm->page_table_lock);
while (from < end) {
- pud_t *pud = pud_alloc(current->mm, dir, from);
+ pud_t *pud = pud_alloc(mm, dir, from);
error = -ENOMEM;
if (!pud)
break;
@@ -147,8 +146,7 @@
from = (from + PGDIR_SIZE) & PGDIR_MASK;
dir++;
}
- flush_tlb_range(vma, beg, end);
- spin_unlock(&mm->page_table_lock);
+ flush_tlb_range(vma, beg, end);
return error;
}
diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c
index 240143b..02cf36e 100644
--- a/arch/um/kernel/skas/mmu.c
+++ b/arch/um/kernel/skas/mmu.c
@@ -28,7 +28,6 @@
pmd_t *pmd;
pte_t *pte;
- spin_lock(&mm->page_table_lock);
pgd = pgd_offset(mm, proc);
pud = pud_alloc(mm, pgd, proc);
if (!pud)
@@ -63,7 +62,6 @@
*pte = mk_pte(virt_to_page(kernel), __pgprot(_PAGE_PRESENT));
*pte = pte_mkexec(*pte);
*pte = pte_wrprotect(*pte);
- spin_unlock(&mm->page_table_lock);
return(0);
out_pmd:
@@ -71,7 +69,6 @@
out_pte:
pmd_free(pmd);
out:
- spin_unlock(&mm->page_table_lock);
return(-ENOMEM);
}