[PATCH] mm: init_mm without ptlock

First step in pushing down the page_table_lock.  init_mm.page_table_lock has
been used throughout the architectures (usually for ioremap): not to serialize
kernel address space allocation (that's usually vmlist_lock), but because
pud_alloc,pmd_alloc,pte_alloc_kernel expect caller holds it.

Reverse that: don't lock or unlock init_mm.page_table_lock in any of the
architectures; instead rely on pud_alloc,pmd_alloc,pte_alloc_kernel to take
and drop it when allocating a new one, to check lest a racing task already
did.  Similarly no page_table_lock in vmalloc's map_vm_area.

Some temporary ugliness in __pud_alloc and __pmd_alloc: since they also handle
user mms, which are converted only by a later patch, for now they have to lock
differently according to whether or not it's init_mm.

If sources get muddled, there's a danger that an arch source taking
init_mm.page_table_lock will be mixed with common source also taking it (or
neither take it).  So break the rules and make another change, which should
break the build for such a mismatch: remove the redundant mm arg from
pte_alloc_kernel (ppc64 scrapped its distinct ioremap_mm in 2.6.13).

Exceptions: arm26 used pte_alloc_kernel on user mm, now pte_alloc_map; ia64
used pte_alloc_map on init_mm, now pte_alloc_kernel; parisc had bad args to
pmd_alloc and pte_alloc_kernel in unused USE_HPPA_IOREMAP code; ppc64
map_io_page forgot to unlock on failure; ppc mmu_mapin_ram and ppc64 im_free
took page_table_lock for no good reason.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

26 files changed, 54 insertions, 114 deletions

diff --git a/arch/alpha/mm/remap.c b/arch/alpha/mm/remap.c
index 19817ad3d89b..a78356c3ead5 100644
--- a/arch/alpha/mm/remap.c
+++ b/arch/alpha/mm/remap.c
@@ -2,7 +2,6 @@
 #include <asm/pgalloc.h>
 #include <asm/cacheflush.h>
 
-/* called with the page_table_lock held */
 static inline void 
 remap_area_pte(pte_t * pte, unsigned long address, unsigned long size, 
                unsigned long phys_addr, unsigned long flags)
@@ -31,7 +30,6 @@ remap_area_pte(pte_t * pte, unsigned long address, unsigned long size,
         } while (address && (address < end));
 }
 
-/* called with the page_table_lock held */
 static inline int 
 remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size, 
                unsigned long phys_addr, unsigned long flags)
@@ -46,7 +44,7 @@ remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,
         if (address >= end)
                 BUG();
         do {
-                pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address);
+                pte_t * pte = pte_alloc_kernel(pmd, address);
                 if (!pte)
                         return -ENOMEM;
                 remap_area_pte(pte, address, end - address, 
@@ -70,7 +68,6 @@ __alpha_remap_area_pages(unsigned long address, unsigned long phys_addr,
         flush_cache_all();
         if (address >= end)
                 BUG();
-        spin_lock(&init_mm.page_table_lock);
         do {
                 pmd_t *pmd;
                 pmd = pmd_alloc(&init_mm, dir, address);
@@ -84,7 +81,6 @@ __alpha_remap_area_pages(unsigned long address, unsigned long phys_addr,
                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
                 dir++;
         } while (address && (address < end));
-        spin_unlock(&init_mm.page_table_lock);
         return error;
 }
 
diff --git a/arch/arm/mm/consistent.c b/arch/arm/mm/consistent.c
index 82f4d5e27c54..47b0b767f080 100644
--- a/arch/arm/mm/consistent.c
+++ b/arch/arm/mm/consistent.c
@@ -397,8 +397,6 @@ static int __init consistent_init(void)
         pte_t *pte;
         int ret = 0;
 
-        spin_lock(&init_mm.page_table_lock);
-
         do {
                 pgd = pgd_offset(&init_mm, CONSISTENT_BASE);
                 pmd = pmd_alloc(&init_mm, pgd, CONSISTENT_BASE);
@@ -409,7 +407,7 @@ static int __init consistent_init(void)
                 }
                 WARN_ON(!pmd_none(*pmd));
 
-                pte = pte_alloc_kernel(&init_mm, pmd, CONSISTENT_BASE);
+                pte = pte_alloc_kernel(pmd, CONSISTENT_BASE);
                 if (!pte) {
                         printk(KERN_ERR "%s: no pte tables\n", __func__);
                         ret = -ENOMEM;
@@ -419,8 +417,6 @@ static int __init consistent_init(void)
                 consistent_pte = pte;
         } while (0);
 
-        spin_unlock(&init_mm.page_table_lock);
-
         return ret;
 }
 
diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
index 6fb1258df1b5..0f128c28fee4 100644
--- a/arch/arm/mm/ioremap.c
+++ b/arch/arm/mm/ioremap.c
@@ -75,7 +75,7 @@ remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,
 
         pgprot = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY | L_PTE_WRITE | flags);
         do {
-                pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address);
+                pte_t * pte = pte_alloc_kernel(pmd, address);
                 if (!pte)
                         return -ENOMEM;
                 remap_area_pte(pte, address, end - address, address + phys_addr, pgprot);
@@ -97,7 +97,6 @@ remap_area_pages(unsigned long start, unsigned long phys_addr,
         phys_addr -= address;
         dir = pgd_offset(&init_mm, address);
         BUG_ON(address >= end);
-        spin_lock(&init_mm.page_table_lock);
         do {
                 pmd_t *pmd = pmd_alloc(&init_mm, dir, address);
                 if (!pmd) {
@@ -114,7 +113,6 @@ remap_area_pages(unsigned long start, unsigned long phys_addr,
                 dir++;
         } while (address && (address < end));
 
-        spin_unlock(&init_mm.page_table_lock);
         flush_cache_vmap(start, end);
         return err;
 }
diff --git a/arch/arm26/mm/memc.c b/arch/arm26/mm/memc.c
index 8e8a2bb2487d..d6b008b8db76 100644
--- a/arch/arm26/mm/memc.c
+++ b/arch/arm26/mm/memc.c
@@ -92,7 +92,7 @@ pgd_t *get_pgd_slow(struct mm_struct *mm)
         if (!new_pmd)
                 goto no_pmd;
 
-        new_pte = pte_alloc_kernel(mm, new_pmd, 0);
+        new_pte = pte_alloc_map(mm, new_pmd, 0);
         if (!new_pte)
                 goto no_pte;
 
@@ -101,6 +101,7 @@ pgd_t *get_pgd_slow(struct mm_struct *mm)
         init_pte = pte_offset(init_pmd, 0);
 
         set_pte(new_pte, *init_pte);
+        pte_unmap(new_pte);
 
         /*
          * the page table entries are zeroed
diff --git a/arch/cris/mm/ioremap.c b/arch/cris/mm/ioremap.c
index ebba11e270fa..a92ac9877582 100644
--- a/arch/cris/mm/ioremap.c
+++ b/arch/cris/mm/ioremap.c
@@ -52,7 +52,7 @@ static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned lo
         if (address >= end)
                 BUG();
         do {
-                pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address);
+                pte_t * pte = pte_alloc_kernel(pmd, address);
                 if (!pte)
                         return -ENOMEM;
                 remap_area_pte(pte, address, end - address, address + phys_addr, prot);
@@ -74,7 +74,6 @@ static int remap_area_pages(unsigned long address, unsigned long phys_addr,
         flush_cache_all();
         if (address >= end)
                 BUG();
-        spin_lock(&init_mm.page_table_lock);
         do {
                 pud_t *pud;
                 pmd_t *pmd;
@@ -94,7 +93,6 @@ static int remap_area_pages(unsigned long address, unsigned long phys_addr,
                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
                 dir++;
         } while (address && (address < end));
-        spin_unlock(&init_mm.page_table_lock);
         flush_tlb_all();
         return error;
 }
diff --git a/arch/frv/mm/dma-alloc.c b/arch/frv/mm/dma-alloc.c
index cfc4f97490c6..342823aad758 100644
--- a/arch/frv/mm/dma-alloc.c
+++ b/arch/frv/mm/dma-alloc.c
@@ -55,21 +55,18 @@ static int map_page(unsigned long va, unsigned long pa, pgprot_t prot)
         pte_t *pte;
         int err = -ENOMEM;
 
-        spin_lock(&init_mm.page_table_lock);
-
         /* Use upper 10 bits of VA to index the first level map */
         pge = pgd_offset_k(va);
         pue = pud_offset(pge, va);
         pme = pmd_offset(pue, va);
 
         /* Use middle 10 bits of VA to index the second-level map */
-        pte = pte_alloc_kernel(&init_mm, pme, va);
+        pte = pte_alloc_kernel(pme, va);
         if (pte != 0) {
                 err = 0;
                 set_pte(pte, mk_pte_phys(pa & PAGE_MASK, prot));
         }
 
-        spin_unlock(&init_mm.page_table_lock);
         return err;
 }
 
diff --git a/arch/i386/mm/ioremap.c b/arch/i386/mm/ioremap.c
index f379b8d67558..5d09de8d1c6b 100644
--- a/arch/i386/mm/ioremap.c
+++ b/arch/i386/mm/ioremap.c
@@ -28,7 +28,7 @@ static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
         unsigned long pfn;
 
         pfn = phys_addr >> PAGE_SHIFT;
-        pte = pte_alloc_kernel(&init_mm, pmd, addr);
+        pte = pte_alloc_kernel(pmd, addr);
         if (!pte)
                 return -ENOMEM;
         do {
@@ -87,14 +87,12 @@ static int ioremap_page_range(unsigned long addr,
         flush_cache_all();
         phys_addr -= addr;
         pgd = pgd_offset_k(addr);
-        spin_lock(&init_mm.page_table_lock);
         do {
                 next = pgd_addr_end(addr, end);
                 err = ioremap_pud_range(pgd, addr, next, phys_addr+addr, flags);
                 if (err)
                         break;
         } while (pgd++, addr = next, addr != end);
-        spin_unlock(&init_mm.page_table_lock);
         flush_tlb_all();
         return err;
 }
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 0063b2c50908..e3215ba64ffd 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -275,26 +275,21 @@ put_kernel_page (struct page *page, unsigned long address, pgprot_t pgprot)
 
         pgd = pgd_offset_k(address);            /* note: this is NOT pgd_offset()! */
 
-        spin_lock(&init_mm.page_table_lock);
         {
                 pud = pud_alloc(&init_mm, pgd, address);
                 if (!pud)
                         goto out;
-
                 pmd = pmd_alloc(&init_mm, pud, address);
                 if (!pmd)
                         goto out;
-                pte = pte_alloc_map(&init_mm, pmd, address);
+                pte = pte_alloc_kernel(pmd, address);
                 if (!pte)
                         goto out;
-                if (!pte_none(*pte)) {
-                        pte_unmap(pte);
+                if (!pte_none(*pte))
                         goto out;
-                }
                 set_pte(pte, mk_pte(page, pgprot));
-                pte_unmap(pte);
         }
-  out:  spin_unlock(&init_mm.page_table_lock);
+  out:
         /* no need for flush_tlb */
         return page;
 }
diff --git a/arch/m32r/mm/ioremap.c b/arch/m32r/mm/ioremap.c
index 70c59055c19c..a151849a605e 100644
--- a/arch/m32r/mm/ioremap.c
+++ b/arch/m32r/mm/ioremap.c
@@ -67,7 +67,7 @@ remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,
         if (address >= end)
                 BUG();
         do {
-                pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address);
+                pte_t * pte = pte_alloc_kernel(pmd, address);
                 if (!pte)
                         return -ENOMEM;
                 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
@@ -90,7 +90,6 @@ remap_area_pages(unsigned long address, unsigned long phys_addr,
         flush_cache_all();
         if (address >= end)
                 BUG();
-        spin_lock(&init_mm.page_table_lock);
         do {
                 pmd_t *pmd;
                 pmd = pmd_alloc(&init_mm, dir, address);
@@ -104,7 +103,6 @@ remap_area_pages(unsigned long address, unsigned long phys_addr,
                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
                 dir++;
         } while (address && (address < end));
-        spin_unlock(&init_mm.page_table_lock);
         flush_tlb_all();
         return error;
 }
diff --git a/arch/m68k/mm/kmap.c b/arch/m68k/mm/kmap.c
index 5dcb3fa35ea9..fe2383e36b06 100644
--- a/arch/m68k/mm/kmap.c
+++ b/arch/m68k/mm/kmap.c
@@ -201,7 +201,7 @@ void *__ioremap(unsigned long physaddr, unsigned long size, int cacheflag)
                         virtaddr += PTRTREESIZE;
                         size -= PTRTREESIZE;
                 } else {
-                        pte_dir = pte_alloc_kernel(&init_mm, pmd_dir, virtaddr);
+                        pte_dir = pte_alloc_kernel(pmd_dir, virtaddr);
                         if (!pte_dir) {
                                 printk("ioremap: no mem for pte_dir\n");
                                 return NULL;
diff --git a/arch/m68k/sun3x/dvma.c b/arch/m68k/sun3x/dvma.c
index 32e55adfeb8e..117481e86305 100644
--- a/arch/m68k/sun3x/dvma.c
+++ b/arch/m68k/sun3x/dvma.c
@@ -116,7 +116,7 @@ inline int dvma_map_cpu(unsigned long kaddr,
                         pte_t *pte;
                         unsigned long end3;
 
-                        if((pte = pte_alloc_kernel(&init_mm, pmd, vaddr)) == NULL) {
+                        if((pte = pte_alloc_kernel(pmd, vaddr)) == NULL) {
                                 ret = -ENOMEM;
                                 goto out;
                         }
diff --git a/arch/mips/mm/ioremap.c b/arch/mips/mm/ioremap.c
index 9c44ca70befa..3101d1db5592 100644
--- a/arch/mips/mm/ioremap.c
+++ b/arch/mips/mm/ioremap.c
@@ -55,7 +55,7 @@ static inline int remap_area_pmd(pmd_t * pmd, unsigned long address,
         if (address >= end)
                 BUG();
         do {
-                pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address);
+                pte_t * pte = pte_alloc_kernel(pmd, address);
                 if (!pte)
                         return -ENOMEM;
                 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
@@ -77,7 +77,6 @@ static int remap_area_pages(unsigned long address, phys_t phys_addr,
         flush_cache_all();
         if (address >= end)
                 BUG();
-        spin_lock(&init_mm.page_table_lock);
         do {
                 pud_t *pud;
                 pmd_t *pmd;
@@ -96,7 +95,6 @@ static int remap_area_pages(unsigned long address, phys_t phys_addr,
                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
                 dir++;
         } while (address && (address < end));
-        spin_unlock(&init_mm.page_table_lock);
         flush_tlb_all();
         return error;
 }
diff --git a/arch/parisc/kernel/pci-dma.c b/arch/parisc/kernel/pci-dma.c
index ae6213d71670..f94a02ef3d95 100644
--- a/arch/parisc/kernel/pci-dma.c
+++ b/arch/parisc/kernel/pci-dma.c
@@ -114,7 +114,7 @@ static inline int map_pmd_uncached(pmd_t * pmd, unsigned long vaddr,
         if (end > PGDIR_SIZE)
                 end = PGDIR_SIZE;
         do {
-                pte_t * pte = pte_alloc_kernel(&init_mm, pmd, vaddr);
+                pte_t * pte = pte_alloc_kernel(pmd, vaddr);
                 if (!pte)
                         return -ENOMEM;
                 if (map_pte_uncached(pte, orig_vaddr, end - vaddr, paddr_ptr))
diff --git a/arch/parisc/mm/ioremap.c b/arch/parisc/mm/ioremap.c
index f2df502cdae3..5c7a1b3b9326 100644
--- a/arch/parisc/mm/ioremap.c
+++ b/arch/parisc/mm/ioremap.c
@@ -52,7 +52,7 @@ static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned lo
         if (address >= end)
                 BUG();
         do {
-                pte_t * pte = pte_alloc_kernel(NULL, pmd, address);
+                pte_t * pte = pte_alloc_kernel(pmd, address);
                 if (!pte)
                         return -ENOMEM;
                 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
@@ -75,10 +75,9 @@ static int remap_area_pages(unsigned long address, unsigned long phys_addr,
         flush_cache_all();
         if (address >= end)
                 BUG();
-        spin_lock(&init_mm.page_table_lock);
         do {
                 pmd_t *pmd;
-                pmd = pmd_alloc(dir, address);
+                pmd = pmd_alloc(&init_mm, dir, address);
                 error = -ENOMEM;
                 if (!pmd)
                         break;
@@ -89,7 +88,6 @@ static int remap_area_pages(unsigned long address, unsigned long phys_addr,
                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
                 dir++;
         } while (address && (address < end));
-        spin_unlock(&init_mm.page_table_lock);
         flush_tlb_all();
         return error;
 }
diff --git a/arch/ppc/kernel/dma-mapping.c b/arch/ppc/kernel/dma-mapping.c
index 0f710d2baec6..685fd0defe23 100644
--- a/arch/ppc/kernel/dma-mapping.c
+++ b/arch/ppc/kernel/dma-mapping.c
@@ -335,8 +335,6 @@ static int __init dma_alloc_init(void)
         pte_t *pte;
         int ret = 0;
 
-        spin_lock(&init_mm.page_table_lock);
-
         do {
                 pgd = pgd_offset(&init_mm, CONSISTENT_BASE);
                 pmd = pmd_alloc(&init_mm, pgd, CONSISTENT_BASE);
@@ -347,7 +345,7 @@ static int __init dma_alloc_init(void)
                 }
                 WARN_ON(!pmd_none(*pmd));
 
-                pte = pte_alloc_kernel(&init_mm, pmd, CONSISTENT_BASE);
+                pte = pte_alloc_kernel(pmd, CONSISTENT_BASE);
                 if (!pte) {
                         printk(KERN_ERR "%s: no pte tables\n", __func__);
                         ret = -ENOMEM;
@@ -357,8 +355,6 @@ static int __init dma_alloc_init(void)
                 consistent_pte = pte;
         } while (0);
 
-        spin_unlock(&init_mm.page_table_lock);
-
         return ret;
 }
 
diff --git a/arch/ppc/mm/4xx_mmu.c b/arch/ppc/mm/4xx_mmu.c
index b7bcbc232f39..4d006aa1a0d1 100644
--- a/arch/ppc/mm/4xx_mmu.c
+++ b/arch/ppc/mm/4xx_mmu.c
@@ -110,13 +110,11 @@ unsigned long __init mmu_mapin_ram(void)
                 pmd_t *pmdp;
                 unsigned long val = p | _PMD_SIZE_16M | _PAGE_HWEXEC | _PAGE_HWWRITE;
 
-                spin_lock(&init_mm.page_table_lock);
                 pmdp = pmd_offset(pgd_offset_k(v), v);
                 pmd_val(*pmdp++) = val;
                 pmd_val(*pmdp++) = val;
                 pmd_val(*pmdp++) = val;
                 pmd_val(*pmdp++) = val;
-                spin_unlock(&init_mm.page_table_lock);
 
                 v += LARGE_PAGE_SIZE_16M;
                 p += LARGE_PAGE_SIZE_16M;
@@ -127,10 +125,8 @@ unsigned long __init mmu_mapin_ram(void)
                 pmd_t *pmdp;
                 unsigned long val = p | _PMD_SIZE_4M | _PAGE_HWEXEC | _PAGE_HWWRITE;
 
-                spin_lock(&init_mm.page_table_lock);
                 pmdp = pmd_offset(pgd_offset_k(v), v);
                 pmd_val(*pmdp) = val;
-                spin_unlock(&init_mm.page_table_lock);
 
                 v += LARGE_PAGE_SIZE_4M;
                 p += LARGE_PAGE_SIZE_4M;
diff --git a/arch/ppc/mm/pgtable.c b/arch/ppc/mm/pgtable.c
index 43505b1fc5d8..6ea9185fd120 100644
--- a/arch/ppc/mm/pgtable.c
+++ b/arch/ppc/mm/pgtable.c
@@ -280,18 +280,16 @@ map_page(unsigned long va, phys_addr_t pa, int flags)
         pte_t *pg;
         int err = -ENOMEM;
 
-        spin_lock(&init_mm.page_table_lock);
         /* Use upper 10 bits of VA to index the first level map */
         pd = pmd_offset(pgd_offset_k(va), va);
         /* Use middle 10 bits of VA to index the second-level map */
-        pg = pte_alloc_kernel(&init_mm, pd, va);
+        pg = pte_alloc_kernel(pd, va);
         if (pg != 0) {
                 err = 0;
                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, __pgprot(flags)));
                 if (mem_init_done)
                         flush_HPTE(0, va, pmd_val(*pd));
         }
-        spin_unlock(&init_mm.page_table_lock);
         return err;
 }
 
diff --git a/arch/ppc64/mm/imalloc.c b/arch/ppc64/mm/imalloc.c
index c65b87b92756..f4ca29cf5364 100644
--- a/arch/ppc64/mm/imalloc.c
+++ b/arch/ppc64/mm/imalloc.c
@@ -300,12 +300,7 @@ void im_free(void * addr)
         for (p = &imlist ; (tmp = *p) ; p = &tmp->next) {
                 if (tmp->addr == addr) {
                         *p = tmp->next;
-
-                        /* XXX: do we need the lock? */
-                        spin_lock(&init_mm.page_table_lock);
                         unmap_vm_area(tmp);
-                        spin_unlock(&init_mm.page_table_lock);
-
                         kfree(tmp);
                         up(&imlist_sem);
                         return;
diff --git a/arch/ppc64/mm/init.c b/arch/ppc64/mm/init.c
index be64b157afce..a45584b3440c 100644
--- a/arch/ppc64/mm/init.c
+++ b/arch/ppc64/mm/init.c
@@ -155,7 +155,6 @@ static int map_io_page(unsigned long ea, unsigned long pa, int flags)
         unsigned long vsid;
 
         if (mem_init_done) {
-                spin_lock(&init_mm.page_table_lock);
                 pgdp = pgd_offset_k(ea);
                 pudp = pud_alloc(&init_mm, pgdp, ea);
                 if (!pudp)
@@ -163,12 +162,11 @@ static int map_io_page(unsigned long ea, unsigned long pa, int flags)
                 pmdp = pmd_alloc(&init_mm, pudp, ea);
                 if (!pmdp)
                         return -ENOMEM;
-                ptep = pte_alloc_kernel(&init_mm, pmdp, ea);
+                ptep = pte_alloc_kernel(pmdp, ea);
                 if (!ptep)
                         return -ENOMEM;
                 set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
                                                           __pgprot(flags)));
-                spin_unlock(&init_mm.page_table_lock);
         } else {
                 unsigned long va, vpn, hash, hpteg;
 
diff --git a/arch/s390/mm/ioremap.c b/arch/s390/mm/ioremap.c
index c6c39d868bc8..0f6e9ecbefe2 100644
--- a/arch/s390/mm/ioremap.c
+++ b/arch/s390/mm/ioremap.c
@@ -58,7 +58,7 @@ static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned lo
         if (address >= end)
                 BUG();
         do {
-                pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address);
+                pte_t * pte = pte_alloc_kernel(pmd, address);
                 if (!pte)
                         return -ENOMEM;
                 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
@@ -80,7 +80,6 @@ static int remap_area_pages(unsigned long address, unsigned long phys_addr,
         flush_cache_all();
         if (address >= end)
                 BUG();
-        spin_lock(&init_mm.page_table_lock);
         do {
                 pmd_t *pmd;
                 pmd = pmd_alloc(&init_mm, dir, address);
@@ -94,7 +93,6 @@ static int remap_area_pages(unsigned long address, unsigned long phys_addr,
                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
                 dir++;
         } while (address && (address < end));
-        spin_unlock(&init_mm.page_table_lock);
         flush_tlb_all();
         return 0;
 }
diff --git a/arch/sh/mm/ioremap.c b/arch/sh/mm/ioremap.c
index 9f490c2742f0..e794e27a72f1 100644
--- a/arch/sh/mm/ioremap.c
+++ b/arch/sh/mm/ioremap.c
@@ -57,7 +57,7 @@ static inline int remap_area_pmd(pmd_t * pmd, unsigned long address,
         if (address >= end)
                 BUG();
         do {
-                pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address);
+                pte_t * pte = pte_alloc_kernel(pmd, address);
                 if (!pte)
                         return -ENOMEM;
                 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
@@ -79,7 +79,6 @@ int remap_area_pages(unsigned long address, unsigned long phys_addr,
         flush_cache_all();
         if (address >= end)
                 BUG();
-        spin_lock(&init_mm.page_table_lock);
         do {
                 pmd_t *pmd;
                 pmd = pmd_alloc(&init_mm, dir, address);
@@ -93,7 +92,6 @@ int remap_area_pages(unsigned long address, unsigned long phys_addr,
                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
                 dir++;
         } while (address && (address < end));
-        spin_unlock(&init_mm.page_table_lock);
         flush_tlb_all();
         return error;
 }
diff --git a/arch/sh64/mm/ioremap.c b/arch/sh64/mm/ioremap.c
index f4003da556bc..fb1866fa2c9d 100644
--- a/arch/sh64/mm/ioremap.c
+++ b/arch/sh64/mm/ioremap.c
@@ -79,7 +79,7 @@ static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned lo
                 BUG();
 
         do {
-                pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address);
+                pte_t * pte = pte_alloc_kernel(pmd, address);
                 if (!pte)
                         return -ENOMEM;
                 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
@@ -101,7 +101,6 @@ static int remap_area_pages(unsigned long address, unsigned long phys_addr,
         flush_cache_all();
         if (address >= end)
                 BUG();
-        spin_lock(&init_mm.page_table_lock);
         do {
                 pmd_t *pmd = pmd_alloc(&init_mm, dir, address);
                 error = -ENOMEM;
@@ -115,7 +114,6 @@ static int remap_area_pages(unsigned long address, unsigned long phys_addr,
                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
                 dir++;
         } while (address && (address < end));
-        spin_unlock(&init_mm.page_table_lock);
         flush_tlb_all();
         return 0;
 }
diff --git a/arch/x86_64/mm/ioremap.c b/arch/x86_64/mm/ioremap.c
index 6972df480d2b..ecf7acb5db9b 100644
--- a/arch/x86_64/mm/ioremap.c
+++ b/arch/x86_64/mm/ioremap.c
@@ -60,7 +60,7 @@ static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned lo
         if (address >= end)
                 BUG();
         do {
-                pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address);
+                pte_t * pte = pte_alloc_kernel(pmd, address);
                 if (!pte)
                         return -ENOMEM;
                 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
@@ -105,7 +105,6 @@ static int remap_area_pages(unsigned long address, unsigned long phys_addr,
         flush_cache_all();
         if (address >= end)
                 BUG();
-        spin_lock(&init_mm.page_table_lock);
         do {
                 pud_t *pud;
                 pud = pud_alloc(&init_mm, pgd, address);
@@ -119,7 +118,6 @@ static int remap_area_pages(unsigned long address, unsigned long phys_addr,
                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
                 pgd++;
         } while (address && (address < end));
-        spin_unlock(&init_mm.page_table_lock);
         flush_tlb_all();
         return error;
 }
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 89398032bc4b..b9fa82b96d9e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -706,7 +706,7 @@ static inline void unmap_shared_mapping_range(struct address_space *mapping,
 extern int vmtruncate(struct inode * inode, loff_t offset);
 extern pud_t *FASTCALL(__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address));
 extern pmd_t *FASTCALL(__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address));
-extern pte_t *FASTCALL(pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsigned long address));
+extern pte_t *FASTCALL(pte_alloc_kernel(pmd_t *pmd, unsigned long address));
 extern pte_t *FASTCALL(pte_alloc_map(struct mm_struct *mm, pmd_t *pmd, unsigned long address));
 extern int install_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, struct page *page, pgprot_t prot);
 extern int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, unsigned long pgoff, pgprot_t prot);
diff --git a/mm/memory.c b/mm/memory.c
index 692ad810263d..95a4553c75f7 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -307,28 +307,22 @@ out:
         return pte_offset_map(pmd, address);
 }
 
-pte_t fastcall * pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
+pte_t fastcall * pte_alloc_kernel(pmd_t *pmd, unsigned long address)
 {
         if (!pmd_present(*pmd)) {
                 pte_t *new;
 
-                spin_unlock(&mm->page_table_lock);
-                new = pte_alloc_one_kernel(mm, address);
-                spin_lock(&mm->page_table_lock);
+                new = pte_alloc_one_kernel(&init_mm, address);
                 if (!new)
                         return NULL;
 
-                /*
-                 * Because we dropped the lock, we should re-check the
-                 * entry, as somebody else could have populated it..
-                 */
-                if (pmd_present(*pmd)) {
+                spin_lock(&init_mm.page_table_lock);
+                if (pmd_present(*pmd))
                         pte_free_kernel(new);
-                        goto out;
-                }
-                pmd_populate_kernel(mm, pmd, new);
+                else
+                        pmd_populate_kernel(&init_mm, pmd, new);
+                spin_unlock(&init_mm.page_table_lock);
         }
-out:
         return pte_offset_kernel(pmd, address);
 }
 
@@ -2097,30 +2091,30 @@ int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 #ifndef __PAGETABLE_PUD_FOLDED
 /*
  * Allocate page upper directory.
- *
- * We've already handled the fast-path in-line, and we own the
- * page table lock.
+ * We've already handled the fast-path in-line.
  */
 pud_t fastcall *__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
 {
         pud_t *new;
 
-        spin_unlock(&mm->page_table_lock);
+        if (mm != &init_mm)             /* Temporary bridging hack */
+                spin_unlock(&mm->page_table_lock);
         new = pud_alloc_one(mm, address);
-        spin_lock(&mm->page_table_lock);
-        if (!new)
+        if (!new) {
+                if (mm != &init_mm)     /* Temporary bridging hack */
+                        spin_lock(&mm->page_table_lock);
                 return NULL;
+        }
 
-        /*
-         * Because we dropped the lock, we should re-check the
-         * entry, as somebody else could have populated it..
-         */
+        spin_lock(&mm->page_table_lock);
         if (pgd_present(*pgd)) {
                 pud_free(new);
                 goto out;
         }
         pgd_populate(mm, pgd, new);
  out:
+        if (mm == &init_mm)             /* Temporary bridging hack */
+                spin_unlock(&mm->page_table_lock);
         return pud_offset(pgd, address);
 }
 #endif /* __PAGETABLE_PUD_FOLDED */
@@ -2128,24 +2122,22 @@ pud_t fastcall *__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long addr
 #ifndef __PAGETABLE_PMD_FOLDED
 /*
  * Allocate page middle directory.
- *
- * We've already handled the fast-path in-line, and we own the
- * page table lock.
+ * We've already handled the fast-path in-line.
  */
 pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
 {
         pmd_t *new;
 
-        spin_unlock(&mm->page_table_lock);
+        if (mm != &init_mm)             /* Temporary bridging hack */
+                spin_unlock(&mm->page_table_lock);
         new = pmd_alloc_one(mm, address);
-        spin_lock(&mm->page_table_lock);
-        if (!new)
+        if (!new) {
+                if (mm != &init_mm)     /* Temporary bridging hack */
+                        spin_lock(&mm->page_table_lock);
                 return NULL;
+        }
 
-        /*
-         * Because we dropped the lock, we should re-check the
-         * entry, as somebody else could have populated it..
-         */
+        spin_lock(&mm->page_table_lock);
 #ifndef __ARCH_HAS_4LEVEL_HACK
         if (pud_present(*pud)) {
                 pmd_free(new);
@@ -2161,6 +2153,8 @@ pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long addr
 #endif /* __ARCH_HAS_4LEVEL_HACK */
 
  out:
+        if (mm == &init_mm)             /* Temporary bridging hack */
+                spin_unlock(&mm->page_table_lock);
         return pmd_offset(pud, address);
 }
 #endif /* __PAGETABLE_PMD_FOLDED */
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 5e9120598799..54a90e83cb31 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -89,7 +89,7 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr,
 {
         pte_t *pte;
 
-        pte = pte_alloc_kernel(&init_mm, pmd, addr);
+        pte = pte_alloc_kernel(pmd, addr);
         if (!pte)
                 return -ENOMEM;
         do {
@@ -147,14 +147,12 @@ int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages)
 
         BUG_ON(addr >= end);
         pgd = pgd_offset_k(addr);
-        spin_lock(&init_mm.page_table_lock);
         do {
                 next = pgd_addr_end(addr, end);
                 err = vmap_pud_range(pgd, addr, next, prot, pages);
                 if (err)
                         break;
         } while (pgd++, addr = next, addr != end);
-        spin_unlock(&init_mm.page_table_lock);
         flush_cache_vmap((unsigned long) area->addr, end);
         return err;
 }