diff options
| author | Hugh Dickins <hugh@veritas.com> | 2005-10-29 18:16:21 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-10-29 21:40:40 -0700 |
| commit | 872fec16d9a0ed3b75b8893aa217e49cca575ee5 (patch) | |
| tree | 1dfc8b9f2754bdfff645188e497865c00201d535 /arch/ppc64 | |
| parent | 46dea3d092d23a58b42499cc8a21de0fad079f4a (diff) | |
[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>
Diffstat (limited to 'arch/ppc64')
| -rw-r--r-- | arch/ppc64/mm/imalloc.c | 5 | ||||
| -rw-r--r-- | arch/ppc64/mm/init.c | 4 |
2 files changed, 1 insertions, 8 deletions
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; |