diff options
| author | Hugh Dickins | 2005-10-29 18:16:21 -0700 |
|---|---|---|
| committer | Linus Torvalds | 2005-10-29 21:40:40 -0700 |
| commit | 872fec16d9a0ed3b75b8893aa217e49cca575ee5 (patch) | |
| tree | 1dfc8b9f2754bdfff645188e497865c00201d535 /arch/ppc/mm | |
| 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/ppc/mm')
| -rw-r--r-- | arch/ppc/mm/4xx_mmu.c | 4 | ||||
| -rw-r--r-- | arch/ppc/mm/pgtable.c | 4 |
2 files changed, 1 insertions, 7 deletions
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; } |