diff options
| author | Hugh Dickins <hugh@veritas.com> | 2005-10-30 04:16:21 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-10-30 07:40:40 +0300 |
| commit | 872fec16d9a0ed3b75b8893aa217e49cca575ee5 (patch) | |
| tree | 1dfc8b9f2754bdfff645188e497865c00201d535 /arch/m68k | |
| parent | 46dea3d092d23a58b42499cc8a21de0fad079f4a (diff) | |
| download | linux-872fec16d9a0ed3b75b8893aa217e49cca575ee5.tar.xz | |
[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/m68k')
| -rw-r--r-- | arch/m68k/mm/kmap.c | 2 | ||||
| -rw-r--r-- | arch/m68k/sun3x/dvma.c | 2 |
2 files changed, 2 insertions, 2 deletions
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; } |