diff options
author | Hugh Dickins <hugh@veritas.com> | 2005-10-30 01:16:21 (GMT) |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-10-30 04:40:40 (GMT) |
commit | 872fec16d9a0ed3b75b8893aa217e49cca575ee5 (patch) | |
tree | 1dfc8b9f2754bdfff645188e497865c00201d535 /arch/ia64 | |
parent | 46dea3d092d23a58b42499cc8a21de0fad079f4a (diff) | |
download | linux-fsl-qoriq-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/ia64')
-rw-r--r-- | arch/ia64/mm/init.c | 11 |
1 files changed, 3 insertions, 8 deletions
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c index 0063b2c..e3215ba 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; } |