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[PATCH] mm: arches skip ptlock

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Convert those few architectures which are calling pud_alloc, pmd_alloc,
pte_alloc_map on a user mm, not to take the page_table_lock first, nor drop it
after.  Each of these can continue to use pte_alloc_map, no need to change
over to pte_alloc_map_lock, they're neither racy nor swappable.

In the sparc64 io_remap_pfn_range, flush_tlb_range then falls outside of the
page_table_lock: that's okay, on sparc64 it's like flush_tlb_mm, and that has
always been called from outside of page_table_lock in dup_mmap.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Hugh Dickins
2005-10-29 18:16:24 -07:00
committed by Linus Torvalds
parent c74df32c72
commit b462705ac6
5 changed files with 3 additions and 39 deletions
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15
arch/arm26/mm/memc.c
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@@ -78,12 +78,6 @@ pgd_t *get_pgd_slow(struct mm_struct *mm)
if (!new_pgd)
goto no_pgd;
/*
* This lock is here just to satisfy pmd_alloc and pte_lock
* FIXME: I bet we could avoid taking it pretty much altogether
*/
spin_lock(&mm->page_table_lock);
/*
* On ARM, first page must always be allocated since it contains
* the machine vectors.
@@ -113,23 +107,14 @@ pgd_t *get_pgd_slow(struct mm_struct *mm)
memcpy(new_pgd + FIRST_KERNEL_PGD_NR, init_pgd + FIRST_KERNEL_PGD_NR,
(PTRS_PER_PGD - FIRST_KERNEL_PGD_NR) * sizeof(pgd_t));
spin_unlock(&mm->page_table_lock);
/* update MEMC tables */
cpu_memc_update_all(new_pgd);
return new_pgd;
no_pte:
spin_unlock(&mm->page_table_lock);
pmd_free(new_pmd);
free_pgd_slow(new_pgd);
return NULL;
no_pmd:
spin_unlock(&mm->page_table_lock);
free_pgd_slow(new_pgd);
return NULL;
no_pgd:
return NULL;
}