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Implement the protection check required by the pmap_extract_and_hold()

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specification.  This enables the elimination of Giant from that function.

Reviewed by:	tegge@
This commit is contained in:
alc 2004-06-22 19:35:43 +00:00
parent 44f3169ef7
commit cb68933ca4
1 changed files with 24 additions and 8 deletions
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32
sys/i386/i386/pmap.c
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@ -860,18 +860,34 @@ pmap_extract(pmap, va)
vm_page_t vm_page_t
pmap_extract_and_hold(pmap_t pmap, vm_offset_t va, vm_prot_t prot) pmap_extract_and_hold(pmap_t pmap, vm_offset_t va, vm_prot_t prot)
{ {
vm_paddr_t pa; pd_entry_t pde;
pt_entry_t pte;
vm_page_t m; vm_page_t m;
m = NULL; m = NULL;
mtx_lock(&Giant); if (pmap == NULL)
if ((pa = pmap_extract(pmap, va)) != 0) { return (m);
m = PHYS_TO_VM_PAGE(pa); vm_page_lock_queues();
vm_page_lock_queues(); PMAP_LOCK(pmap);
vm_page_hold(m); pde = *pmap_pde(pmap, va);
vm_page_unlock_queues(); if (pde != 0) {
if (pde & PG_PS) {
if ((pde & PG_RW) || (prot & VM_PROT_WRITE) == 0) {
m = PHYS_TO_VM_PAGE((pde & ~PDRMASK) |
(va & PDRMASK));
vm_page_hold(m);
}
} else {
pte = *pmap_pte_quick(pmap, va);
if (pte != 0 &&
((pte & PG_RW) || (prot & VM_PROT_WRITE) == 0)) {
m = PHYS_TO_VM_PAGE(pte & PG_FRAME);
vm_page_hold(m);
}
}
} }
mtx_unlock(&Giant); vm_page_unlock_queues();
PMAP_UNLOCK(pmap);
return (m); return (m);
} }