Permit vm_pager_has_page() to run with a shared lock. Introduce
VM_OBJECT_DROP/VM_OBJECT_PICKUP to handle functions that are called with uncertain lock state. Reviewed by: kib, markj Tested by: pho Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D21310
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parent
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Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=351235
@ -255,6 +255,10 @@ extern struct vm_object kernel_object_store;
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rw_wowned(&(object)->lock)
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#define VM_OBJECT_WUNLOCK(object) \
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rw_wunlock(&(object)->lock)
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#define VM_OBJECT_DROP(object) \
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lock_class_rw.lc_unlock(&(object)->lock.lock_object)
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#define VM_OBJECT_PICKUP(object, state) \
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lock_class_rw.lc_lock(&(object)->lock.lock_object, (state))
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struct vnode;
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@ -151,7 +151,7 @@ vm_pager_has_page(
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) {
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boolean_t ret;
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VM_OBJECT_ASSERT_WLOCKED(object);
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VM_OBJECT_ASSERT_LOCKED(object);
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ret = (*pagertab[object->type]->pgo_haspage)
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(object, offset, before, after);
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return (ret);
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@ -355,13 +355,14 @@ vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
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{
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struct vnode *vp = object->handle;
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daddr_t bn;
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uintptr_t lockstate;
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int err;
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daddr_t reqblock;
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int poff;
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int bsize;
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int pagesperblock, blocksperpage;
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VM_OBJECT_ASSERT_WLOCKED(object);
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VM_OBJECT_ASSERT_LOCKED(object);
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/*
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* If no vp or vp is doomed or marked transparent to VM, we do not
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* have the page.
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@ -384,9 +385,9 @@ vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
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blocksperpage = (PAGE_SIZE / bsize);
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reqblock = pindex * blocksperpage;
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}
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VM_OBJECT_WUNLOCK(object);
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lockstate = VM_OBJECT_DROP(object);
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err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before);
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VM_OBJECT_WLOCK(object);
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VM_OBJECT_PICKUP(object, lockstate);
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if (err)
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return TRUE;
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if (bn == -1)
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