436 lines
12 KiB
C
436 lines
12 KiB
C
/*
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* Copyright © 2006-2009, Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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* Place - Suite 330, Boston, MA 02111-1307 USA.
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*
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* Author: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
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*/
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#include <linux/iova.h>
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void
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init_iova_domain(struct iova_domain *iovad, unsigned long pfn_32bit)
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{
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spin_lock_init(&iovad->iova_rbtree_lock);
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iovad->rbroot = RB_ROOT;
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iovad->cached32_node = NULL;
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iovad->dma_32bit_pfn = pfn_32bit;
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}
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static struct rb_node *
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__get_cached_rbnode(struct iova_domain *iovad, unsigned long *limit_pfn)
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{
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if ((*limit_pfn != iovad->dma_32bit_pfn) ||
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(iovad->cached32_node == NULL))
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return rb_last(&iovad->rbroot);
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else {
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struct rb_node *prev_node = rb_prev(iovad->cached32_node);
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struct iova *curr_iova =
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container_of(iovad->cached32_node, struct iova, node);
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*limit_pfn = curr_iova->pfn_lo - 1;
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return prev_node;
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}
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}
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static void
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__cached_rbnode_insert_update(struct iova_domain *iovad,
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unsigned long limit_pfn, struct iova *new)
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{
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if (limit_pfn != iovad->dma_32bit_pfn)
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return;
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iovad->cached32_node = &new->node;
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}
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static void
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__cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free)
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{
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struct iova *cached_iova;
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struct rb_node *curr;
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if (!iovad->cached32_node)
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return;
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curr = iovad->cached32_node;
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cached_iova = container_of(curr, struct iova, node);
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if (free->pfn_lo >= cached_iova->pfn_lo) {
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struct rb_node *node = rb_next(&free->node);
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struct iova *iova = container_of(node, struct iova, node);
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/* only cache if it's below 32bit pfn */
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if (node && iova->pfn_lo < iovad->dma_32bit_pfn)
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iovad->cached32_node = node;
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else
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iovad->cached32_node = NULL;
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}
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}
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/* Computes the padding size required, to make the
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* the start address naturally aligned on its size
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*/
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static int
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iova_get_pad_size(int size, unsigned int limit_pfn)
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{
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unsigned int pad_size = 0;
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unsigned int order = ilog2(size);
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if (order)
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pad_size = (limit_pfn + 1) % (1 << order);
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return pad_size;
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}
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static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
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unsigned long size, unsigned long limit_pfn,
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struct iova *new, bool size_aligned)
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{
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struct rb_node *prev, *curr = NULL;
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unsigned long flags;
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unsigned long saved_pfn;
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unsigned int pad_size = 0;
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/* Walk the tree backwards */
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spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
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saved_pfn = limit_pfn;
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curr = __get_cached_rbnode(iovad, &limit_pfn);
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prev = curr;
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while (curr) {
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struct iova *curr_iova = container_of(curr, struct iova, node);
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if (limit_pfn < curr_iova->pfn_lo)
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goto move_left;
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else if (limit_pfn < curr_iova->pfn_hi)
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goto adjust_limit_pfn;
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else {
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if (size_aligned)
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pad_size = iova_get_pad_size(size, limit_pfn);
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if ((curr_iova->pfn_hi + size + pad_size) <= limit_pfn)
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break; /* found a free slot */
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}
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adjust_limit_pfn:
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limit_pfn = curr_iova->pfn_lo - 1;
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move_left:
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prev = curr;
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curr = rb_prev(curr);
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}
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if (!curr) {
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if (size_aligned)
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pad_size = iova_get_pad_size(size, limit_pfn);
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if ((IOVA_START_PFN + size + pad_size) > limit_pfn) {
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spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
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return -ENOMEM;
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}
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}
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/* pfn_lo will point to size aligned address if size_aligned is set */
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new->pfn_lo = limit_pfn - (size + pad_size) + 1;
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new->pfn_hi = new->pfn_lo + size - 1;
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/* Insert the new_iova into domain rbtree by holding writer lock */
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/* Add new node and rebalance tree. */
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{
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struct rb_node **entry, *parent = NULL;
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/* If we have 'prev', it's a valid place to start the
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insertion. Otherwise, start from the root. */
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if (prev)
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entry = &prev;
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else
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entry = &iovad->rbroot.rb_node;
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/* Figure out where to put new node */
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while (*entry) {
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struct iova *this = container_of(*entry,
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struct iova, node);
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parent = *entry;
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if (new->pfn_lo < this->pfn_lo)
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entry = &((*entry)->rb_left);
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else if (new->pfn_lo > this->pfn_lo)
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entry = &((*entry)->rb_right);
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else
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BUG(); /* this should not happen */
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}
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/* Add new node and rebalance tree. */
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rb_link_node(&new->node, parent, entry);
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rb_insert_color(&new->node, &iovad->rbroot);
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}
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__cached_rbnode_insert_update(iovad, saved_pfn, new);
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spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
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return 0;
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}
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static void
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iova_insert_rbtree(struct rb_root *root, struct iova *iova)
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{
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struct rb_node **new = &(root->rb_node), *parent = NULL;
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/* Figure out where to put new node */
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while (*new) {
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struct iova *this = container_of(*new, struct iova, node);
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parent = *new;
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if (iova->pfn_lo < this->pfn_lo)
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new = &((*new)->rb_left);
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else if (iova->pfn_lo > this->pfn_lo)
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new = &((*new)->rb_right);
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else
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BUG(); /* this should not happen */
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}
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/* Add new node and rebalance tree. */
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rb_link_node(&iova->node, parent, new);
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rb_insert_color(&iova->node, root);
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}
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/**
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* alloc_iova - allocates an iova
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* @iovad - iova domain in question
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* @size - size of page frames to allocate
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* @limit_pfn - max limit address
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* @size_aligned - set if size_aligned address range is required
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* This function allocates an iova in the range limit_pfn to IOVA_START_PFN
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* looking from limit_pfn instead from IOVA_START_PFN. If the size_aligned
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* flag is set then the allocated address iova->pfn_lo will be naturally
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* aligned on roundup_power_of_two(size).
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*/
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struct iova *
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alloc_iova(struct iova_domain *iovad, unsigned long size,
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unsigned long limit_pfn,
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bool size_aligned)
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{
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struct iova *new_iova;
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int ret;
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new_iova = alloc_iova_mem();
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if (!new_iova)
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return NULL;
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/* If size aligned is set then round the size to
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* to next power of two.
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*/
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if (size_aligned)
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size = __roundup_pow_of_two(size);
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ret = __alloc_and_insert_iova_range(iovad, size, limit_pfn,
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new_iova, size_aligned);
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if (ret) {
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free_iova_mem(new_iova);
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return NULL;
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}
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return new_iova;
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}
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/**
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* find_iova - find's an iova for a given pfn
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* @iovad - iova domain in question.
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* pfn - page frame number
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* This function finds and returns an iova belonging to the
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* given doamin which matches the given pfn.
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*/
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struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn)
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{
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unsigned long flags;
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struct rb_node *node;
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/* Take the lock so that no other thread is manipulating the rbtree */
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spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
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node = iovad->rbroot.rb_node;
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while (node) {
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struct iova *iova = container_of(node, struct iova, node);
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/* If pfn falls within iova's range, return iova */
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if ((pfn >= iova->pfn_lo) && (pfn <= iova->pfn_hi)) {
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spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
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/* We are not holding the lock while this iova
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* is referenced by the caller as the same thread
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* which called this function also calls __free_iova()
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* and it is by desing that only one thread can possibly
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* reference a particular iova and hence no conflict.
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*/
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return iova;
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}
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if (pfn < iova->pfn_lo)
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node = node->rb_left;
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else if (pfn > iova->pfn_lo)
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node = node->rb_right;
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}
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spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
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return NULL;
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}
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/**
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* __free_iova - frees the given iova
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* @iovad: iova domain in question.
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* @iova: iova in question.
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* Frees the given iova belonging to the giving domain
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*/
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void
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__free_iova(struct iova_domain *iovad, struct iova *iova)
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{
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unsigned long flags;
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spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
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__cached_rbnode_delete_update(iovad, iova);
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rb_erase(&iova->node, &iovad->rbroot);
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spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
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free_iova_mem(iova);
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}
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/**
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* free_iova - finds and frees the iova for a given pfn
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* @iovad: - iova domain in question.
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* @pfn: - pfn that is allocated previously
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* This functions finds an iova for a given pfn and then
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* frees the iova from that domain.
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*/
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void
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free_iova(struct iova_domain *iovad, unsigned long pfn)
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{
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struct iova *iova = find_iova(iovad, pfn);
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if (iova)
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__free_iova(iovad, iova);
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}
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/**
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* put_iova_domain - destroys the iova doamin
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* @iovad: - iova domain in question.
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* All the iova's in that domain are destroyed.
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*/
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void put_iova_domain(struct iova_domain *iovad)
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{
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struct rb_node *node;
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unsigned long flags;
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spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
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node = rb_first(&iovad->rbroot);
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while (node) {
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struct iova *iova = container_of(node, struct iova, node);
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rb_erase(node, &iovad->rbroot);
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free_iova_mem(iova);
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node = rb_first(&iovad->rbroot);
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}
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spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
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}
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static int
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__is_range_overlap(struct rb_node *node,
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unsigned long pfn_lo, unsigned long pfn_hi)
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{
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struct iova *iova = container_of(node, struct iova, node);
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if ((pfn_lo <= iova->pfn_hi) && (pfn_hi >= iova->pfn_lo))
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return 1;
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return 0;
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}
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static struct iova *
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__insert_new_range(struct iova_domain *iovad,
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unsigned long pfn_lo, unsigned long pfn_hi)
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{
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struct iova *iova;
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iova = alloc_iova_mem();
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if (!iova)
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return iova;
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iova->pfn_hi = pfn_hi;
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iova->pfn_lo = pfn_lo;
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iova_insert_rbtree(&iovad->rbroot, iova);
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return iova;
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}
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static void
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__adjust_overlap_range(struct iova *iova,
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unsigned long *pfn_lo, unsigned long *pfn_hi)
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{
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if (*pfn_lo < iova->pfn_lo)
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iova->pfn_lo = *pfn_lo;
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if (*pfn_hi > iova->pfn_hi)
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*pfn_lo = iova->pfn_hi + 1;
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}
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/**
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* reserve_iova - reserves an iova in the given range
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* @iovad: - iova domain pointer
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* @pfn_lo: - lower page frame address
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* @pfn_hi:- higher pfn adderss
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* This function allocates reserves the address range from pfn_lo to pfn_hi so
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* that this address is not dished out as part of alloc_iova.
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*/
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struct iova *
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reserve_iova(struct iova_domain *iovad,
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unsigned long pfn_lo, unsigned long pfn_hi)
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{
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struct rb_node *node;
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unsigned long flags;
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struct iova *iova;
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unsigned int overlap = 0;
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spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
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for (node = rb_first(&iovad->rbroot); node; node = rb_next(node)) {
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if (__is_range_overlap(node, pfn_lo, pfn_hi)) {
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iova = container_of(node, struct iova, node);
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__adjust_overlap_range(iova, &pfn_lo, &pfn_hi);
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if ((pfn_lo >= iova->pfn_lo) &&
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(pfn_hi <= iova->pfn_hi))
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goto finish;
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overlap = 1;
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} else if (overlap)
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break;
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}
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/* We are here either because this is the first reserver node
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* or need to insert remaining non overlap addr range
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*/
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iova = __insert_new_range(iovad, pfn_lo, pfn_hi);
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finish:
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spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
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return iova;
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}
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/**
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* copy_reserved_iova - copies the reserved between domains
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* @from: - source doamin from where to copy
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* @to: - destination domin where to copy
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* This function copies reserved iova's from one doamin to
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* other.
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*/
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void
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copy_reserved_iova(struct iova_domain *from, struct iova_domain *to)
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{
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unsigned long flags;
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struct rb_node *node;
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spin_lock_irqsave(&from->iova_rbtree_lock, flags);
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for (node = rb_first(&from->rbroot); node; node = rb_next(node)) {
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struct iova *iova = container_of(node, struct iova, node);
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struct iova *new_iova;
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new_iova = reserve_iova(to, iova->pfn_lo, iova->pfn_hi);
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if (!new_iova)
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printk(KERN_ERR "Reserve iova range %lx@%lx failed\n",
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iova->pfn_lo, iova->pfn_lo);
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}
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spin_unlock_irqrestore(&from->iova_rbtree_lock, flags);
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}
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