[PATCH 2/2] iova32
Chris Wilson
chris at chris-wilson.co.uk
Sat Jan 16 16:05:03 UTC 2021
---
drivers/iommu/iova.c | 187 +++++++++++++++++++++++++------------------
include/linux/iova.h | 6 +-
2 files changed, 110 insertions(+), 83 deletions(-)
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index 0c43c2b5f040..72d1ec7baa15 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -40,15 +40,15 @@ init_iova_domain(struct iova_domain *iovad, unsigned long granule,
spin_lock_init(&iovad->iova_rbtree_lock);
iovad->rbroot = RB_ROOT;
- iovad->cached_node = &iovad->anchor.node;
- iovad->cached32_node = &iovad->anchor.node;
iovad->granule = granule;
iovad->start_pfn = start_pfn;
iovad->dma_32bit_pfn = 1UL << (32 - iova_shift(iovad));
- iovad->max32_alloc_size = iovad->dma_32bit_pfn;
iovad->flush_cb = NULL;
iovad->fq = NULL;
- iovad->anchor.pfn_lo = iovad->anchor.pfn_hi = IOVA_ANCHOR;
+ INIT_LIST_HEAD(&iovad->holes);
+ list_add(&iovad->anchor.hole, &iovad->holes);
+ iovad->anchor.pfn_lo = IOVA_ANCHOR;
+ iovad->anchor.pfn_hi = start_pfn - 1;
rb_link_node(&iovad->anchor.node, NULL, &iovad->rbroot.rb_node);
rb_insert_color(&iovad->anchor.node, &iovad->rbroot);
init_iova_rcaches(iovad);
@@ -114,42 +114,6 @@ int init_iova_flush_queue(struct iova_domain *iovad,
}
EXPORT_SYMBOL_GPL(init_iova_flush_queue);
-static struct rb_node *
-__get_cached_rbnode(struct iova_domain *iovad, unsigned long limit_pfn)
-{
- if (limit_pfn <= iovad->dma_32bit_pfn)
- return iovad->cached32_node;
-
- return iovad->cached_node;
-}
-
-static void
-__cached_rbnode_insert_update(struct iova_domain *iovad, struct iova *new)
-{
- if (new->pfn_hi < iovad->dma_32bit_pfn)
- iovad->cached32_node = &new->node;
- else
- iovad->cached_node = &new->node;
-}
-
-static void
-__cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free)
-{
- struct iova *cached_iova;
-
- cached_iova = rb_entry(iovad->cached32_node, struct iova, node);
- if (free == cached_iova ||
- (free->pfn_hi < iovad->dma_32bit_pfn &&
- free->pfn_lo >= cached_iova->pfn_lo)) {
- iovad->cached32_node = rb_next(&free->node);
- iovad->max32_alloc_size = iovad->dma_32bit_pfn;
- }
-
- cached_iova = rb_entry(iovad->cached_node, struct iova, node);
- if (free->pfn_lo >= cached_iova->pfn_lo)
- iovad->cached_node = rb_next(&free->node);
-}
-
/* Insert the iova into domain rbtree by holding writer lock */
static void
iova_insert_rbtree(struct rb_root *root, struct iova *iova,
@@ -178,65 +142,77 @@ iova_insert_rbtree(struct rb_root *root, struct iova *iova,
rb_insert_color(&iova->node, root);
}
+static struct iova *iova_entry(struct iova_domain *iovad, struct rb_node *node)
+{
+ return node ? rb_entry(node, struct iova, node) : &iovad->anchor;
+}
+
static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
unsigned long size, unsigned long limit_pfn,
struct iova *new, bool size_aligned)
{
- struct rb_node *curr, *prev;
- struct iova *curr_iova;
- unsigned long flags;
- unsigned long new_pfn, retry_pfn;
unsigned long align_mask = ~0UL;
- unsigned long high_pfn = limit_pfn, low_pfn = iovad->start_pfn;
+ struct iova *prev, *next;
+ unsigned long new_pfn;
+ unsigned long flags;
+ struct iova *it;
if (size_aligned)
align_mask <<= fls_long(size - 1);
- /* Walk the tree backwards */
+ if (size > ((limit_pfn - iovad->start_pfn) & align_mask))
+ return -ENOMEM;
+
spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
- if (limit_pfn <= iovad->dma_32bit_pfn &&
- size >= iovad->max32_alloc_size)
- goto iova32_full;
+ if (limit_pfn <= iovad->dma_32bit_pfn) {
+ list_for_each_entry(it, &iovad->holes, hole) {
+ new_pfn = it->pfn_hi + 1;
+ if (new_pfn >= limit_pfn)
+ break;
- curr = __get_cached_rbnode(iovad, limit_pfn);
- curr_iova = rb_entry(curr, struct iova, node);
- retry_pfn = curr_iova->pfn_hi + 1;
+ new_pfn = (new_pfn + ~align_mask) & align_mask;
+ if (new_pfn > limit_pfn - size)
+ break;
-retry:
- do {
- high_pfn = min(high_pfn, curr_iova->pfn_lo);
- new_pfn = (high_pfn - size) & align_mask;
- prev = curr;
- curr = rb_prev(curr);
- curr_iova = rb_entry(curr, struct iova, node);
- } while (curr && new_pfn <= curr_iova->pfn_hi && new_pfn >= low_pfn);
-
- if (high_pfn < size || new_pfn < low_pfn) {
- if (low_pfn == iovad->start_pfn && retry_pfn < limit_pfn) {
- high_pfn = limit_pfn;
- low_pfn = retry_pfn;
- curr = &iovad->anchor.node;
- curr_iova = rb_entry(curr, struct iova, node);
- goto retry;
+ prev = it;
+ next = iova_entry(iovad, rb_next(&it->node));
+ if (new_pfn + size - 1 < next->pfn_lo)
+ goto done;
}
- iovad->max32_alloc_size = size;
- goto iova32_full;
- }
+ } else {
+ list_for_each_entry_reverse(it, &iovad->holes, hole) {
+ new_pfn = min(it->pfn_lo, limit_pfn);
+ if (new_pfn < size)
+ break;
+ new_pfn = (new_pfn - size) & align_mask;
+ if (new_pfn < iovad->start_pfn)
+ break;
+
+ next = it;
+ prev = iova_entry(iovad, rb_prev(&it->node));
+ if (new_pfn > prev->pfn_hi)
+ goto done;
+ }
+ }
+ spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
+ return -ENOMEM;
+
+done:
/* pfn_lo will point to size aligned address if size_aligned is set */
new->pfn_lo = new_pfn;
new->pfn_hi = new->pfn_lo + size - 1;
/* If we have 'prev', it's a valid place to start the insertion. */
- iova_insert_rbtree(&iovad->rbroot, new, prev);
- __cached_rbnode_insert_update(iovad, new);
+ iova_insert_rbtree(&iovad->rbroot, new, &prev->node);
+
+ if (new->pfn_hi < next->pfn_lo - 1)
+ list_add(&new->hole, &prev->hole);
+ if (prev->pfn_hi == new->pfn_lo - 1)
+ list_del(&prev->hole);
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
return 0;
-
-iova32_full:
- spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
- return -ENOMEM;
}
static struct kmem_cache *iova_cache;
@@ -345,10 +321,38 @@ private_find_iova(struct iova_domain *iovad, unsigned long pfn)
return NULL;
}
+static void remove_hole(struct iova_domain *iovad, struct iova *iova)
+{
+ struct iova *prev, *next;
+
+ prev = iova_entry(iovad, rb_prev(&iova->node));
+ if (prev->pfn_hi == iova->pfn_lo - 1) {
+ struct iova *it = iova;
+
+ do {
+ next = rb_entry(rb_next(&it->node), struct iova, node);
+ if (!next) {
+ list_add_tail(&prev->hole, &iovad->holes);
+ break;
+ }
+ if (it->pfn_hi < next->pfn_lo - 1) {
+ list_add_tail(&prev->hole, &it->hole);
+ break;
+ }
+
+ it = next;
+ } while (1);
+ }
+
+ next = iova_entry(iovad, rb_next(&iova->node));
+ if (iova->pfn_hi < next->pfn_lo - 1)
+ list_del(&iova->hole);
+}
+
static void private_free_iova(struct iova_domain *iovad, struct iova *iova)
{
assert_spin_locked(&iovad->iova_rbtree_lock);
- __cached_rbnode_delete_update(iovad, iova);
+ remove_hole(iovad, iova);
rb_erase(&iova->node, &iovad->rbroot);
free_iova_mem(iova);
}
@@ -656,6 +660,26 @@ alloc_and_init_iova(unsigned long pfn_lo, unsigned long pfn_hi)
return iova;
}
+static void insert_hole(struct iova_domain *iovad, struct iova *iova)
+{
+ struct iova *prev, *it;
+
+ it = rb_entry(rb_next(&iova->node), struct iova, node);
+ if (iova->pfn_hi < it->pfn_lo - 1) {
+ it = iova;
+ do {
+ prev = rb_entry(rb_prev(&it->node), struct iova, node);
+ if (!prev || prev->pfn_hi < it->pfn_lo - 1)
+ break;
+ if (prev->pfn_hi == iova->pfn_lo - 1)
+ list_del(&prev->hole);
+ it = prev;
+ } while (1);
+
+ list_add(&iova->hole, prev ? &prev->hole : &iovad->holes);
+ }
+}
+
static struct iova *
__insert_new_range(struct iova_domain *iovad,
unsigned long pfn_lo, unsigned long pfn_hi)
@@ -663,8 +687,11 @@ __insert_new_range(struct iova_domain *iovad,
struct iova *iova;
iova = alloc_and_init_iova(pfn_lo, pfn_hi);
- if (iova)
- iova_insert_rbtree(&iovad->rbroot, iova, NULL);
+ if (!iova)
+ return NULL;
+
+ iova_insert_rbtree(&iovad->rbroot, iova, NULL);
+ insert_hole(iovad, iova);
return iova;
}
diff --git a/include/linux/iova.h b/include/linux/iova.h
index 76e16ae20729..8b75a5b5f8f4 100644
--- a/include/linux/iova.h
+++ b/include/linux/iova.h
@@ -11,6 +11,7 @@
#include <linux/types.h>
#include <linux/kernel.h>
+#include <linux/list.h>
#include <linux/rbtree.h>
#include <linux/atomic.h>
#include <linux/dma-mapping.h>
@@ -18,6 +19,7 @@
/* iova structure */
struct iova {
struct rb_node node;
+ struct list_head hole;
unsigned long pfn_hi; /* Highest allocated pfn */
unsigned long pfn_lo; /* Lowest allocated pfn */
};
@@ -68,12 +70,9 @@ struct iova_fq {
struct iova_domain {
spinlock_t iova_rbtree_lock; /* Lock to protect update of rbtree */
struct rb_root rbroot; /* iova domain rbtree root */
- struct rb_node *cached_node; /* Save last alloced node */
- struct rb_node *cached32_node; /* Save last 32-bit alloced node */
unsigned long granule; /* pfn granularity for this domain */
unsigned long start_pfn; /* Lower limit for this domain */
unsigned long dma_32bit_pfn;
- unsigned long max32_alloc_size; /* Size of last failed allocation */
struct iova_fq __percpu *fq; /* Flush Queue */
atomic64_t fq_flush_start_cnt; /* Number of TLB flushes that
@@ -82,6 +81,7 @@ struct iova_domain {
atomic64_t fq_flush_finish_cnt; /* Number of TLB flushes that
have been finished */
+ struct list_head holes;
struct iova anchor; /* rbtree lookup anchor */
struct iova_rcache rcaches[IOVA_RANGE_CACHE_MAX_SIZE]; /* IOVA range caches */
--
2.20.1
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