* Re: [PATCH] iommu: iova: Consolidate code for adding new node to iovad domain rbtree
2017-02-23 8:17 ` [PATCH] iommu: iova: Consolidate code for adding new node to iovad domain rbtree Marek Szyprowski
@ 2017-02-23 11:59 ` Robin Murphy
0 siblings, 0 replies; 2+ messages in thread
From: Robin Murphy @ 2017-02-23 11:59 UTC (permalink / raw)
To: Marek Szyprowski, iommu, linux-kernel; +Cc: Bartlomiej Zolnierkiewicz
On 23/02/17 08:17, Marek Szyprowski wrote:
> This patch consolidates almost the same code used in iova_insert_rbtree()
> and __alloc_and_insert_iova_range() functions. There is no functional change.
>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
> drivers/iommu/iova.c | 85 +++++++++++++++++++---------------------------------
> 1 file changed, 31 insertions(+), 54 deletions(-)
>
> diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
> index b7268a14184f..32b9c2fb37b6 100644
> --- a/drivers/iommu/iova.c
> +++ b/drivers/iommu/iova.c
> @@ -100,6 +100,32 @@ static unsigned long iova_rcache_get(struct iova_domain *iovad,
> }
> }
>
> +/* Insert the iova into domain rbtree by holding writer lock */
> +static void
> +iova_insert_rbtree(struct rb_root *root, struct iova *iova,
> + struct rb_node *start)
> +{
> + struct rb_node **new, *parent = NULL;
> +
> + new = (start) ? &start : &(root->rb_node);
> + /* Figure out where to put new node */
> + while (*new) {
> + struct iova *this = rb_entry(*new, struct iova, node);
> +
> + parent = *new;
> +
> + if (iova->pfn_lo < this->pfn_lo)
> + new = &((*new)->rb_left);
> + else if (iova->pfn_lo > this->pfn_lo)
> + new = &((*new)->rb_right);
> + else
> + BUG(); /* this should not happen */
Ooh, if we're touching this, can we downgrade it to a WARN()? Granted,
allocating an IOVA region of size 0 is not a reasonable thing to do
intentionally, but the fact that it's guaranteed to take down the kernel
is perhaps a bit much (I hit it soooo many times back when debugging the
iommu_dma_map_sg() stuff).
Nice tidyup otherwise, though.
Robin.
> + }
> + /* Add new node and rebalance tree. */
> + rb_link_node(&iova->node, parent, new);
> + rb_insert_color(&iova->node, root);
> +}
> +
> /*
> * Computes the padding size required, to make the start address
> * naturally aligned on the power-of-two order of its size
> @@ -157,35 +183,8 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
> new->pfn_lo = limit_pfn - (size + pad_size) + 1;
> new->pfn_hi = new->pfn_lo + size - 1;
>
> - /* Insert the new_iova into domain rbtree by holding writer lock */
> - /* Add new node and rebalance tree. */
> - {
> - struct rb_node **entry, *parent = NULL;
> -
> - /* If we have 'prev', it's a valid place to start the
> - insertion. Otherwise, start from the root. */
> - if (prev)
> - entry = &prev;
> - else
> - entry = &iovad->rbroot.rb_node;
> -
> - /* Figure out where to put new node */
> - while (*entry) {
> - struct iova *this = rb_entry(*entry, struct iova, node);
> - parent = *entry;
> -
> - if (new->pfn_lo < this->pfn_lo)
> - entry = &((*entry)->rb_left);
> - else if (new->pfn_lo > this->pfn_lo)
> - entry = &((*entry)->rb_right);
> - else
> - BUG(); /* this should not happen */
> - }
> -
> - /* Add new node and rebalance tree. */
> - rb_link_node(&new->node, parent, entry);
> - rb_insert_color(&new->node, &iovad->rbroot);
> - }
> + /* 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, saved_pfn, new);
>
> spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
> @@ -194,28 +193,6 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
> return 0;
> }
>
> -static void
> -iova_insert_rbtree(struct rb_root *root, struct iova *iova)
> -{
> - struct rb_node **new = &(root->rb_node), *parent = NULL;
> - /* Figure out where to put new node */
> - while (*new) {
> - struct iova *this = rb_entry(*new, struct iova, node);
> -
> - parent = *new;
> -
> - if (iova->pfn_lo < this->pfn_lo)
> - new = &((*new)->rb_left);
> - else if (iova->pfn_lo > this->pfn_lo)
> - new = &((*new)->rb_right);
> - else
> - BUG(); /* this should not happen */
> - }
> - /* Add new node and rebalance tree. */
> - rb_link_node(&iova->node, parent, new);
> - rb_insert_color(&iova->node, root);
> -}
> -
> static struct kmem_cache *iova_cache;
> static unsigned int iova_cache_users;
> static DEFINE_MUTEX(iova_cache_mutex);
> @@ -505,7 +482,7 @@ void put_iova_domain(struct iova_domain *iovad)
>
> iova = alloc_and_init_iova(pfn_lo, pfn_hi);
> if (iova)
> - iova_insert_rbtree(&iovad->rbroot, iova);
> + iova_insert_rbtree(&iovad->rbroot, iova, NULL);
>
> return iova;
> }
> @@ -612,11 +589,11 @@ struct iova *
> rb_erase(&iova->node, &iovad->rbroot);
>
> if (prev) {
> - iova_insert_rbtree(&iovad->rbroot, prev);
> + iova_insert_rbtree(&iovad->rbroot, prev, NULL);
> iova->pfn_lo = pfn_lo;
> }
> if (next) {
> - iova_insert_rbtree(&iovad->rbroot, next);
> + iova_insert_rbtree(&iovad->rbroot, next, NULL);
> iova->pfn_hi = pfn_hi;
> }
> spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
>
^ permalink raw reply [flat|nested] 2+ messages in thread