On 2022-03-01 01:59, yf.wang--- via iommu wrote:
From: Yunfei Wang yf.wang@mediatek.com
In alloc_iova_fast function, if __alloc_and_insert_iova_range fail, alloc_iova_fast will try flushing rcache and retry alloc iova, but this has an issue:
Since __alloc_and_insert_iova_range fail will set the current alloc iova size to max32_alloc_size (iovad->max32_alloc_size = size), when the retry is executed into the __alloc_and_insert_iova_range function, the retry action will be blocked by the check condition (size >= iovad->max32_alloc_size) and goto iova32_full directly, causes the action of retry regular alloc iova in __alloc_and_insert_iova_range to not actually be executed.
Based on the above, so need reset max32_alloc_size before retry alloc iova when alloc iova fail, that is set the initial dma_32bit_pfn value of iovad to max32_alloc_size, so that the action of retry alloc iova in __alloc_and_insert_iova_range can be executed.
Have you observed this making any difference in practice?
Given that both free_cpu_cached_iovas() and free_global_cached_iovas() call iova_magazine_free_pfns(), which calls remove_iova(), which calls __cached_rbnode_delete_update(), I'm thinking no...
Robin.
Signed-off-by: Yunfei Wang yf.wang@mediatek.com Cc: stable@vger.kernel.org # 5.10.*
v2: Cc stable@vger.kernel.org 1. This patch needs to be merged stable branch, add stable@vger.kernel.org in mail list.
drivers/iommu/iova.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c index b28c9435b898..0c085ae8293f 100644 --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -453,6 +453,7 @@ alloc_iova_fast(struct iova_domain *iovad, unsigned long size, retry: new_iova = alloc_iova(iovad, size, limit_pfn, true); if (!new_iova) {
unsigned long flags;if (!flush_rcache) @@ -463,6 +464,12 @@ alloc_iova_fast(struct iova_domain *iovad, unsigned long size, for_each_online_cpu(cpu) free_cpu_cached_iovas(cpu, iovad); free_global_cached_iovas(iovad);
/* Reset max32_alloc_size after flushing rcache for retry */spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);iovad->max32_alloc_size = iovad->dma_32bit_pfn;spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);- goto retry; }
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