On 2022-03-01 01:59, yf.wang--- via iommu wrote:
From: Yunfei Wang <yf.wang@xxxxxxxxxxxx>
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@xxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # 5.10.*
---
v2: Cc stable@xxxxxxxxxxxxxxx
1. This patch needs to be merged stable branch, add stable@xxxxxxxxxxxxxxx
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;
unsigned int cpu;
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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