Re: [PATCH v4 1/7] iommu: Move iotlb_sync_map out from __iommu_map
flat view
From: Doug Anderson <dianders@chromium.org>
Date: 2021-02-02 01:08:18
Also in:
linux-iommu, linux-mediatek, lkml
Hi, On Thu, Jan 7, 2021 at 4:31 AM Yong Wu [off-list ref] wrote:
quoted hunk ↗ jump to hunk
@@ -2438,18 +2435,31 @@ static int __iommu_map(struct iommu_domain *domain, unsigned long iova, return ret; } +static int _iommu_map(struct iommu_domain *domain, unsigned long iova, + phys_addr_t paddr, size_t size, int prot, gfp_t gfp) +{ + const struct iommu_ops *ops = domain->ops; + int ret; + + ret = __iommu_map(domain, iova, paddr, size, prot, GFP_KERNEL);
The above is broken. Instead of GFP_KERNEL it should be passing "gfp".
quoted hunk ↗ jump to hunk
+ if (ret == 0 && ops->iotlb_sync_map) + ops->iotlb_sync_map(domain); + + return ret; +} + int iommu_map(struct iommu_domain *domain, unsigned long iova, phys_addr_t paddr, size_t size, int prot) { might_sleep(); - return __iommu_map(domain, iova, paddr, size, prot, GFP_KERNEL); + return _iommu_map(domain, iova, paddr, size, prot, GFP_KERNEL); } EXPORT_SYMBOL_GPL(iommu_map); int iommu_map_atomic(struct iommu_domain *domain, unsigned long iova, phys_addr_t paddr, size_t size, int prot) { - return __iommu_map(domain, iova, paddr, size, prot, GFP_ATOMIC); + return _iommu_map(domain, iova, paddr, size, prot, GFP_ATOMIC);
Specifically the above bug means we drop the "GFP_ATOMIC" here. It means we trigger a warning, like this (on a downstream kernel with the patch backported): BUG: sleeping function called from invalid context at mm/page_alloc.c:4726 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 9, name: ksoftirqd/0 CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.4.93-12508-gc10c93e28e39 #1 Call trace: dump_backtrace+0x0/0x154 show_stack+0x20/0x2c dump_stack+0xa0/0xfc ___might_sleep+0x11c/0x12c __might_sleep+0x50/0x84 __alloc_pages_nodemask+0xf8/0x2bc __arm_lpae_alloc_pages+0x48/0x1b4 __arm_lpae_map+0x124/0x274 __arm_lpae_map+0x1cc/0x274 arm_lpae_map+0x140/0x170 arm_smmu_map+0x78/0xbc __iommu_map+0xd4/0x210 _iommu_map+0x4c/0x84 iommu_map_atomic+0x44/0x58 __iommu_dma_map+0x8c/0xc4 iommu_dma_map_page+0xac/0xf0 --- A quick (but not very tested) fix at: https://lore.kernel.org/r/20210201170611.1.I64a7b62579287d668d7c89e105dcedf45d641063@changeid/ (local) -Doug _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel