From 37f0c7a8df7ad719a68fa1c2dbf066cfebc391a7 Mon Sep 17 00:00:00 2001 From: Leon Romanovsky Date: Fri, 14 Nov 2025 11:07:04 +0200 Subject: block-dma: properly take MMIO path In commit eadaa8b255f3 ("dma-mapping: introduce new DMA attribute to indicate MMIO memory"), DMA_ATTR_MMIO attribute was added to describe MMIO addresses, which require to avoid any memory cache flushing, as an outcome of the discussion pointed in Link tag below. In case of PCI_P2PDMA_MAP_THRU_HOST_BRIDGE transfer, blk-mq-dm logic treated this as regular page and relied on "struct page" DMA flow. That flow performs CPU cache flushing, which shouldn't be done here, and doesn't set IOMMU_MMIO flag in DMA-IOMMU case. As a solution, let's encode peer-to-peer transaction type in NVMe IOD flags variable and provide it to blk-mq-dma API. Link: https://lore.kernel.org/all/f912c446-1ae9-4390-9c11-00dce7bf0fd3@arm.com/ Reviewed-by: Christoph Hellwig Reviewed-by: Chaitanya Kulkarni Reviewed-by: Keith Busch Signed-off-by: Leon Romanovsky Signed-off-by: Jens Axboe --- include/linux/bio-integrity.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux/bio-integrity.h') diff --git a/include/linux/bio-integrity.h b/include/linux/bio-integrity.h index 3d05296a5afe..21e4652dcfd2 100644 --- a/include/linux/bio-integrity.h +++ b/include/linux/bio-integrity.h @@ -13,7 +13,6 @@ enum bip_flags { BIP_CHECK_GUARD = 1 << 5, /* guard check */ BIP_CHECK_REFTAG = 1 << 6, /* reftag check */ BIP_CHECK_APPTAG = 1 << 7, /* apptag check */ - BIP_P2P_DMA = 1 << 8, /* using P2P address */ BIP_MEMPOOL = 1 << 15, /* buffer backed by mempool */ }; -- cgit v1.2.3