linux-kernel - [PATCH] dma-direct: don't truncate dma_required

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Date:   Mon,  5 Aug 2019 17:51:53 +0200
From:   Lucas Stach <l.stach@...gutronix.de>
To:     Christoph Hellwig <hch@....de>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Robin Murphy <robin.murphy@....com>
Cc:     iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        kernel@...gutronix.de, patchwork-lst@...gutronix.de
Subject: [PATCH] dma-direct: don't truncate dma_required_mask to bus addressing capabilities

The dma required_mask needs to reflect the actual addressing capabilities
needed to handle the whole system RAM. When truncated down to the bus
addressing capabilities dma_addressing_limited() will incorrectly signal
no limitations for devices which are restricted by the bus_dma_mask.

Fixes: b4ebe6063204 (dma-direct: implement complete bus_dma_mask handling)
Signed-off-by: Lucas Stach <l.stach@...gutronix.de>
---
 kernel/dma/direct.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 59bdceea3737..7ba3480fc546 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -47,9 +47,6 @@ u64 dma_direct_get_required_mask(struct device *dev)
 {
 	u64 max_dma = phys_to_dma_direct(dev, (max_pfn - 1) << PAGE_SHIFT);
 
-	if (dev->bus_dma_mask && dev->bus_dma_mask < max_dma)
-		max_dma = dev->bus_dma_mask;
-
 	return (1ULL << (fls64(max_dma) - 1)) * 2 - 1;
 }
 
-- 
2.20.1