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From: Logan Gunthorpe <logang@deltatee.com>
To: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	Christoph Hellwig <hch@lst.de>
Cc: Logan Gunthorpe <logang@deltatee.com>,
	Marshall Midden <marshallmidden@gmail.com>,
	Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>
Subject: [PATCH] iommu/dma: fix incorrect error return on iommu deferred attach
Date: Wed, 27 Oct 2021 11:47:57 -0600	[thread overview]
Message-ID: <20211027174757.119755-1-logang@deltatee.com> (raw)

scsi_dma_map() was reporting a failure during boot on an AMD machine
with the IOMMU enabled.

  scsi_dma_map failed: request for 36 bytes!

The issue was tracked down to a mistake in logic: should not return
an error if iommu_deferred_attach() returns zero.

Reported-by: Marshall Midden <marshallmidden@gmail.com>
Fixes: dabb16f67215 ("iommu/dma: return error code from iommu_dma_map_sg()")
Link: https://lore.kernel.org/all/CAD2CkAWjS8=kKwEEN4cgVNjyFORUibzEiCUA-X+SMtbo0JoMmA@mail.gmail.com
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Will Deacon <will@kernel.org>
---
 drivers/iommu/dma-iommu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

If possible, this fix should really get into Linus's tree before the
v5.15 release.

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 896bea04c347..3e5a21b0bb24 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -1016,7 +1016,8 @@ static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,

 	if (static_branch_unlikely(&iommu_deferred_attach_enabled)) {
 		ret = iommu_deferred_attach(dev, domain);
-		goto out;
+		if (ret)
+			goto out;
 	}

 	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))

base-commit: 3906fe9bb7f1a2c8667ae54e967dc8690824f4ea
--
2.30.2

WARNING: multiple messages have this Message-ID (diff)
From: Logan Gunthorpe <logang@deltatee.com>
To: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	Christoph Hellwig <hch@lst.de>
Cc: Will Deacon <will@kernel.org>,
	Marshall Midden <marshallmidden@gmail.com>,
	Logan Gunthorpe <logang@deltatee.com>
Subject: [PATCH] iommu/dma: fix incorrect error return on iommu deferred attach
Date: Wed, 27 Oct 2021 11:47:57 -0600	[thread overview]
Message-ID: <20211027174757.119755-1-logang@deltatee.com> (raw)

scsi_dma_map() was reporting a failure during boot on an AMD machine
with the IOMMU enabled.

  scsi_dma_map failed: request for 36 bytes!

The issue was tracked down to a mistake in logic: should not return
an error if iommu_deferred_attach() returns zero.

Reported-by: Marshall Midden <marshallmidden@gmail.com>
Fixes: dabb16f67215 ("iommu/dma: return error code from iommu_dma_map_sg()")
Link: https://lore.kernel.org/all/CAD2CkAWjS8=kKwEEN4cgVNjyFORUibzEiCUA-X+SMtbo0JoMmA@mail.gmail.com
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Will Deacon <will@kernel.org>
---
 drivers/iommu/dma-iommu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

If possible, this fix should really get into Linus's tree before the
v5.15 release.

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 896bea04c347..3e5a21b0bb24 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -1016,7 +1016,8 @@ static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,

 	if (static_branch_unlikely(&iommu_deferred_attach_enabled)) {
 		ret = iommu_deferred_attach(dev, domain);
-		goto out;
+		if (ret)
+			goto out;
 	}

 	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))

base-commit: 3906fe9bb7f1a2c8667ae54e967dc8690824f4ea
--
2.30.2
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

             reply	other threads:[~2021-10-27 17:48 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-27 17:47 Logan Gunthorpe [this message]
2021-10-27 17:47 ` [PATCH] iommu/dma: fix incorrect error return on iommu deferred attach Logan Gunthorpe
2021-11-01  9:21 ` John Garry
2021-11-01  9:21   ` John Garry

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