[PATCH] iommu/dma: Clean up redundant MSI cookie check

[PATCH] iommu/dma: Clean up redundant MSI cookie check

[Robin Murphy]

The has_msi_cookie() condition only mattered transiently as an artefact
of the cookie rework being done in parallel with the sw_msi rework. Once
combined, calls to iommu_dma_sw_msi() are themselves dispatched based on
domain->cookie_type, so checking again is clearly redundant.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
 drivers/iommu/dma-iommu.c | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 1b8012123232..5d9d282540bc 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -2162,12 +2162,6 @@ void iommu_setup_dma_ops(struct device *dev, struct iommu_domain *domain)
 	dev_clear_dma_iommu(dev);
 }
 
-static bool has_msi_cookie(const struct iommu_domain *domain)
-{
-	return domain && (domain->cookie_type == IOMMU_COOKIE_DMA_IOVA ||
-			  domain->cookie_type == IOMMU_COOKIE_DMA_MSI);
-}
-
 static size_t cookie_msi_granule(const struct iommu_domain *domain)
 {
 	switch (domain->cookie_type) {
@@ -2249,11 +2243,6 @@ int iommu_dma_sw_msi(struct iommu_domain *domain, struct msi_desc *desc,
 	struct device *dev = msi_desc_to_dev(desc);
 	const struct iommu_dma_msi_page *msi_page;
 
-	if (!has_msi_cookie(domain)) {
-		msi_desc_set_iommu_msi_iova(desc, 0, 0);
-		return 0;
-	}
-
 	iommu_group_mutex_assert(dev);
 	msi_page = iommu_dma_get_msi_page(dev, msi_addr, domain);
 	if (!msi_page)
-- 
2.54.0.dirty

Re: [PATCH] iommu/dma: Clean up redundant MSI cookie check

[Nicolin Chen]

On Fri, Oct 02, 2026 at 05:34:58PM +0100, Robin Murphy wrote:
> The has_msi_cookie() condition only mattered transiently as an artefact
> of the cookie rework being done in parallel with the sw_msi rework. Once
> combined, calls to iommu_dma_sw_msi() are themselves dispatched based on
> domain->cookie_type, so checking again is clearly redundant.
> 
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>

Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>