linux-kernel - [PATCH] iommu/amd: Use atomic64_inc

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Message-ID: <20241007084356.47799-1-ubizjak@gmail.com>
Date: Mon,  7 Oct 2024 10:43:31 +0200
From: Uros Bizjak <ubizjak@...il.com>
To: iommu@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Cc: Uros Bizjak <ubizjak@...il.com>,
	Joerg Roedel <joro@...tes.org>,
	Suravee Suthikulpanit <suravee.suthikulpanit@....com>,
	Will Deacon <will@...nel.org>,
	Robin Murphy <robin.murphy@....com>
Subject: [PATCH] iommu/amd: Use atomic64_inc_return() in iommu.c

Use atomic64_inc_return(&ref) instead of atomic64_add_return(1, &ref)
to use optimized implementation and ease register pressure around
the primitive for targets that implement optimized variant.

Signed-off-by: Uros Bizjak <ubizjak@...il.com>
Cc: Joerg Roedel <joro@...tes.org>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
Cc: Will Deacon <will@...nel.org>
Cc: Robin Murphy <robin.murphy@....com>
---
 drivers/iommu/amd/iommu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 8364cd6fa47d..074effba7fbe 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -1230,7 +1230,7 @@ static int iommu_completion_wait(struct amd_iommu *iommu)
 	if (!iommu->need_sync)
 		return 0;
 
-	data = atomic64_add_return(1, &iommu->cmd_sem_val);
+	data = atomic64_inc_return(&iommu->cmd_sem_val);
 	build_completion_wait(&cmd, iommu, data);
 
 	raw_spin_lock_irqsave(&iommu->lock, flags);
@@ -2890,7 +2890,7 @@ static void iommu_flush_irt_and_complete(struct amd_iommu *iommu, u16 devid)
 		return;
 
 	build_inv_irt(&cmd, devid);
-	data = atomic64_add_return(1, &iommu->cmd_sem_val);
+	data = atomic64_inc_return(&iommu->cmd_sem_val);
 	build_completion_wait(&cmd2, iommu, data);
 
 	raw_spin_lock_irqsave(&iommu->lock, flags);
-- 
2.46.2