linux-kernel - [PATCH v2 2/2] iova: Remove magazine BUG

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Date:   Mon, 5 Sep 2022 17:11:23 +0800
From:   John Garry <john.garry@...wei.com>
To:     <robin.murphy@....com>, <joro@...tes.org>, <will@...nel.org>
CC:     <iommu@...ts.linux.dev>, <linux-kernel@...r.kernel.org>,
        <linuxarm@...wei.com>, John Garry <john.garry@...wei.com>
Subject: [PATCH v2 2/2] iova: Remove magazine BUG_ON() checks

Two of the magazine helpers have BUG_ON() checks, as follows:
- iova_magazine_pop() - here we ensure that the mag is not empty. However we
  already ensure that in the only caller, __iova_rcache_get().
- iova_magazine_push() - here we ensure that the mag is not full. However
  we already ensure that in the only caller, __iova_rcache_insert().

As described, the two bug checks are pointless so drop them.

Signed-off-by: John Garry <john.garry@...wei.com>
Acked-by: Robin Murphy <robin.murphy@....com>
---
 drivers/iommu/iova.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index 580fdf669922..8aece052ce72 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -694,8 +694,6 @@ static unsigned long iova_magazine_pop(struct iova_magazine *mag,
 	int i;
 	unsigned long pfn;
 
-	BUG_ON(iova_magazine_empty(mag));
-
 	/* Only fall back to the rbtree if we have no suitable pfns at all */
 	for (i = mag->size - 1; mag->pfns[i] > limit_pfn; i--)
 		if (i == 0)
@@ -710,8 +708,6 @@ static unsigned long iova_magazine_pop(struct iova_magazine *mag,
 
 static void iova_magazine_push(struct iova_magazine *mag, unsigned long pfn)
 {
-	BUG_ON(iova_magazine_full(mag));
-
 	mag->pfns[mag->size++] = pfn;
 }
 
-- 
2.35.3