linux-kernel - [PATCH 5.7 005/376] media: staging: imgu: do not hold spinlock during freeing mmu page table

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Date:   Fri, 19 Jun 2020 16:28:43 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Bingbu Cao <bingbu.cao@...el.com>,
        Tomasz Figa <tfiga@...omium.org>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.7 005/376] media: staging: imgu: do not hold spinlock during freeing mmu page table

From: Bingbu Cao <bingbu.cao@...el.com>

[ Upstream commit e1ebe9f9c88e5a78fcc4670a9063c9b3cd87dda4 ]

ImgU need set the mmu page table in memory as uncached, and set back
to write-back when free the page table by set_memory_wb(),
set_memory_wb() can not do flushing without interrupt, so the spinlock
should not be hold during ImgU page alloc and free, the interrupt
should be enabled during memory cache flush.

This patch release spinlock before freeing pages table.

Signed-off-by: Bingbu Cao <bingbu.cao@...el.com>
Reviewed-by: Tomasz Figa <tfiga@...omium.org>
Signed-off-by: Sakari Ailus <sakari.ailus@...ux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/staging/media/ipu3/ipu3-mmu.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/media/ipu3/ipu3-mmu.c b/drivers/staging/media/ipu3/ipu3-mmu.c
index 5f3ff964f3e7..cb9bf5fb29a5 100644
--- a/drivers/staging/media/ipu3/ipu3-mmu.c
+++ b/drivers/staging/media/ipu3/ipu3-mmu.c
@@ -174,8 +174,10 @@ static u32 *imgu_mmu_get_l2pt(struct imgu_mmu *mmu, u32 l1pt_idx)
 	spin_lock_irqsave(&mmu->lock, flags);
 
 	l2pt = mmu->l2pts[l1pt_idx];
-	if (l2pt)
-		goto done;
+	if (l2pt) {
+		spin_unlock_irqrestore(&mmu->lock, flags);
+		return l2pt;
+	}
 
 	spin_unlock_irqrestore(&mmu->lock, flags);
 
@@ -190,8 +192,9 @@ static u32 *imgu_mmu_get_l2pt(struct imgu_mmu *mmu, u32 l1pt_idx)
 
 	l2pt = mmu->l2pts[l1pt_idx];
 	if (l2pt) {
+		spin_unlock_irqrestore(&mmu->lock, flags);
 		imgu_mmu_free_page_table(new_l2pt);
-		goto done;
+		return l2pt;
 	}
 
 	l2pt = new_l2pt;
@@ -200,7 +203,6 @@ static u32 *imgu_mmu_get_l2pt(struct imgu_mmu *mmu, u32 l1pt_idx)
 	pteval = IPU3_ADDR2PTE(virt_to_phys(new_l2pt));
 	mmu->l1pt[l1pt_idx] = pteval;
 
-done:
 	spin_unlock_irqrestore(&mmu->lock, flags);
 	return l2pt;
 }
-- 
2.25.1