linux-kernel - [PATCH 4.9 01/32] iommu/amd: Fix backport of 140456f994195b568ecd7fc2287a34eadffef3ca

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Date:   Mon,  2 Aug 2021 15:44:21 +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, Andrey Ryabinin <arbn@...dex-team.com>,
        Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        kernel test robot <lkp@...el.com>,
        Nathan Chancellor <nathan@...nel.org>,
        Joerg Roedel <jroedel@...e.de>
Subject: [PATCH 4.9 01/32] iommu/amd: Fix backport of 140456f994195b568ecd7fc2287a34eadffef3ca

From: Nathan Chancellor <nathan@...nel.org>

Clang warns:

drivers/iommu/amd_iommu.c:1335:6: warning: variable 'flags' is used
uninitialized whenever 'if' condition is true
[-Wsometimes-uninitialized]
        if (!pte)
            ^~~~
drivers/iommu/amd_iommu.c:1352:40: note: uninitialized use occurs here
        spin_unlock_irqrestore(&domain->lock, flags);
                                              ^~~~~
drivers/iommu/amd_iommu.c:1335:2: note: remove the 'if' if its condition
is always false
        if (!pte)
        ^~~~~~~~~
drivers/iommu/amd_iommu.c:1331:21: note: initialize the variable 'flags'
to silence this warning
        unsigned long flags;
                           ^
                            = 0
1 warning generated.

The backport of commit 140456f99419 ("iommu/amd: Fix sleeping in atomic
in increase_address_space()") to 4.9 as commit 1d648460d7c5 ("iommu/amd:
Fix sleeping in atomic in increase_address_space()") failed to keep the
"return false", which in 4.9 needs to be a regular "return" due to a
lack of commit f15d9a992f90 ("iommu/amd: Remove domain->updated").

This resolves the warning and matches the 4.14-4.19 backport.

Cc: Andrey Ryabinin <arbn@...dex-team.com>
Cc: Joerg Roedel <joro@...tes.org>
Cc: Will Deacon <will@...nel.org>
Fixes: 1d648460d7c5 ("iommu/amd: Fix sleeping in atomic in increase_address_space()")
Reported-by: kernel test robot <lkp@...el.com>
Signed-off-by: Nathan Chancellor <nathan@...nel.org>
Acked-by: Joerg Roedel <jroedel@...e.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/iommu/amd_iommu.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1333,7 +1333,7 @@ static void increase_address_space(struc
 
 	pte = (void *)get_zeroed_page(gfp);
 	if (!pte)
-		goto out;
+		return;
 
 	spin_lock_irqsave(&domain->lock, flags);