From: Pranith Kumar <bobby.prani@gmail.com>
To: Peter Hurley <peter@hurleysoftware.com>,
Pranith Kumar <pranith@gatech.edu>,
dwmw2@infradead.org, joro@8bytes.org
Cc: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/1] use documented cmpxchg api
Date: Fri, 06 Jun 2014 10:27:24 -0400 [thread overview]
Message-ID: <5391CFCC.6060507@gmail.com> (raw)
In-Reply-To: <53919E24.3010206@hurleysoftware.com>
On 06/06/2014 06:55 AM, Peter Hurley wrote:
>
> This won't work either, and should generate a compile or link error
> on CONFIG_X86_32.
>
> The auto-sizing done by __cmpxchg() does not substitute the cmpxchg8b
> instruction for the cmpxchg instruction. __X86_CASE_Q is defined as -1 for
> CONFIG_X86_32 so the 8-byte size variant is dead-code, and calls
> __cmpxchg_wrong_size() instead.
>
>
Fixed with the following v3:
use the documented cmpxchg64 instead of __cmpxchg64.
This kills the last user of said API in drivers code.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
---
drivers/iommu/intel-iommu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 6bb3277..270113f 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -293,7 +293,7 @@ static inline u64 dma_pte_addr(struct dma_pte *pte)
return pte->val & VTD_PAGE_MASK;
#else
/* Must have a full atomic 64-bit read */
- return __cmpxchg64(&pte->val, 0ULL, 0ULL) & VTD_PAGE_MASK;
+ return cmpxchg64(&pte->val, 0ULL, 0ULL) & VTD_PAGE_MASK;
#endif
}
-- 1.7.9.5
prev parent reply other threads:[~2014-06-06 14:27 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-05 22:19 [PATCH 1/1] use documented cmpxchg api Pranith Kumar
2014-06-06 0:34 ` Peter Hurley
2014-06-06 1:03 ` Pranith Kumar
2014-06-06 10:55 ` Peter Hurley
2014-06-06 14:27 ` Pranith Kumar [this message]
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