linux-kernel - [tip:x86/cleanups] x86/pci-calgary: Fix iommu_free() comparison of unsigned expression >= 0

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Message-ID: <tip-68dee8e2f2cacc54d038394e70d22411dee89da2@git.kernel.org>
Date:   Sat, 4 Feb 2017 08:19:17 -0800
From:   tip-bot for Nikola Pajkovsky <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     mingo@...nel.org, mulix@...ix.org, npajkovsky@...e.cz,
        jdmason@...zu.us, hpa@...or.com, tglx@...utronix.de,
        linux-kernel@...r.kernel.org
Subject: [tip:x86/cleanups] x86/pci-calgary: Fix iommu_free() comparison of
 unsigned expression >= 0

Commit-ID:  68dee8e2f2cacc54d038394e70d22411dee89da2
Gitweb:     http://git.kernel.org/tip/68dee8e2f2cacc54d038394e70d22411dee89da2
Author:     Nikola Pajkovsky <npajkovsky@...e.cz>
AuthorDate: Tue, 15 Nov 2016 09:47:49 +0100
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Sat, 4 Feb 2017 09:27:06 +0100

x86/pci-calgary: Fix iommu_free() comparison of unsigned expression >= 0

commit 8fd524b355da ("x86: Kill bad_dma_address variable") has killed
bad_dma_address variable and used instead of macro DMA_ERROR_CODE
which is always zero. Since dma_addr is unsigned, the statement

   dma_addr >= DMA_ERROR_CODE

is always true, and not needed.

arch/x86/kernel/pci-calgary_64.c: In function ‘iommu_free’:
arch/x86/kernel/pci-calgary_64.c:299:2: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits]
  if (unlikely((dma_addr >= DMA_ERROR_CODE) && (dma_addr < badend))) {

Fixes: 8fd524b355da ("x86: Kill bad_dma_address variable")
Signed-off-by: Nikola Pajkovsky <npajkovsky@...e.cz>
Cc: iommu@...ts.linux-foundation.org
Cc: Jon Mason <jdmason@...zu.us>
Cc: Muli Ben-Yehuda <mulix@...ix.org>
Link: http://lkml.kernel.org/r/7612c0f9dd7c1290407dbf8e809def922006920b.1479161177.git.npajkovsky@suse.cz
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>

---
 arch/x86/kernel/pci-calgary_64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/pci-calgary_64.c b/arch/x86/kernel/pci-calgary_64.c
index 5d400ba..d475179 100644
--- a/arch/x86/kernel/pci-calgary_64.c
+++ b/arch/x86/kernel/pci-calgary_64.c
@@ -296,7 +296,7 @@ static void iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
 
 	/* were we called with bad_dma_address? */
 	badend = DMA_ERROR_CODE + (EMERGENCY_PAGES * PAGE_SIZE);
-	if (unlikely((dma_addr >= DMA_ERROR_CODE) && (dma_addr < badend))) {
+	if (unlikely(dma_addr < badend)) {
 		WARN(1, KERN_ERR "Calgary: driver tried unmapping bad DMA "
 		       "address 0x%Lx\n", dma_addr);
 		return;