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From:   Denis Efremov <efremov@linux.com>
To:     Bjorn Helgaas <bhelgaas@google.com>
Cc:     Denis Efremov <efremov@linux.com>, linux-kernel@vger.kernel.org,
        linux-pci@vger.kernel.org, Andrew Murray <andrew.murray@arm.com>,
        kvm@vger.kernel.org, Cornelia Huck <cohuck@redhat.com>,
        Alex Williamson <alex.williamson@redhat.com>
Subject: [PATCH v3 17/26] vfio_pci: Loop using PCI_STD_NUM_BARS
Date:   Mon, 16 Sep 2019 23:41:49 +0300
Message-Id: <20190916204158.6889-18-efremov@linux.com>
In-Reply-To: <20190916204158.6889-1-efremov@linux.com>
References: <20190916204158.6889-1-efremov@linux.com>
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Refactor loops to use idiomatic C style and avoid the fencepost error
of using "i < PCI_STD_RESOURCE_END" when "i <= PCI_STD_RESOURCE_END"
is required, e.g., commit 2f686f1d9bee ("PCI: Correct PCI_STD_RESOURCE_END
usage").

To iterate through all possible BARs, loop conditions changed to the
*number* of BARs "i < PCI_STD_NUM_BARS", instead of the index of the last
valid BAR "i <= PCI_STD_RESOURCE_END".

Cc: Cornelia Huck <cohuck@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Denis Efremov <efremov@linux.com>
---
 drivers/vfio/pci/vfio_pci.c         | 11 ++++++----
 drivers/vfio/pci/vfio_pci_config.c  | 32 +++++++++++++++--------------
 drivers/vfio/pci/vfio_pci_private.h |  4 ++--
 3 files changed, 26 insertions(+), 21 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 703948c9fbe1..cb7d220d3246 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -110,13 +110,15 @@ static inline bool vfio_pci_is_vga(struct pci_dev *pdev)
 static void vfio_pci_probe_mmaps(struct vfio_pci_device *vdev)
 {
 	struct resource *res;
-	int bar;
+	int i;
 	struct vfio_pci_dummy_resource *dummy_res;
 
 	INIT_LIST_HEAD(&vdev->dummy_resources_list);
 
-	for (bar = PCI_STD_RESOURCES; bar <= PCI_STD_RESOURCE_END; bar++) {
-		res = vdev->pdev->resource + bar;
+	for (i = 0; i < PCI_STD_NUM_BARS; i++) {
+		int bar = i + PCI_STD_RESOURCES;
+
+		res = &vdev->pdev->resource[bar];
 
 		if (!IS_ENABLED(CONFIG_VFIO_PCI_MMAP))
 			goto no_mmap;
@@ -399,7 +401,8 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev)
 
 	vfio_config_free(vdev);
 
-	for (bar = PCI_STD_RESOURCES; bar <= PCI_STD_RESOURCE_END; bar++) {
+	for (i = 0; i < PCI_STD_NUM_BARS; i++) {
+		bar = i + PCI_STD_RESOURCES;
 		if (!vdev->barmap[bar])
 			continue;
 		pci_iounmap(pdev, vdev->barmap[bar]);
diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index f0891bd8444c..90c0b80f8acf 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -450,30 +450,32 @@ static void vfio_bar_fixup(struct vfio_pci_device *vdev)
 {
 	struct pci_dev *pdev = vdev->pdev;
 	int i;
-	__le32 *bar;
+	__le32 *vbar;
 	u64 mask;
 
-	bar = (__le32 *)&vdev->vconfig[PCI_BASE_ADDRESS_0];
+	vbar = (__le32 *)&vdev->vconfig[PCI_BASE_ADDRESS_0];
 
-	for (i = PCI_STD_RESOURCES; i <= PCI_STD_RESOURCE_END; i++, bar++) {
-		if (!pci_resource_start(pdev, i)) {
-			*bar = 0; /* Unmapped by host = unimplemented to user */
+	for (i = 0; i < PCI_STD_NUM_BARS; i++, vbar++) {
+		int bar = i + PCI_STD_RESOURCES;
+
+		if (!pci_resource_start(pdev, bar)) {
+			*vbar = 0; /* Unmapped by host = unimplemented to user */
 			continue;
 		}
 
-		mask = ~(pci_resource_len(pdev, i) - 1);
+		mask = ~(pci_resource_len(pdev, bar) - 1);
 
-		*bar &= cpu_to_le32((u32)mask);
-		*bar |= vfio_generate_bar_flags(pdev, i);
+		*vbar &= cpu_to_le32((u32)mask);
+		*vbar |= vfio_generate_bar_flags(pdev, bar);
 
-		if (*bar & cpu_to_le32(PCI_BASE_ADDRESS_MEM_TYPE_64)) {
-			bar++;
-			*bar &= cpu_to_le32((u32)(mask >> 32));
+		if (*vbar & cpu_to_le32(PCI_BASE_ADDRESS_MEM_TYPE_64)) {
+			vbar++;
+			*vbar &= cpu_to_le32((u32)(mask >> 32));
 			i++;
 		}
 	}
 
-	bar = (__le32 *)&vdev->vconfig[PCI_ROM_ADDRESS];
+	vbar = (__le32 *)&vdev->vconfig[PCI_ROM_ADDRESS];
 
 	/*
 	 * NB. REGION_INFO will have reported zero size if we weren't able
@@ -483,14 +485,14 @@ static void vfio_bar_fixup(struct vfio_pci_device *vdev)
 	if (pci_resource_start(pdev, PCI_ROM_RESOURCE)) {
 		mask = ~(pci_resource_len(pdev, PCI_ROM_RESOURCE) - 1);
 		mask |= PCI_ROM_ADDRESS_ENABLE;
-		*bar &= cpu_to_le32((u32)mask);
+		*vbar &= cpu_to_le32((u32)mask);
 	} else if (pdev->resource[PCI_ROM_RESOURCE].flags &
 					IORESOURCE_ROM_SHADOW) {
 		mask = ~(0x20000 - 1);
 		mask |= PCI_ROM_ADDRESS_ENABLE;
-		*bar &= cpu_to_le32((u32)mask);
+		*vbar &= cpu_to_le32((u32)mask);
 	} else
-		*bar = 0;
+		*vbar = 0;
 
 	vdev->bardirty = false;
 }
diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h
index ee6ee91718a4..8a2c7607d513 100644
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -86,8 +86,8 @@ struct vfio_pci_reflck {
 
 struct vfio_pci_device {
 	struct pci_dev		*pdev;
-	void __iomem		*barmap[PCI_STD_RESOURCE_END + 1];
-	bool			bar_mmap_supported[PCI_STD_RESOURCE_END + 1];
+	void __iomem		*barmap[PCI_STD_NUM_BARS];
+	bool			bar_mmap_supported[PCI_STD_NUM_BARS];
 	u8			*pci_config_map;
 	u8			*vconfig;
 	struct perm_bits	*msi_perm;
-- 
2.21.0