linux-kernel - [PATCH 2/3] viafb: Fix initialization error paths

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Message-Id: <1272663589-4950-3-git-send-email-corbet@lwn.net>
Date:	Fri, 30 Apr 2010 15:39:48 -0600
From:	Jonathan Corbet <corbet@....net>
To:	linux-kernel@...r.kernel.org
Cc:	Harald Welte <laforge@...monks.org>, linux-fbdev@...r.kernel.org,
	JosephChan@....com.tw, ScottFang@...tech.com.cn,
	Bruno Prémont <bonbons@...ux-vserver.org>,
	Florian Tobias Schandinat <FlorianSchandinat@....de>
Subject: [PATCH 2/3] viafb: Fix initialization error paths

Properly localize error cleanup, and make sure that the iomem regions are
unmapped if framebuffer initialization fails.

Reported-by: Bruno Prémont <bonbons@...ux-vserver.org>
Signed-off-by: Jonathan Corbet <corbet@....net>
---
 drivers/video/via/via-core.c |   36 +++++++++++++++++++++++++-----------
 1 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/video/via/via-core.c b/drivers/video/via/via-core.c
index 58256d0..1c6835e 100644
--- a/drivers/video/via/via-core.c
+++ b/drivers/video/via/via-core.c
@@ -453,26 +453,40 @@ static int viafb_get_fb_size_from_pci(int chip_type)
  */
 static int __devinit via_pci_setup_mmio(struct viafb_dev *vdev)
 {
+	int ret;
 	/*
-	 * Hook up to the device registers.
+	 * Hook up to the device registers.  Note that we soldier
+	 * on if it fails; the framebuffer can operate (without
+	 * acceleration) without this region.
 	 */
 	vdev->engine_start = pci_resource_start(vdev->pdev, 1);
 	vdev->engine_len = pci_resource_len(vdev->pdev, 1);
-	/* If this fails, others will notice later */
 	vdev->engine_mmio = ioremap_nocache(vdev->engine_start,
 			vdev->engine_len);
-
+	if (vdev->engine_mmio == NULL)
+		dev_err(&vdev->pdev->dev,
+				"Unable to map engine MMIO; operation will be "
+				"slow and crippled.\n");
 	/*
-	 * Likewise with I/O memory.
+	 * Map in framebuffer memory.  For now, failure here is
+	 * fatal.  Unfortunately, in the absence of significant
+	 * vmalloc space, failure here is also entirely plausible.
+	 * Eventually we want to move away from mapping this
+	 * entire region.
 	 */
 	vdev->fbmem_start = pci_resource_start(vdev->pdev, 0);
-	vdev->fbmem_len = viafb_get_fb_size_from_pci(vdev->chip_type);
-	if (vdev->fbmem_len < 0)
-		return vdev->fbmem_len;
+	ret = vdev->fbmem_len = viafb_get_fb_size_from_pci(vdev->chip_type);
+	if (ret < 0)
+		goto out_unmap;
 	vdev->fbmem = ioremap_nocache(vdev->fbmem_start, vdev->fbmem_len);
-	if (vdev->fbmem == NULL)
-		return -ENOMEM;
+	if (vdev->fbmem == NULL) {
+		ret = -ENOMEM;
+		goto out_unmap;
+	}
 	return 0;
+out_unmap:
+	iounmap(vdev->engine_mmio);
+	return ret;
 }
 
 static void __devexit via_pci_teardown_mmio(struct viafb_dev *vdev)
@@ -565,13 +579,13 @@ static int __devinit via_pci_probe(struct pci_dev *pdev,
 	spin_lock_init(&global_dev.reg_lock);
 	ret = via_pci_setup_mmio(&global_dev);
 	if (ret)
-		goto out_teardown;
+		return ret;
 	/*
 	 * Set up the framebuffer device
 	 */
 	ret = via_fb_pci_probe(&global_dev);
 	if (ret)
-		return ret;
+		goto out_teardown;
 	/*
 	 * Create our subdevices.
 	 */
-- 
1.7.0.1

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