From dc25ab067645eabd037f1a23d49a666f9e0b8c68 Mon Sep 17 00:00:00 2001
From: Sam Bobroff <sbobroff@linux.ibm.com>
Date: Mon, 5 Nov 2018 16:57:47 +1100
Subject: [PATCH] drm/ast: Fix incorrect free on ioregs
Git-commit: dc25ab067645eabd037f1a23d49a666f9e0b8c68
Patch-mainline: 4.20-rc5
References: bsc#1051510

If the platform has no IO space, ioregs is placed next to the already
allocated regs. In this case, it should not be separately freed.

This prevents a kernel warning from __vunmap "Trying to vfree()
nonexistent vm area" when unloading the driver.

Fixes: 0dd68309b9c5 ("drm/ast: Try to use MMIO registers when PIO isn't supported")

Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/ast/ast_main.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/ast/ast_main.c
+++ b/drivers/gpu/drm/ast/ast_main.c
@@ -583,7 +583,8 @@ void ast_driver_unload(struct drm_device
 	drm_mode_config_cleanup(dev);
 
 	ast_mm_fini(ast);
-	pci_iounmap(dev->pdev, ast->ioregs);
+	if (ast->ioregs != ast->regs + AST_IO_MM_OFFSET)
+		pci_iounmap(dev->pdev, ast->ioregs);
 	pci_iounmap(dev->pdev, ast->regs);
 	kfree(ast);
 }