drm/ast: Fix incorrect free on ioregs

BugLink: https://bugs.launchpad.net/bugs/1837161
commit dc25ab067645eabd037f1a23d49a666f9e0b8c68 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/gpu/drm/ast/ast_main.c b/drivers/gpu/drm/ast/ast_main.c
index dac355812adcbdcea7d68a40ff44bca90b0e0dcf..373700c05a00f9f3890d48fee79317edf77cedd8 100644 (file)
--- 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 *dev)
        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);
 }