staging: sm750fb: add missing pci_release_region on error and removal

hw_sm750_map() calls pci_request_region() but never releases the
region on error paths or in lynxfb_pci_remove(). This causes a
resource leak that prevents the PCI region from being mapped again
after driver removal or a failed probe. A TODO comment in the code
acknowledges this missing cleanup.

Restructure the error handling in hw_sm750_map() to properly release
the PCI region on ioremap failures, and add pci_release_region() to
lynxfb_pci_remove().

Signed-off-by: Artem Lytkin <iprintercanon@gmail.com>
Cc: stable <stable@kernel.org>
Link: https://patch.msgid.link/20260216202038.1828-1-iprintercanon@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: 4RH1T3CT0R7

drivers/staging/sm750fb/sm750.c

@@ -1123,6 +1123,7 @@ static void lynxfb_pci_remove(struct pci_dev *pdev)
 
 	iounmap(sm750_dev->pvReg);
 	iounmap(sm750_dev->pvMem);
+	pci_release_region(pdev, 1);
 	kfree(g_settings);
 }
 

drivers/staging/sm750fb/sm750_hw.c

@@ -36,16 +36,11 @@ int hw_sm750_map(struct sm750_dev *sm750_dev, struct pci_dev *pdev)
 
 	pr_info("mmio phyAddr = %lx\n", sm750_dev->vidreg_start);
 
-	/*
-	 * reserve the vidreg space of smi adaptor
-	 * if you do this, you need to add release region code
-	 * in lynxfb_remove, or memory will not be mapped again
-	 * successfully
-	 */
+	/* reserve the vidreg space of smi adaptor */
 	ret = pci_request_region(pdev, 1, "sm750fb");
 	if (ret) {
 		pr_err("Can not request PCI regions.\n");
-		goto exit;
+		return ret;
 	}
 
 	/* now map mmio and vidmem */
@@ -54,7 +49,7 @@ int hw_sm750_map(struct sm750_dev *sm750_dev, struct pci_dev *pdev)
 	if (!sm750_dev->pvReg) {
 		pr_err("mmio failed\n");
 		ret = -EFAULT;
-		goto exit;
+		goto err_release_region;
 	}
 	pr_info("mmio virtual addr = %p\n", sm750_dev->pvReg);
 
@@ -79,13 +74,18 @@ int hw_sm750_map(struct sm750_dev *sm750_dev, struct pci_dev *pdev)
 	sm750_dev->pvMem =
 		ioremap_wc(sm750_dev->vidmem_start, sm750_dev->vidmem_size);
 	if (!sm750_dev->pvMem) {
-		iounmap(sm750_dev->pvReg);
 		pr_err("Map video memory failed\n");
 		ret = -EFAULT;
-		goto exit;
+		goto err_unmap_reg;
 	}
 	pr_info("video memory vaddr = %p\n", sm750_dev->pvMem);
-exit:
+
+	return 0;
+
+err_unmap_reg:
+	iounmap(sm750_dev->pvReg);
+err_release_region:
+	pci_release_region(pdev, 1);
 	return ret;
 }