ata: pata_pxa: Fix potential NULL pointer dereference in pxa_ata_probe()

devm_ioremap() returns NULL on error. Currently, pxa_ata_probe() does
not check for this case, which can result in a NULL pointer dereference.

Add NULL check after devm_ioremap() to prevent this issue.

Fixes: 2dc6c6f ("[ARM] pata_pxa: DMA-capable PATA driver")
Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>

Author: Henry Martin

drivers/ata/pata_pxa.c

@@ -223,10 +223,16 @@ static int pxa_ata_probe(struct platform_device *pdev)
 
 	ap->ioaddr.cmd_addr	= devm_ioremap(&pdev->dev, cmd_res->start,
 						resource_size(cmd_res));
+	if (!ap->ioaddr.cmd_addr)
+		return -ENOMEM;
 	ap->ioaddr.ctl_addr	= devm_ioremap(&pdev->dev, ctl_res->start,
 						resource_size(ctl_res));
+	if (!ap->ioaddr.ctl_addr)
+		return -ENOMEM;
 	ap->ioaddr.bmdma_addr	= devm_ioremap(&pdev->dev, dma_res->start,
 						resource_size(dma_res));
+	if (!ap->ioaddr.bmdma_addr)
+		return -ENOMEM;
 
 	/*
 	 * Adjust register offsets