Re: [PATCH v4 01/10] libata: fix ata_host_alloc_pinfo()

Avoid static checkers warnings about a potential NULL pointer
dereference for the port info variable pi. To do so, test that at least
one port info is available on entry to ata_host_alloc_pinfo() and start
the ata port initialization for loop with pi initialized to a non-NULL
pointer. Within the for loop, get the next port info (if it is not NULL)
after initializing the ata port using the previous port info.

Reported-by: kernel test robot <redacted>
Signed-off-by: Damien Le Moal <redacted>
---
  drivers/ata/libata-core.c | 16 +++++++++++-----
  1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 61c762961ca8..b17e161c07e2 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c

@@ -5441,16 +5441,17 @@ struct ata_host *ata_host_alloc_pinfo(struct device *dev,
  	struct ata_host *host;
  	int i, j;
  
+	/* We must have at least one port info */
+	if (!ppi[0])
+		return NULL;
+
  	host = ata_host_alloc(dev, n_ports);
  	if (!host)
  		return NULL;
  
-	for (i = 0, j = 0, pi = NULL; i < host->n_ports; i++) {
+	for (i = 0, j = 0, pi = ppi[0]; i < host->n_ports; i++) {
  		struct ata_port *ap = host->ports[i];
  
-		if (ppi[j])
-			pi = ppi[j++];
-
  		ap->pio_mask = pi->pio_mask;
  		ap->mwdma_mask = pi->mwdma_mask;
  		ap->udma_mask = pi->udma_mask;

@@ -5458,8 +5459,13 @@ struct ata_host *ata_host_alloc_pinfo(struct device *dev,
  		ap->link.flags |= pi->link_flags;
  		ap->ops = pi->port_ops;
  
-		if (!host->ops && (pi->port_ops != &ata_dummy_port_ops))
+		if (!host->ops && pi->port_ops != &ata_dummy_port_ops)
  			host->ops = pi->port_ops;
+
+		if (ppi[j + 1]) {
+			j++;
+			pi = ppi[j];
+		}
  	}
  
  	return host;