libata: remove superfluous NULL pointer checks

host->ports[] always contain pointers to valid port structures since
a "dummy port" structure is used in case if there is no physical port.

This patch takes care of two entries from Dan's list:

drivers/ata/sata_sil.c +535 sil_interrupt(13) warning: variable derefenced before check 'ap'
drivers/ata/sata_mv.c +2517 mv_unexpected_intr(6) warning: variable derefenced before check 'ap'

and of another needless NULL pointer check in pata_octeon_cf.c.

Reported-by: Dan Carpenter <error27@gmail.com>
Cc: corbet@lwn.net
Cc: eteo@redhat.com
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

3 files changed, 4 insertions, 3 deletions

diff --git a/drivers/ata/pata_octeon_cf.c b/drivers/ata/pata_octeon_cf.c
index 8d9343accf3c..abdd19fe990a 100644
--- a/drivers/ata/pata_octeon_cf.c
+++ b/drivers/ata/pata_octeon_cf.c
@@ -653,7 +653,8 @@ static irqreturn_t octeon_cf_interrupt(int irq, void *dev_instance)
 
                 ap = host->ports[i];
                 ocd = ap->dev->platform_data;
-                if (!ap || (ap->flags & ATA_FLAG_DISABLED))
+
+                if (ap->flags & ATA_FLAG_DISABLED)
                         continue;
 
                 ocd = ap->dev->platform_data;
diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index 23714aefb825..c19417e02208 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -2514,7 +2514,7 @@ static void mv_unexpected_intr(struct ata_port *ap, int edma_was_enabled)
         char *when = "idle";
 
         ata_ehi_clear_desc(ehi);
-        if (!ap || (ap->flags & ATA_FLAG_DISABLED)) {
+        if (ap->flags & ATA_FLAG_DISABLED) {
                 when = "disabled";
         } else if (edma_was_enabled) {
                 when = "EDMA enabled";
diff --git a/drivers/ata/sata_sil.c b/drivers/ata/sata_sil.c
index 030ec079b184..35bd5cc7f285 100644
--- a/drivers/ata/sata_sil.c
+++ b/drivers/ata/sata_sil.c
@@ -532,7 +532,7 @@ static irqreturn_t sil_interrupt(int irq, void *dev_instance)
                 struct ata_port *ap = host->ports[i];
                 u32 bmdma2 = readl(mmio_base + sil_port[ap->port_no].bmdma2);
 
-                if (unlikely(!ap || ap->flags & ATA_FLAG_DISABLED))
+                if (unlikely(ap->flags & ATA_FLAG_DISABLED))
                         continue;
 
                 /* turn off SATA_IRQ if not supported */