drivers/ata/sata_dwc_460ex.c: add missing kfree

Currently, error handling code in this function calls the function
sata_dwc_port_stop, but this function has essentially no effect if hsdevp
has not been stored in ap, which is the case throughout this function.  The
only effect is to print a debugging message including ap->print_id.

The code is rewritten to not call sata_dwc_port_stop, but instead to jump
to a local label that prints the original error message and the print_id
information.  In the case where hsdevp has been already allocated (but not
yet stored in ap), this value is freed as well.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@exists@
local idexpression x;
statement S,S1;
expression E;
identifier fl;
expression *ptr != NULL;
@@

x = \(kmalloc\|kzalloc\|kcalloc\)(...);
...
if (x == NULL) S
<... when != x
     when != if (...) { <+...kfree(x)...+> }
     when any
     when != true x == NULL
x->fl
...>
(
if (x == NULL) S1
|
if (...) { ... when != x
               when forall
(
 return \(0\|<+...x...+>\|ptr\);
|
* return ...;
)
}
)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

1 files changed, 6 insertions, 8 deletions

diff --git a/drivers/ata/sata_dwc_460ex.c b/drivers/ata/sata_dwc_460ex.c
index 0a9a774a7e1e..5c4237452f50 100644
--- a/drivers/ata/sata_dwc_460ex.c
+++ b/drivers/ata/sata_dwc_460ex.c
@@ -1329,7 +1329,7 @@ static int sata_dwc_port_start(struct ata_port *ap)
                         dev_err(ap->dev, "%s: dma_alloc_coherent failed\n",
                                  __func__);
                         err = -ENOMEM;
-                        goto CLEANUP;
+                        goto CLEANUP_ALLOC;
                 }
         }
 
@@ -1349,15 +1349,13 @@ static int sata_dwc_port_start(struct ata_port *ap)
         /* Clear any error bits before libata starts issuing commands */
         clear_serror();
         ap->private_data = hsdevp;
+        dev_dbg(ap->dev, "%s: done\n", __func__);
+        return 0;
 
+CLEANUP_ALLOC:
+        kfree(hsdevp);
 CLEANUP:
-        if (err) {
-                sata_dwc_port_stop(ap);
-                dev_dbg(ap->dev, "%s: fail\n", __func__);
-        } else {
-                dev_dbg(ap->dev, "%s: done\n", __func__);
-        }
-
+        dev_dbg(ap->dev, "%s: fail. ap->id = %d\n", __func__, ap->print_id);
         return err;
 }