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drivers/ata/libata: Move dereference after NULL test

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In each case, if the NULL test on qc is needed, then the derefernce
should be after the NULL test.

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

// <smpl>
@match exists@
expression x, E;
identifier fld;
@@

* x->fld
  ... when != \(x = E\|&x\)
* x == NULL
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This commit is contained in:
Julia Lawall 2009-10-17 08:41:47 +02:00 committed by Jeff Garzik
parent e65cc194f7
commit a1104016ce
1 changed files with 6 additions and 3 deletions
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9
drivers/ata/libata-core.c
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@ -4919,10 +4919,11 @@ struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev)
*/
void ata_qc_free(struct ata_queued_cmd *qc)
{
struct ata_port *ap = qc->ap;
struct ata_port *ap;
unsigned int tag;
WARN_ON_ONCE(qc == NULL); /* ata_qc_from_tag _might_ return NULL */
ap = qc->ap;
qc->flags = 0;
tag = qc->tag;
@ -4934,11 +4935,13 @@ void ata_qc_free(struct ata_queued_cmd *qc)
void __ata_qc_complete(struct ata_queued_cmd *qc)
{
struct ata_port *ap = qc->ap;
struct ata_link *link = qc->dev->link;
struct ata_port *ap;
struct ata_link *link;
WARN_ON_ONCE(qc == NULL); /* ata_qc_from_tag _might_ return NULL */
WARN_ON_ONCE(!(qc->flags & ATA_QCFLAG_ACTIVE));
ap = qc->ap;
link = qc->dev->link;
if (likely(qc->flags & ATA_QCFLAG_DMAMAP))
ata_sg_clean(qc);