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Commit a1104016 authored by Julia Lawall's avatar Julia Lawall Committed by Jeff Garzik
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drivers/ata/libata: Move dereference after NULL test 

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: default avatarJulia Lawall <julia@diku.dk>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
parent e65cc194

drivers/ata/libata-core.c

+6 −3
Original line number Original line Diff line number Diff line
@@ -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)

void ata_qc_free(struct ata_queued_cmd *qc)

{

{

	struct ata_port *ap = qc->ap;

	struct ata_port *ap;

	unsigned int tag;

	unsigned int tag;





	WARN_ON_ONCE(qc == NULL); /* ata_qc_from_tag _might_ return NULL */

	WARN_ON_ONCE(qc == NULL); /* ata_qc_from_tag _might_ return NULL */

	ap = qc->ap;





	qc->flags = 0;

	qc->flags = 0;

	tag = qc->tag;

	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)

void __ata_qc_complete(struct ata_queued_cmd *qc)

{

{

	struct ata_port *ap = qc->ap;

	struct ata_port *ap;

	struct ata_link *link = qc->dev->link;

	struct ata_link *link;





	WARN_ON_ONCE(qc == NULL); /* ata_qc_from_tag _might_ return NULL */

	WARN_ON_ONCE(qc == NULL); /* ata_qc_from_tag _might_ return NULL */

	WARN_ON_ONCE(!(qc->flags & ATA_QCFLAG_ACTIVE));

	WARN_ON_ONCE(!(qc->flags & ATA_QCFLAG_ACTIVE));

	ap = qc->ap;

	link = qc->dev->link;





	if (likely(qc->flags & ATA_QCFLAG_DMAMAP))

	if (likely(qc->flags & ATA_QCFLAG_DMAMAP))

		ata_sg_clean(qc);

		ata_sg_clean(qc);