[PATCH] libata: make the owner of a qc responsible for freeing it

qc used to be freed automatically on command completion.  However, as
a qc can carry information about its completion status, it can be
useful to its owner/issuer after command completion.  This patch makes
freeing qc responsibility of its owner.  This simplifies
ata_exec_internal() and makes command turn-around for atapi request
sensing less hackish.

This change was originally suggested by Jeff Garzik.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 46ccea2..d58b659 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -235,7 +235,7 @@
 struct ata_queued_cmd;
 
 /* typedefs */
-typedef int (*ata_qc_cb_t) (struct ata_queued_cmd *qc);
+typedef void (*ata_qc_cb_t) (struct ata_queued_cmd *qc);
 
 struct ata_ioports {
 	unsigned long		cmd_addr;