[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/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 0e493236294941bf636f021f809dc60f06d60c76..15df633521d006d164192e1c38a729d58ebe73de 100644 (file)
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1072,24 +1072,12 @@ static unsigned int ata_pio_modes(const struct ata_device *adev)
           timing API will get this right anyway */
 }
 
-struct ata_exec_internal_arg {
-       unsigned int err_mask;
-       struct ata_taskfile *tf;
-       struct completion *waiting;
-};
-
-int ata_qc_complete_internal(struct ata_queued_cmd *qc)
+void ata_qc_complete_internal(struct ata_queued_cmd *qc)
 {
-       struct ata_exec_internal_arg *arg = qc->private_data;
-       struct completion *waiting = arg->waiting;
+       struct completion *waiting = qc->private_data;
 
-       if (!(qc->err_mask & ~AC_ERR_DEV))
-               qc->ap->ops->tf_read(qc->ap, arg->tf);
-       arg->err_mask = qc->err_mask;
-       arg->waiting = NULL;
+       qc->ap->ops->tf_read(qc->ap, &qc->tf);
        complete(waiting);
-
-       return 0;
 }
 
 /**
@@ -1120,7 +1108,7 @@ ata_exec_internal(struct ata_port *ap, struct ata_device *dev,
        struct ata_queued_cmd *qc;
        DECLARE_COMPLETION(wait);
        unsigned long flags;
-       struct ata_exec_internal_arg arg;
+       unsigned int err_mask;
 
        spin_lock_irqsave(&ap->host_set->lock, flags);
 
@@ -1134,9 +1122,7 @@ ata_exec_internal(struct ata_port *ap, struct ata_device *dev,
                qc->nsect = buflen / ATA_SECT_SIZE;
        }
 
-       arg.waiting = &wait;
-       arg.tf = tf;
-       qc->private_data = &arg;
+       qc->private_data = &wait;
        qc->complete_fn = ata_qc_complete_internal;
 
        if (ata_qc_issue(qc))
@@ -1153,7 +1139,7 @@ ata_exec_internal(struct ata_port *ap, struct ata_device *dev,
                 * before the caller cleans up, it will result in a
                 * spurious interrupt.  We can live with that.
                 */
-               if (arg.waiting) {
+               if (qc->flags & ATA_QCFLAG_ACTIVE) {
                        qc->err_mask = AC_ERR_OTHER;
                        ata_qc_complete(qc);
                        printk(KERN_WARNING "ata%u: qc timeout (cmd 0x%x)\n",
@@ -1163,7 +1149,12 @@ ata_exec_internal(struct ata_port *ap, struct ata_device *dev,
                spin_unlock_irqrestore(&ap->host_set->lock, flags);
        }
 
-       return arg.err_mask;
+       *tf = qc->tf;
+       err_mask = qc->err_mask;
+
+       ata_qc_free(qc);
+
+       return err_mask;
 
  issue_fail:
        ata_qc_free(qc);
@@ -3633,8 +3624,6 @@ void ata_qc_free(struct ata_queued_cmd *qc)
 
 void ata_qc_complete(struct ata_queued_cmd *qc)
 {
-       int rc;
-
        assert(qc != NULL);     /* ata_qc_from_tag _might_ return NULL */
        assert(qc->flags & ATA_QCFLAG_ACTIVE);
 
@@ -3648,17 +3637,7 @@ void ata_qc_complete(struct ata_queued_cmd *qc)
        qc->flags &= ~ATA_QCFLAG_ACTIVE;
 
        /* call completion callback */
-       rc = qc->complete_fn(qc);
-
-       /* if callback indicates not to complete command (non-zero),
-        * return immediately
-        */
-       if (rc != 0)
-               return;
-
-       ata_qc_free(qc);
-
-       VPRINTK("EXIT\n");
+       qc->complete_fn(qc);
 }
 
 static inline int ata_should_dma_map(struct ata_queued_cmd *qc)

diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 0e65bfe92e6fd7c860a14bddf71b51d00abd3989..ce3fe928a386767745dc1e1aec923be1be769898 100644 (file)
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -1219,7 +1219,7 @@ nothing_to_do:
        return 1;
 }
 
-static int ata_scsi_qc_complete(struct ata_queued_cmd *qc)
+static void ata_scsi_qc_complete(struct ata_queued_cmd *qc)
 {
        struct scsi_cmnd *cmd = qc->scsicmd;
        u8 *cdb = cmd->cmnd;
@@ -1256,7 +1256,7 @@ static int ata_scsi_qc_complete(struct ata_queued_cmd *qc)
 
        qc->scsidone(cmd);
 
-       return 0;
+       ata_qc_free(qc);
 }
 
 /**
@@ -1982,7 +1982,7 @@ void ata_scsi_badcmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *), u8
        done(cmd);
 }
 
-static int atapi_sense_complete(struct ata_queued_cmd *qc)
+static void atapi_sense_complete(struct ata_queued_cmd *qc)
 {
        if (qc->err_mask && ((qc->err_mask & AC_ERR_DEV) == 0))
                /* FIXME: not quite right; we don't want the
@@ -1993,7 +1993,7 @@ static int atapi_sense_complete(struct ata_queued_cmd *qc)
                ata_gen_ata_desc_sense(qc);
 
        qc->scsidone(qc->scsicmd);
-       return 0;
+       ata_qc_free(qc);
 }
 
 /* is it pointless to prefer PIO for "safety reasons"? */
@@ -2050,7 +2050,7 @@ static void atapi_request_sense(struct ata_queued_cmd *qc)
        DPRINTK("EXIT\n");
 }
 
-static int atapi_qc_complete(struct ata_queued_cmd *qc)
+static void atapi_qc_complete(struct ata_queued_cmd *qc)
 {
        struct scsi_cmnd *cmd = qc->scsicmd;
        unsigned int err_mask = qc->err_mask;
@@ -2060,7 +2060,7 @@ static int atapi_qc_complete(struct ata_queued_cmd *qc)
        if (unlikely(err_mask & AC_ERR_DEV)) {
                cmd->result = SAM_STAT_CHECK_CONDITION;
                atapi_request_sense(qc);
-               return 1;
+               return;
        }
 
        else if (unlikely(err_mask))
@@ -2100,7 +2100,7 @@ static int atapi_qc_complete(struct ata_queued_cmd *qc)
        }
 
        qc->scsidone(cmd);
-       return 0;
+       ata_qc_free(qc);
 }
 /**
  *     atapi_xlat - Initialize PACKET taskfile

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 46ccea2158924d71a2b1cd1166686c979465ad67..d58b659cf3f52729b9421a316df20e56f19ca904 100644 (file)
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -235,7 +235,7 @@ struct ata_port;
 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;