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author | Tejun Heo <htejun@gmail.com> | 2005-12-13 14:48:31 +0900 |
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committer | Jeff Garzik <jgarzik@pobox.com> | 2005-12-13 01:34:45 -0500 |
commit | a2a7a662f80d8b7f2295a36de1f9b033ed0b910c (patch) | |
tree | a04872ba93c1eff094d2d37a0435e1d965d43f22 /drivers | |
parent | 575ab52a218e4ff0667a6cbd972c3af443ee8713 (diff) | |
download | op-kernel-dev-a2a7a662f80d8b7f2295a36de1f9b033ed0b910c.zip op-kernel-dev-a2a7a662f80d8b7f2295a36de1f9b033ed0b910c.tar.gz |
[PATCH] libata: implement ata_exec_internal()
This patch implements ata_exec_internal() function which performs
libata internal command execution. Previously, this was done by each
user by manually initializing a qc, issueing it, waiting for its
completion and handling errors. In addition to obvious code
factoring, using ata_exec_internal() fixes the following bugs.
* qc not freed on issue failure
* ap->qactive clearing could race with the next internal command
* race between timeout handling and irq
* ignoring error condition not represented in tf->status
Also, qc & hardware are not accessed anymore once it's completed,
making internal commands more conformant with general semantics.
ata_exec_internal() also makes it easy to issue internal commands from
multiple threads if that becomes necessary.
This patch only implements ata_exec_internal(). A following patch
will convert all users.
Signed-off-by: Tejun Heo <htejun@gmail.com>
--
Jeff, all patches have been regenerated against upstream branch as of
today. (575ab52a218e4ff0667a6cbd972c3af443ee8713)
Also, I took out a debug printk from ata_exec_internal (don't know how
that one got left there). Other than that, all patches are identical
to the previous posting.
Thanks. :-)
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/scsi/libata-core.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c index a0060cf..de80abe 100644 --- a/drivers/scsi/libata-core.c +++ b/drivers/scsi/libata-core.c @@ -1046,6 +1046,105 @@ static unsigned int ata_pio_modes(const struct ata_device *adev) return modes; } +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) +{ + struct ata_exec_internal_arg *arg = qc->private_data; + struct completion *waiting = arg->waiting; + + 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; + complete(waiting); + + return 0; +} + +/** + * ata_exec_internal - execute libata internal command + * @ap: Port to which the command is sent + * @dev: Device to which the command is sent + * @tf: Taskfile registers for the command and the result + * @dma_dir: Data tranfer direction of the command + * @buf: Data buffer of the command + * @buflen: Length of data buffer + * + * Executes libata internal command with timeout. @tf contains + * command on entry and result on return. Timeout and error + * conditions are reported via return value. No recovery action + * is taken after a command times out. It's caller's duty to + * clean up after timeout. + * + * LOCKING: + * None. Should be called with kernel context, might sleep. + */ + +static unsigned +ata_exec_internal(struct ata_port *ap, struct ata_device *dev, + struct ata_taskfile *tf, + int dma_dir, void *buf, unsigned int buflen) +{ + u8 command = tf->command; + struct ata_queued_cmd *qc; + DECLARE_COMPLETION(wait); + unsigned long flags; + struct ata_exec_internal_arg arg; + + spin_lock_irqsave(&ap->host_set->lock, flags); + + qc = ata_qc_new_init(ap, dev); + BUG_ON(qc == NULL); + + qc->tf = *tf; + qc->dma_dir = dma_dir; + if (dma_dir != DMA_NONE) { + ata_sg_init_one(qc, buf, buflen); + qc->nsect = buflen / ATA_SECT_SIZE; + } + + arg.waiting = &wait; + arg.tf = tf; + qc->private_data = &arg; + qc->complete_fn = ata_qc_complete_internal; + + if (ata_qc_issue(qc)) + goto issue_fail; + + spin_unlock_irqrestore(&ap->host_set->lock, flags); + + if (!wait_for_completion_timeout(&wait, ATA_TMOUT_INTERNAL)) { + spin_lock_irqsave(&ap->host_set->lock, flags); + + /* We're racing with irq here. If we lose, the + * following test prevents us from completing the qc + * again. If completion irq occurs after here but + * before the caller cleans up, it will result in a + * spurious interrupt. We can live with that. + */ + if (arg.waiting) { + qc->err_mask = AC_ERR_OTHER; + ata_qc_complete(qc); + printk(KERN_WARNING "ata%u: qc timeout (cmd 0x%x)\n", + ap->id, command); + } + + spin_unlock_irqrestore(&ap->host_set->lock, flags); + } + + return arg.err_mask; + + issue_fail: + ata_qc_free(qc); + spin_unlock_irqrestore(&ap->host_set->lock, flags); + return AC_ERR_OTHER; +} + static int ata_qc_wait_err(struct ata_queued_cmd *qc, struct completion *wait) { |