提交 a2a7a662 编写于 作者: T Tejun Heo 提交者: Jeff Garzik

[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: NTejun Heo <htejun@gmail.com>

--

Jeff, all patches have been regenerated against upstream branch as of
today.  (575ab52a)

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: NJeff Garzik <jgarzik@pobox.com>
上级 575ab52a
......@@ -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)
{
......
......@@ -135,6 +135,8 @@ enum {
ATA_TMOUT_BOOT_QUICK = 7 * HZ, /* hueristic */
ATA_TMOUT_CDB = 30 * HZ,
ATA_TMOUT_CDB_QUICK = 5 * HZ,
ATA_TMOUT_INTERNAL = 30 * HZ,
ATA_TMOUT_INTERNAL_QUICK = 5 * HZ,
/* ATA bus states */
BUS_UNKNOWN = 0,
......
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