Tejun Heo wrote:
This patch implements hotplug by polling - hp-poll. It is used for
* hotplug event detection on controllers which don't provide PHY
status changed interrupt.
* hotplug event detection on disabled ports after reset failure.
libata used to leave such ports in frozen state to protect the
system from malfunctioning controller/device. With hp-poll, hotplug
events no such ports are watched safely by polling, such that
removing/replacing the malfunctioning device triggers EH retry on
the port.
There are three port ops for hp-poll - hp_poll_activate, hp_poll,
hp_poll_deactivate. Only hp_poll is mandatory for hp-poll to work.
This patch also implements SATA standard polling callbacks which poll
SError.N/X bits - sata_std_hp_poll_activate() and sata_std_hp_poll().
By default, hp-poll is enabled only on disabled ports. If a LLD
doesn't support hotplug interrupts but can poll for hotplug events, it
should indicate it by setting ATA_FLAG_HP_POLLING which tells libata
to turn on hp-poll by default.
Putting port into any static powersave mode or setting
libata.hotplug_polling_interval to zero disables hp-poll.
Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
NAK, there is no reason why a global poll list is needed. Simply having
a struct workqueue in each schedule-able entity implicitly creates such
a list. But regardless, this is another example of adding
cross-controller synchronization, where none is needed.
If the worker fired per-host_set, then you could use an ata_port dynamic
flag to indicate the poll-active ports, for the ata_hp_poll_worker() loop.
If the worker fires per-port, then no loop or mutex is needed at all.
You could simply call the hp_poll hook.
@@ -633,6 +637,10 @@ struct ata_port_operations {
void (*error_handler) (struct ata_port *ap);
void (*post_internal_cmd) (struct ata_queued_cmd *qc);
+ void (*hp_poll_activate) (struct ata_port *ap);
+ void (*hp_poll_deactivate) (struct ata_port *ap);
+ int (*hp_poll) (struct ata_port *ap);
+
irqreturn_t (*irq_handler)(int, void *, struct pt_regs *);
void (*irq_clear) (struct ata_port *);
All new hooks require at least a one-two sentence description in the
DocBook docs, telling driver writers how to use them.
Jeff
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