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(), sata_std_hp_poll(),
sata_std_hp_poll_port_excl() and sata_std_hp_poll_hostset_excl().
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.
Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
---
drivers/scsi/libata-core.c | 134 ++++++++++++++++++++++++++++++++++++++++++++
drivers/scsi/libata-eh.c | 134 +++++++++++++++++++++++++++++++++++++++++++-
drivers/scsi/libata.h | 5 ++
include/linux/libata.h | 12 ++++
4 files changed, 283 insertions(+), 2 deletions(-)
7af09db1d75b71f1e45ec9ea1163edab03af56c9
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 46ae4bc..8ed0c37 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -2840,6 +2840,126 @@ void ata_std_postreset(struct ata_port *
}
/**
+ * sata_std_hp_poll_activate - standard SATA hotplug polling activation
+ * @ap: the target ata_port
+ *
+ * Activate SATA std hotplug polling.
+ *
+ * LOCKING:
+ * Kernel thread context (may sleep).
+ */
+void sata_std_hp_poll_activate(struct ata_port *ap)
+{
+ u32 serror;
+
+ sata_scr_read(ap, SCR_ERROR, &serror);
+ serror &= SERR_PHYRDY_CHG | SERR_DEV_XCHG;
+ if (serror)
+ sata_scr_write(ap, SCR_ERROR, serror);
+
+ ap->hp_poll_data = 0;
+}
+
+/**
+ * sata_std_hp_poll - standard SATA hotplug polling callback
+ * @ap: the target ata_port
+ *
+ * Poll SError.N/X for hotplug event. Hotplug event is triggered
+ * only after PHY stays stable for at least one full polling
+ * interval after the first event detection.
+ *
+ * LOCKING:
+ * spin_lock_irqsave(host_set lock)
+ *
+ * RETURNS:
+ * 1 if hotplug event has occurred, 0 otherwise.
+ */
+int sata_std_hp_poll(struct ata_port *ap)
+{
+ unsigned long state = (unsigned long)ap->hp_poll_data;
+ u32 serror;
+ int rc = 0;
+
+ sata_scr_read(ap, SCR_ERROR, &serror);
+ serror &= SERR_PHYRDY_CHG | SERR_DEV_XCHG;
+
+ switch (state) {
+ case 0:
+ if (serror) {
+ /* PHY status could be bouncing crazy due to
+ * faulty controller or device. Don't fire
+ * hotplug event till hotplug event stays
+ * quiescent for one full polling interval.
+ */
+ sata_scr_write(ap, SCR_ERROR, serror);
+ state = 1;
+ }
+ break;
+
+ case 1:
+ if (!serror)
+ rc = 1;
+ else
+ sata_scr_write(ap, SCR_ERROR, serror);
+ break;
+ }
+
+ ap->hp_poll_data = (void *)(unsigned long)state;
+
+ return rc;
+}
+
+/**
+ * sata_std_hp_poll_port_excl - sata_std_hp_poll with port exclusion
+ * @ap: the target ata_port
+ *
+ * SATA standard hp_poll callback for controllers which don't
+ * allow access to SCR registers while the port is active.
+ *
+ * LOCKING:
+ * spin_lock_irqsave(host_set lock)
+ *
+ * RETURNS:
+ * 1 if hotplug event has occurred, 0 otherwise.
+ */
+int sata_std_hp_poll_port_excl(struct ata_port *ap)
+{
+ if (ap->qc_active)
+ return 0;
+
+ return sata_std_hp_poll(ap);
+}
+
+/**
+ * sata_std_hp_poll_hostset_excl - sata_std_hp_poll with host_set exclusion
+ * @ap: the target ata_port
+ *
+ * SATA standard hp_poll callback for controllers which don't
+ * allow access to SCR registers while any port in the host_set
+ * is active. How dumb can you get? Surprise, VIA did it.
+ *
+ * LOCKING:
+ * spin_lock_irqsave(host_set lock)
+ *
+ * RETURNS:
+ * 1 if hotplug event has occurred, 0 otherwise.
+ */
+int sata_std_hp_poll_hostset_excl(struct ata_port *ap)
+{
+ struct ata_host_set *host_set = ap->host_set;
+ int i;
+
+ for (i = 0; i < host_set->n_ports; i++) {
+ struct ata_port *t_ap = host_set->ports[i];
+
+ if (t_ap->qc_active)
+ return 0;
+ }
+
+ return sata_std_hp_poll(ap);
+}
+
+/**
* ata_dev_same_device - Determine whether new ID matches configured device
* @dev: device to compare against
* @new_class: class of the new device
@@ -5290,6 +5410,7 @@ #endif
INIT_WORK(&ap->scsi_rescan_task, ata_scsi_dev_rescan, ap);
INIT_LIST_HEAD(&ap->eh_done_q);
init_waitqueue_head(&ap->eh_wait_q);
+ INIT_LIST_HEAD(&ap->hp_poll_entry);
/* set cable type */
ap->cbl = ATA_CBL_NONE;
@@ -5586,6 +5707,9 @@ void ata_port_detach(struct ata_port *ap
cancel_delayed_work(&ap->hotplug_task);
flush_workqueue(ata_aux_wq);
+ /* deactivate hotplug polling */
+ ata_hp_poll_deactivate(ap);
+
/* remove the associated SCSI host */
scsi_remove_host(ap->host);
}
@@ -5832,6 +5956,12 @@ static int __init ata_init(void)
static void __exit ata_exit(void)
{
+ /* hp_poll_list gotta be empty by now and thus hp_poll_work
+ * isn't rearming.
+ */
+ WARN_ON(!list_empty(&hp_poll_list));
+ cancel_delayed_work(&hp_poll_work);
+
destroy_workqueue(ata_wq);
destroy_workqueue(ata_aux_wq);
}
@@ -5966,6 +6096,10 @@ EXPORT_SYMBOL_GPL(ata_std_prereset);
EXPORT_SYMBOL_GPL(ata_std_softreset);
EXPORT_SYMBOL_GPL(sata_std_hardreset);
EXPORT_SYMBOL_GPL(ata_std_postreset);
+EXPORT_SYMBOL_GPL(sata_std_hp_poll_activate);
+EXPORT_SYMBOL_GPL(sata_std_hp_poll);
+EXPORT_SYMBOL_GPL(sata_std_hp_poll_port_excl);
+EXPORT_SYMBOL_GPL(sata_std_hp_poll_hostset_excl);
EXPORT_SYMBOL_GPL(ata_dev_revalidate);
EXPORT_SYMBOL_GPL(ata_dev_classify);
EXPORT_SYMBOL_GPL(ata_dev_pair);
diff --git a/drivers/scsi/libata-eh.c b/drivers/scsi/libata-eh.c
index 4b6aa30..bd89608 100644
--- a/drivers/scsi/libata-eh.c
+++ b/drivers/scsi/libata-eh.c
@@ -34,6 +34,8 @@
#include <linux/config.h>
#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_eh.h>
@@ -45,6 +47,17 @@ #include <linux/libata.h>
#include "libata.h"
+static unsigned long hotplug_polling_interval = 2000;
+module_param(hotplug_polling_interval, ulong, 0644);
+MODULE_PARM_DESC(hotplug_polling_interval,
+ "Hotplug polling interval in milliseconds (default 2000)");
+
+static void ata_hp_poll_worker(void *data);
+
+static DEFINE_MUTEX(hp_poll_mutex);
+struct list_head hp_poll_list = LIST_HEAD_INIT(hp_poll_list);
+DECLARE_WORK(hp_poll_work, ata_hp_poll_worker, NULL);
+
static void __ata_port_freeze(struct ata_port *ap);
static void ata_eh_finish(struct ata_port *ap);
static void ata_eh_handle_port_suspend(struct ata_port *ap);
@@ -617,7 +630,10 @@ int ata_port_freeze(struct ata_port *ap)
* ata_eh_freeze_port - EH helper to freeze port
* @ap: ATA port to freeze
*
- * Freeze @ap.
+ * Freeze @ap. As the 'freeze' operation means 'shutdown event
+ * reporting', it is a perfect place to deactivate hp-poll. Note
+ * that ata_port_freeze() always invokes EH and eventually this
+ * function, so deactivating hp-poll in this function is enough.
*
* LOCKING:
* None.
@@ -629,6 +645,8 @@ void ata_eh_freeze_port(struct ata_port
if (!ap->ops->error_handler)
return;
+ ata_hp_poll_deactivate(ap);
+
spin_lock_irqsave(ap->lock, flags);
__ata_port_freeze(ap);
spin_unlock_irqrestore(ap->lock, flags);
@@ -638,7 +656,7 @@ void ata_eh_freeze_port(struct ata_port
* ata_port_thaw_port - EH helper to thaw port
* @ap: ATA port to thaw
*
- * Thaw frozen port @ap.
+ * Thaw frozen port @ap and activate hp-poll if necessary.
*
* LOCKING:
* None.
@@ -659,6 +677,9 @@ void ata_eh_thaw_port(struct ata_port *a
spin_unlock_irqrestore(ap->lock, flags);
+ if (ap->flags & ATA_FLAG_HP_POLLING)
+ ata_hp_poll_activate(ap);
+
DPRINTK("ata%u port thawed\n", ap->id);
}
@@ -2037,6 +2058,9 @@ static int ata_eh_recover(struct ata_por
out:
if (rc) {
+ /* recovery failed, activate hp-poll */
+ ata_hp_poll_activate(ap);
+
for (i = 0; i < ATA_MAX_DEVICES; i++)
ata_dev_disable(&ap->device[i]);
}
@@ -2225,3 +2249,109 @@ static void ata_eh_handle_port_resume(st
}
spin_unlock_irqrestore(ap->lock, flags);
}
+
+static void ata_hp_poll_worker(void *data)
+{
+ unsigned long flags = 0; /* shut up, gcc */
+ struct ata_port *ap, *next;
+ spinlock_t *held_lock = NULL;
+
+ mutex_lock(&hp_poll_mutex);
+
+ list_for_each_entry_safe(ap, next, &hp_poll_list, hp_poll_entry) {
+ int rc;
+
+ /* Ports belonging to sharing a lock are registered
+ * sequentially. Cache locking.
+ */
+ if (ap->lock != held_lock) {
+ if (held_lock)
+ spin_unlock_irqrestore(held_lock, flags);
+ spin_lock_irqsave(ap->lock, flags);
+ held_lock = ap->lock;
+ }
+
+ /* Poll. Positive return value indicates hotplug
+ * event while negative indicates error condition.
+ */
+ rc = ap->ops->hp_poll(ap);
+ if (rc) {
+ if (rc > 0) {
+ ata_ehi_hotplugged(&ap->eh_info);
+ ata_port_freeze(ap);
+ }
+ list_del_init(&ap->hp_poll_entry);
+ }
+ }
+
+ if (held_lock)
+ spin_unlock_irqrestore(held_lock, flags);
+
+ if (!list_empty(&hp_poll_list))
+ schedule_delayed_work(&hp_poll_work,
+ hotplug_polling_interval * HZ / 1000);
+
+ mutex_unlock(&hp_poll_mutex);
+}
+
+/**
+ * ata_hp_poll_activate - activate hotplug polling
+ * @ap: host port to activate hotplug polling for
+ *
+ * Activate hotplug probing for @ap.
+ *
+ * LOCKING:
+ * Kernel thread context (may sleep).
+ */
+void ata_hp_poll_activate(struct ata_port *ap)
+{
+ struct list_head *pos;
+
+ if (!ap->ops->hp_poll || !list_empty(&ap->hp_poll_entry))
+ return;
+
+ if (ap->ops->hp_poll_activate)
+ ap->ops->hp_poll_activate(ap);
+
+ mutex_lock(&hp_poll_mutex);
+
+ if (list_empty(&hp_poll_list))
+ schedule_delayed_work(&hp_poll_work,
+ hotplug_polling_interval * HZ / 1000);
+
+ /* group poll entries by lock to cache locking when polling */
+ list_for_each(pos, &hp_poll_list) {
+ struct ata_port *pos_ap =
+ list_entry(pos, struct ata_port, hp_poll_entry);
+
+ if (ap->lock == pos_ap->lock)
+ break;
+ }
+
+ list_add(&ap->hp_poll_entry, pos);
+ ap->hp_poll_data = 0;
+
+ mutex_unlock(&hp_poll_mutex);
+}
+
+/**
+ * ata_hp_poll_deactivate - deactivate hotplug polling
+ * @ap: host port to deactivate hotplug polling for
+ *
+ * Deactivate hotplug probing for @ap.
+ *
+ * LOCKING:
+ * Kernel thread context (may sleep).
+ */
+void ata_hp_poll_deactivate(struct ata_port *ap)
+{
+ if (list_empty(&ap->hp_poll_entry))
+ return;
+
+ mutex_lock(&hp_poll_mutex);
+ list_del_init(&ap->hp_poll_entry);
+ mutex_unlock(&hp_poll_mutex);
+
+ if (ap->ops->hp_poll_deactivate)
+ ap->ops->hp_poll_deactivate(ap);
+}
diff --git a/drivers/scsi/libata.h b/drivers/scsi/libata.h
index c325679..3171dde 100644
--- a/drivers/scsi/libata.h
+++ b/drivers/scsi/libata.h
@@ -109,9 +109,14 @@ extern void ata_schedule_scsi_eh(struct
extern void ata_scsi_dev_rescan(void *data);
/* libata-eh.c */
+extern struct list_head hp_poll_list;
+extern struct work_struct hp_poll_work;
+
extern enum scsi_eh_timer_return ata_scsi_timed_out(struct scsi_cmnd *cmd);
extern void ata_scsi_error(struct Scsi_Host *host);
extern void ata_port_wait_eh(struct ata_port *ap);
extern void ata_qc_schedule_eh(struct ata_queued_cmd *qc);
+extern void ata_hp_poll_activate(struct ata_port *ap);
+extern void ata_hp_poll_deactivate(struct ata_port *ap);
#endif /* __LIBATA_H__ */
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 6cc497a..2ceca5f 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -162,6 +162,7 @@ enum {
ATA_FLAG_SKIP_D2H_BSY = (1 << 12), /* can't wait for the first D2H
* Register FIS clearing BSY */
ATA_FLAG_DEBUGMSG = (1 << 13),
+ ATA_FLAG_HP_POLLING = (1 << 14), /* hotplug by polling */
/* The following flag belongs to ap->pflags but is kept in
* ap->flags because it's referenced in many LLDs and will be
@@ -553,6 +554,9 @@ struct ata_port {
pm_message_t pm_mesg;
int *pm_result;
+ struct list_head hp_poll_entry; /* hotplug poll list entry */
+ void *hp_poll_data;
+
void *private_data;
u8 sector_buf[ATA_SECT_SIZE]; /* owned by EH */
@@ -600,6 +604,10 @@ 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 *);
@@ -667,6 +675,10 @@ extern int ata_std_prereset(struct ata_p
extern int ata_std_softreset(struct ata_port *ap, unsigned int *classes);
extern int sata_std_hardreset(struct ata_port *ap, unsigned int *class);
extern void ata_std_postreset(struct ata_port *ap, unsigned int *classes);
+extern void sata_std_hp_poll_activate(struct ata_port *ap);
+extern int sata_std_hp_poll(struct ata_port *ap);
+extern int sata_std_hp_poll_port_excl(struct ata_port *ap);
+extern int sata_std_hp_poll_hostset_excl(struct ata_port *ap);
extern int ata_dev_revalidate(struct ata_device *dev, int post_reset);
extern void ata_port_disable(struct ata_port *);
extern void ata_std_ports(struct ata_ioports *ioaddr);
--
1.3.2
-
: send the line "unsubscribe linux-ide" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
