[RFC][PATCH v2 1/2] libsas: Alloc dynamic work to avoid missing sas events

[Yijing Wang]

Now libsas hotplug work is static, LLDD driver queue
the hotplug work into shost->work_q. If LLDD driver
burst post lots hotplug event to libsas, the hotplug
events may pending in the workqueue like

shost->workq
tail | PHYE_LOSS_OF_SIGNAL  | PORTE_BYTES_DMAED | head

In this case, if a new PORTE_BYTES_DMAED event coming,
it would be lost, because we can not queue a work which
is already pending in the workqueue, also libsas has a
pending bit to avoid queue the same event.

The lost hotplug event make something confusing, e.g.
we have sas disks connected hardware, but we can not
found them in kernel.

This patch remove the static defined hotplug work,
and use dynamic work to avoid missing hotplug events.

Signed-off-by: Yijing Wang 
Signed-off-by: Yousong He 
Signed-off-by: Qilin Chen 
---
 drivers/scsi/libsas/sas_event.c| 61 ++
 drivers/scsi/libsas/sas_init.c |  5 +---
 drivers/scsi/libsas/sas_internal.h |  3 ++
 drivers/scsi/libsas/sas_phy.c  | 50 +--
 drivers/scsi/libsas/sas_port.c | 23 +++---
 include/scsi/libsas.h  |  8 -
 6 files changed, 66 insertions(+), 84 deletions(-)

diff --git a/drivers/scsi/libsas/sas_event.c b/drivers/scsi/libsas/sas_event.c
index aadbd53..091f5c4 100644
--- a/drivers/scsi/libsas/sas_event.c
+++ b/drivers/scsi/libsas/sas_event.c
@@ -27,6 +27,10 @@
 #include "sas_internal.h"
 #include "sas_dump.h"
 
+static const work_func_t sas_ha_event_fns[HA_NUM_EVENTS] = {
+   [HAE_RESET] = sas_hae_reset,
+};
+
 void sas_queue_work(struct sas_ha_struct *ha, struct sas_work *sw)
 {
if (!test_bit(SAS_HA_REGISTERED, >state))
@@ -40,17 +44,14 @@ void sas_queue_work(struct sas_ha_struct *ha, struct 
sas_work *sw)
scsi_queue_work(ha->core.shost, >work);
 }
 
-static void sas_queue_event(int event, unsigned long *pending,
-   struct sas_work *work,
+static void sas_queue_event(int event, struct sas_work *work,
struct sas_ha_struct *ha)
 {
-   if (!test_and_set_bit(event, pending)) {
-   unsigned long flags;
+   unsigned long flags;
 
-   spin_lock_irqsave(>lock, flags);
-   sas_queue_work(ha, work);
-   spin_unlock_irqrestore(>lock, flags);
-   }
+   spin_lock_irqsave(>lock, flags);
+   sas_queue_work(ha, work);
+   spin_unlock_irqrestore(>lock, flags);
 }
 
 
@@ -111,52 +112,60 @@ void sas_enable_revalidation(struct sas_ha_struct *ha)
if (!test_and_clear_bit(ev, >pending))
continue;
 
-   sas_queue_event(ev, >pending, >disc_work[ev].work, ha);
+   sas_queue_event(ev, >disc_work[ev].work, ha);
}
mutex_unlock(>disco_mutex);
 }
 
 static void notify_ha_event(struct sas_ha_struct *sas_ha, enum ha_event event)
 {
+   struct sas_ha_event *ev;
+
BUG_ON(event >= HA_NUM_EVENTS);
 
-   sas_queue_event(event, _ha->pending,
-   _ha->ha_events[event].work, sas_ha);
+   ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
+   if (!ev)
+   return;
+
+   INIT_SAS_WORK(>work, sas_ha_event_fns[event]);
+   ev->ha = sas_ha;
+   sas_queue_event(event, >work, sas_ha);
 }
 
 static void notify_port_event(struct asd_sas_phy *phy, enum port_event event)
 {
+   struct asd_sas_event *ev;
struct sas_ha_struct *ha = phy->ha;
 
BUG_ON(event >= PORT_NUM_EVENTS);
 
-   sas_queue_event(event, >port_events_pending,
-   >port_events[event].work, ha);
+   ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
+   if (!ev)
+   return;
+
+   INIT_SAS_WORK(>work, sas_port_event_fns[event]);
+   ev->phy = phy;
+   sas_queue_event(event, >work, ha);
 }
 
 void sas_notify_phy_event(struct asd_sas_phy *phy, enum phy_event event)
 {
+   struct asd_sas_event *ev;
struct sas_ha_struct *ha = phy->ha;
 
BUG_ON(event >= PHY_NUM_EVENTS);
 
-   sas_queue_event(event, >phy_events_pending,
-   >phy_events[event].work, ha);
+   ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
+   if (!ev)
+   return;
+
+   INIT_SAS_WORK(>work, sas_phy_event_fns[event]);
+   ev->phy = phy;
+   sas_queue_event(event, >work, ha);
 }
 
 int sas_init_events(struct sas_ha_struct *sas_ha)
 {
-   static const work_func_t sas_ha_event_fns[HA_NUM_EVENTS] = {
-   [HAE_RESET] = sas_hae_reset,
-   };
-
-   int i;
-
-   for (i = 0; i < HA_NUM_EVENTS; i++) {
-   INIT_SAS_WORK(_ha->ha_events[i].work, sas_ha_event_fns[i]);
-   sas_ha->ha_events[i].ha = sas_ha;
-   }
-
sas_ha->notify_ha_event = notify_ha_event;
sas_ha->notify_port_event = notify_port_event;
sas_ha->notify_phy_event = sas_notify_phy_event;
diff --git 

[RFC][PATCH v2 1/2] libsas: Alloc dynamic work to avoid missing sas events

[Yijing Wang]

Now libsas hotplug work is static, LLDD driver queue
the hotplug work into shost->work_q. If LLDD driver
burst post lots hotplug event to libsas, the hotplug
events may pending in the workqueue like

shost->workq
tail | PHYE_LOSS_OF_SIGNAL  | PORTE_BYTES_DMAED | head

In this case, if a new PORTE_BYTES_DMAED event coming,
it would be lost, because we can not queue a work which
is already pending in the workqueue, also libsas has a
pending bit to avoid queue the same event.

The lost hotplug event make something confusing, e.g.
we have sas disks connected hardware, but we can not
found them in kernel.

This patch remove the static defined hotplug work,
and use dynamic work to avoid missing hotplug events.

Signed-off-by: Yijing Wang 
Signed-off-by: Yousong He 
Signed-off-by: Qilin Chen 
---
 drivers/scsi/libsas/sas_event.c| 61 ++
 drivers/scsi/libsas/sas_init.c |  5 +---
 drivers/scsi/libsas/sas_internal.h |  3 ++
 drivers/scsi/libsas/sas_phy.c  | 50 +--
 drivers/scsi/libsas/sas_port.c | 23 +++---
 include/scsi/libsas.h  |  8 -
 6 files changed, 66 insertions(+), 84 deletions(-)

diff --git a/drivers/scsi/libsas/sas_event.c b/drivers/scsi/libsas/sas_event.c
index aadbd53..091f5c4 100644
--- a/drivers/scsi/libsas/sas_event.c
+++ b/drivers/scsi/libsas/sas_event.c
@@ -27,6 +27,10 @@
 #include "sas_internal.h"
 #include "sas_dump.h"
 
+static const work_func_t sas_ha_event_fns[HA_NUM_EVENTS] = {
+   [HAE_RESET] = sas_hae_reset,
+};
+
 void sas_queue_work(struct sas_ha_struct *ha, struct sas_work *sw)
 {
if (!test_bit(SAS_HA_REGISTERED, >state))
@@ -40,17 +44,14 @@ void sas_queue_work(struct sas_ha_struct *ha, struct 
sas_work *sw)
scsi_queue_work(ha->core.shost, >work);
 }
 
-static void sas_queue_event(int event, unsigned long *pending,
-   struct sas_work *work,
+static void sas_queue_event(int event, struct sas_work *work,
struct sas_ha_struct *ha)
 {
-   if (!test_and_set_bit(event, pending)) {
-   unsigned long flags;
+   unsigned long flags;
 
-   spin_lock_irqsave(>lock, flags);
-   sas_queue_work(ha, work);
-   spin_unlock_irqrestore(>lock, flags);
-   }
+   spin_lock_irqsave(>lock, flags);
+   sas_queue_work(ha, work);
+   spin_unlock_irqrestore(>lock, flags);
 }
 
 
@@ -111,52 +112,60 @@ void sas_enable_revalidation(struct sas_ha_struct *ha)
if (!test_and_clear_bit(ev, >pending))
continue;
 
-   sas_queue_event(ev, >pending, >disc_work[ev].work, ha);
+   sas_queue_event(ev, >disc_work[ev].work, ha);
}
mutex_unlock(>disco_mutex);
 }
 
 static void notify_ha_event(struct sas_ha_struct *sas_ha, enum ha_event event)
 {
+   struct sas_ha_event *ev;
+
BUG_ON(event >= HA_NUM_EVENTS);
 
-   sas_queue_event(event, _ha->pending,
-   _ha->ha_events[event].work, sas_ha);
+   ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
+   if (!ev)
+   return;
+
+   INIT_SAS_WORK(>work, sas_ha_event_fns[event]);
+   ev->ha = sas_ha;
+   sas_queue_event(event, >work, sas_ha);
 }
 
 static void notify_port_event(struct asd_sas_phy *phy, enum port_event event)
 {
+   struct asd_sas_event *ev;
struct sas_ha_struct *ha = phy->ha;
 
BUG_ON(event >= PORT_NUM_EVENTS);
 
-   sas_queue_event(event, >port_events_pending,
-   >port_events[event].work, ha);
+   ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
+   if (!ev)
+   return;
+
+   INIT_SAS_WORK(>work, sas_port_event_fns[event]);
+   ev->phy = phy;
+   sas_queue_event(event, >work, ha);
 }
 
 void sas_notify_phy_event(struct asd_sas_phy *phy, enum phy_event event)
 {
+   struct asd_sas_event *ev;
struct sas_ha_struct *ha = phy->ha;
 
BUG_ON(event >= PHY_NUM_EVENTS);
 
-   sas_queue_event(event, >phy_events_pending,
-   >phy_events[event].work, ha);
+   ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
+   if (!ev)
+   return;
+
+   INIT_SAS_WORK(>work, sas_phy_event_fns[event]);
+   ev->phy = phy;
+   sas_queue_event(event, >work, ha);
 }
 
 int sas_init_events(struct sas_ha_struct *sas_ha)
 {
-   static const work_func_t sas_ha_event_fns[HA_NUM_EVENTS] = {
-   [HAE_RESET] = sas_hae_reset,
-   };
-
-   int i;
-
-   for (i = 0; i < HA_NUM_EVENTS; i++) {
-   INIT_SAS_WORK(_ha->ha_events[i].work, sas_ha_event_fns[i]);
-   sas_ha->ha_events[i].ha = sas_ha;
-   }
-
sas_ha->notify_ha_event = notify_ha_event;
sas_ha->notify_port_event = notify_port_event;
sas_ha->notify_phy_event = sas_notify_phy_event;
diff --git a/drivers/scsi/libsas/sas_init.c b/drivers/scsi/libsas/sas_init.c
index