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Subject[PATCH 14/15] libsas: Provide a generic SATL registration function
Date

Decouple libsas and sas_ata so that the latter can be provided as a
plug-in module for the former. Any module wishing to provide SATL
services registers itself with libsas; when SATA devices are
discovered, libsas will module_get/put as necessary to ensure that
the module cannot go away accidentally. At this time, the ability
to start a SAS HBA without a SATL, load a SATL later, and then
rerun device discovery; that may be addressed in a later patch.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
---
drivers/scsi/libsas/Kconfig | 11 +++
drivers/scsi/libsas/sas_discover.c | 6 --
drivers/scsi/libsas/sas_scsi_host.c | 134 ++++++++++++++++++++++++++++++++---
include/scsi/libsas.h | 30 +-------
include/scsi/sas_ata.h | 37 +++++++++-
5 files changed, 174 insertions(+), 44 deletions(-)
diff --git a/drivers/scsi/libsas/Kconfig b/drivers/scsi/libsas/Kconfig
index b64e391..9c06eec 100644
--- a/drivers/scsi/libsas/Kconfig
+++ b/drivers/scsi/libsas/Kconfig
@@ -24,12 +24,21 @@ #

config SCSI_SAS_LIBSAS
tristate "SAS Domain Transport Attributes"
- depends on SCSI && ATA
+ depends on SCSI
select SCSI_SAS_ATTRS
help
This provides transport specific helpers for SAS drivers which
use the domain device construct (like the aic94xxx).

+config SCSI_SAS_SATL
+ tristate "Serial ATA Translation Layer (SATL) on SAS controllers"
+ depends on SCSI_SAS_LIBSAS && ATA
+ default y
+ help
+ This provides an ATA translation layer between libsas and
+ libata to load SATA devices that are connected to SAS
+ controllers.
+
config SCSI_SAS_LIBSAS_DEBUG
bool "Compile the SAS Domain Transport Attributes in debug mode"
default y
diff --git a/drivers/scsi/libsas/sas_discover.c b/drivers/scsi/libsas/sas_discover.c
index 758b153..01ff15c 100644
--- a/drivers/scsi/libsas/sas_discover.c
+++ b/drivers/scsi/libsas/sas_discover.c
@@ -476,12 +476,6 @@ cont1:
if (!dev->parent)
sas_sata_propagate_sas_addr(dev);

- /* XXX Hint: register this SATA device with SATL.
- When this returns, dev->sata_dev->lu is alive and
- present.
- sas_satl_register_dev(dev);
- */
-
sas_fill_in_rphy(dev, dev->rphy);

return 0;
diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c
index 59409be..c1a1e06 100644
--- a/drivers/scsi/libsas/sas_scsi_host.c
+++ b/drivers/scsi/libsas/sas_scsi_host.c
@@ -46,6 +46,9 @@ #include <linux/libata.h>
#define TO_SAS_TASK(_scsi_cmd) ((void *)(_scsi_cmd)->host_scribble)
#define ASSIGN_SAS_TASK(_sc, _t) do { (_sc)->host_scribble = (void *) _t; } while (0)

+static DEFINE_SPINLOCK(satl_ops_lock);
+static struct satl_operations *satl_ops;
+
static void sas_scsi_task_done(struct sas_task *task)
{
struct task_status_struct *ts = &task->task_status;
@@ -215,8 +218,8 @@ int sas_queuecommand(struct scsi_cmnd *c
unsigned long flags;

spin_lock_irqsave(dev->sata_dev.ap->lock, flags);
- res = ata_sas_queuecmd(cmd, scsi_done,
- dev->sata_dev.ap);
+ res = satl_ops->queuecommand(cmd, scsi_done,
+ dev->sata_dev.ap);
spin_unlock_irqrestore(dev->sata_dev.ap->lock, flags);
goto out;
}
@@ -574,8 +577,9 @@ int sas_ioctl(struct scsi_device *sdev,
{
struct domain_device *dev = sdev_to_domain_dev(sdev);

- if (dev_is_sata(dev))
- return ata_scsi_ioctl(sdev, cmd, arg);
+ if (dev_is_sata(dev)) {
+ return satl_ops->ioctl(sdev, cmd, arg);
+ }

return -EINVAL;
}
@@ -615,6 +619,29 @@ static inline struct domain_device *sas_
return sas_find_dev_by_rphy(rphy);
}

+static int sas_target_alloc_sata(struct domain_device *dev,
+ struct scsi_target *starget)
+{
+ int res = -ENODEV;
+
+ /* Do we have a SATL available? */
+ if (!get_satl())
+ goto satl_found;
+
+ request_module("sas_ata");
+ if (!get_satl())
+ goto satl_found;
+
+ SAS_DPRINTK("sas_ata not loaded, ignoring SATA devices\n");
+ goto no_satl;
+
+satl_found:
+ res = satl_ops->init_target(dev, starget);
+
+no_satl:
+ return res;
+}
+
int sas_target_alloc(struct scsi_target *starget)
{
struct domain_device *found_dev = sas_find_target(starget);
@@ -624,7 +651,7 @@ int sas_target_alloc(struct scsi_target
return -ENODEV;

if (dev_is_sata(found_dev)) {
- res = sas_ata_init_host_and_port(found_dev, starget);
+ res = sas_target_alloc_sata(found_dev, starget);
if (res)
return res;
}
@@ -644,7 +671,7 @@ int sas_slave_configure(struct scsi_devi
BUG_ON(dev->rphy->identify.device_type != SAS_END_DEVICE);

if (dev_is_sata(dev)) {
- ata_sas_slave_configure(scsi_dev, dev->sata_dev.ap);
+ satl_ops->configure_port(scsi_dev, dev->sata_dev.ap);
return 0;
}

@@ -672,7 +699,7 @@ void sas_slave_destroy(struct scsi_devic
struct domain_device *dev = sdev_to_domain_dev(scsi_dev);

if (dev_is_sata(dev))
- ata_port_disable(dev->sata_dev.ap);
+ satl_ops->deactivate_port(dev->sata_dev.ap);
}

int sas_change_queue_depth(struct scsi_device *scsi_dev, int new_depth)
@@ -849,7 +876,7 @@ int sas_slave_alloc(struct scsi_device *
struct domain_device *dev = sdev_to_domain_dev(scsi_dev);

if (dev_is_sata(dev))
- return ata_sas_port_init(dev->sata_dev.ap);
+ return satl_ops->init_port(dev->sata_dev.ap);

return 0;
}
@@ -861,8 +888,11 @@ void sas_target_destroy(struct scsi_targ
if (!found_dev)
return;

- if (dev_is_sata(found_dev))
- ata_sas_port_destroy(found_dev->sata_dev.ap);
+ if (dev_is_sata(found_dev)) {
+ if (found_dev->sata_dev.ap)
+ satl_ops->destroy_port(found_dev->sata_dev.ap);
+ put_satl();
+ }

return;
}
@@ -925,6 +955,85 @@ void sas_task_abort(struct sas_task *tas
SAS_DPRINTK("%s: Could not kill task!\n", __FUNCTION__);
}

+struct sas_task *sas_alloc_task(gfp_t flags)
+{
+ extern kmem_cache_t *sas_task_cache;
+ struct sas_task *task = kmem_cache_alloc(sas_task_cache, flags);
+
+ if (task) {
+ memset(task, 0, sizeof(*task));
+ INIT_LIST_HEAD(&task->list);
+ spin_lock_init(&task->task_state_lock);
+ task->task_state_flags = SAS_TASK_STATE_PENDING;
+ init_timer(&task->timer);
+ init_completion(&task->completion);
+ }
+
+ return task;
+}
+
+void sas_free_task(struct sas_task *task)
+{
+ if (task) {
+ extern kmem_cache_t *sas_task_cache;
+ BUG_ON(!list_empty(&task->list));
+ kmem_cache_free(sas_task_cache, task);
+ }
+}
+
+/* Jump table to ATA translation layer functions */
+int sas_register_satl(struct satl_operations *ops)
+{
+ int res = -ENODEV;
+
+ spin_lock(&satl_ops_lock);
+ if (satl_ops)
+ goto out;
+ satl_ops = ops;
+ res = 0;
+out:
+ spin_unlock(&satl_ops_lock);
+ return res;
+}
+
+int sas_unregister_satl(struct satl_operations *ops)
+{
+ int res = -ENODEV;
+
+ spin_lock(&satl_ops_lock);
+ if (satl_ops != ops)
+ goto out;
+ satl_ops = NULL;
+ res = 0;
+out:
+ spin_unlock(&satl_ops_lock);
+ return res;
+}
+
+int get_satl(void)
+{
+ int res = -ENODEV;
+
+ spin_lock(&satl_ops_lock);
+
+ if (!satl_ops)
+ goto out;
+ if (!try_module_get(satl_ops->owner))
+ goto out;
+ res = 0;
+
+out:
+ spin_unlock(&satl_ops_lock);
+ return res;
+}
+
+void put_satl(void)
+{
+ spin_lock(&satl_ops_lock);
+ module_put(satl_ops->owner);
+ spin_unlock(&satl_ops_lock);
+}
+
EXPORT_SYMBOL_GPL(sas_queuecommand);
EXPORT_SYMBOL_GPL(sas_target_alloc);
EXPORT_SYMBOL_GPL(sas_slave_configure);
@@ -939,3 +1048,8 @@ EXPORT_SYMBOL_GPL(sas_task_abort);
EXPORT_SYMBOL_GPL(sas_phy_reset);
EXPORT_SYMBOL_GPL(sas_phy_enable);
EXPORT_SYMBOL_GPL(sas_set_phy_speed);
+EXPORT_SYMBOL_GPL(sas_register_satl);
+EXPORT_SYMBOL_GPL(sas_unregister_satl);
+EXPORT_SYMBOL_GPL(sas_queue_up);
+EXPORT_SYMBOL_GPL(sas_alloc_task);
+EXPORT_SYMBOL_GPL(sas_free_task);
diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
index 7dcf593..90748ce 100644
--- a/include/scsi/libsas.h
+++ b/include/scsi/libsas.h
@@ -549,31 +549,8 @@ #define SAS_TASK_STATE_ABORTED 4
#define SAS_TASK_INITIATOR_ABORTED 8
#define SAS_TASK_AT_INITIATOR 16

-static inline struct sas_task *sas_alloc_task(gfp_t flags)
-{
- extern kmem_cache_t *sas_task_cache;
- struct sas_task *task = kmem_cache_alloc(sas_task_cache, flags);
-
- if (task) {
- memset(task, 0, sizeof(*task));
- INIT_LIST_HEAD(&task->list);
- spin_lock_init(&task->task_state_lock);
- task->task_state_flags = SAS_TASK_STATE_PENDING;
- init_timer(&task->timer);
- init_completion(&task->completion);
- }
-
- return task;
-}
-
-static inline void sas_free_task(struct sas_task *task)
-{
- if (task) {
- extern kmem_cache_t *sas_task_cache;
- BUG_ON(!list_empty(&task->list));
- kmem_cache_free(sas_task_cache, task);
- }
-}
+struct sas_task *sas_alloc_task(gfp_t flags);
+void sas_free_task(struct sas_task *task);

struct sas_domain_function_template {
/* The class calls these to notify the LLDD of an event. */
@@ -649,4 +626,7 @@ extern int sas_slave_alloc(struct scsi_d
extern int sas_ioctl(struct scsi_device *sdev, int cmd, void __user *arg);
void sas_task_abort(struct sas_task *task);

+int get_satl(void);
+void put_satl(void);
+
#endif /* _SASLIB_H_ */
diff --git a/include/scsi/sas_ata.h b/include/scsi/sas_ata.h
index 72a1904..bb4a1cb 100644
--- a/include/scsi/sas_ata.h
+++ b/include/scsi/sas_ata.h
@@ -28,12 +28,45 @@ #define _SAS_ATA_H_
#include <linux/libata.h>
#include <scsi/libsas.h>

+struct satl_operations {
+ struct module *owner;
+
+ int (*init_target) (struct domain_device *found_dev,
+ struct scsi_target *starget);
+ int (*queuecommand) (struct scsi_cmnd *cmd,
+ void (*done)(struct scsi_cmnd *),
+ struct ata_port *ap);
+ int (*ioctl) (struct scsi_device *dev, int cmd,
+ void __user *arg);
+ int (*configure_port) (struct scsi_device *,
+ struct ata_port *);
+ void (*deactivate_port) (struct ata_port *);
+ void (*destroy_port) (struct ata_port *);
+ int (*init_port) (struct ata_port *);
+};
+
+int sas_register_satl(struct satl_operations *satl_ops);
+int sas_unregister_satl(struct satl_operations *satl_ops);
+
+#ifdef CONFIG_SCSI_SAS_SATL_MODULE
+# define SAS_ATA_AVAILABLE
+#endif
+
+#ifdef CONFIG_SCSI_SAS_SATL
+# define SAS_ATA_AVAILABLE
+#endif
+
+#ifdef SAS_ATA_AVAILABLE
+
static inline int dev_is_sata(struct domain_device *dev)
{
return (dev->rphy->identify.target_port_protocols & SAS_PROTOCOL_SATA);
}

-int sas_ata_init_host_and_port(struct domain_device *found_dev,
- struct scsi_target *starget);
+#else
+
+#define dev_is_sata(x) (0)
+
+#endif /* SAS_ATA_AVAILABLE */

#endif /* _SAS_ATA_H_ */
-
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