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Message-Id: <20071029213157.781B71F8181@havoc.gtf.org>
Date: Mon, 29 Oct 2007 17:31:57 -0400 (EDT)
From: Jeff Garzik <jeff@...zik.org>
To: Linux-SCSI <linux-scsi@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH v5 1/2] SCSI: add asynchronous event notification API
Originally based on a patch by Kristen Carlson Accardi @ Intel.
Copious input from James Bottomley.
Signed-off-by: Jeff Garzik <jgarzik@...hat.com>
---
drivers/scsi/scsi_lib.c | 136 ++++++++++++++++++++++++++++++++++++++++++++
drivers/scsi/scsi_scan.c | 3 +
drivers/scsi/scsi_sysfs.c | 47 +++++++++++++++
include/scsi/scsi_device.h | 25 ++++++++
4 files changed, 211 insertions(+), 0 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 61fdaf0..304213e 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2115,6 +2115,142 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
EXPORT_SYMBOL(scsi_device_set_state);
/**
+ * sdev_evt_emit - emit a single SCSI device uevent
+ * @sdev: associated SCSI device
+ * @evt: event to emit
+ *
+ * Send a single uevent (scsi_event) to the associated scsi_device.
+ */
+static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
+{
+ int idx = 0;
+ char *envp[3];
+
+ switch (evt->evt_type) {
+ case SDEV_EVT_MEDIA_CHANGE:
+ envp[idx++] = "SDEV_MEDIA_CHANGE=1";
+ break;
+
+ default:
+ /* do nothing */
+ break;
+ }
+
+ envp[idx++] = NULL;
+
+ kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
+}
+
+/**
+ * sdev_evt_thread - send a uevent for each scsi event
+ * @work: work struct for scsi_device
+ *
+ * Dispatch queued events to their associated scsi_device kobjects
+ * as uevents.
+ */
+void scsi_evt_thread(struct work_struct *work)
+{
+ struct scsi_device *sdev;
+ LIST_HEAD(event_list);
+
+ sdev = container_of(work, struct scsi_device, event_work);
+
+ while (1) {
+ struct scsi_event *evt;
+ struct list_head *this, *tmp;
+ unsigned long flags;
+
+ spin_lock_irqsave(&sdev->list_lock, flags);
+ list_splice_init(&sdev->event_list, &event_list);
+ spin_unlock_irqrestore(&sdev->list_lock, flags);
+
+ if (list_empty(&event_list))
+ break;
+
+ list_for_each_safe(this, tmp, &event_list) {
+ evt = list_entry(this, struct scsi_event, node);
+ list_del(&evt->node);
+ scsi_evt_emit(sdev, evt);
+ kfree(evt);
+ }
+ }
+}
+
+/**
+ * sdev_evt_send - send asserted event to uevent thread
+ * @sdev: scsi_device event occurred on
+ * @evt: event to send
+ *
+ * Assert scsi device event asynchronously.
+ */
+void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
+{
+ unsigned long flags;
+
+ if (!test_bit(evt->evt_type, sdev->supported_events)) {
+ kfree(evt);
+ return;
+ }
+
+ spin_lock_irqsave(&sdev->list_lock, flags);
+ list_add_tail(&evt->node, &sdev->event_list);
+ schedule_work(&sdev->event_work);
+ spin_unlock_irqrestore(&sdev->list_lock, flags);
+}
+EXPORT_SYMBOL_GPL(sdev_evt_send);
+
+/**
+ * sdev_evt_alloc - allocate a new scsi event
+ * @evt_type: type of event to allocate
+ * @gfpflags: GFP flags for allocation
+ *
+ * Allocates and returns a new scsi_event.
+ */
+struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
+ gfp_t gfpflags)
+{
+ struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
+ if (!evt)
+ return NULL;
+
+ evt->evt_type = evt_type;
+ INIT_LIST_HEAD(&evt->node);
+
+ /* evt_type-specific initialization, if any */
+ switch (evt_type) {
+ case SDEV_EVT_MEDIA_CHANGE:
+ default:
+ /* do nothing */
+ break;
+ }
+
+ return evt;
+}
+EXPORT_SYMBOL_GPL(sdev_evt_alloc);
+
+/**
+ * sdev_evt_send_simple - send asserted event to uevent thread
+ * @sdev: scsi_device event occurred on
+ * @evt_type: type of event to send
+ * @gfpflags: GFP flags for allocation
+ *
+ * Assert scsi device event asynchronously, given an event type.
+ */
+void sdev_evt_send_simple(struct scsi_device *sdev,
+ enum scsi_device_event evt_type, gfp_t gfpflags)
+{
+ struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
+ if (!evt) {
+ sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
+ evt_type);
+ return;
+ }
+
+ sdev_evt_send(sdev, evt);
+}
+EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
+
+/**
* scsi_device_quiesce - Block user issued commands.
* @sdev: scsi device to quiesce.
*
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index b53c5f6..40ea71c 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -236,6 +236,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
struct scsi_device *sdev;
int display_failure_msg = 1, ret;
struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
+ extern void scsi_evt_thread(struct work_struct *work);
sdev = kzalloc(sizeof(*sdev) + shost->transportt->device_size,
GFP_ATOMIC);
@@ -254,7 +255,9 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
INIT_LIST_HEAD(&sdev->same_target_siblings);
INIT_LIST_HEAD(&sdev->cmd_list);
INIT_LIST_HEAD(&sdev->starved_entry);
+ INIT_LIST_HEAD(&sdev->event_list);
spin_lock_init(&sdev->list_lock);
+ INIT_WORK(&sdev->event_work, scsi_evt_thread);
sdev->sdev_gendev.parent = get_device(&starget->dev);
sdev->sdev_target = starget;
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index d531cee..f374fdc 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -268,6 +268,7 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work)
struct scsi_device *sdev;
struct device *parent;
struct scsi_target *starget;
+ struct list_head *this, *tmp;
unsigned long flags;
sdev = container_of(work, struct scsi_device, ew.work);
@@ -282,6 +283,16 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work)
list_del(&sdev->starved_entry);
spin_unlock_irqrestore(sdev->host->host_lock, flags);
+ cancel_work_sync(&sdev->event_work);
+
+ list_for_each_safe(this, tmp, &sdev->event_list) {
+ struct scsi_event *evt;
+
+ evt = list_entry(this, struct scsi_event, node);
+ list_del(&evt->node);
+ kfree(evt);
+ }
+
if (sdev->request_queue) {
sdev->request_queue->queuedata = NULL;
/* user context needed to free queue */
@@ -614,6 +625,41 @@ sdev_show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
}
static DEVICE_ATTR(modalias, S_IRUGO, sdev_show_modalias, NULL);
+#define DECLARE_EVT_SHOW(name, Cap_name) \
+static ssize_t \
+sdev_show_evt_##name(struct device *dev, struct device_attribute *attr, \
+ char *buf) \
+{ \
+ struct scsi_device *sdev = to_scsi_device(dev); \
+ int val = test_bit(SDEV_EVT_##Cap_name, sdev->supported_events);\
+ return snprintf(buf, 20, "%d\n", val); \
+}
+
+#define DECLARE_EVT_STORE(name, Cap_name) \
+static ssize_t \
+sdev_store_evt_##name(struct device *dev, struct device_attribute *attr, \
+ const char *buf, size_t count) \
+{ \
+ struct scsi_device *sdev = to_scsi_device(dev); \
+ int val = simple_strtoul(buf, NULL, 0); \
+ if (val == 0) \
+ clear_bit(SDEV_EVT_##Cap_name, sdev->supported_events); \
+ else if (val == 1) \
+ set_bit(SDEV_EVT_##Cap_name, sdev->supported_events); \
+ else \
+ return -EINVAL; \
+ return count; \
+}
+
+#define DECLARE_EVT(name, Cap_name) \
+ DECLARE_EVT_SHOW(name, Cap_name) \
+ DECLARE_EVT_STORE(name, Cap_name) \
+ static DEVICE_ATTR(evt_##name, S_IRUGO, sdev_show_evt_##name, \
+ sdev_store_evt_##name);
+#define REF_EVT(name) &dev_attr_evt_##name.attr
+
+DECLARE_EVT(media_change, MEDIA_CHANGE)
+
/* Default template for device attributes. May NOT be modified */
static struct attribute *scsi_sdev_attrs[] = {
&dev_attr_device_blocked.attr,
@@ -631,6 +677,7 @@ static struct attribute *scsi_sdev_attrs[] = {
&dev_attr_iodone_cnt.attr,
&dev_attr_ioerr_cnt.attr,
&dev_attr_modalias.attr,
+ REF_EVT(media_change),
NULL
};
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index d5057bc..66e9058 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -46,6 +46,22 @@ enum scsi_device_state {
* to the scsi lld. */
};
+enum scsi_device_event {
+ SDEV_EVT_MEDIA_CHANGE = 1, /* media has changed */
+
+ SDEV_EVT_LAST = SDEV_EVT_MEDIA_CHANGE,
+ SDEV_EVT_MAXBITS = SDEV_EVT_LAST + 1
+};
+
+struct scsi_event {
+ enum scsi_device_event evt_type;
+ struct list_head node;
+
+ /* put union of data structures, for non-simple event types,
+ * here
+ */
+};
+
struct scsi_device {
struct Scsi_Host *host;
struct request_queue *request_queue;
@@ -127,6 +143,10 @@ struct scsi_device {
unsigned guess_capacity:1; /* READ_CAPACITY might be too high by 1 */
unsigned retry_hwerror:1; /* Retry HARDWARE_ERROR */
+ DECLARE_BITMAP(supported_events, SDEV_EVT_MAXBITS); /* supported events */
+ struct list_head event_list; /* asserted events */
+ struct work_struct event_work;
+
unsigned int device_blocked; /* Device returned QUEUE_FULL. */
unsigned int max_device_blocked; /* what device_blocked counts down from */
@@ -275,6 +295,11 @@ extern int scsi_test_unit_ready(struct scsi_device *sdev, int timeout,
int retries);
extern int scsi_device_set_state(struct scsi_device *sdev,
enum scsi_device_state state);
+extern struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
+ gfp_t gfpflags);
+extern void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt);
+extern void sdev_evt_send_simple(struct scsi_device *sdev,
+ enum scsi_device_event evt_type, gfp_t gfpflags);
extern int scsi_device_quiesce(struct scsi_device *sdev);
extern void scsi_device_resume(struct scsi_device *sdev);
extern void scsi_target_quiesce(struct scsi_target *);
--
1.5.2.4
-
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