From a341cd0f6a0fde1f85fec9aa8f81f824ea4a3f92 Mon Sep 17 00:00:00 2001 From: Jeff Garzik Date: Mon, 29 Oct 2007 17:15:22 -0400 Subject: [PATCH] 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 --- 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(+) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 88de771d3569..0e81e4cf8876 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -2114,6 +2114,142 @@ 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 b53c5f67e372..40ea71cd2ca6 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 d531ceeb0d8c..f374fdcb6815 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 d5057bc338ff..66e9058357e0 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 *); -- 2.39.5