#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/blkdev.h>
-#include <asm/semaphore.h>
+#include <linux/delay.h>
+#include <linux/kthread.h>
+#include <linux/spinlock.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
MODULE_PARM_DESC(max_luns,
"last scsi LUN (should be between 1 and 2^32-1)");
+#ifdef CONFIG_SCSI_SCAN_ASYNC
+#define SCSI_SCAN_TYPE_DEFAULT "async"
+#else
+#define SCSI_SCAN_TYPE_DEFAULT "sync"
+#endif
+
+static char scsi_scan_type[6] = SCSI_SCAN_TYPE_DEFAULT;
+
+module_param_string(scan, scsi_scan_type, sizeof(scsi_scan_type), S_IRUGO);
+MODULE_PARM_DESC(scan, "sync, async or none");
+
/*
* max_scsi_report_luns: the maximum number of LUNS that will be
* returned from the REPORT LUNS command. 8 times this value must
"Timeout (in seconds) waiting for devices to answer INQUIRY."
" Default is 5. Some non-compliant devices need more.");
+static DEFINE_SPINLOCK(async_scan_lock);
+static LIST_HEAD(scanning_hosts);
+
+struct async_scan_data {
+ struct list_head list;
+ struct Scsi_Host *shost;
+ struct completion prev_finished;
+};
+
+/**
+ * scsi_complete_async_scans - Wait for asynchronous scans to complete
+ *
+ * Asynchronous scans add themselves to the scanning_hosts list. Once
+ * that list is empty, we know that the scans are complete. Rather than
+ * waking up periodically to check the state of the list, we pretend to be
+ * a scanning task by adding ourselves at the end of the list and going to
+ * sleep. When the task before us wakes us up, we take ourselves off the
+ * list and return.
+ */
+int scsi_complete_async_scans(void)
+{
+ struct async_scan_data *data;
+
+ do {
+ if (list_empty(&scanning_hosts))
+ return 0;
+ /* If we can't get memory immediately, that's OK. Just
+ * sleep a little. Even if we never get memory, the async
+ * scans will finish eventually.
+ */
+ data = kmalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ msleep(1);
+ } while (!data);
+
+ data->shost = NULL;
+ init_completion(&data->prev_finished);
+
+ spin_lock(&async_scan_lock);
+ /* Check that there's still somebody else on the list */
+ if (list_empty(&scanning_hosts))
+ goto done;
+ list_add_tail(&data->list, &scanning_hosts);
+ spin_unlock(&async_scan_lock);
+
+ printk(KERN_INFO "scsi: waiting for bus probes to complete ...\n");
+ wait_for_completion(&data->prev_finished);
+
+ spin_lock(&async_scan_lock);
+ list_del(&data->list);
+ done:
+ spin_unlock(&async_scan_lock);
+
+ kfree(data);
+ return 0;
+}
+
+#ifdef MODULE
+/* Only exported for the benefit of scsi_wait_scan */
+EXPORT_SYMBOL_GPL(scsi_complete_async_scans);
+#endif
+
/**
* scsi_unlock_floptical - unlock device via a special MODE SENSE command
* @sdev: scsi device to send command to
* SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
**/
static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
- int *bflags)
+ int *bflags, int async)
{
/*
* XXX do not save the inquiry, since it can change underneath us,
* register it and tell the rest of the kernel
* about it.
*/
- if (scsi_sysfs_add_sdev(sdev) != 0)
+ if (!async && scsi_sysfs_add_sdev(sdev) != 0)
return SCSI_SCAN_NO_RESPONSE;
return SCSI_SCAN_LUN_PRESENT;
goto out_free_result;
}
- res = scsi_add_lun(sdev, result, &bflags);
+ res = scsi_add_lun(sdev, result, &bflags, shost->async_scan);
if (res == SCSI_SCAN_LUN_PRESENT) {
if (bflags & BLIST_KEY) {
sdev->lockable = 0;
{
struct Scsi_Host *shost = dev_to_shost(parent);
+ if (strncmp(scsi_scan_type, "none", 4) == 0)
+ return;
+
+ if (!shost->async_scan)
+ scsi_complete_async_scans();
+
mutex_lock(&shost->scan_mutex);
if (scsi_host_scan_allowed(shost))
__scsi_scan_target(parent, channel, id, lun, rescan);
"%s: <%u:%u:%u>\n",
__FUNCTION__, channel, id, lun));
+ if (!shost->async_scan)
+ scsi_complete_async_scans();
+
if (((channel != SCAN_WILD_CARD) && (channel > shost->max_channel)) ||
((id != SCAN_WILD_CARD) && (id >= shost->max_id)) ||
((lun != SCAN_WILD_CARD) && (lun > shost->max_lun)))
return 0;
}
+static void scsi_sysfs_add_devices(struct Scsi_Host *shost)
+{
+ struct scsi_device *sdev;
+ shost_for_each_device(sdev, shost) {
+ if (scsi_sysfs_add_sdev(sdev) != 0)
+ scsi_destroy_sdev(sdev);
+ }
+}
+
+/**
+ * scsi_prep_async_scan - prepare for an async scan
+ * @shost: the host which will be scanned
+ * Returns: a cookie to be passed to scsi_finish_async_scan()
+ *
+ * Tells the midlayer this host is going to do an asynchronous scan.
+ * It reserves the host's position in the scanning list and ensures
+ * that other asynchronous scans started after this one won't affect the
+ * ordering of the discovered devices.
+ */
+static struct async_scan_data *scsi_prep_async_scan(struct Scsi_Host *shost)
+{
+ struct async_scan_data *data;
+
+ if (strncmp(scsi_scan_type, "sync", 4) == 0)
+ return NULL;
+
+ if (shost->async_scan) {
+ printk("%s called twice for host %d", __FUNCTION__,
+ shost->host_no);
+ dump_stack();
+ return NULL;
+ }
+
+ data = kmalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ goto err;
+ data->shost = scsi_host_get(shost);
+ if (!data->shost)
+ goto err;
+ init_completion(&data->prev_finished);
+
+ spin_lock(&async_scan_lock);
+ shost->async_scan = 1;
+ if (list_empty(&scanning_hosts))
+ complete(&data->prev_finished);
+ list_add_tail(&data->list, &scanning_hosts);
+ spin_unlock(&async_scan_lock);
+
+ return data;
+
+ err:
+ kfree(data);
+ return NULL;
+}
+
+/**
+ * scsi_finish_async_scan - asynchronous scan has finished
+ * @data: cookie returned from earlier call to scsi_prep_async_scan()
+ *
+ * All the devices currently attached to this host have been found.
+ * This function announces all the devices it has found to the rest
+ * of the system.
+ */
+static void scsi_finish_async_scan(struct async_scan_data *data)
+{
+ struct Scsi_Host *shost;
+
+ if (!data)
+ return;
+
+ shost = data->shost;
+ if (!shost->async_scan) {
+ printk("%s called twice for host %d", __FUNCTION__,
+ shost->host_no);
+ dump_stack();
+ return;
+ }
+
+ wait_for_completion(&data->prev_finished);
+
+ scsi_sysfs_add_devices(shost);
+
+ spin_lock(&async_scan_lock);
+ shost->async_scan = 0;
+ list_del(&data->list);
+ if (!list_empty(&scanning_hosts)) {
+ struct async_scan_data *next = list_entry(scanning_hosts.next,
+ struct async_scan_data, list);
+ complete(&next->prev_finished);
+ }
+ spin_unlock(&async_scan_lock);
+
+ scsi_host_put(shost);
+ kfree(data);
+}
+
+static void do_scsi_scan_host(struct Scsi_Host *shost)
+{
+ if (shost->hostt->scan_finished) {
+ unsigned long start = jiffies;
+ if (shost->hostt->scan_start)
+ shost->hostt->scan_start(shost);
+
+ while (!shost->hostt->scan_finished(shost, jiffies - start))
+ msleep(10);
+ } else {
+ scsi_scan_host_selected(shost, SCAN_WILD_CARD, SCAN_WILD_CARD,
+ SCAN_WILD_CARD, 0);
+ }
+}
+
+static int do_scan_async(void *_data)
+{
+ struct async_scan_data *data = _data;
+ do_scsi_scan_host(data->shost);
+ scsi_finish_async_scan(data);
+ return 0;
+}
+
/**
* scsi_scan_host - scan the given adapter
* @shost: adapter to scan
**/
void scsi_scan_host(struct Scsi_Host *shost)
{
- scsi_scan_host_selected(shost, SCAN_WILD_CARD, SCAN_WILD_CARD,
- SCAN_WILD_CARD, 0);
+ struct async_scan_data *data;
+
+ if (strncmp(scsi_scan_type, "none", 4) == 0)
+ return;
+
+ data = scsi_prep_async_scan(shost);
+ if (!data) {
+ do_scsi_scan_host(shost);
+ return;
+ }
+
+ kthread_run(do_scan_async, data, "scsi_scan_%d", shost->host_no);
}
EXPORT_SYMBOL(scsi_scan_host);
git.openpandora.org / pandora-kernel.git / blobdiff