[SCSI] sd: fix cache flushing on module removal (and individual device removal)
The fix isn't actually in sd: it's in scsi_device_get(). I modified it
to allow devices to be returned in SDEV_CANCEL, but not SDEV_DEL. This
means that the device_remove_driver, which occurs in device_del() in
scsi_remove_device() after the device has gone into SDEV_CANCEL is now
effective at flushing the cache.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 94df671..3784392 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -851,14 +851,14 @@
*/
int scsi_device_get(struct scsi_device *sdev)
{
- if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
+ if (sdev->sdev_state == SDEV_DEL)
return -ENXIO;
if (!get_device(&sdev->sdev_gendev))
return -ENXIO;
- if (!try_module_get(sdev->host->hostt->module)) {
- put_device(&sdev->sdev_gendev);
- return -ENXIO;
- }
+ /* We can fail this if we're doing SCSI operations
+ * from module exit (like cache flush) */
+ try_module_get(sdev->host->hostt->module);
+
return 0;
}
EXPORT_SYMBOL(scsi_device_get);
@@ -873,7 +873,10 @@
*/
void scsi_device_put(struct scsi_device *sdev)
{
- module_put(sdev->host->hostt->module);
+ /* The module refcount will be zero if scsi_device_get()
+ * was called from a module removal routine */
+ if (likely(module_refcount(sdev->host->hostt->module) != 0))
+ module_put(sdev->host->hostt->module);
put_device(&sdev->sdev_gendev);
}
EXPORT_SYMBOL(scsi_device_put);