[SCSI] sr,sd: send media state change modification events

This will send for a card reader slot (remove/add media):
  UEVENT[1187091572.155884] change   /devices/pci0000:00/0000:00:1d.7/usb5/5-2/5-2:1.0/host7/target7:0:0/7:0:0:0 (scsi)
  UEVENT[1187091572.162314] remove   /block/sdb/sdb1 (block)
  UEVENT[1187091572.172464] add      /block/sdb/sdb1 (block)
  UEVENT[1187091572.175408] change   /devices/pci0000:00/0000:00:1d.7/usb5/5-2/5-2:1.0/host7/target7:0:0/7:0:0:0 (scsi)

and for a DVD drive (add/eject media):
  UEVENT[1187091590.189159] change   /devices/pci0000:00/0000:00:1f.1/host4/target4:0:0/4:0:0:0 (scsi)
  UEVENT[1187091590.957124] add      /module/isofs (module)
  UEVENT[1187091604.468207] change   /devices/pci0000:00/0000:00:1f.1/host4/target4:0:0/4:0:0:0 (scsi)

Userspace gets events, even for unpartitioned media. This unifies
the event handling for asynchronoous events (AN) and events caused by
perodical polling the device from userspace.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>

[jejb: modified for new event API]

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

4 files changed, 28 insertions, 12 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index a69b155f39a2..18343a6acd8e 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -749,8 +749,11 @@ static int sd_media_changed(struct gendisk *disk)
          * can deal with it then.  It is only because of unrecoverable errors
          * that we would ever take a device offline in the first place.
          */
-        if (!scsi_device_online(sdp))
-                goto not_present;
+        if (!scsi_device_online(sdp)) {
+                set_media_not_present(sdkp);
+                retval = 1;
+                goto out;
+        }
 
         /*
          * Using TEST_UNIT_READY enables differentiation between drive with
@@ -762,6 +765,7 @@ static int sd_media_changed(struct gendisk *disk)
          * sd_revalidate() is called.
          */
         retval = -ENODEV;
+
         if (scsi_block_when_processing_errors(sdp))
                 retval = scsi_test_unit_ready(sdp, SD_TIMEOUT, SD_MAX_RETRIES);
 
@@ -771,8 +775,11 @@ static int sd_media_changed(struct gendisk *disk)
          * and we will figure it out later once the drive is
          * available again.
          */
-        if (retval)
-                 goto not_present;
+        if (retval) {
+                set_media_not_present(sdkp);
+                retval = 1;
+                goto out;
+        }
 
         /*
          * For removable scsi disk we have to recognise the presence
@@ -783,12 +790,11 @@ static int sd_media_changed(struct gendisk *disk)
 
         retval = sdp->changed;
         sdp->changed = 0;
-
+out:
+        if (retval != sdkp->previous_state)
+                sdev_evt_send_simple(sdp, SDEV_EVT_MEDIA_CHANGE, GFP_KERNEL);
+        sdkp->previous_state = retval;
         return retval;
-
-not_present:
-        set_media_not_present(sdkp);
-        return 1;
 }
 
 static int sd_sync_cache(struct scsi_disk *sdkp)
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index c61999031141..7702681d93f9 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -192,8 +192,9 @@ static int sr_media_change(struct cdrom_device_info *cdi, int slot)
                  * and we will figure it out later once the drive is
                  * available again.  */
                 cd->device->changed = 1;
-                return 1;       /* This will force a flush, if called from
-                                 * check_disk_change */
+                /* This will force a flush, if called from check_disk_change */
+                retval = 1;
+                goto out;
         };
 
         retval = cd->device->changed;
@@ -203,9 +204,16 @@ static int sr_media_change(struct cdrom_device_info *cdi, int slot)
         if (retval) {
                 /* check multisession offset etc */
                 sr_cd_check(cdi);
-
                 get_sectorsize(cd);
         }
+
+out:
+        /* Notify userspace, that media has changed. */
+        if (retval != cd->previous_state)
+                sdev_evt_send_simple(cd->device, SDEV_EVT_MEDIA_CHANGE,
+                                     GFP_KERNEL);
+        cd->previous_state = retval;
+
         return retval;
 }
  
diff --git a/drivers/scsi/sr.h b/drivers/scsi/sr.h
index d65de9621b27..0d04e2878c9d 100644
--- a/drivers/scsi/sr.h
+++ b/drivers/scsi/sr.h
@@ -37,6 +37,7 @@ typedef struct scsi_cd {
         unsigned xa_flag:1;     /* CD has XA sectors ? */
         unsigned readcd_known:1;        /* drive supports READ_CD (0xbe) */
         unsigned readcd_cdda:1; /* reading audio data using READ_CD */
+        unsigned previous_state:1;      /* media has changed */
         struct cdrom_device_info cdi;
         /* We hold gendisk and scsi_device references on probe and use
          * the refs on this kref to decide when to release them */
diff --git a/include/scsi/sd.h b/include/scsi/sd.h
index f7513313ef0d..8ea9f7358ac1 100644
--- a/include/scsi/sd.h
+++ b/include/scsi/sd.h
@@ -41,6 +41,7 @@ struct scsi_disk {
         u32             index;
         u8              media_present;
         u8              write_prot;
+        unsigned        previous_state : 1;
         unsigned        WCE : 1;        /* state of disk WCE bit */
         unsigned        RCD : 1;        /* state of disk RCD bit, unused */
         unsigned        DPOFUA : 1;     /* state of disk DPOFUA bit */