Revert "sd: implement sd_check_events()"

This reverts commit c8d2e937355d02db3055c2fc203e5f017297ee1f.

We run into merging problems with the SCSI tree, revert this one
so it can be handled by a postmerge tree there.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

2 files changed, 41 insertions, 47 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index b179b0e39a3b..8d488a9fef00 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -991,50 +991,30 @@ out:
 
 static void set_media_not_present(struct scsi_disk *sdkp)
 {
-        if (sdkp->media_present)
-                sdkp->device->changed = 1;
         sdkp->media_present = 0;
         sdkp->capacity = 0;
-}
-
-static int media_not_present(struct scsi_disk *sdkp,
-                             struct scsi_sense_hdr *sshdr)
-{
-        if (!scsi_sense_valid(sshdr))
-                return 0;
-
-        /* not invoked for commands that could return deferred errors */
-        switch (sshdr->sense_key) {
-        case UNIT_ATTENTION:
-                sdkp->device->changed = 1;
-                /* fall through */
-        case NOT_READY:
-                /* medium not present */
-                if (sshdr->asc == 0x3A) {
-                        set_media_not_present(sdkp);
-                        return 1;
-                }
-        }
-        return 0;
+        sdkp->device->changed = 1;
 }
 
 /**
- *      sd_check_events - check media events
- *      @disk: kernel device descriptor
- *      @clearing: disk events currently being cleared
+ *      sd_media_changed - check if our medium changed
+ *      @disk: kernel device descriptor 
  *
- *      Returns mask of DISK_EVENT_*.
+ *      Returns 0 if not applicable or no change; 1 if change
  *
  *      Note: this function is invoked from the block subsystem.
  **/
-static unsigned int sd_check_events(struct gendisk *disk, unsigned int clearing)
+static int sd_media_changed(struct gendisk *disk)
 {
         struct scsi_disk *sdkp = scsi_disk(disk);
         struct scsi_device *sdp = sdkp->device;
         struct scsi_sense_hdr *sshdr = NULL;
         int retval;
 
-        SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_check_events\n"));
+        SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_media_changed\n"));
+
+        if (!sdp->removable)
+                return 0;
 
         /*
          * If the device is offline, don't send any commands - just pretend as
@@ -1044,6 +1024,7 @@ static unsigned int sd_check_events(struct gendisk *disk, unsigned int clearing)
          */
         if (!scsi_device_online(sdp)) {
                 set_media_not_present(sdkp);
+                retval = 1;
                 goto out;
         }
 
@@ -1064,30 +1045,26 @@ static unsigned int sd_check_events(struct gendisk *disk, unsigned int clearing)
                                               sshdr);
         }
 
-        /* failed to execute TUR, assume media not present */
-        if (host_byte(retval)) {
+        if (retval) {
                 set_media_not_present(sdkp);
+                retval = 1;
                 goto out;
         }
 
-        if (media_not_present(sdkp, sshdr))
-                goto out;
-
         /*
          * For removable scsi disk we have to recognise the presence
-         * of a disk in the drive.
+         * of a disk in the drive. This is kept in the struct scsi_disk
+         * struct and tested at open !  Daniel Roche (dan@lectra.fr)
          */
-        if (!sdkp->media_present)
-                sdp->changed = 1;
         sdkp->media_present = 1;
+
+        retval = sdp->changed;
+        sdp->changed = 0;
 out:
-        /* for backward compatibility */
-        if (sdp->changed)
+        if (retval != sdkp->previous_state)
                 sdev_evt_send_simple(sdp, SDEV_EVT_MEDIA_CHANGE, GFP_KERNEL);
+        sdkp->previous_state = retval;
         kfree(sshdr);
-
-        retval = sdp->changed ? DISK_EVENT_MEDIA_CHANGE : 0;
-        sdp->changed = 0;
         return retval;
 }
 
@@ -1180,7 +1157,7 @@ static const struct block_device_operations sd_fops = {
 #ifdef CONFIG_COMPAT
         .compat_ioctl           = sd_compat_ioctl,
 #endif
-        .check_events           = sd_check_events,
+        .media_changed          = sd_media_changed,
         .revalidate_disk        = sd_revalidate_disk,
         .unlock_native_capacity = sd_unlock_native_capacity,
 };
@@ -1316,6 +1293,23 @@ static int sd_done(struct scsi_cmnd *SCpnt)
         return good_bytes;
 }
 
+static int media_not_present(struct scsi_disk *sdkp,
+                             struct scsi_sense_hdr *sshdr)
+{
+
+        if (!scsi_sense_valid(sshdr))
+                return 0;
+        /* not invoked for commands that could return deferred errors */
+        if (sshdr->sense_key != NOT_READY &&
+            sshdr->sense_key != UNIT_ATTENTION)
+                return 0;
+        if (sshdr->asc != 0x3A) /* medium not present */
+                return 0;
+
+        set_media_not_present(sdkp);
+        return 1;
+}
+
 /*
  * spinup disk - called only in sd_revalidate_disk()
  */
@@ -1490,7 +1484,7 @@ static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device *sdp,
          */
         if (sdp->removable &&
             sense_valid && sshdr->sense_key == NOT_READY)
-                set_media_not_present(sdkp);
+                sdp->changed = 1;
 
         /*
          * We used to set media_present to 0 here to indicate no media
@@ -2345,10 +2339,8 @@ static void sd_probe_async(void *data, async_cookie_t cookie)
 
         gd->driverfs_dev = &sdp->sdev_gendev;
         gd->flags = GENHD_FL_EXT_DEVT;
-        if (sdp->removable) {
+        if (sdp->removable)
                 gd->flags |= GENHD_FL_REMOVABLE;
-                gd->events |= DISK_EVENT_MEDIA_CHANGE;
-        }
 
         add_disk(gd);
         sd_dif_config_host(sdkp);
@@ -2430,6 +2422,7 @@ static int sd_probe(struct device *dev)
         sdkp->disk = gd;
         sdkp->index = index;
         atomic_set(&sdkp->openers, 0);
+        sdkp->previous_state = 1;
 
         if (!sdp->request_queue->rq_timeout) {
                 if (sdp->type != TYPE_MOD)
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index c9d8f6ca49e2..55488faf0815 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -55,6 +55,7 @@ struct scsi_disk {
         u8              media_present;
         u8              write_prot;
         u8              protection_type;/* Data Integrity Field */
+        unsigned        previous_state : 1;
         unsigned        ATO : 1;        /* state of disk ATO bit */
         unsigned        WCE : 1;        /* state of disk WCE bit */
         unsigned        RCD : 1;        /* state of disk RCD bit, unused */