[SCSI] sd: implement sd_check_events()

Replace sd_media_change() with sd_check_events().

* Move media removed logic into set_media_not_present() and
  media_not_present() and set sdev->changed iff an existing media is
  removed or the device indicates UNIT_ATTENTION.

* Make sd_check_events() sets sdev->changed if previously missing
  media becomes present.

* Event is reported only if sdev->changed is set.

This makes media presence event reported if scsi_disk->media_present
actually changed or the device indicated UNIT_ATTENTION.  For backward
compatibility, SDEV_EVT_MEDIA_CHANGE is generated each time
sd_check_events() detects media change event.

[jejb: fix boot failure]
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jens Axboe <jaxboe@fusionio.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index b65e65a..7d25746 100644 (file)
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -990,30 +990,51 @@ out:
 
 static void set_media_not_present(struct scsi_disk *sdkp)
 {
-       sdkp->media_present = 0;
-       sdkp->capacity = 0;
-       sdkp->device->changed = 1;
+       if (sdkp->media_present)
+               sdkp->device->changed = 1;
+
+       if (sdkp->device->removable) {
+               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:
+       case NOT_READY:
+               /* medium not present */
+               if (sshdr->asc == 0x3A) {
+                       set_media_not_present(sdkp);
+                       return 1;
+               }
+       }
+       return 0;
 }
 
 /**
- *     sd_media_changed - check if our medium changed
- *     @disk: kernel device descriptor 
+ *     sd_check_events - check media events
+ *     @disk: kernel device descriptor
+ *     @clearing: disk events currently being cleared
  *
- *     Returns 0 if not applicable or no change; 1 if change
+ *     Returns mask of DISK_EVENT_*.
  *
  *     Note: this function is invoked from the block subsystem.
  **/
-static int sd_media_changed(struct gendisk *disk)
+static unsigned int sd_check_events(struct gendisk *disk, unsigned int clearing)
 {
        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_media_changed\n"));
-
-       if (!sdp->removable)
-               return 0;
+       SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_check_events\n"));
 
        /*
         * If the device is offline, don't send any commands - just pretend as
@@ -1043,40 +1064,37 @@ static int sd_media_changed(struct gendisk *disk)
                                              sshdr);
        }
 
-       if (retval) {
+       /* failed to execute TUR, assume media not present */
+       if (host_byte(retval)) {
                set_media_not_present(sdkp);
                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. This is kept in the struct scsi_disk
-        * struct and tested at open !  Daniel Roche (dan@lectra.fr)
+        * of a disk in the drive.
         */
+       if (!sdkp->media_present)
+               sdp->changed = 1;
        sdkp->media_present = 1;
-
 out:
        /*
-        * Report a media change under the following conditions:
+        * sdp->changed is set under the following conditions:
         *
-        *      Medium is present now and wasn't present before.
-        *      Medium wasn't present before and is present now.
-        *      Medium was present at all times, but it changed while
-        *              we weren't looking (sdp->changed is set).
+        *      Medium present state has changed in either direction.
+        *      Device has indicated UNIT_ATTENTION.
         *
-        * If there was no medium before and there is no medium now then
-        * don't report a change, even if a medium was inserted and removed
-        * while we weren't looking.
+        * Report SDEV_EVT_MEDIA_CHANGE too for backward compatibility.
         */
-       retval = (sdkp->media_present != sdkp->previous_state ||
-                       (sdkp->media_present && sdp->changed));
-       if (retval)
+       if (sdp->changed)
                sdev_evt_send_simple(sdp, SDEV_EVT_MEDIA_CHANGE, GFP_KERNEL);
-       sdkp->previous_state = sdkp->media_present;
-
-       /* sdp->changed indicates medium was changed or is not present */
-       sdp->changed = !sdkp->media_present;
        kfree(sshdr);
+
+       retval = sdp->changed ? DISK_EVENT_MEDIA_CHANGE : 0;
+       sdp->changed = 0;
        return retval;
 }
 
@@ -1169,7 +1187,7 @@ static const struct block_device_operations sd_fops = {
 #ifdef CONFIG_COMPAT
        .compat_ioctl           = sd_compat_ioctl,
 #endif
-       .media_changed          = sd_media_changed,
+       .check_events           = sd_check_events,
        .revalidate_disk        = sd_revalidate_disk,
        .unlock_native_capacity = sd_unlock_native_capacity,
 };
@@ -1312,23 +1330,6 @@ 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()
  */
@@ -1503,7 +1504,7 @@ static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device *sdp,
         */
        if (sdp->removable &&
            sense_valid && sshdr->sense_key == NOT_READY)
-               sdp->changed = 1;
+               set_media_not_present(sdkp);
 
        /*
         * We used to set media_present to 0 here to indicate no media
@@ -2389,8 +2390,10 @@ 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);
@@ -2472,7 +2475,6 @@ 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 55488fa..c9d8f6c 100644 (file)
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -55,7 +55,6 @@ 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 */