Merge branch 'for-2.6.38/event-handling' into for-2.6.38/core

6 files changed, 156 insertions, 102 deletions

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index af13c62dc473..14033a36bcd0 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -1348,7 +1348,10 @@ static int cdrom_select_disc(struct cdrom_device_info *cdi, int slot)
         if (!CDROM_CAN(CDC_SELECT_DISC))
                 return -EDRIVE_CANT_DO_THIS;
 
-        (void) cdi->ops->media_changed(cdi, slot);
+        if (cdi->ops->check_events)
+                cdi->ops->check_events(cdi, 0, slot);
+        else
+                cdi->ops->media_changed(cdi, slot);
 
         if (slot == CDSL_NONE) {
                 /* set media changed bits, on both queues */
@@ -1392,6 +1395,42 @@ static int cdrom_select_disc(struct cdrom_device_info *cdi, int slot)
         return slot;
 }
 
+/*
+ * As cdrom implements an extra ioctl consumer for media changed
+ * event, it needs to buffer ->check_events() output, such that event
+ * is not lost for both the usual VFS and ioctl paths.
+ * cdi->{vfs|ioctl}_events are used to buffer pending events for each
+ * path.
+ *
+ * XXX: Locking is non-existent.  cdi->ops->check_events() can be
+ * called in parallel and buffering fields are accessed without any
+ * exclusion.  The original media_changed code had the same problem.
+ * It might be better to simply deprecate CDROM_MEDIA_CHANGED ioctl
+ * and remove this cruft altogether.  It doesn't have much usefulness
+ * at this point.
+ */
+static void cdrom_update_events(struct cdrom_device_info *cdi,
+                                unsigned int clearing)
+{
+        unsigned int events;
+
+        events = cdi->ops->check_events(cdi, clearing, CDSL_CURRENT);
+        cdi->vfs_events |= events;
+        cdi->ioctl_events |= events;
+}
+
+unsigned int cdrom_check_events(struct cdrom_device_info *cdi,
+                                unsigned int clearing)
+{
+        unsigned int events;
+
+        cdrom_update_events(cdi, clearing);
+        events = cdi->vfs_events;
+        cdi->vfs_events = 0;
+        return events;
+}
+EXPORT_SYMBOL(cdrom_check_events);
+
 /* We want to make media_changed accessible to the user through an
  * ioctl. The main problem now is that we must double-buffer the
  * low-level implementation, to assure that the VFS and the user both
@@ -1403,15 +1442,26 @@ int media_changed(struct cdrom_device_info *cdi, int queue)
 {
         unsigned int mask = (1 << (queue & 1));
         int ret = !!(cdi->mc_flags & mask);
+        bool changed;
 
         if (!CDROM_CAN(CDC_MEDIA_CHANGED))
-            return ret;
+                return ret;
+
         /* changed since last call? */
-        if (cdi->ops->media_changed(cdi, CDSL_CURRENT)) {
+        if (cdi->ops->check_events) {
+                BUG_ON(!queue); /* shouldn't be called from VFS path */
+                cdrom_update_events(cdi, DISK_EVENT_MEDIA_CHANGE);
+                changed = cdi->ioctl_events & DISK_EVENT_MEDIA_CHANGE;
+                cdi->ioctl_events = 0;
+        } else
+                changed = cdi->ops->media_changed(cdi, CDSL_CURRENT);
+
+        if (changed) {
                 cdi->mc_flags = 0x3;    /* set bit on both queues */
                 ret |= 1;
                 cdi->media_written = 0;
         }
+
         cdi->mc_flags &= ~mask;         /* clear bit */
         return ret;
 }
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index eafeeda6e194..13bf89145b18 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1984,8 +1984,7 @@ EXPORT_SYMBOL(scsi_mode_sense);
  *              in.
  *
  *      Returns zero if unsuccessful or an error if TUR failed.  For
- *      removable media, a return of NOT_READY or UNIT_ATTENTION is
- *      translated to success, with the ->changed flag updated.
+ *      removable media, UNIT_ATTENTION sets ->changed flag.
  **/
 int
 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
@@ -2012,16 +2011,6 @@ scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
         } while (scsi_sense_valid(sshdr) &&
                  sshdr->sense_key == UNIT_ATTENTION && --retries);
 
-        if (!sshdr)
-                /* could not allocate sense buffer, so can't process it */
-                return result;
-
-        if (sdev->removable && scsi_sense_valid(sshdr) &&
-            (sshdr->sense_key == UNIT_ATTENTION ||
-             sshdr->sense_key == NOT_READY)) {
-                sdev->changed = 1;
-                result = 0;
-        }
         if (!sshdr_external)
                 kfree(sshdr);
         return result;
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index b9ab3a590e4b..8d488a9fef00 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1045,15 +1045,7 @@ static int sd_media_changed(struct gendisk *disk)
                                               sshdr);
         }
 
-        /*
-         * Unable to test, unit probably not ready.   This usually
-         * means there is no disc in the drive.  Mark as changed,
-         * and we will figure it out later once the drive is
-         * available again.
-         */
-        if (retval || (scsi_sense_valid(sshdr) &&
-                       /* 0x3a is medium not present */
-                       sshdr->asc == 0x3a)) {
+        if (retval) {
                 set_media_not_present(sdkp);
                 retval = 1;
                 goto out;
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index d7b383c96d5d..be6baf8ad704 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -104,14 +104,15 @@ static void sr_release(struct cdrom_device_info *);
 static void get_sectorsize(struct scsi_cd *);
 static void get_capabilities(struct scsi_cd *);
 
-static int sr_media_change(struct cdrom_device_info *, int);
+static unsigned int sr_check_events(struct cdrom_device_info *cdi,
+                                    unsigned int clearing, int slot);
 static int sr_packet(struct cdrom_device_info *, struct packet_command *);
 
 static struct cdrom_device_ops sr_dops = {
         .open                   = sr_open,
         .release                = sr_release,
         .drive_status           = sr_drive_status,
-        .media_changed          = sr_media_change,
+        .check_events           = sr_check_events,
         .tray_move              = sr_tray_move,
         .lock_door              = sr_lock_door,
         .select_speed           = sr_select_speed,
@@ -165,90 +166,96 @@ static void scsi_cd_put(struct scsi_cd *cd)
         mutex_unlock(&sr_ref_mutex);
 }
 
-/* identical to scsi_test_unit_ready except that it doesn't
- * eat the NOT_READY returns for removable media */
-int sr_test_unit_ready(struct scsi_device *sdev, struct scsi_sense_hdr *sshdr)
+static unsigned int sr_get_events(struct scsi_device *sdev)
 {
-        int retries = MAX_RETRIES;
-        int the_result;
-        u8 cmd[] = {TEST_UNIT_READY, 0, 0, 0, 0, 0 };
+        u8 buf[8];
+        u8 cmd[] = { GET_EVENT_STATUS_NOTIFICATION,
+                     1,                 /* polled */
+                     0, 0,              /* reserved */
+                     1 << 4,            /* notification class: media */
+                     0, 0,              /* reserved */
+                     0, sizeof(buf),    /* allocation length */
+                     0,                 /* control */
+        };
+        struct event_header *eh = (void *)buf;
+        struct media_event_desc *med = (void *)(buf + 4);
+        struct scsi_sense_hdr sshdr;
+        int result;
 
-        /* issue TEST_UNIT_READY until the initial startup UNIT_ATTENTION
-         * conditions are gone, or a timeout happens
-         */
-        do {
-                the_result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL,
-                                              0, sshdr, SR_TIMEOUT,
-                                              retries--, NULL);
-                if (scsi_sense_valid(sshdr) &&
-                    sshdr->sense_key == UNIT_ATTENTION)
-                        sdev->changed = 1;
-
-        } while (retries > 0 &&
-                 (!scsi_status_is_good(the_result) ||
-                  (scsi_sense_valid(sshdr) &&
-                   sshdr->sense_key == UNIT_ATTENTION)));
-        return the_result;
+        result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buf, sizeof(buf),
+                                  &sshdr, SR_TIMEOUT, MAX_RETRIES, NULL);
+        if (scsi_sense_valid(&sshdr) && sshdr.sense_key == UNIT_ATTENTION)
+                return DISK_EVENT_MEDIA_CHANGE;
+
+        if (result || be16_to_cpu(eh->data_len) < sizeof(*med))
+                return 0;
+
+        if (eh->nea || eh->notification_class != 0x4)
+                return 0;
+
+        if (med->media_event_code == 1)
+                return DISK_EVENT_EJECT_REQUEST;
+        else if (med->media_event_code == 2)
+                return DISK_EVENT_MEDIA_CHANGE;
+        return 0;
 }
 
 /*
- * This function checks to see if the media has been changed in the
- * CDROM drive.  It is possible that we have already sensed a change,
- * or the drive may have sensed one and not yet reported it.  We must
- * be ready for either case. This function always reports the current
- * value of the changed bit.  If flag is 0, then the changed bit is reset.
- * This function could be done as an ioctl, but we would need to have
- * an inode for that to work, and we do not always have one.
+ * This function checks to see if the media has been changed or eject
+ * button has been pressed.  It is possible that we have already
+ * sensed a change, or the drive may have sensed one and not yet
+ * reported it.  The past events are accumulated in sdev->changed and
+ * returned together with the current state.
  */
-
-static int sr_media_change(struct cdrom_device_info *cdi, int slot)
+static unsigned int sr_check_events(struct cdrom_device_info *cdi,
+                                    unsigned int clearing, int slot)
 {
         struct scsi_cd *cd = cdi->handle;
-        int retval;
-        struct scsi_sense_hdr *sshdr;
+        bool last_present;
+        struct scsi_sense_hdr sshdr;
+        unsigned int events;
+        int ret;
 
-        if (CDSL_CURRENT != slot) {
-                /* no changer support */
-                return -EINVAL;
-        }
+        /* no changer support */
+        if (CDSL_CURRENT != slot)
+                return 0;
 
-        sshdr =  kzalloc(sizeof(*sshdr), GFP_KERNEL);
-        retval = sr_test_unit_ready(cd->device, sshdr);
-        if (retval || (scsi_sense_valid(sshdr) &&
-                       /* 0x3a is medium not present */
-                       sshdr->asc == 0x3a)) {
-                /* Media not present or unable to test, unit probably not
-                 * ready. This usually means there is no disc in the drive.
-                 * Mark as changed, and we will figure it out later once
-                 * the drive is available again.
-                 */
-                cd->device->changed = 1;
-                /* This will force a flush, if called from check_disk_change */
-                retval = 1;
-                goto out;
-        };
+        events = sr_get_events(cd->device);
+        /*
+         * GET_EVENT_STATUS_NOTIFICATION is enough unless MEDIA_CHANGE
+         * is being cleared.  Note that there are devices which hang
+         * if asked to execute TUR repeatedly.
+         */
+        if (!(clearing & DISK_EVENT_MEDIA_CHANGE))
+                goto skip_tur;
+
+        /* let's see whether the media is there with TUR */
+        last_present = cd->media_present;
+        ret = scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr);
+
+        /*
+         * Media is considered to be present if TUR succeeds or fails with
+         * sense data indicating something other than media-not-present
+         * (ASC 0x3a).
+         */
+        cd->media_present = scsi_status_is_good(ret) ||
+                (scsi_sense_valid(&sshdr) && sshdr.asc != 0x3a);
 
-        retval = cd->device->changed;
-        cd->device->changed = 0;
-        /* If the disk changed, the capacity will now be different,
-         * so we force a re-read of this information */
-        if (retval) {
-                /* check multisession offset etc */
-                sr_cd_check(cdi);
-                get_sectorsize(cd);
+        if (last_present != cd->media_present)
+                events |= DISK_EVENT_MEDIA_CHANGE;
+skip_tur:
+        if (cd->device->changed) {
+                events |= DISK_EVENT_MEDIA_CHANGE;
+                cd->device->changed = 0;
         }
 
-out:
-        /* Notify userspace, that media has changed. */
-        if (retval != cd->previous_state)
+        /* for backward compatibility */
+        if (events & DISK_EVENT_MEDIA_CHANGE)
                 sdev_evt_send_simple(cd->device, SDEV_EVT_MEDIA_CHANGE,
                                      GFP_KERNEL);
-        cd->previous_state = retval;
-        kfree(sshdr);
-
-        return retval;
+        return events;
 }
- 
+
 /*
  * sr_done is the interrupt routine for the device driver.
  *
@@ -533,10 +540,25 @@ out:
         return ret;
 }
 
-static int sr_block_media_changed(struct gendisk *disk)
+static unsigned int sr_block_check_events(struct gendisk *disk,
+                                          unsigned int clearing)
 {
         struct scsi_cd *cd = scsi_cd(disk);
-        return cdrom_media_changed(&cd->cdi);
+        return cdrom_check_events(&cd->cdi, clearing);
+}
+
+static int sr_block_revalidate_disk(struct gendisk *disk)
+{
+        struct scsi_cd *cd = scsi_cd(disk);
+        struct scsi_sense_hdr sshdr;
+
+        /* if the unit is not ready, nothing more to do */
+        if (scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr))
+                return 0;
+
+        sr_cd_check(&cd->cdi);
+        get_sectorsize(cd);
+        return 0;
 }
 
 static const struct block_device_operations sr_bdops =
@@ -545,7 +567,8 @@ static const struct block_device_operations sr_bdops =
         .open           = sr_block_open,
         .release        = sr_block_release,
         .ioctl          = sr_block_ioctl,
-        .media_changed  = sr_block_media_changed,
+        .check_events   = sr_block_check_events,
+        .revalidate_disk = sr_block_revalidate_disk,
         /* 
          * No compat_ioctl for now because sr_block_ioctl never
          * seems to pass arbitary ioctls down to host drivers.
@@ -618,6 +641,7 @@ static int sr_probe(struct device *dev)
         sprintf(disk->disk_name, "sr%d", minor);
         disk->fops = &sr_bdops;
         disk->flags = GENHD_FL_CD;
+        disk->events = DISK_EVENT_MEDIA_CHANGE | DISK_EVENT_EJECT_REQUEST;
 
         blk_queue_rq_timeout(sdev->request_queue, SR_TIMEOUT);
 
@@ -627,7 +651,7 @@ static int sr_probe(struct device *dev)
         cd->disk = disk;
         cd->capacity = 0x1fffff;
         cd->device->changed = 1;        /* force recheck CD type */
-        cd->previous_state = 1;
+        cd->media_present = 1;
         cd->use = 1;
         cd->readcd_known = 0;
         cd->readcd_cdda = 0;
@@ -780,7 +804,7 @@ static void get_capabilities(struct scsi_cd *cd)
         }
 
         /* eat unit attentions */
-        sr_test_unit_ready(cd->device, &sshdr);
+        scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr);
 
         /* ask for mode page 0x2a */
         rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, 128,
diff --git a/drivers/scsi/sr.h b/drivers/scsi/sr.h
index 1e144dfdbd4b..e036f1dc83c8 100644
--- a/drivers/scsi/sr.h
+++ b/drivers/scsi/sr.h
@@ -40,7 +40,7 @@ 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 */
+        unsigned media_present:1;       /* media is present */
         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 */
@@ -61,7 +61,6 @@ int sr_select_speed(struct cdrom_device_info *cdi, int speed);
 int sr_audio_ioctl(struct cdrom_device_info *, unsigned int, void *);
 
 int sr_is_xa(Scsi_CD *);
-int sr_test_unit_ready(struct scsi_device *sdev, struct scsi_sense_hdr *sshdr);
 
 /* sr_vendor.c */
 void sr_vendor_init(Scsi_CD *);
diff --git a/drivers/scsi/sr_ioctl.c b/drivers/scsi/sr_ioctl.c
index 3cd8ffbad577..8be30554119b 100644
--- a/drivers/scsi/sr_ioctl.c
+++ b/drivers/scsi/sr_ioctl.c
@@ -307,7 +307,7 @@ int sr_drive_status(struct cdrom_device_info *cdi, int slot)
                 /* we have no changer support */
                 return -EINVAL;
         }
-        if (0 == sr_test_unit_ready(cd->device, &sshdr))
+        if (!scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr))
                 return CDS_DISC_OK;
 
         /* SK/ASC/ASCQ of 2/4/1 means "unit is becoming ready" */