sd: implement sd_check_events()

Replace sd_media_change() with sd_check_events(). sd used to set the changed state whenever the device is not ready, which can cause event loop while the device is not ready. Media presence handling code is changed such that the changed state is set iff the media presence actually changes. UA still always sets the changed state and NOT_READY always (at least where it used to set ->changed) clears media presence, so no event is lost. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

sd: implement sd_check_events()
Replace sd_media_change() with sd_check_events(). sd used to set the changed state whenever the device is not ready, which can cause event loop while the device is not ready. Media presence handling code is changed such that the changed state is set iff the media presence actually changes. UA still always sets the changed state and NOT_READY always (at least where it used to set ->changed) clears media presence, so no event is lost. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Tejun Heo · Jens Axboe
1 parent 93aae17af1
Showing 2 changed files with 47 additions and 41 deletions Side-by-side Diff
drivers/scsi/sd.c
drivers/scsi/sd.h
@@ -991,31 +991,51 @@
  
 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;
-	sdkp->device->changed = 1;
 }
  
+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;
+}
+
 /**
- *	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"));
+	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_check_events\n"));
  
-	if (!sdp->removable)
-		return 0;
-
 	/*
 	 * If the device is offline, don't send any commands - just pretend as
 	 * if the command failed.  If the device ever comes back online, we
@@ -1024,7 +1044,6 @@
 	 */
 	if (!scsi_device_online(sdp)) {
 		set_media_not_present(sdkp);
-		retval = 1;
 		goto out;
 	}
  
  
  
  
  
  
  
  
  
@@ -1045,26 +1064,30 @@
 					      sshdr);
 	}
  
-	if (retval) {
+	/* failed to execute TUR, assume media not present */
+	if (host_byte(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. 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;
-
-	retval = sdp->changed;
-	sdp->changed = 0;
 out:
-	if (retval != sdkp->previous_state)
+	/* for backward compatibility */
+	if (sdp->changed)
 		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;
 }
  
@@ -1157,7 +1180,7 @@
 #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,
 };
@@ -1293,23 +1316,6 @@
 	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()
  */
@@ -1484,7 +1490,7 @@
 	 */
 	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
  
@@ -2339,8 +2345,10 @@
  
 	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);
@@ -2422,7 +2430,6 @@
 	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)
@@ -55,7 +55,6 @@
 	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 */
...	...	@@ -991,31 +991,51 @@
991	991
992	992	static void set_media_not_present(struct scsi_disk *sdkp)
993	993	{
	994	+ if (sdkp->media_present)
	995	+ sdkp->device->changed = 1;
994	996	sdkp->media_present = 0;
995	997	sdkp->capacity = 0;
996		- sdkp->device->changed = 1;
997	998	}
998	999
	1000	+static int media_not_present(struct scsi_disk *sdkp,
	1001	+ struct scsi_sense_hdr *sshdr)
	1002	+{
	1003	+ if (!scsi_sense_valid(sshdr))
	1004	+ return 0;
	1005	+
	1006	+ /* not invoked for commands that could return deferred errors */
	1007	+ switch (sshdr->sense_key) {
	1008	+ case UNIT_ATTENTION:
	1009	+ sdkp->device->changed = 1;
	1010	+ /* fall through */
	1011	+ case NOT_READY:
	1012	+ /* medium not present */
	1013	+ if (sshdr->asc == 0x3A) {
	1014	+ set_media_not_present(sdkp);
	1015	+ return 1;
	1016	+ }
	1017	+ }
	1018	+ return 0;
	1019	+}
	1020	+
999	1021	/**
1000		- * sd_media_changed - check if our medium changed
1001		- * @disk: kernel device descriptor
	1022	+ * sd_check_events - check media events
	1023	+ * @disk: kernel device descriptor
	1024	+ * @clearing: disk events currently being cleared
1002	1025	*
1003		- * Returns 0 if not applicable or no change; 1 if change
	1026	+ * Returns mask of DISK_EVENT_*.
1004	1027	*
1005	1028	* Note: this function is invoked from the block subsystem.
1006	1029	**/
1007		-static int sd_media_changed(struct gendisk *disk)
	1030	+static unsigned int sd_check_events(struct gendisk *disk, unsigned int clearing)
1008	1031	{
1009	1032	struct scsi_disk *sdkp = scsi_disk(disk);
1010	1033	struct scsi_device *sdp = sdkp->device;
1011	1034	struct scsi_sense_hdr *sshdr = NULL;
1012	1035	int retval;
1013	1036
1014		- SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_media_changed\n"));
	1037	+ SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_check_events\n"));
1015	1038
1016		- if (!sdp->removable)
1017		- return 0;
1018		-
1019	1039	/*
1020	1040	* If the device is offline, don't send any commands - just pretend as
1021	1041	* if the command failed. If the device ever comes back online, we
...	...	@@ -1024,7 +1044,6 @@
1024	1044	*/
1025	1045	if (!scsi_device_online(sdp)) {
1026	1046	set_media_not_present(sdkp);
1027		- retval = 1;
1028	1047	goto out;
1029	1048	}
1030	1049
1031	1050
1032	1051
1033	1052
1034	1053
1035	1054
1036	1055
1037	1056
1038	1057
...	...	@@ -1045,26 +1064,30 @@
1045	1064	sshdr);
1046	1065	}
1047	1066
1048		- if (retval) {
	1067	+ /* failed to execute TUR, assume media not present */
	1068	+ if (host_byte(retval)) {
1049	1069	set_media_not_present(sdkp);
1050		- retval = 1;
1051	1070	goto out;
1052	1071	}
1053	1072
	1073	+ if (media_not_present(sdkp, sshdr))
	1074	+ goto out;
	1075	+
1054	1076	/*
1055	1077	* For removable scsi disk we have to recognise the presence
1056		- * of a disk in the drive. This is kept in the struct scsi_disk
1057		- * struct and tested at open ! Daniel Roche (dan@lectra.fr)
	1078	+ * of a disk in the drive.
1058	1079	*/
	1080	+ if (!sdkp->media_present)
	1081	+ sdp->changed = 1;
1059	1082	sdkp->media_present = 1;
1060		-
1061		- retval = sdp->changed;
1062		- sdp->changed = 0;
1063	1083	out:
1064		- if (retval != sdkp->previous_state)
	1084	+ /* for backward compatibility */
	1085	+ if (sdp->changed)
1065	1086	sdev_evt_send_simple(sdp, SDEV_EVT_MEDIA_CHANGE, GFP_KERNEL);
1066		- sdkp->previous_state = retval;
1067	1087	kfree(sshdr);
	1088	+
	1089	+ retval = sdp->changed ? DISK_EVENT_MEDIA_CHANGE : 0;
	1090	+ sdp->changed = 0;
1068	1091	return retval;
1069	1092	}
1070	1093
...	...	@@ -1157,7 +1180,7 @@
1157	1180	#ifdef CONFIG_COMPAT
1158	1181	.compat_ioctl = sd_compat_ioctl,
1159	1182	#endif
1160		- .media_changed = sd_media_changed,
	1183	+ .check_events = sd_check_events,
1161	1184	.revalidate_disk = sd_revalidate_disk,
1162	1185	.unlock_native_capacity = sd_unlock_native_capacity,
1163	1186	};
...	...	@@ -1293,23 +1316,6 @@
1293	1316	return good_bytes;
1294	1317	}
1295	1318
1296		-static int media_not_present(struct scsi_disk *sdkp,
1297		- struct scsi_sense_hdr *sshdr)
1298		-{
1299		-
1300		- if (!scsi_sense_valid(sshdr))
1301		- return 0;
1302		- /* not invoked for commands that could return deferred errors */
1303		- if (sshdr->sense_key != NOT_READY &&
1304		- sshdr->sense_key != UNIT_ATTENTION)
1305		- return 0;
1306		- if (sshdr->asc != 0x3A) /* medium not present */
1307		- return 0;
1308		-
1309		- set_media_not_present(sdkp);
1310		- return 1;
1311		-}
1312		-
1313	1319	/*
1314	1320	* spinup disk - called only in sd_revalidate_disk()
1315	1321	*/
...	...	@@ -1484,7 +1490,7 @@
1484	1490	*/
1485	1491	if (sdp->removable &&
1486	1492	sense_valid && sshdr->sense_key == NOT_READY)
1487		- sdp->changed = 1;
	1493	+ set_media_not_present(sdkp);
1488	1494
1489	1495	/*
1490	1496	* We used to set media_present to 0 here to indicate no media
1491	1497
...	...	@@ -2339,8 +2345,10 @@
2339	2345
2340	2346	gd->driverfs_dev = &sdp->sdev_gendev;
2341	2347	gd->flags = GENHD_FL_EXT_DEVT;
2342		- if (sdp->removable)
	2348	+ if (sdp->removable) {
2343	2349	gd->flags \|= GENHD_FL_REMOVABLE;
	2350	+ gd->events \|= DISK_EVENT_MEDIA_CHANGE;
	2351	+ }
2344	2352
2345	2353	add_disk(gd);
2346	2354	sd_dif_config_host(sdkp);
...	...	@@ -2422,7 +2430,6 @@
2422	2430	sdkp->disk = gd;
2423	2431	sdkp->index = index;
2424	2432	atomic_set(&sdkp->openers, 0);
2425		- sdkp->previous_state = 1;
2426	2433
2427	2434	if (!sdp->request_queue->rq_timeout) {
2428	2435	if (sdp->type != TYPE_MOD)
...	...	@@ -55,7 +55,6 @@
55	55	u8 media_present;
56	56	u8 write_prot;
57	57	u8 protection_type;/* Data Integrity Field */
58		- unsigned previous_state : 1;
59	58	unsigned ATO : 1; /* state of disk ATO bit */
60	59	unsigned WCE : 1; /* state of disk WCE bit */
61	60	unsigned RCD : 1; /* state of disk RCD bit, unused */