[SCSI] sr: fix test unit ready responses

Commit 210ba1d1 updated sr.c to use
the scsi_test_unit_ready() function.  Unfortunately, this has the
wrong characteristic of eating NOT_READY returns which sr.c relies on
for tray status.

Fix by rolling an internal sr_test_unit_ready() that doesn't do this.
Tested-by: Daniel Drake <dsd@gentoo.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/sr.c

@@ -163,6 +163,29 @@ 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)
+{
+	int retries = MAX_RETRIES;
+	int the_result;
+	u8 cmd[] = {TEST_UNIT_READY, 0, 0, 0, 0, 0 };
+
+	/* 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--);
+
+	} while (retries > 0 &&
+		 (!scsi_status_is_good(the_result) ||
+		  (scsi_sense_valid(sshdr) &&
+		   sshdr->sense_key == UNIT_ATTENTION)));
+	return the_result;
+}
+
 /*
  * 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,
@@ -185,8 +208,7 @@ static int sr_media_change(struct cdrom_device_info *cdi, int slot)
 	}
 
 	sshdr =  kzalloc(sizeof(*sshdr), GFP_KERNEL);
-	retval = scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES,
-				      sshdr);
+	retval = sr_test_unit_ready(cd->device, sshdr);
 	if (retval || (scsi_sense_valid(sshdr) &&
 		       /* 0x3a is medium not present */
 		       sshdr->asc == 0x3a)) {
@@ -733,10 +755,8 @@ static void get_capabilities(struct scsi_cd *cd)
 {
 	unsigned char *buffer;
 	struct scsi_mode_data data;
-	unsigned char cmd[MAX_COMMAND_SIZE];
 	struct scsi_sense_hdr sshdr;
-	unsigned int the_result;
-	int retries, rc, n;
+	int rc, n;
 
 	static const char *loadmech[] =
 	{
@@ -758,23 +778,8 @@ static void get_capabilities(struct scsi_cd *cd)
 		return;
 	}
 
-	/* issue TEST_UNIT_READY until the initial startup UNIT_ATTENTION
-	 * conditions are gone, or a timeout happens
-	 */
-	retries = 0;
-	do {
-		memset((void *)cmd, 0, MAX_COMMAND_SIZE);
-		cmd[0] = TEST_UNIT_READY;
-
-		the_result = scsi_execute_req (cd->device, cmd, DMA_NONE, NULL,
-					       0, &sshdr, SR_TIMEOUT,
-					       MAX_RETRIES);
-
-		retries++;
-	} while (retries < 5 && 
-		 (!scsi_status_is_good(the_result) ||
-		  (scsi_sense_valid(&sshdr) &&
-		   sshdr.sense_key == UNIT_ATTENTION)));
+	/* eat unit attentions */
+	sr_test_unit_ready(cd->device, &sshdr);
 
 	/* ask for mode page 0x2a */
 	rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, 128,

drivers/scsi/sr.h

@@ -61,6 +61,7 @@ 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 *);

drivers/scsi/sr_ioctl.c

@@ -306,8 +306,7 @@ int sr_drive_status(struct cdrom_device_info *cdi, int slot)
 		/* we have no changer support */
 		return -EINVAL;
 	}
-	if (0 == scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES,
-				      &sshdr))
+	if (0 == sr_test_unit_ready(cd->device, &sshdr))
 		return CDS_DISC_OK;
 
 	if (!cdrom_get_media_event(cdi, &med)) {