[PATCH] s390: tape driver.

From: Martin Schwidefsky <schwidefsky@de.ibm.com>

 - Add module license gpl.
 - Add debug messages.
 - Make blocksize persistent after close. Limit blocksize to 64k.
 - Check tape state against TS_INIT/TS_UNUSED for special case of
   medium sense and assign.
 - Assign tape as soon as they are set online and unassign when set offline.
 - Correct implementation of MT_EOD.
 - Add backward compatible tape.agent hotplug support (to be removed as soon
   as a full blown tape class is implemented).
 - Add state to differentiate between character device and block device access.
 - Make tape block device usable.
 - Add 34xx seek speedup code.
 - Fix device reference counting.
 - Fix online-offline-online cycle.
 - Add timeout to standard assign function.
 - Correct calculation of device index in tape_get_device().
 - Check idal buffer for fixed block size reads and writes.
 - Adapt to notify api change in cio.
 - Add sysfs attributes for tape state, first minor, current operation and
   current blocksize.

drivers/s390/char/tape.h

@@ -12,18 +12,32 @@
 #ifndef _TAPE_H
 #define _TAPE_H
 
+#include <asm/ccwdev.h>
+#include <asm/debug.h>
+#include <asm/idals.h>
 #include <linux/config.h>
 #include <linux/blkdev.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/mtio.h>
 #include <linux/interrupt.h>
-#include <asm/ccwdev.h>
-#include <asm/debug.h>
-#include <asm/idals.h>
+#include <linux/workqueue.h>
 
 struct gendisk;
 
+/*
+ * Define DBF_LIKE_HELL for lots of messages in the debug feature.
+ */
+#define DBF_LIKE_HELL
+#ifdef  DBF_LIKE_HELL
+#define DBF_LH(level, str, ...) \
+do { \
+	debug_sprintf_event(tape_dbf_area, level, str, ## __VA_ARGS__); \
+} while (0)
+#else
+#define DBF_LH(level, str, ...) do {} while(0)
+#endif
+
 /*
  * macros s390 debug feature (dbf)
  */
@@ -46,7 +60,11 @@ do { \
 #define TAPEBLOCK_HSEC_S2B	2
 #define TAPEBLOCK_RETRIES	5
 
-#define TAPE_BUSY(td) (td->treq != NULL)
+/* Event types for hotplug */
+#define TAPE_HOTPLUG_CHAR_ADD     1
+#define TAPE_HOTPLUG_BLOCK_ADD    2
+#define TAPE_HOTPLUG_CHAR_REMOVE  3
+#define TAPE_HOTPLUG_BLOCK_REMOVE 4
 
 enum tape_medium_state {
 	MS_UNKNOWN,
@@ -58,6 +76,7 @@ enum tape_medium_state {
 enum tape_state {
 	TS_UNUSED=0,
 	TS_IN_USE,
+	TS_BLKUSE,
 	TS_INIT,
 	TS_NOT_OPER,
 	TS_SIZE
@@ -130,8 +149,6 @@ struct tape_discipline {
 	struct module *owner;
 	int  (*setup_device)(struct tape_device *);
 	void (*cleanup_device)(struct tape_device *);
-	int (*assign)(struct tape_device *);
-	int (*unassign)(struct tape_device *);
 	int (*irq)(struct tape_device *, struct tape_request *, struct irb *);
 	struct tape_request *(*read_block)(struct tape_device *, size_t);
 	struct tape_request *(*write_block)(struct tape_device *, size_t);
@@ -168,13 +185,17 @@ struct tape_char_data {
 struct tape_blk_data
 {
 	/* Block device request queue. */
-	request_queue_t *request_queue;
+	request_queue_t *	request_queue;
 	spinlock_t		request_queue_lock;
-	/* Block frontend tasklet */
-	struct tasklet_struct tasklet;
+
+	/* Task to move entries from block request to CCS request queue. */
+	struct work_struct	requeue_task;
+	atomic_t		requeue_scheduled;
+
 	/* Current position on the tape. */
 	long			block_position;
-	struct gendisk *disk;
+	int			medium_changed;
+	struct gendisk *	disk;
 };
 #endif
 
@@ -183,11 +204,11 @@ struct tape_device {
 	/* entry in tape_device_list */
 	struct list_head		node;
 
-	struct ccw_device *cdev;
+	struct ccw_device *		cdev;
 
 	/* Device discipline information. */
-	struct tape_discipline *discipline;
-	void *discdata;
+	struct tape_discipline *	discipline;
+	void *				discdata;
 
 	/* Generic status flags */
 	long				tape_generic_status;
@@ -196,7 +217,7 @@ struct tape_device {
 	wait_queue_head_t		state_change_wq;
 	enum tape_state			tape_state;
 	enum tape_medium_state		medium_state;
-	unsigned char          *modeset_byte;
+	unsigned char *			modeset_byte;
 
 	/* Reference count. */
 	atomic_t			ref_count;
@@ -204,7 +225,15 @@ struct tape_device {
 	/* Request queue. */
 	struct list_head		req_queue;
 
-	int first_minor;	       /* each tape device has two minors */
+	/* Each tape device has (currently) two minor numbers. */
+	int				first_minor;
+
+	/* Number of tapemarks required for correct termination. */
+	int				required_tapemarks;
+
+	/* Block ID of the BOF */
+	unsigned int			bof;
+
 	/* Character device frontend data */
 	struct tape_char_data		char_data;
 #ifdef CONFIG_S390_TAPE_BLOCK
@@ -219,6 +248,7 @@ extern void tape_free_request(struct tape_request *);
 extern int tape_do_io(struct tape_device *, struct tape_request *);
 extern int tape_do_io_async(struct tape_device *, struct tape_request *);
 extern int tape_do_io_interruptible(struct tape_device *, struct tape_request *);
+void tape_hotplug_event(struct tape_device *, int major, int action);
 
 static inline int
 tape_do_io_free(struct tape_device *device, struct tape_request *request)
@@ -234,19 +264,19 @@ extern int tape_oper_handler(int irq, int status);
 extern void tape_noper_handler(int irq, int status);
 extern int tape_open(struct tape_device *);
 extern int tape_release(struct tape_device *);
-extern int tape_assign(struct tape_device *);
-extern int tape_unassign(struct tape_device *);
 extern int tape_mtop(struct tape_device *, int, int);
+extern void tape_state_set(struct tape_device *, enum tape_state);
 
 extern int tape_enable_device(struct tape_device *, struct tape_discipline *);
 extern void tape_disable_device(struct tape_device *device);
 
 /* Externals from tape_devmap.c */
 extern int tape_generic_probe(struct ccw_device *);
-extern int tape_generic_remove(struct ccw_device *);
+extern void tape_generic_remove(struct ccw_device *);
 
 extern struct tape_device *tape_get_device(int devindex);
-extern void tape_put_device(struct tape_device *);
+extern struct tape_device *tape_get_device_reference(struct tape_device *);
+extern struct tape_device *tape_put_device(struct tape_device *);
 
 /* Externals from tape_char.c */
 extern int tapechar_init(void);

drivers/s390/char/tape_char.c

@@ -19,8 +19,9 @@
 #include <asm/uaccess.h>
 
 #include "tape.h"
+#include "tape_std.h"
 
-#define PRINTK_HEADER "TCHAR:"
+#define PRINTK_HEADER "TAPE_CHAR: "
 
 #define TAPECHAR_MAJOR		0	/* get dynamic major */
 
@@ -52,12 +53,14 @@ static int tapechar_major = TAPECHAR_MAJOR;
 int
 tapechar_setup_device(struct tape_device * device)
 {
+	tape_hotplug_event(device, tapechar_major, TAPE_HOTPLUG_CHAR_ADD);
 	return 0;
 }
 
 void
 tapechar_cleanup_device(struct tape_device *device)
 {
+	tape_hotplug_event(device, tapechar_major, TAPE_HOTPLUG_CHAR_REMOVE);
 }
 
 /*
@@ -81,15 +84,27 @@ tapechar_check_idalbuffer(struct tape_device *device, size_t block_size)
 	struct idal_buffer *new;
 
 	if (device->char_data.idal_buf != NULL &&
-	    device->char_data.idal_buf->size >= block_size)
+	    device->char_data.idal_buf->size == block_size)
 		return 0;
-	/* The current idal buffer is not big enough. Allocate a new one. */
+
+	if (block_size > MAX_BLOCKSIZE) {
+		DBF_EVENT(3, "Invalid blocksize (%zd > %d)\n",
+			block_size, MAX_BLOCKSIZE);
+		PRINT_ERR("Invalid blocksize (%zd> %d)\n",
+			block_size, MAX_BLOCKSIZE);
+		return -EINVAL;
+	}
+
+	/* The current idal buffer is not correct. Allocate a new one. */
 	new = idal_buffer_alloc(block_size, 0);
 	if (new == NULL)
 		return -ENOMEM;
+
 	if (device->char_data.idal_buf != NULL)
 		idal_buffer_free(device->char_data.idal_buf);
+
 	device->char_data.idal_buf = new;
+
 	return 0;
 }
 
@@ -116,6 +131,16 @@ tapechar_read (struct file *filp, char *data, size_t count, loff_t *ppos)
 		DBF_EVENT(6, "TCHAR:ppos wrong\n");
 		return -EOVERFLOW;
 	}
+
+	/*
+	 * If the tape isn't terminated yet, do it now. And since we then
+	 * are at the end of the tape there wouldn't be anything to read
+	 * anyways. So we return immediatly.
+	 */
+	if(device->required_tapemarks) {
+		return tape_std_terminate_write(device);
+	}
+
 	/* Find out block size to use */
 	if (device->char_data.block_size != 0) {
 		if (count < device->char_data.block_size) {
@@ -126,10 +151,17 @@ tapechar_read (struct file *filp, char *data, size_t count, loff_t *ppos)
 		block_size = device->char_data.block_size;
 	} else {
 		block_size = count;
+	}
+
 	rc = tapechar_check_idalbuffer(device, block_size);
 	if (rc)
 		return rc;
-	}
+
+#ifdef CONFIG_S390_TAPE_BLOCK
+	/* Changes position. */
+	device->blk_data.medium_changed = 1;
+#endif
+
 	DBF_EVENT(6, "TCHAR:nbytes: %lx\n", block_size);
 	/* Let the discipline build the ccw chain. */
 	request = device->discipline->read_block(device, block_size);
@@ -182,11 +214,18 @@ tapechar_write(struct file *filp, const char *data, size_t count, loff_t *ppos)
 		nblocks = count / block_size;
 	} else {
 		block_size = count;
+		nblocks = 1;
+	}
+
 	rc = tapechar_check_idalbuffer(device, block_size);
 	if (rc)
 		return rc;
-		nblocks = 1;
-	}
+
+#ifdef CONFIG_S390_TAPE_BLOCK
+	/* Changes position. */
+	device->blk_data.medium_changed = 1;
+#endif
+
 	DBF_EVENT(6,"TCHAR:nbytes: %lx\n", block_size);
 	DBF_EVENT(6, "TCHAR:nblocks: %x\n", nblocks);
 	/* Let the discipline build the ccw chain. */
@@ -225,6 +264,17 @@ tapechar_write(struct file *filp, const char *data, size_t count, loff_t *ppos)
 			rc = 0;
 
 	}
+
+	/*
+	 * After doing a write we always need two tapemarks to correctly
+	 * terminate the tape (one to terminate the file, the second to
+	 * flag the end of recorded data.
+	 * Since process_eov positions the tape in front of the written
+	 * tapemark it doesn't hurt to write two marks again.
+	 */
+	if (!rc)
+		device->required_tapemarks = 2;
+
 	return rc ? rc : written;
 }
 
@@ -237,24 +287,28 @@ tapechar_open (struct inode *inode, struct file *filp)
 	struct tape_device *device;
 	int minor, rc;
 
+	DBF_EVENT(6, "TCHAR:open: %i:%i\n",
+		imajor(filp->f_dentry->d_inode),
+		iminor(filp->f_dentry->d_inode));
+
 	if (imajor(filp->f_dentry->d_inode) != tapechar_major)
 		return -ENODEV;
+
 	minor = iminor(filp->f_dentry->d_inode);
 	device = tape_get_device(minor / TAPE_MINORS_PER_DEV);
 	if (IS_ERR(device)) {
+		DBF_EVENT(3, "TCHAR:open: tape_get_device() failed\n");
 		return PTR_ERR(device);
 	}
-	DBF_EVENT(6, "TCHAR:open: %x\n", iminor(inode));
+
+
 	rc = tape_open(device);
-	if (rc == 0) {
-		rc = tape_assign(device);
 	if (rc == 0) {
 		filp->private_data = device;
 		return 0;
 	}
-		tape_release(device);
-	}
 	tape_put_device(device);
+
 	return rc;
 }
 
@@ -267,29 +321,32 @@ tapechar_release(struct inode *inode, struct file *filp)
 {
 	struct tape_device *device;
 
-	device = (struct tape_device *) filp->private_data;
 	DBF_EVENT(6, "TCHAR:release: %x\n", iminor(inode));
-#if 0
-	// FIXME: this is broken. Either MTWEOF/MTWEOF/MTBSR is done
-	// EVERYTIME the user switches from write to something different
-	// or it is not done at all. The second is IMHO better because
-	// we should NEVER do something the user didn't request.
-	if (device->last_op == TO_WRI)
-		tapechar_terminate_write(device);
-#endif
+	device = (struct tape_device *) filp->private_data;
+
 	/*
-	 * If this is the rewinding tape minor then rewind.
+	 * If this is the rewinding tape minor then rewind. In that case we
+	 * write all required tapemarks. Otherwise only one to terminate the
+	 * file.
 	 */
-	if ((iminor(inode) & 1) != 0)
+	if ((iminor(inode) & 1) != 0) {
+		if (device->required_tapemarks)
+			tape_std_terminate_write(device);
 		tape_mtop(device, MTREW, 1);
+	} else {
+		if (device->required_tapemarks > 1) {
+			if (tape_mtop(device, MTWEOF, 1) == 0)
+				device->required_tapemarks--;
+		}
+	}
+
 	if (device->char_data.idal_buf != NULL) {
 		idal_buffer_free(device->char_data.idal_buf);
 		device->char_data.idal_buf = NULL;
 	}
-	device->char_data.block_size = 0;
 	tape_release(device);
-	tape_unassign(device);
-	tape_put_device(device);
+	filp->private_data = tape_put_device(device);
+
 	return 0;
 }
 
@@ -314,7 +371,40 @@ tapechar_ioctl(struct inode *inp, struct file *filp,
 			return -EFAULT;
 		if (op.mt_count < 0)
 			return -EINVAL;
-		return tape_mtop(device, op.mt_op, op.mt_count);
+
+		/*
+		 * Operations that change tape position should write final
+		 * tapemarks.
+		 */
+		switch (op.mt_op) {
+			case MTFSF:
+			case MTBSF:
+			case MTFSR:
+			case MTBSR:
+			case MTREW:
+			case MTOFFL:
+			case MTEOM:
+			case MTRETEN:
+			case MTBSFM:
+			case MTFSFM:
+			case MTSEEK:
+#ifdef CONFIG_S390_TAPE_BLOCK
+				device->blk_data.medium_changed = 1;
+#endif
+				if (device->required_tapemarks)
+					tape_std_terminate_write(device);
+			default:
+				;
+		}
+		rc = tape_mtop(device, op.mt_op, op.mt_count);
+
+		if (op.mt_op == MTWEOF && rc == 0) {
+			if (op.mt_count > device->required_tapemarks)
+				device->required_tapemarks = 0;
+			else
+				device->required_tapemarks -= op.mt_count;
+		}
+		return rc;
 	}
 	if (no == MTIOCPOS) {
 		/* MTIOCPOS: query the tape position. */
@@ -333,19 +423,30 @@ tapechar_ioctl(struct inode *inp, struct file *filp,
 		struct mtget get;
 
 		memset(&get, 0, sizeof(get));
-		rc = tape_mtop(device, MTTELL, 1);
-		if (rc < 0)
-			return rc;
 		get.mt_type = MT_ISUNKNOWN;
+		get.mt_resid = 0 /* device->devstat.rescnt */;
 		get.mt_dsreg = device->tape_state;
 		/* FIXME: mt_gstat, mt_erreg, mt_fileno */
-		get.mt_resid = 0 /* device->devstat.rescnt */;
 		get.mt_gstat = 0;
 		get.mt_erreg = 0;
 		get.mt_fileno = 0;
+		get.mt_gstat  = device->tape_generic_status;
+
+		if (device->medium_state == MS_LOADED) {
+			rc = tape_mtop(device, MTTELL, 1);
+
+			if (rc < 0)
+				return rc;
+
+			if (rc == 0)
+				get.mt_gstat |= GMT_BOT(~0);
+
 			get.mt_blkno = rc;
+		}
+
 		if (copy_to_user((char *) data, &get, sizeof(get)) != 0)
 			return -EFAULT;
+
 		return 0;
 	}
 	/* Try the discipline ioctl function. */

drivers/s390/char/tape_proc.c

@@ -18,7 +18,7 @@
 
 #include "tape.h"
 
-#define PRINTK_HEADER "T390:"
+#define PRINTK_HEADER "TAPE_PROC: "
 
 static const char *tape_med_st_verbose[MS_SIZE] =
 {
@@ -42,19 +42,19 @@ static int tape_proc_show(struct seq_file *m, void *v)
 
 	n = (unsigned long) v - 1;
 	if (!n) {
-		seq_printf(m, "TapeNo\tDevNo\tCuType\tCuModel\tDevType\t"
-			   "DevMod\tBlkSize\tState\tOp\tMedState\n");
+		seq_printf(m, "TapeNo\tBusID      CuType/Model\t"
+			"DevType/Model\tBlkSize\tState\tOp\tMedState\n");
 	}
 	device = tape_get_device(n);
 	if (IS_ERR(device))
 		return 0;
 	spin_lock_irq(get_ccwdev_lock(device->cdev));
 	seq_printf(m, "%d\t", (int) n);
-	seq_printf(m, "%s\t", device->cdev->dev.bus_id);
-	seq_printf(m, "%04X\t", device->cdev->id.cu_type);
+	seq_printf(m, "%-10.10s ", device->cdev->dev.bus_id);
+	seq_printf(m, "%04X/", device->cdev->id.cu_type);
 	seq_printf(m, "%02X\t", device->cdev->id.cu_model);
-	seq_printf(m, "%04X\t", device->cdev->id.dev_type);
-	seq_printf(m, "%02X\t", device->cdev->id.dev_model);
+	seq_printf(m, "%04X/", device->cdev->id.dev_type);
+	seq_printf(m, "%02X\t\t", device->cdev->id.dev_model);
 	if (device->char_data.block_size == 0)
 		seq_printf(m, "auto\t");
 	else

drivers/s390/char/tape_std.h

@@ -10,9 +10,16 @@
  */
 
 #ifndef _TAPE_STD_H
-
 #define _TAPE_STD_H
 
+#include <asm/tape390.h>
+
+/*
+ * Biggest block size to handle. Currently 64K because we only build
+ * channel programs without data chaining.
+ */
+#define MAX_BLOCKSIZE   65535
+
 /*
  * The CCW commands for the Tape type of command.
  */
@@ -105,7 +112,8 @@ struct tape_request *tape_std_bwrite(struct request *,
 int tape_std_assign(struct tape_device *);
 int tape_std_unassign(struct tape_device *);
 int tape_std_read_block_id(struct tape_device *device, __u64 *id);
-int tape_std_display(struct tape_device *, int, unsigned long);
+int tape_std_display(struct tape_device *, struct display_struct *disp);
+int tape_std_terminate_write(struct tape_device *);
 
 /* Standard magnetic tape commands. */
 int tape_std_mtbsf(struct tape_device *, int);