Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 1037 insertions, 0 deletions

diff --git a/drivers/scsi/ch.c b/drivers/scsi/ch.c
new file mode 100644
index 000000000..4010fdbf8
--- /dev/null
+++ b/drivers/scsi/ch.c
@@ -0,0 +1,1037 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SCSI Media Changer device driver for Linux 2.6
+ *
+ *     (c) 1996-2003 Gerd Knorr <kraxel@bytesex.org>
+ *
+ */
+
+#define VERSION "0.25"
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/major.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/blkdev.h>
+#include <linux/completion.h>
+#include <linux/compat.h>
+#include <linux/chio.h>			/* here are all the ioctls */
+#include <linux/mutex.h>
+#include <linux/idr.h>
+#include <linux/slab.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_driver.h>
+#include <scsi/scsi_ioctl.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_dbg.h>
+
+#define CH_DT_MAX       16
+#define CH_TYPES        8
+#define CH_MAX_DEVS     128
+
+MODULE_DESCRIPTION("device driver for scsi media changer devices");
+MODULE_AUTHOR("Gerd Knorr <kraxel@bytesex.org>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_CHARDEV_MAJOR(SCSI_CHANGER_MAJOR);
+MODULE_ALIAS_SCSI_DEVICE(TYPE_MEDIUM_CHANGER);
+
+static int init = 1;
+module_param(init, int, 0444);
+MODULE_PARM_DESC(init, \
+    "initialize element status on driver load (default: on)");
+
+static int timeout_move = 300;
+module_param(timeout_move, int, 0644);
+MODULE_PARM_DESC(timeout_move,"timeout for move commands "
+		 "(default: 300 seconds)");
+
+static int timeout_init = 3600;
+module_param(timeout_init, int, 0644);
+MODULE_PARM_DESC(timeout_init,"timeout for INITIALIZE ELEMENT STATUS "
+		 "(default: 3600 seconds)");
+
+static int verbose = 1;
+module_param(verbose, int, 0644);
+MODULE_PARM_DESC(verbose,"be verbose (default: on)");
+
+static int debug;
+module_param(debug, int, 0644);
+MODULE_PARM_DESC(debug,"enable/disable debug messages, also prints more "
+		 "detailed sense codes on scsi errors (default: off)");
+
+static int dt_id[CH_DT_MAX] = { [ 0 ... (CH_DT_MAX-1) ] = -1 };
+static int dt_lun[CH_DT_MAX];
+module_param_array(dt_id,  int, NULL, 0444);
+module_param_array(dt_lun, int, NULL, 0444);
+
+/* tell the driver about vendor-specific slots */
+static int vendor_firsts[CH_TYPES-4];
+static int vendor_counts[CH_TYPES-4];
+module_param_array(vendor_firsts, int, NULL, 0444);
+module_param_array(vendor_counts, int, NULL, 0444);
+
+static const char * vendor_labels[CH_TYPES-4] = {
+	"v0", "v1", "v2", "v3"
+};
+// module_param_string_array(vendor_labels, NULL, 0444);
+
+#define ch_printk(prefix, ch, fmt, a...) \
+	sdev_prefix_printk(prefix, (ch)->device, (ch)->name, fmt, ##a)
+
+#define DPRINTK(fmt, arg...)						\
+do {									\
+	if (debug)							\
+		ch_printk(KERN_DEBUG, ch, fmt, ##arg);			\
+} while (0)
+#define VPRINTK(level, fmt, arg...)					\
+do {									\
+	if (verbose)							\
+		ch_printk(level, ch, fmt, ##arg);			\
+} while (0)
+
+/* ------------------------------------------------------------------- */
+
+#define MAX_RETRIES   1
+
+static const struct class ch_sysfs_class = {
+	.name = "scsi_changer",
+};
+
+typedef struct {
+	struct kref         ref;
+	struct list_head    list;
+	int                 minor;
+	char                name[8];
+	struct scsi_device  *device;
+	struct scsi_device  **dt;        /* ptrs to data transfer elements */
+	u_int               firsts[CH_TYPES];
+	u_int               counts[CH_TYPES];
+	u_int		    voltags;
+	struct mutex	    lock;
+} scsi_changer;
+
+static DEFINE_IDR(ch_index_idr);
+static DEFINE_SPINLOCK(ch_index_lock);
+
+static const struct {
+	unsigned char  sense;
+	unsigned char  asc;
+	unsigned char  ascq;
+	int	       errno;
+} ch_err[] = {
+/* Just filled in what looks right. Hav'nt checked any standard paper for
+   these errno assignments, so they may be wrong... */
+	{
+		.sense  = ILLEGAL_REQUEST,
+		.asc    = 0x21,
+		.ascq   = 0x01,
+		.errno  = EBADSLT, /* Invalid element address */
+	},{
+		.sense  = ILLEGAL_REQUEST,
+		.asc    = 0x28,
+		.ascq   = 0x01,
+		.errno  = EBADE,   /* Import or export element accessed */
+	},{
+		.sense  = ILLEGAL_REQUEST,
+		.asc    = 0x3B,
+		.ascq   = 0x0D,
+		.errno  = EXFULL,  /* Medium destination element full */
+	},{
+		.sense  = ILLEGAL_REQUEST,
+		.asc    = 0x3B,
+		.ascq   = 0x0E,
+		.errno  = EBADE,   /* Medium source element empty */
+	},{
+		.sense  = ILLEGAL_REQUEST,
+		.asc    = 0x20,
+		.ascq   = 0x00,
+		.errno  = EBADRQC, /* Invalid command operation code */
+	},{
+	        /* end of list */
+	}
+};
+
+/* ------------------------------------------------------------------- */
+
+static int ch_find_errno(struct scsi_sense_hdr *sshdr)
+{
+	int i,errno = 0;
+
+	/* Check to see if additional sense information is available */
+	if (scsi_sense_valid(sshdr) &&
+	    sshdr->asc != 0) {
+		for (i = 0; ch_err[i].errno != 0; i++) {
+			if (ch_err[i].sense == sshdr->sense_key &&
+			    ch_err[i].asc   == sshdr->asc &&
+			    ch_err[i].ascq  == sshdr->ascq) {
+				errno = -ch_err[i].errno;
+				break;
+			}
+		}
+	}
+	if (errno == 0)
+		errno = -EIO;
+	return errno;
+}
+
+static int
+ch_do_scsi(scsi_changer *ch, unsigned char *cmd, int cmd_len,
+	   void *buffer, unsigned int buflength, enum req_op op)
+{
+	int errno = 0, timeout, result;
+	struct scsi_sense_hdr sshdr;
+	struct scsi_failure failure_defs[] = {
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = SCMD_FAILURE_ASC_ANY,
+			.ascq = SCMD_FAILURE_ASCQ_ANY,
+			.allowed = 3,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{}
+	};
+	struct scsi_failures failures = {
+		.failure_definitions = failure_defs,
+	};
+	const struct scsi_exec_args exec_args = {
+		.sshdr = &sshdr,
+		.failures = &failures,
+	};
+
+	timeout = (cmd[0] == INITIALIZE_ELEMENT_STATUS)
+		? timeout_init : timeout_move;
+
+	result = scsi_execute_cmd(ch->device, cmd, op, buffer, buflength,
+				  timeout * HZ, MAX_RETRIES, &exec_args);
+	if (result < 0)
+		return result;
+	if (scsi_sense_valid(&sshdr)) {
+		if (debug)
+			scsi_print_sense_hdr(ch->device, ch->name, &sshdr);
+		errno = ch_find_errno(&sshdr);
+	}
+	return errno;
+}
+
+/* ------------------------------------------------------------------------ */
+
+static int
+ch_elem_to_typecode(scsi_changer *ch, u_int elem)
+{
+	int i;
+
+	for (i = 0; i < CH_TYPES; i++) {
+		if (elem >= ch->firsts[i]  &&
+		    elem <  ch->firsts[i] +
+	            ch->counts[i])
+			return i+1;
+	}
+	return 0;
+}
+
+static int
+ch_read_element_status(scsi_changer *ch, u_int elem, char *data)
+{
+	u_char  cmd[12];
+	u_char  *buffer;
+	int     result;
+
+	buffer = kmalloc(512, GFP_KERNEL);
+	if(!buffer)
+		return -ENOMEM;
+
+ retry:
+	memset(cmd,0,sizeof(cmd));
+	cmd[0] = READ_ELEMENT_STATUS;
+	cmd[1] = ((ch->device->lun & 0x7) << 5) |
+		(ch->voltags ? 0x10 : 0) |
+		ch_elem_to_typecode(ch,elem);
+	cmd[2] = (elem >> 8) & 0xff;
+	cmd[3] = elem        & 0xff;
+	cmd[5] = 1;
+	cmd[9] = 255;
+	if (0 == (result = ch_do_scsi(ch, cmd, 12,
+				      buffer, 256, REQ_OP_DRV_IN))) {
+		if (((buffer[16] << 8) | buffer[17]) != elem) {
+			DPRINTK("asked for element 0x%02x, got 0x%02x\n",
+				elem,(buffer[16] << 8) | buffer[17]);
+			kfree(buffer);
+			return -EIO;
+		}
+		memcpy(data,buffer+16,16);
+	} else {
+		if (ch->voltags) {
+			ch->voltags = 0;
+			VPRINTK(KERN_INFO, "device has no volume tag support\n");
+			goto retry;
+		}
+		DPRINTK("READ ELEMENT STATUS for element 0x%x failed\n",elem);
+	}
+	kfree(buffer);
+	return result;
+}
+
+static int
+ch_init_elem(scsi_changer *ch)
+{
+	int err;
+	u_char cmd[6];
+
+	VPRINTK(KERN_INFO, "INITIALIZE ELEMENT STATUS, may take some time ...\n");
+	memset(cmd,0,sizeof(cmd));
+	cmd[0] = INITIALIZE_ELEMENT_STATUS;
+	cmd[1] = (ch->device->lun & 0x7) << 5;
+	err = ch_do_scsi(ch, cmd, 6, NULL, 0, REQ_OP_DRV_IN);
+	VPRINTK(KERN_INFO, "... finished\n");
+	return err;
+}
+
+static int
+ch_readconfig(scsi_changer *ch)
+{
+	u_char  cmd[10], data[16];
+	u_char  *buffer;
+	int     result,id,lun,i;
+	u_int   elem;
+
+	buffer = kzalloc(512, GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
+
+	memset(cmd,0,sizeof(cmd));
+	cmd[0] = MODE_SENSE;
+	cmd[1] = (ch->device->lun & 0x7) << 5;
+	cmd[2] = 0x1d;
+	cmd[4] = 255;
+	result = ch_do_scsi(ch, cmd, 10, buffer, 255, REQ_OP_DRV_IN);
+	if (0 != result) {
+		cmd[1] |= (1<<3);
+		result  = ch_do_scsi(ch, cmd, 10, buffer, 255, REQ_OP_DRV_IN);
+	}
+	if (0 == result) {
+		ch->firsts[CHET_MT] =
+			(buffer[buffer[3]+ 6] << 8) | buffer[buffer[3]+ 7];
+		ch->counts[CHET_MT] =
+			(buffer[buffer[3]+ 8] << 8) | buffer[buffer[3]+ 9];
+		ch->firsts[CHET_ST] =
+			(buffer[buffer[3]+10] << 8) | buffer[buffer[3]+11];
+		ch->counts[CHET_ST] =
+			(buffer[buffer[3]+12] << 8) | buffer[buffer[3]+13];
+		ch->firsts[CHET_IE] =
+			(buffer[buffer[3]+14] << 8) | buffer[buffer[3]+15];
+		ch->counts[CHET_IE] =
+			(buffer[buffer[3]+16] << 8) | buffer[buffer[3]+17];
+		ch->firsts[CHET_DT] =
+			(buffer[buffer[3]+18] << 8) | buffer[buffer[3]+19];
+		ch->counts[CHET_DT] =
+			(buffer[buffer[3]+20] << 8) | buffer[buffer[3]+21];
+		VPRINTK(KERN_INFO, "type #1 (mt): 0x%x+%d [medium transport]\n",
+			ch->firsts[CHET_MT],
+			ch->counts[CHET_MT]);
+		VPRINTK(KERN_INFO, "type #2 (st): 0x%x+%d [storage]\n",
+			ch->firsts[CHET_ST],
+			ch->counts[CHET_ST]);
+		VPRINTK(KERN_INFO, "type #3 (ie): 0x%x+%d [import/export]\n",
+			ch->firsts[CHET_IE],
+			ch->counts[CHET_IE]);
+		VPRINTK(KERN_INFO, "type #4 (dt): 0x%x+%d [data transfer]\n",
+			ch->firsts[CHET_DT],
+			ch->counts[CHET_DT]);
+	} else {
+		VPRINTK(KERN_INFO, "reading element address assignment page failed!\n");
+	}
+
+	/* vendor specific element types */
+	for (i = 0; i < 4; i++) {
+		if (0 == vendor_counts[i])
+			continue;
+		if (NULL == vendor_labels[i])
+			continue;
+		ch->firsts[CHET_V1+i] = vendor_firsts[i];
+		ch->counts[CHET_V1+i] = vendor_counts[i];
+		VPRINTK(KERN_INFO, "type #%d (v%d): 0x%x+%d [%s, vendor specific]\n",
+			i+5,i+1,vendor_firsts[i],vendor_counts[i],
+			vendor_labels[i]);
+	}
+
+	/* look up the devices of the data transfer elements */
+	ch->dt = kzalloc_objs(*ch->dt, ch->counts[CHET_DT]);
+
+	if (!ch->dt) {
+		kfree(buffer);
+		return -ENOMEM;
+	}
+
+	for (elem = 0; elem < ch->counts[CHET_DT]; elem++) {
+		id  = -1;
+		lun = 0;
+		if (elem < CH_DT_MAX  &&  -1 != dt_id[elem]) {
+			id  = dt_id[elem];
+			lun = dt_lun[elem];
+			VPRINTK(KERN_INFO, "dt 0x%x: [insmod option] ",
+				elem+ch->firsts[CHET_DT]);
+		} else if (0 != ch_read_element_status
+			   (ch,elem+ch->firsts[CHET_DT],data)) {
+			VPRINTK(KERN_INFO, "dt 0x%x: READ ELEMENT STATUS failed\n",
+				elem+ch->firsts[CHET_DT]);
+		} else {
+			VPRINTK(KERN_INFO, "dt 0x%x: ",elem+ch->firsts[CHET_DT]);
+			if (data[6] & 0x80) {
+				VPRINTK(KERN_CONT, "not this SCSI bus\n");
+				ch->dt[elem] = NULL;
+			} else if (0 == (data[6] & 0x30)) {
+				VPRINTK(KERN_CONT, "ID/LUN unknown\n");
+				ch->dt[elem] = NULL;
+			} else {
+				id  = ch->device->id;
+				lun = 0;
+				if (data[6] & 0x20) id  = data[7];
+				if (data[6] & 0x10) lun = data[6] & 7;
+			}
+		}
+		if (-1 != id) {
+			VPRINTK(KERN_CONT, "ID %i, LUN %i, ",id,lun);
+			ch->dt[elem] =
+				scsi_device_lookup(ch->device->host,
+						   ch->device->channel,
+						   id,lun);
+			if (!ch->dt[elem]) {
+				/* should not happen */
+				VPRINTK(KERN_CONT, "Huh? device not found!\n");
+			} else {
+				VPRINTK(KERN_CONT, "name: %8.8s %16.16s %4.4s\n",
+					ch->dt[elem]->vendor,
+					ch->dt[elem]->model,
+					ch->dt[elem]->rev);
+			}
+		}
+	}
+	ch->voltags = 1;
+	kfree(buffer);
+
+	return 0;
+}
+
+/* ------------------------------------------------------------------------ */
+
+static int
+ch_position(scsi_changer *ch, u_int trans, u_int elem, int rotate)
+{
+	u_char  cmd[10];
+
+	DPRINTK("position: 0x%x\n",elem);
+	if (0 == trans)
+		trans = ch->firsts[CHET_MT];
+	memset(cmd,0,sizeof(cmd));
+	cmd[0]  = POSITION_TO_ELEMENT;
+	cmd[1]  = (ch->device->lun & 0x7) << 5;
+	cmd[2]  = (trans >> 8) & 0xff;
+	cmd[3]  =  trans       & 0xff;
+	cmd[4]  = (elem  >> 8) & 0xff;
+	cmd[5]  =  elem        & 0xff;
+	cmd[8]  = rotate ? 1 : 0;
+	return ch_do_scsi(ch, cmd, 10, NULL, 0, REQ_OP_DRV_IN);
+}
+
+static int
+ch_move(scsi_changer *ch, u_int trans, u_int src, u_int dest, int rotate)
+{
+	u_char  cmd[12];
+
+	DPRINTK("move: 0x%x => 0x%x\n",src,dest);
+	if (0 == trans)
+		trans = ch->firsts[CHET_MT];
+	memset(cmd,0,sizeof(cmd));
+	cmd[0]  = MOVE_MEDIUM;
+	cmd[1]  = (ch->device->lun & 0x7) << 5;
+	cmd[2]  = (trans >> 8) & 0xff;
+	cmd[3]  =  trans       & 0xff;
+	cmd[4]  = (src   >> 8) & 0xff;
+	cmd[5]  =  src         & 0xff;
+	cmd[6]  = (dest  >> 8) & 0xff;
+	cmd[7]  =  dest        & 0xff;
+	cmd[10] = rotate ? 1 : 0;
+	return ch_do_scsi(ch, cmd, 12, NULL, 0, REQ_OP_DRV_IN);
+}
+
+static int
+ch_exchange(scsi_changer *ch, u_int trans, u_int src,
+	    u_int dest1, u_int dest2, int rotate1, int rotate2)
+{
+	u_char  cmd[12];
+
+	DPRINTK("exchange: 0x%x => 0x%x => 0x%x\n",
+		src,dest1,dest2);
+	if (0 == trans)
+		trans = ch->firsts[CHET_MT];
+	memset(cmd,0,sizeof(cmd));
+	cmd[0]  = EXCHANGE_MEDIUM;
+	cmd[1]  = (ch->device->lun & 0x7) << 5;
+	cmd[2]  = (trans >> 8) & 0xff;
+	cmd[3]  =  trans       & 0xff;
+	cmd[4]  = (src   >> 8) & 0xff;
+	cmd[5]  =  src         & 0xff;
+	cmd[6]  = (dest1 >> 8) & 0xff;
+	cmd[7]  =  dest1       & 0xff;
+	cmd[8]  = (dest2 >> 8) & 0xff;
+	cmd[9]  =  dest2       & 0xff;
+	cmd[10] = (rotate1 ? 1 : 0) | (rotate2 ? 2 : 0);
+
+	return ch_do_scsi(ch, cmd, 12, NULL, 0, REQ_OP_DRV_IN);
+}
+
+static void
+ch_check_voltag(char *tag)
+{
+	int i;
+
+	for (i = 0; i < 32; i++) {
+		/* restrict to ascii */
+		if (tag[i] >= 0x7f || tag[i] < 0x20)
+			tag[i] = ' ';
+		/* don't allow search wildcards */
+		if (tag[i] == '?' ||
+		    tag[i] == '*')
+			tag[i] = ' ';
+	}
+}
+
+static int
+ch_set_voltag(scsi_changer *ch, u_int elem,
+	      int alternate, int clear, u_char *tag)
+{
+	u_char  cmd[12];
+	u_char  *buffer;
+	int result;
+
+	buffer = kzalloc(512, GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
+
+	DPRINTK("%s %s voltag: 0x%x => \"%s\"\n",
+		clear     ? "clear"     : "set",
+		alternate ? "alternate" : "primary",
+		elem, tag);
+	memset(cmd,0,sizeof(cmd));
+	cmd[0]  = SEND_VOLUME_TAG;
+	cmd[1] = ((ch->device->lun & 0x7) << 5) |
+		ch_elem_to_typecode(ch,elem);
+	cmd[2] = (elem >> 8) & 0xff;
+	cmd[3] = elem        & 0xff;
+	cmd[5] = clear
+		? (alternate ? 0x0d : 0x0c)
+		: (alternate ? 0x0b : 0x0a);
+
+	cmd[9] = 255;
+
+	memcpy(buffer,tag,32);
+	ch_check_voltag(buffer);
+
+	result = ch_do_scsi(ch, cmd, 12, buffer, 256, REQ_OP_DRV_OUT);
+	kfree(buffer);
+	return result;
+}
+
+static int ch_gstatus(scsi_changer *ch, int type, unsigned char __user *dest)
+{
+	int retval = 0;
+	u_char data[16];
+	unsigned int i;
+
+	mutex_lock(&ch->lock);
+	for (i = 0; i < ch->counts[type]; i++) {
+		if (0 != ch_read_element_status
+		    (ch, ch->firsts[type]+i,data)) {
+			retval = -EIO;
+			break;
+		}
+		put_user(data[2], dest+i);
+		if (data[2] & CESTATUS_EXCEPT)
+			VPRINTK(KERN_INFO, "element 0x%x: asc=0x%x, ascq=0x%x\n",
+				ch->firsts[type]+i,
+				(int)data[4],(int)data[5]);
+		retval = ch_read_element_status
+			(ch, ch->firsts[type]+i,data);
+		if (0 != retval)
+			break;
+	}
+	mutex_unlock(&ch->lock);
+	return retval;
+}
+
+/* ------------------------------------------------------------------------ */
+
+static void ch_destroy(struct kref *ref)
+{
+	scsi_changer *ch = container_of(ref, scsi_changer, ref);
+
+	ch->device = NULL;
+	kfree(ch->dt);
+	kfree(ch);
+}
+
+static int
+ch_release(struct inode *inode, struct file *file)
+{
+	scsi_changer *ch = file->private_data;
+
+	scsi_device_put(ch->device);
+	file->private_data = NULL;
+	kref_put(&ch->ref, ch_destroy);
+	return 0;
+}
+
+static int
+ch_open(struct inode *inode, struct file *file)
+{
+	scsi_changer *ch;
+	int minor = iminor(inode);
+
+	spin_lock(&ch_index_lock);
+	ch = idr_find(&ch_index_idr, minor);
+
+	if (ch == NULL || !kref_get_unless_zero(&ch->ref)) {
+		spin_unlock(&ch_index_lock);
+		return -ENXIO;
+	}
+	spin_unlock(&ch_index_lock);
+	if (scsi_device_get(ch->device)) {
+		kref_put(&ch->ref, ch_destroy);
+		return -ENXIO;
+	}
+	/* Synchronize with ch_probe() */
+	mutex_lock(&ch->lock);
+	file->private_data = ch;
+	mutex_unlock(&ch->lock);
+	return 0;
+}
+
+static int
+ch_checkrange(scsi_changer *ch, unsigned int type, unsigned int unit)
+{
+	if (type >= CH_TYPES  ||  unit >= ch->counts[type])
+		return -1;
+	return 0;
+}
+
+struct changer_element_status32 {
+	int		ces_type;
+	compat_uptr_t	ces_data;
+};
+#define CHIOGSTATUS32  _IOW('c', 8, struct changer_element_status32)
+
+static long ch_ioctl(struct file *file,
+		    unsigned int cmd, unsigned long arg)
+{
+	scsi_changer *ch = file->private_data;
+	int retval;
+	void __user *argp = (void __user *)arg;
+
+	retval = scsi_ioctl_block_when_processing_errors(ch->device, cmd,
+			file->f_flags & O_NDELAY);
+	if (retval)
+		return retval;
+
+	switch (cmd) {
+	case CHIOGPARAMS:
+	{
+		struct changer_params params;
+
+		params.cp_curpicker = 0;
+		params.cp_npickers  = ch->counts[CHET_MT];
+		params.cp_nslots    = ch->counts[CHET_ST];
+		params.cp_nportals  = ch->counts[CHET_IE];
+		params.cp_ndrives   = ch->counts[CHET_DT];
+
+		if (copy_to_user(argp, &params, sizeof(params)))
+			return -EFAULT;
+		return 0;
+	}
+	case CHIOGVPARAMS:
+	{
+		struct changer_vendor_params vparams;
+
+		memset(&vparams,0,sizeof(vparams));
+		if (ch->counts[CHET_V1]) {
+			vparams.cvp_n1  = ch->counts[CHET_V1];
+			strscpy(vparams.cvp_label1, vendor_labels[0],
+				sizeof(vparams.cvp_label1));
+		}
+		if (ch->counts[CHET_V2]) {
+			vparams.cvp_n2  = ch->counts[CHET_V2];
+			strscpy(vparams.cvp_label2, vendor_labels[1],
+				sizeof(vparams.cvp_label2));
+		}
+		if (ch->counts[CHET_V3]) {
+			vparams.cvp_n3  = ch->counts[CHET_V3];
+			strscpy(vparams.cvp_label3, vendor_labels[2],
+				sizeof(vparams.cvp_label3));
+		}
+		if (ch->counts[CHET_V4]) {
+			vparams.cvp_n4  = ch->counts[CHET_V4];
+			strscpy(vparams.cvp_label4, vendor_labels[3],
+				sizeof(vparams.cvp_label4));
+		}
+		if (copy_to_user(argp, &vparams, sizeof(vparams)))
+			return -EFAULT;
+		return 0;
+	}
+
+	case CHIOPOSITION:
+	{
+		struct changer_position pos;
+
+		if (copy_from_user(&pos, argp, sizeof (pos)))
+			return -EFAULT;
+
+		if (0 != ch_checkrange(ch, pos.cp_type, pos.cp_unit)) {
+			DPRINTK("CHIOPOSITION: invalid parameter\n");
+			return -EBADSLT;
+		}
+		mutex_lock(&ch->lock);
+		retval = ch_position(ch,0,
+				     ch->firsts[pos.cp_type] + pos.cp_unit,
+				     pos.cp_flags & CP_INVERT);
+		mutex_unlock(&ch->lock);
+		return retval;
+	}
+
+	case CHIOMOVE:
+	{
+		struct changer_move mv;
+
+		if (copy_from_user(&mv, argp, sizeof (mv)))
+			return -EFAULT;
+
+		if (0 != ch_checkrange(ch, mv.cm_fromtype, mv.cm_fromunit) ||
+		    0 != ch_checkrange(ch, mv.cm_totype,   mv.cm_tounit  )) {
+			DPRINTK("CHIOMOVE: invalid parameter\n");
+			return -EBADSLT;
+		}
+
+		mutex_lock(&ch->lock);
+		retval = ch_move(ch,0,
+				 ch->firsts[mv.cm_fromtype] + mv.cm_fromunit,
+				 ch->firsts[mv.cm_totype]   + mv.cm_tounit,
+				 mv.cm_flags & CM_INVERT);
+		mutex_unlock(&ch->lock);
+		return retval;
+	}
+
+	case CHIOEXCHANGE:
+	{
+		struct changer_exchange mv;
+
+		if (copy_from_user(&mv, argp, sizeof (mv)))
+			return -EFAULT;
+
+		if (0 != ch_checkrange(ch, mv.ce_srctype,  mv.ce_srcunit ) ||
+		    0 != ch_checkrange(ch, mv.ce_fdsttype, mv.ce_fdstunit) ||
+		    0 != ch_checkrange(ch, mv.ce_sdsttype, mv.ce_sdstunit)) {
+			DPRINTK("CHIOEXCHANGE: invalid parameter\n");
+			return -EBADSLT;
+		}
+
+		mutex_lock(&ch->lock);
+		retval = ch_exchange
+			(ch,0,
+			 ch->firsts[mv.ce_srctype]  + mv.ce_srcunit,
+			 ch->firsts[mv.ce_fdsttype] + mv.ce_fdstunit,
+			 ch->firsts[mv.ce_sdsttype] + mv.ce_sdstunit,
+			 mv.ce_flags & CE_INVERT1, mv.ce_flags & CE_INVERT2);
+		mutex_unlock(&ch->lock);
+		return retval;
+	}
+
+	case CHIOGSTATUS:
+	{
+		struct changer_element_status ces;
+
+		if (copy_from_user(&ces, argp, sizeof (ces)))
+			return -EFAULT;
+		if (ces.ces_type < 0 || ces.ces_type >= CH_TYPES)
+			return -EINVAL;
+
+		return ch_gstatus(ch, ces.ces_type, ces.ces_data);
+	}
+#ifdef CONFIG_COMPAT
+	case CHIOGSTATUS32:
+	{
+		struct changer_element_status32 ces32;
+
+		if (copy_from_user(&ces32, argp, sizeof(ces32)))
+			return -EFAULT;
+		if (ces32.ces_type < 0 || ces32.ces_type >= CH_TYPES)
+			return -EINVAL;
+
+		return ch_gstatus(ch, ces32.ces_type,
+				  compat_ptr(ces32.ces_data));
+	}
+#endif
+	case CHIOGELEM:
+	{
+		struct changer_get_element cge;
+		u_char ch_cmd[12];
+		u_char *buffer;
+		unsigned int elem;
+		int     result,i;
+
+		if (copy_from_user(&cge, argp, sizeof (cge)))
+			return -EFAULT;
+
+		if (0 != ch_checkrange(ch, cge.cge_type, cge.cge_unit))
+			return -EINVAL;
+		elem = ch->firsts[cge.cge_type] + cge.cge_unit;
+
+		buffer = kmalloc(512, GFP_KERNEL);
+		if (!buffer)
+			return -ENOMEM;
+		mutex_lock(&ch->lock);
+
+	voltag_retry:
+		memset(ch_cmd, 0, sizeof(ch_cmd));
+		ch_cmd[0] = READ_ELEMENT_STATUS;
+		ch_cmd[1] = ((ch->device->lun & 0x7) << 5) |
+			(ch->voltags ? 0x10 : 0) |
+			ch_elem_to_typecode(ch,elem);
+		ch_cmd[2] = (elem >> 8) & 0xff;
+		ch_cmd[3] = elem        & 0xff;
+		ch_cmd[5] = 1;
+		ch_cmd[9] = 255;
+
+		result = ch_do_scsi(ch, ch_cmd, 12, buffer, 256, REQ_OP_DRV_IN);
+		if (!result) {
+			cge.cge_status = buffer[18];
+			cge.cge_flags = 0;
+			if (buffer[18] & CESTATUS_EXCEPT) {
+				cge.cge_errno = EIO;
+			}
+			if (buffer[25] & 0x80) {
+				cge.cge_flags |= CGE_SRC;
+				if (buffer[25] & 0x40)
+					cge.cge_flags |= CGE_INVERT;
+				elem = (buffer[26]<<8) | buffer[27];
+				for (i = 0; i < 4; i++) {
+					if (elem >= ch->firsts[i] &&
+					    elem <  ch->firsts[i] + ch->counts[i]) {
+						cge.cge_srctype = i;
+						cge.cge_srcunit = elem-ch->firsts[i];
+					}
+				}
+			}
+			if ((buffer[22] & 0x30) == 0x30) {
+				cge.cge_flags |= CGE_IDLUN;
+				cge.cge_id  = buffer[23];
+				cge.cge_lun = buffer[22] & 7;
+			}
+			if (buffer[9] & 0x80) {
+				cge.cge_flags |= CGE_PVOLTAG;
+				memcpy(cge.cge_pvoltag,buffer+28,36);
+			}
+			if (buffer[9] & 0x40) {
+				cge.cge_flags |= CGE_AVOLTAG;
+				memcpy(cge.cge_avoltag,buffer+64,36);
+			}
+		} else if (ch->voltags) {
+			ch->voltags = 0;
+			VPRINTK(KERN_INFO, "device has no volume tag support\n");
+			goto voltag_retry;
+		}
+		kfree(buffer);
+		mutex_unlock(&ch->lock);
+
+		if (copy_to_user(argp, &cge, sizeof (cge)))
+			return -EFAULT;
+		return result;
+	}
+
+	case CHIOINITELEM:
+	{
+		mutex_lock(&ch->lock);
+		retval = ch_init_elem(ch);
+		mutex_unlock(&ch->lock);
+		return retval;
+	}
+
+	case CHIOSVOLTAG:
+	{
+		struct changer_set_voltag csv;
+		int elem;
+
+		if (copy_from_user(&csv, argp, sizeof(csv)))
+			return -EFAULT;
+
+		if (0 != ch_checkrange(ch, csv.csv_type, csv.csv_unit)) {
+			DPRINTK("CHIOSVOLTAG: invalid parameter\n");
+			return -EBADSLT;
+		}
+		elem = ch->firsts[csv.csv_type] + csv.csv_unit;
+		mutex_lock(&ch->lock);
+		retval = ch_set_voltag(ch, elem,
+				       csv.csv_flags & CSV_AVOLTAG,
+				       csv.csv_flags & CSV_CLEARTAG,
+				       csv.csv_voltag);
+		mutex_unlock(&ch->lock);
+		return retval;
+	}
+
+	default:
+		return scsi_ioctl(ch->device, file->f_mode & FMODE_WRITE, cmd,
+				  argp);
+
+	}
+}
+
+/* ------------------------------------------------------------------------ */
+
+static int ch_probe(struct scsi_device *sd)
+{
+	struct device *dev = &sd->sdev_gendev;
+	struct device *class_dev;
+	int ret;
+	scsi_changer *ch;
+
+	if (sd->type != TYPE_MEDIUM_CHANGER)
+		return -ENODEV;
+
+	ch = kzalloc_obj(*ch);
+	if (NULL == ch)
+		return -ENOMEM;
+
+	idr_preload(GFP_KERNEL);
+	spin_lock(&ch_index_lock);
+	ret = idr_alloc(&ch_index_idr, ch, 0, CH_MAX_DEVS + 1, GFP_NOWAIT);
+	spin_unlock(&ch_index_lock);
+	idr_preload_end();
+
+	if (ret < 0) {
+		if (ret == -ENOSPC)
+			ret = -ENODEV;
+		goto free_ch;
+	}
+
+	ch->minor = ret;
+	sprintf(ch->name,"ch%d",ch->minor);
+	ret = scsi_device_get(sd);
+	if (ret) {
+		sdev_printk(KERN_WARNING, sd, "ch%d: failed to get device\n",
+			    ch->minor);
+		goto remove_idr;
+	}
+
+	mutex_init(&ch->lock);
+	kref_init(&ch->ref);
+	ch->device = sd;
+	class_dev = device_create(&ch_sysfs_class, dev,
+				  MKDEV(SCSI_CHANGER_MAJOR, ch->minor), ch,
+				  "s%s", ch->name);
+	if (IS_ERR(class_dev)) {
+		sdev_printk(KERN_WARNING, sd, "ch%d: device_create failed\n",
+			    ch->minor);
+		ret = PTR_ERR(class_dev);
+		goto put_device;
+	}
+
+	mutex_lock(&ch->lock);
+	ret = ch_readconfig(ch);
+	if (ret) {
+		mutex_unlock(&ch->lock);
+		goto destroy_dev;
+	}
+	if (init)
+		ch_init_elem(ch);
+
+	mutex_unlock(&ch->lock);
+	dev_set_drvdata(dev, ch);
+	sdev_printk(KERN_INFO, sd, "Attached scsi changer %s\n", ch->name);
+
+	return 0;
+destroy_dev:
+	device_destroy(&ch_sysfs_class, MKDEV(SCSI_CHANGER_MAJOR, ch->minor));
+put_device:
+	scsi_device_put(sd);
+remove_idr:
+	idr_remove(&ch_index_idr, ch->minor);
+free_ch:
+	kfree(ch);
+	return ret;
+}
+
+static void ch_remove(struct scsi_device *sd)
+{
+	struct device *dev = &sd->sdev_gendev;
+	scsi_changer *ch = dev_get_drvdata(dev);
+
+	spin_lock(&ch_index_lock);
+	idr_remove(&ch_index_idr, ch->minor);
+	dev_set_drvdata(dev, NULL);
+	spin_unlock(&ch_index_lock);
+
+	device_destroy(&ch_sysfs_class, MKDEV(SCSI_CHANGER_MAJOR, ch->minor));
+	scsi_device_put(ch->device);
+	kref_put(&ch->ref, ch_destroy);
+}
+
+static struct scsi_driver ch_template = {
+	.probe = ch_probe,
+	.remove = ch_remove,
+	.gendrv = {
+		.name	= "ch",
+		.owner	= THIS_MODULE,
+	},
+};
+
+static const struct file_operations changer_fops = {
+	.owner		= THIS_MODULE,
+	.open		= ch_open,
+	.release	= ch_release,
+	.unlocked_ioctl	= ch_ioctl,
+	.compat_ioctl	= compat_ptr_ioctl,
+	.llseek		= noop_llseek,
+};
+
+static int __init init_ch_module(void)
+{
+	int rc;
+
+	printk(KERN_INFO "SCSI Media Changer driver v" VERSION " \n");
+	rc = class_register(&ch_sysfs_class);
+	if (rc)
+		return rc;
+	rc = register_chrdev(SCSI_CHANGER_MAJOR,"ch",&changer_fops);
+	if (rc < 0) {
+		printk("Unable to get major %d for SCSI-Changer\n",
+		       SCSI_CHANGER_MAJOR);
+		goto fail1;
+	}
+	rc = scsi_register_driver(&ch_template);
+	if (rc < 0)
+		goto fail2;
+	return 0;
+
+ fail2:
+	unregister_chrdev(SCSI_CHANGER_MAJOR, "ch");
+ fail1:
+	class_unregister(&ch_sysfs_class);
+	return rc;
+}
+
+static void __exit exit_ch_module(void)
+{
+	scsi_unregister_driver(&ch_template);
+	unregister_chrdev(SCSI_CHANGER_MAJOR, "ch");
+	class_unregister(&ch_sysfs_class);
+	idr_destroy(&ch_index_idr);
+}
+
+module_init(init_ch_module);
+module_exit(exit_ch_module);