[SCSI] sg: fix races during device removal (c6517b79) · Commits · 戴 / test

drivers/scsi/sg.c

+201 −217

Original line number	Diff line number	Diff line
		@@ -101,6 +101,7 @@ static int scatter_elem_sz_prev = SG_SCATTER_SZ;
		#define SG_SECTOR_MSK (SG_SECTOR_SZ - 1)

		static int sg_add(struct device , struct class_interface );
		static void sg_device_destroy(struct kref *kref);
		static void sg_remove(struct device , struct class_interface );

		static DEFINE_IDR(sg_index_idr);
		@@ -158,6 +159,8 @@ typedef struct sg_fd { /* holds the state of a file descriptor */
		char next_cmd_len; /* 0 -> automatic (def), >0 -> use on next write() */
		char keep_orphan; /* 0 -> drop orphan (def), 1 -> keep for read() */
		char mmap_called; /* 0 -> mmap() never called on this fd */
		struct kref f_ref;
		struct execute_work ew;
		} Sg_fd;

		typedef struct sg_device { /* holds the state of each scsi generic device */
		@@ -171,6 +174,7 @@ typedef struct sg_device { /* holds the state of each scsi generic device */
		char sgdebug; /* 0->off, 1->sense, 9->dump dev, 10-> all devs */
		struct gendisk *disk;
		struct cdev * cdev; /* char_dev [sysfs: /sys/cdev/major/sg<n>] */
		struct kref d_ref;
		} Sg_device;

		static int sg_fasync(int fd, struct file *filp, int mode);
		@@ -194,13 +198,14 @@ static void sg_build_reserve(Sg_fd * sfp, int req_size);
		static void sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size);
		static void sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp);
		static Sg_fd sg_add_sfp(Sg_device sdp, int dev);
		static int sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp);
		static void __sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp);
		static void sg_remove_sfp(struct kref *);
		static Sg_request sg_get_rq_mark(Sg_fd sfp, int pack_id);
		static Sg_request sg_add_request(Sg_fd sfp);
		static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
		static int sg_res_in_use(Sg_fd * sfp);
		static Sg_device *sg_lookup_dev(int dev);
		static Sg_device *sg_get_dev(int dev);
		static void sg_put_dev(Sg_device *sdp);
		#ifdef CONFIG_SCSI_PROC_FS
		static int sg_last_dev(void);
		#endif
		@@ -237,22 +242,17 @@ sg_open(struct inode inode, struct file filp)
		nonseekable_open(inode, filp);
		SCSI_LOG_TIMEOUT(3, printk("sg_open: dev=%d, flags=0x%x\n", dev, flags));
		sdp = sg_get_dev(dev);
		if ((!sdp) \|\| (!sdp->device)) {
		unlock_kernel();
		return -ENXIO;
		}
		if (sdp->detached) {
		unlock_kernel();
		return -ENODEV;
		if (IS_ERR(sdp)) {
		retval = PTR_ERR(sdp);
		sdp = NULL;
		goto sg_put;
		}

		/* This driver's module count bumped by fops_get in <linux/fs.h> */
		/* Prevent the device driver from vanishing while we sleep */
		retval = scsi_device_get(sdp->device);
		if (retval) {
		unlock_kernel();
		return retval;
		}
		if (retval)
		goto sg_put;

		if (!((flags & O_NONBLOCK) \|\|
		scsi_block_when_processing_errors(sdp->device))) {
		@@ -303,16 +303,20 @@ sg_open(struct inode inode, struct file filp)
		if ((sfp = sg_add_sfp(sdp, dev)))
		filp->private_data = sfp;
		else {
		if (flags & O_EXCL)
		if (flags & O_EXCL) {
		sdp->exclude = 0; /* undo if error */
		wake_up_interruptible(&sdp->o_excl_wait);
		}
		retval = -ENOMEM;
		goto error_out;
		}
		unlock_kernel();
		return 0;

		retval = 0;
		error_out:
		if (retval)
		scsi_device_put(sdp->device);
		sg_put:
		if (sdp)
		sg_put_dev(sdp);
		unlock_kernel();
		return retval;
		}
		@@ -327,13 +331,13 @@ sg_release(struct inode inode, struct file filp)
		if ((!(sfp = (Sg_fd *) filp->private_data)) \|\| (!(sdp = sfp->parentdp)))
		return -ENXIO;
		SCSI_LOG_TIMEOUT(3, printk("sg_release: %s\n", sdp->disk->disk_name));
		if (0 == sg_remove_sfp(sdp, sfp)) { /* Returns 1 when sdp gone */
		if (!sdp->detached) {
		scsi_device_put(sdp->device);
		}

		sfp->closed = 1;

		sdp->exclude = 0;
		wake_up_interruptible(&sdp->o_excl_wait);
		}

		kref_put(&sfp->f_ref, sg_remove_sfp);
		return 0;
		}

		@@ -755,6 +759,7 @@ sg_common_write(Sg_fd * sfp, Sg_request * srp,
		hp->duration = jiffies_to_msecs(jiffies);

		srp->rq->timeout = timeout;
		kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */
		blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk,
		srp->rq, 1, sg_rq_end_io);
		return 0;
		@@ -1247,24 +1252,23 @@ sg_mmap(struct file filp, struct vm_area_struct vma)
		static void sg_rq_end_io(struct request *rq, int uptodate)
		{
		struct sg_request *srp = rq->end_io_data;
		Sg_device *sdp = NULL;
		Sg_device *sdp;
		Sg_fd *sfp;
		unsigned long iflags;
		unsigned int ms;
		char *sense;
		int result, resid;
		int result, resid, done = 1;

		if (NULL == srp) {
		printk(KERN_ERR "sg_cmd_done: NULL request\n");
		if (WARN_ON(srp->done != 0))
		return;
		}

		sfp = srp->parentfp;
		if (sfp)
		sdp = sfp->parentdp;
		if ((NULL == sdp) \|\| sdp->detached) {
		printk(KERN_INFO "sg_cmd_done: device detached\n");
		if (WARN_ON(sfp == NULL))
		return;
		}

		sdp = sfp->parentdp;
		if (unlikely(sdp->detached))
		printk(KERN_INFO "sg_rq_end_io: device detached\n");

		sense = rq->sense;
		result = rq->errors;
		@@ -1303,33 +1307,26 @@ static void sg_rq_end_io(struct request *rq, int uptodate)
		}
		/* Rely on write phase to clean out srp status values, so no "else" */

		if (sfp->closed) { /* whoops this fd already released, cleanup */
		SCSI_LOG_TIMEOUT(1, printk("sg_cmd_done: already closed, freeing ...\n"));
		sg_finish_rem_req(srp);
		srp = NULL;
		if (NULL == sfp->headrp) {
		SCSI_LOG_TIMEOUT(1, printk("sg_cmd_done: already closed, final cleanup\n"));
		if (0 == sg_remove_sfp(sdp, sfp)) { /* device still present */
		scsi_device_put(sdp->device);
		}
		sfp = NULL;
		}
		} else if (srp && srp->orphan) {
		write_lock_irqsave(&sfp->rq_list_lock, iflags);
		if (unlikely(srp->orphan)) {
		if (sfp->keep_orphan)
		srp->sg_io_owned = 0;
		else {
		sg_finish_rem_req(srp);
		srp = NULL;
		}
		else
		done = 0;
		}
		if (sfp && srp) {
		/* Now wake up any sg_read() that is waiting for this packet. */
		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
		write_lock_irqsave(&sfp->rq_list_lock, iflags);
		srp->done = 1;
		wake_up_interruptible(&sfp->read_wait);
		srp->done = done;
		write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
		}

		if (likely(done)) {
		/* Now wake up any sg_read() that is waiting for this
		* packet.
		*/
		wake_up_interruptible(&sfp->read_wait);
		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
		} else
		sg_finish_rem_req(srp); /* call with srp->done == 0 */

		kref_put(&sfp->f_ref, sg_remove_sfp);
		}

		static struct file_operations sg_fops = {
		@@ -1364,17 +1361,18 @@ static Sg_device sg_alloc(struct gendisk disk, struct scsi_device *scsidp)
		printk(KERN_WARNING "kmalloc Sg_device failure\n");
		return ERR_PTR(-ENOMEM);
		}
		error = -ENOMEM;

		if (!idr_pre_get(&sg_index_idr, GFP_KERNEL)) {
		printk(KERN_WARNING "idr expansion Sg_device failure\n");
		error = -ENOMEM;
		goto out;
		}

		write_lock_irqsave(&sg_index_lock, iflags);
		error = idr_get_new(&sg_index_idr, sdp, &k);
		write_unlock_irqrestore(&sg_index_lock, iflags);

		error = idr_get_new(&sg_index_idr, sdp, &k);
		if (error) {
		write_unlock_irqrestore(&sg_index_lock, iflags);
		printk(KERN_WARNING "idr allocation Sg_device failure: %d\n",
		error);
		goto out;
		@@ -1391,6 +1389,9 @@ static Sg_device sg_alloc(struct gendisk disk, struct scsi_device *scsidp)
		init_waitqueue_head(&sdp->o_excl_wait);
		sdp->sg_tablesize = min(q->max_hw_segments, q->max_phys_segments);
		sdp->index = k;
		kref_init(&sdp->d_ref);

		write_unlock_irqrestore(&sg_index_lock, iflags);

		error = 0;
		out:
		@@ -1401,6 +1402,8 @@ static Sg_device sg_alloc(struct gendisk disk, struct scsi_device *scsidp)
		return sdp;

		overflow:
		idr_remove(&sg_index_idr, k);
		write_unlock_irqrestore(&sg_index_lock, iflags);
		sdev_printk(KERN_WARNING, scsidp,
		"Unable to attach sg device type=%d, minor "
		"number exceeds %d\n", scsidp->type, SG_MAX_DEVS - 1);
		@@ -1488,49 +1491,46 @@ out:
		return error;
		}

		static void
		sg_remove(struct device cl_dev, struct class_interface cl_intf)
		static void sg_device_destroy(struct kref *kref)
		{
		struct sg_device *sdp = container_of(kref, struct sg_device, d_ref);
		unsigned long flags;

		/* CAUTION! Note that the device can still be found via idr_find()
		* even though the refcount is 0. Therefore, do idr_remove() BEFORE
		* any other cleanup.
		*/

		write_lock_irqsave(&sg_index_lock, flags);
		idr_remove(&sg_index_idr, sdp->index);
		write_unlock_irqrestore(&sg_index_lock, flags);

		SCSI_LOG_TIMEOUT(3,
		printk("sg_device_destroy: %s\n",
		sdp->disk->disk_name));

		put_disk(sdp->disk);
		kfree(sdp);
		}

		static void sg_remove(struct device cl_dev, struct class_interface cl_intf)
		{
		struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
		Sg_device *sdp = dev_get_drvdata(cl_dev);
		unsigned long iflags;
		Sg_fd *sfp;
		Sg_fd *tsfp;
		Sg_request *srp;
		Sg_request *tsrp;
		int delay;

		if (!sdp)
		if (!sdp \|\| sdp->detached)
		return;

		delay = 0;
		SCSI_LOG_TIMEOUT(3, printk("sg_remove: %s\n", sdp->disk->disk_name));

		/* Need a write lock to set sdp->detached. */
		write_lock_irqsave(&sg_index_lock, iflags);
		if (sdp->headfp) {
		sdp->detached = 1;
		for (sfp = sdp->headfp; sfp; sfp = tsfp) {
		tsfp = sfp->nextfp;
		for (srp = sfp->headrp; srp; srp = tsrp) {
		tsrp = srp->nextrp;
		if (sfp->closed \|\| (0 == sg_srp_done(srp, sfp)))
		sg_finish_rem_req(srp);
		}
		if (sfp->closed) {
		scsi_device_put(sdp->device);
		__sg_remove_sfp(sdp, sfp);
		} else {
		delay = 1;
		for (sfp = sdp->headfp; sfp; sfp = sfp->nextfp) {
		wake_up_interruptible(&sfp->read_wait);
		kill_fasync(&sfp->async_qp, SIGPOLL,
		POLL_HUP);
		}
		}
		SCSI_LOG_TIMEOUT(3, printk("sg_remove: dev=%d, dirty\n", sdp->index));
		if (NULL == sdp->headfp) {
		idr_remove(&sg_index_idr, sdp->index);
		}
		} else { /* nothing active, simple case */
		SCSI_LOG_TIMEOUT(3, printk("sg_remove: dev=%d\n", sdp->index));
		idr_remove(&sg_index_idr, sdp->index);
		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP);
		}
		write_unlock_irqrestore(&sg_index_lock, iflags);

		@@ -1538,13 +1538,8 @@ sg_remove(struct device cl_dev, struct class_interface cl_intf)
		device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index));
		cdev_del(sdp->cdev);
		sdp->cdev = NULL;
		put_disk(sdp->disk);
		sdp->disk = NULL;
		if (NULL == sdp->headfp)
		kfree(sdp);

		if (delay)
		msleep(10); /* dirty detach so delay device destruction */
		sg_put_dev(sdp);
		}

		module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO \| S_IWUSR);
		@@ -1941,22 +1936,6 @@ sg_get_rq_mark(Sg_fd * sfp, int pack_id)
		return resp;
		}

		#ifdef CONFIG_SCSI_PROC_FS
		static Sg_request *
		sg_get_nth_request(Sg_fd * sfp, int nth)
		{
		Sg_request *resp;
		unsigned long iflags;
		int k;

		read_lock_irqsave(&sfp->rq_list_lock, iflags);
		for (k = 0, resp = sfp->headrp; resp && (k < nth);
		++k, resp = resp->nextrp) ;
		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
		return resp;
		}
		#endif

		/* always adds to end of list */
		static Sg_request *
		sg_add_request(Sg_fd * sfp)
		@@ -2032,22 +2011,6 @@ sg_remove_request(Sg_fd * sfp, Sg_request * srp)
		return res;
		}

		#ifdef CONFIG_SCSI_PROC_FS
		static Sg_fd *
		sg_get_nth_sfp(Sg_device * sdp, int nth)
		{
		Sg_fd *resp;
		unsigned long iflags;
		int k;

		read_lock_irqsave(&sg_index_lock, iflags);
		for (k = 0, resp = sdp->headfp; resp && (k < nth);
		++k, resp = resp->nextfp) ;
		read_unlock_irqrestore(&sg_index_lock, iflags);
		return resp;
		}
		#endif

		static Sg_fd *
		sg_add_sfp(Sg_device * sdp, int dev)
		{
		@@ -2062,6 +2025,7 @@ sg_add_sfp(Sg_device * sdp, int dev)
		init_waitqueue_head(&sfp->read_wait);
		rwlock_init(&sfp->rq_list_lock);

		kref_init(&sfp->f_ref);
		sfp->timeout = SG_DEFAULT_TIMEOUT;
		sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
		sfp->force_packid = SG_DEF_FORCE_PACK_ID;
		@@ -2089,15 +2053,54 @@ sg_add_sfp(Sg_device * sdp, int dev)
		sg_build_reserve(sfp, bufflen);
		SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: bufflen=%d, k_use_sg=%d\n",
		sfp->reserve.bufflen, sfp->reserve.k_use_sg));

		kref_get(&sdp->d_ref);
		__module_get(THIS_MODULE);
		return sfp;
		}

		static void
		__sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp)
		static void sg_remove_sfp_usercontext(struct work_struct *work)
		{
		struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work);
		struct sg_device *sdp = sfp->parentdp;

		/* Cleanup any responses which were never read(). */
		while (sfp->headrp)
		sg_finish_rem_req(sfp->headrp);

		if (sfp->reserve.bufflen > 0) {
		SCSI_LOG_TIMEOUT(6,
		printk("sg_remove_sfp: bufflen=%d, k_use_sg=%d\n",
		(int) sfp->reserve.bufflen,
		(int) sfp->reserve.k_use_sg));
		sg_remove_scat(&sfp->reserve);
		}

		SCSI_LOG_TIMEOUT(6,
		printk("sg_remove_sfp: %s, sfp=0x%p\n",
		sdp->disk->disk_name,
		sfp));
		kfree(sfp);

		scsi_device_put(sdp->device);
		sg_put_dev(sdp);
		module_put(THIS_MODULE);
		}

		static void sg_remove_sfp(struct kref *kref)
		{
		struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref);
		struct sg_device *sdp = sfp->parentdp;
		Sg_fd *fp;
		Sg_fd *prev_fp;
		unsigned long iflags;

		/* CAUTION! Note that sfp can still be found by walking sdp->headfp
		* even though the refcount is now 0. Therefore, unlink sfp from
		* sdp->headfp BEFORE doing any other cleanup.
		*/

		write_lock_irqsave(&sg_index_lock, iflags);
		prev_fp = sdp->headfp;
		if (sfp == prev_fp)
		sdp->headfp = prev_fp->nextfp;
		@@ -2110,54 +2113,10 @@ __sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp)
		prev_fp = fp;
		}
		}
		if (sfp->reserve.bufflen > 0) {
		SCSI_LOG_TIMEOUT(6,
		printk("__sg_remove_sfp: bufflen=%d, k_use_sg=%d\n",
		(int) sfp->reserve.bufflen, (int) sfp->reserve.k_use_sg));
		sg_remove_scat(&sfp->reserve);
		}
		sfp->parentdp = NULL;
		SCSI_LOG_TIMEOUT(6, printk("__sg_remove_sfp: sfp=0x%p\n", sfp));
		kfree(sfp);
		}

		/* Returns 0 in normal case, 1 when detached and sdp object removed */
		static int
		sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp)
		{
		Sg_request *srp;
		Sg_request *tsrp;
		int dirty = 0;
		int res = 0;

		for (srp = sfp->headrp; srp; srp = tsrp) {
		tsrp = srp->nextrp;
		if (sg_srp_done(srp, sfp))
		sg_finish_rem_req(srp);
		else
		++dirty;
		}
		if (0 == dirty) {
		unsigned long iflags;

		write_lock_irqsave(&sg_index_lock, iflags);
		__sg_remove_sfp(sdp, sfp);
		if (sdp->detached && (NULL == sdp->headfp)) {
		idr_remove(&sg_index_idr, sdp->index);
		kfree(sdp);
		res = 1;
		}
		write_unlock_irqrestore(&sg_index_lock, iflags);
		} else {
		/* MOD_INC's to inhibit unloading sg and associated adapter driver */
		/* only bump the access_count if we actually succeeded in
		* throwing another counter on the host module */
		scsi_device_get(sdp->device); /* XXX: retval ignored? */
		sfp->closed = 1; /* flag dirty state on this fd */
		SCSI_LOG_TIMEOUT(1, printk("sg_remove_sfp: worrisome, %d writes pending\n",
		dirty));
		}
		return res;
		wake_up_interruptible(&sdp->o_excl_wait);

		execute_in_process_context(sg_remove_sfp_usercontext, &sfp->ew);
		}

		static int
		@@ -2199,19 +2158,38 @@ sg_last_dev(void)
		}
		#endif

		static Sg_device *
		sg_get_dev(int dev)
		/* must be called with sg_index_lock held */
		static Sg_device *sg_lookup_dev(int dev)
		{
		Sg_device *sdp;
		unsigned long iflags;
		return idr_find(&sg_index_idr, dev);
		}

		read_lock_irqsave(&sg_index_lock, iflags);
		sdp = idr_find(&sg_index_idr, dev);
		read_unlock_irqrestore(&sg_index_lock, iflags);
		static Sg_device *sg_get_dev(int dev)
		{
		struct sg_device *sdp;
		unsigned long flags;

		read_lock_irqsave(&sg_index_lock, flags);
		sdp = sg_lookup_dev(dev);
		if (!sdp)
		sdp = ERR_PTR(-ENXIO);
		else if (sdp->detached) {
		/* If sdp->detached, then the refcount may already be 0, in
		* which case it would be a bug to do kref_get().
		*/
		sdp = ERR_PTR(-ENODEV);
		} else
		kref_get(&sdp->d_ref);
		read_unlock_irqrestore(&sg_index_lock, flags);

		return sdp;
		}

		static void sg_put_dev(struct sg_device *sdp)
		{
		kref_put(&sdp->d_ref, sg_device_destroy);
		}

		#ifdef CONFIG_SCSI_PROC_FS

		static struct proc_dir_entry *sg_proc_sgp = NULL;
		@@ -2468,8 +2446,10 @@ static int sg_proc_seq_show_dev(struct seq_file s, void v)
		struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
		Sg_device *sdp;
		struct scsi_device *scsidp;
		unsigned long iflags;

		sdp = it ? sg_get_dev(it->index) : NULL;
		read_lock_irqsave(&sg_index_lock, iflags);
		sdp = it ? sg_lookup_dev(it->index) : NULL;
		if (sdp && (scsidp = sdp->device) && (!sdp->detached))
		seq_printf(s, "%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\n",
		scsidp->host->host_no, scsidp->channel,
		@@ -2480,6 +2460,7 @@ static int sg_proc_seq_show_dev(struct seq_file s, void v)
		(int) scsi_device_online(scsidp));
		else
		seq_printf(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
		read_unlock_irqrestore(&sg_index_lock, iflags);
		return 0;
		}

		@@ -2493,16 +2474,20 @@ static int sg_proc_seq_show_devstrs(struct seq_file s, void v)
		struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
		Sg_device *sdp;
		struct scsi_device *scsidp;
		unsigned long iflags;

		sdp = it ? sg_get_dev(it->index) : NULL;
		read_lock_irqsave(&sg_index_lock, iflags);
		sdp = it ? sg_lookup_dev(it->index) : NULL;
		if (sdp && (scsidp = sdp->device) && (!sdp->detached))
		seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
		scsidp->vendor, scsidp->model, scsidp->rev);
		else
		seq_printf(s, "<no active device>\n");
		read_unlock_irqrestore(&sg_index_lock, iflags);
		return 0;
		}

		/* must be called while holding sg_index_lock */
		static void sg_proc_debug_helper(struct seq_file s, Sg_device sdp)
		{
		int k, m, new_interface, blen, usg;
		@@ -2512,7 +2497,8 @@ static void sg_proc_debug_helper(struct seq_file s, Sg_device sdp)
		const char * cp;
		unsigned int ms;

		for (k = 0; (fp = sg_get_nth_sfp(sdp, k)); ++k) {
		for (k = 0, fp = sdp->headfp; fp != NULL; ++k, fp = fp->nextfp) {
		read_lock(&fp->rq_list_lock); /* irqs already disabled */
		seq_printf(s, " FD(%d): timeout=%dms bufflen=%d "
		"(res)sgat=%d low_dma=%d\n", k + 1,
		jiffies_to_msecs(fp->timeout),
		@@ -2522,7 +2508,9 @@ static void sg_proc_debug_helper(struct seq_file s, Sg_device sdp)
		seq_printf(s, " cmd_q=%d f_packid=%d k_orphan=%d closed=%d\n",
		(int) fp->cmd_q, (int) fp->force_packid,
		(int) fp->keep_orphan, (int) fp->closed);
		for (m = 0; (srp = sg_get_nth_request(fp, m)); ++m) {
		for (m = 0, srp = fp->headrp;
		srp != NULL;
		++m, srp = srp->nextrp) {
		hp = &srp->header;
		new_interface = (hp->interface_id == '\0') ? 0 : 1;
		if (srp->res_used) {
		@@ -2559,6 +2547,7 @@ static void sg_proc_debug_helper(struct seq_file s, Sg_device sdp)
		}
		if (0 == m)
		seq_printf(s, " No requests active\n");
		read_unlock(&fp->rq_list_lock);
		}
		}

		@@ -2571,25 +2560,20 @@ static int sg_proc_seq_show_debug(struct seq_file s, void v)
		{
		struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
		Sg_device *sdp;
		unsigned long iflags;

		if (it && (0 == it->index)) {
		seq_printf(s, "max_active_device=%d(origin 1)\n",
		(int)it->max);
		seq_printf(s, " def_reserved_size=%d\n", sg_big_buff);
		}
		sdp = it ? sg_get_dev(it->index) : NULL;
		if (sdp) {
		struct scsi_device *scsidp = sdp->device;

		if (NULL == scsidp) {
		seq_printf(s, "device %d detached ??\n",
		(int)it->index);
		return 0;
		}
		read_lock_irqsave(&sg_index_lock, iflags);
		sdp = it ? sg_lookup_dev(it->index) : NULL;
		if (sdp && sdp->headfp) {
		struct scsi_device *scsidp = sdp->device;

		if (sg_get_nth_sfp(sdp, 0)) {
		seq_printf(s, " >>> device=%s ",
		sdp->disk->disk_name);
		seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
		if (sdp->detached)
		seq_printf(s, "detached pending close ");
		else
		@@ -2601,9 +2585,9 @@ static int sg_proc_seq_show_debug(struct seq_file s, void v)
		scsidp->host->hostt->emulated);
		seq_printf(s, " sg_tablesize=%d excl=%d\n",
		sdp->sg_tablesize, sdp->exclude);
		}
		sg_proc_debug_helper(s, sdp);
		}
		read_unlock_irqrestore(&sg_index_lock, iflags);
		return 0;
		}

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