Message-Id: <1465426212-3392-1-git-send-email-jsimmons@infradead.org>
Date:	Wed,  8 Jun 2016 18:50:12 -0400
From:	James Simmons <jsimmons@...radead.org>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	devel@...verdev.osuosl.org,
	Andreas Dilger <andreas.dilger@...el.com>,
	Oleg Drokin <oleg.drokin@...el.com>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Lustre Development List <lustre-devel@...ts.lustre.org>,
	James Simmons <jsimmons@...radead.org>
Subject: [PATCH] staging: lustre: llite: remove lloop device

The lloop device was original developed to work around
the lack of direct I/O for the default loop back device.
Also the lloop device greatly out performed the default
loop back device. The lloop hasn't been worked on for
some time and now it no longer out performs the loop
device and loop now supports direct I/O. Since this is
the case we can delete this device.

Signed-off-by: James Simmons <jsimmons@...radead.org>
---
 drivers/staging/lustre/lustre/Kconfig        |    6 -
 drivers/staging/lustre/lustre/llite/Makefile |    3 -
 drivers/staging/lustre/lustre/llite/lloop.c  |  883 --------------------------
 3 files changed, 0 insertions(+), 892 deletions(-)
 delete mode 100644 drivers/staging/lustre/lustre/llite/lloop.c

diff --git a/drivers/staging/lustre/lustre/Kconfig b/drivers/staging/lustre/lustre/Kconfig
index 8ac7cd4..9f5d75f 100644
--- a/drivers/staging/lustre/lustre/Kconfig
+++ b/drivers/staging/lustre/lustre/Kconfig
@@ -54,9 +54,3 @@ config LUSTRE_TRANSLATE_ERRNOS
 	bool
 	depends on LUSTRE_FS && !X86
 	default y
-
-config LUSTRE_LLITE_LLOOP
-	tristate "Lustre virtual block device"
-	depends on LUSTRE_FS && BLOCK
-	depends on !PPC_64K_PAGES && !ARM64_64K_PAGES && !MICROBLAZE_64K_PAGES && !PAGE_SIZE_64KB && !IA64_PAGE_SIZE_64KB && !PARISC_PAGE_SIZE_64KB
-	default m
diff --git a/drivers/staging/lustre/lustre/llite/Makefile b/drivers/staging/lustre/lustre/llite/Makefile
index 2ce10ff..19701e7 100644
--- a/drivers/staging/lustre/lustre/llite/Makefile
+++ b/drivers/staging/lustre/lustre/llite/Makefile
@@ -1,5 +1,4 @@
 obj-$(CONFIG_LUSTRE_FS) += lustre.o
-obj-$(CONFIG_LUSTRE_LLITE_LLOOP) += llite_lloop.o
 lustre-y := dcache.o dir.o file.o llite_close.o llite_lib.o llite_nfs.o \
 	    rw.o namei.o symlink.o llite_mmap.o \
 	    xattr.o xattr_cache.o remote_perm.o llite_rmtacl.o \
@@ -7,5 +6,3 @@ lustre-y := dcache.o dir.o file.o llite_close.o llite_lib.o llite_nfs.o \
 	    glimpse.o lcommon_cl.o lcommon_misc.o \
 	    vvp_dev.o vvp_page.o vvp_lock.o vvp_io.o vvp_object.o vvp_req.o \
 	    lproc_llite.o
-
-llite_lloop-y := lloop.o
diff --git a/drivers/staging/lustre/lustre/llite/lloop.c b/drivers/staging/lustre/lustre/llite/lloop.c
deleted file mode 100644
index 813a9a3..0000000
--- a/drivers/staging/lustre/lustre/llite/lloop.c
+++ /dev/null
@@ -1,883 +0,0 @@
-/*
- * GPL HEADER START
- *
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 only,
- * as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License version 2 for more details (a copy is included
- * in the LICENSE file that accompanied this code).
- *
- * You should have received a copy of the GNU General Public License
- * version 2 along with this program; If not, see
- * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
- *
- * GPL HEADER END
- */
-/*
- * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
- * Use is subject to license terms.
- *
- * Copyright (c) 2011, 2012, Intel Corporation.
- */
-/*
- * This file is part of Lustre, http://www.lustre.org/
- * Lustre is a trademark of Sun Microsystems, Inc.
- */
-
-/*
- *  linux/drivers/block/loop.c
- *
- *  Written by Theodore Ts'o, 3/29/93
- *
- * Copyright 1993 by Theodore Ts'o.  Redistribution of this file is
- * permitted under the GNU General Public License.
- *
- * Modularized and updated for 1.1.16 kernel - Mitch Dsouza 28th May 1994
- * Adapted for 1.3.59 kernel - Andries Brouwer, 1 Feb 1996
- *
- * Fixed do_loop_request() re-entrancy - Vincent.Renardias@....com Mar 20, 1997
- *
- * Added devfs support - Richard Gooch <rgooch@...f.csiro.au> 16-Jan-1998
- *
- * Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998
- *
- * Loadable modules and other fixes by AK, 1998
- *
- * Maximum number of loop devices now dynamic via max_loop module parameter.
- * Russell Kroll <rkroll@...loits.org> 19990701
- *
- * Maximum number of loop devices when compiled-in now selectable by passing
- * max_loop=<1-255> to the kernel on boot.
- * Erik I. Bols?, <eriki@...olde.no>, Oct 31, 1999
- *
- * Completely rewrite request handling to be make_request_fn style and
- * non blocking, pushing work to a helper thread. Lots of fixes from
- * Al Viro too.
- * Jens Axboe <axboe@...e.de>, Nov 2000
- *
- * Support up to 256 loop devices
- * Heinz Mauelshagen <mge@...tina.com>, Feb 2002
- *
- * Support for falling back on the write file operation when the address space
- * operations prepare_write and/or commit_write are not available on the
- * backing filesystem.
- * Anton Altaparmakov, 16 Feb 2005
- *
- * Still To Fix:
- * - Advisory locking is ignored here.
- * - Should use an own CAP_* category instead of CAP_SYS_ADMIN
- *
- */
-
-#include <linux/module.h>
-
-#include <linux/sched.h>
-#include <linux/fs.h>
-#include <linux/file.h>
-#include <linux/stat.h>
-#include <linux/errno.h>
-#include <linux/major.h>
-#include <linux/wait.h>
-#include <linux/blkdev.h>
-#include <linux/blkpg.h>
-#include <linux/init.h>
-#include <linux/swap.h>
-#include <linux/slab.h>
-#include <linux/suspend.h>
-#include <linux/writeback.h>
-#include <linux/buffer_head.h>		/* for invalidate_bdev() */
-#include <linux/completion.h>
-#include <linux/highmem.h>
-#include <linux/gfp.h>
-#include <linux/pagevec.h>
-#include <linux/uaccess.h>
-
-#include "../include/lustre_lib.h"
-#include "../include/lustre_lite.h"
-#include "llite_internal.h"
-
-#define LLOOP_MAX_SEGMENTS	LNET_MAX_IOV
-
-/* Possible states of device */
-enum {
-	LLOOP_UNBOUND,
-	LLOOP_BOUND,
-	LLOOP_RUNDOWN,
-};
-
-struct lloop_device {
-	int		  lo_number;
-	int		  lo_refcnt;
-	loff_t	       lo_offset;
-	loff_t	       lo_sizelimit;
-	int		  lo_flags;
-	struct file	 *lo_backing_file;
-	struct block_device *lo_device;
-	unsigned	     lo_blocksize;
-
-	gfp_t		  old_gfp_mask;
-
-	spinlock_t		lo_lock;
-	struct bio		*lo_bio;
-	struct bio		*lo_biotail;
-	int			lo_state;
-	struct semaphore	lo_sem;
-	struct mutex		lo_ctl_mutex;
-	atomic_t	 lo_pending;
-	wait_queue_head_t	  lo_bh_wait;
-
-	struct request_queue *lo_queue;
-
-	const struct lu_env *lo_env;
-	struct cl_io	 lo_io;
-	struct ll_dio_pages  lo_pvec;
-
-	/* data to handle bio for lustre. */
-	struct lo_request_data {
-		struct page *lrd_pages[LLOOP_MAX_SEGMENTS];
-		loff_t       lrd_offsets[LLOOP_MAX_SEGMENTS];
-	} lo_requests[1];
-};
-
-/*
- * Loop flags
- */
-enum {
-	LO_FLAGS_READ_ONLY       = 1,
-};
-
-static int lloop_major;
-#define MAX_LOOP_DEFAULT  16
-static int max_loop = MAX_LOOP_DEFAULT;
-static struct lloop_device *loop_dev;
-static struct gendisk **disks;
-static struct mutex lloop_mutex;
-static void *ll_iocontrol_magic;
-
-static loff_t get_loop_size(struct lloop_device *lo, struct file *file)
-{
-	loff_t size, offset, loopsize;
-
-	/* Compute loopsize in bytes */
-	size = i_size_read(file->f_mapping->host);
-	offset = lo->lo_offset;
-	loopsize = size - offset;
-	if (lo->lo_sizelimit > 0 && lo->lo_sizelimit < loopsize)
-		loopsize = lo->lo_sizelimit;
-
-	/*
-	 * Unfortunately, if we want to do I/O on the device,
-	 * the number of 512-byte sectors has to fit into a sector_t.
-	 */
-	return loopsize >> 9;
-}
-
-static int do_bio_lustrebacked(struct lloop_device *lo, struct bio *head)
-{
-	const struct lu_env  *env   = lo->lo_env;
-	struct cl_io	 *io    = &lo->lo_io;
-	struct inode	 *inode = file_inode(lo->lo_backing_file);
-	struct cl_object     *obj = ll_i2info(inode)->lli_clob;
-	pgoff_t	       offset;
-	int		   ret;
-	int		   rw;
-	u32		   page_count = 0;
-	struct bio_vec       bvec;
-	struct bvec_iter   iter;
-	struct bio	   *bio;
-	ssize_t	       bytes;
-
-	struct ll_dio_pages  *pvec = &lo->lo_pvec;
-	struct page	 **pages = pvec->ldp_pages;
-	loff_t	       *offsets = pvec->ldp_offsets;
-
-	truncate_inode_pages(inode->i_mapping, 0);
-
-	/* initialize the IO */
-	memset(io, 0, sizeof(*io));
-	io->ci_obj = obj;
-	ret = cl_io_init(env, io, CIT_MISC, obj);
-	if (ret)
-		return io->ci_result;
-	io->ci_lockreq = CILR_NEVER;
-
-	rw = head->bi_rw;
-	for (bio = head; bio ; bio = bio->bi_next) {
-		LASSERT(rw == bio->bi_rw);
-
-		offset = (pgoff_t)(bio->bi_iter.bi_sector << 9) + lo->lo_offset;
-		bio_for_each_segment(bvec, bio, iter) {
-			BUG_ON(bvec.bv_offset != 0);
-			BUG_ON(bvec.bv_len != PAGE_SIZE);
-
-			pages[page_count] = bvec.bv_page;
-			offsets[page_count] = offset;
-			page_count++;
-			offset += bvec.bv_len;
-		}
-		LASSERT(page_count <= LLOOP_MAX_SEGMENTS);
-	}
-
-	ll_stats_ops_tally(ll_i2sbi(inode),
-			(rw == WRITE) ? LPROC_LL_BRW_WRITE : LPROC_LL_BRW_READ,
-			page_count);
-
-	pvec->ldp_size = page_count << PAGE_SHIFT;
-	pvec->ldp_nr = page_count;
-
-	/* FIXME: in ll_direct_rw_pages, it has to allocate many cl_page{}s to
-	 * write those pages into OST. Even worse case is that more pages
-	 * would be asked to write out to swap space, and then finally get here
-	 * again.
-	 * Unfortunately this is NOT easy to fix.
-	 * Thoughts on solution:
-	 * 0. Define a reserved pool for cl_pages, which could be a list of
-	 *    pre-allocated cl_pages;
-	 * 1. Define a new operation in cl_object_operations{}, says clo_depth,
-	 *    which measures how many layers for this lustre object. Generally
-	 *    speaking, the depth would be 2, one for llite, and one for lovsub.
-	 *    However, for SNS, there will be more since we need additional page
-	 *    to store parity;
-	 * 2. Reserve the # of (page_count * depth) cl_pages from the reserved
-	 *    pool. Afterwards, the clio would allocate the pages from reserved
-	 *    pool, this guarantees we needn't allocate the cl_pages from
-	 *    generic cl_page slab cache.
-	 *    Of course, if there is NOT enough pages in the pool, we might
-	 *    be asked to write less pages once, this purely depends on
-	 *    implementation. Anyway, we should be careful to avoid deadlocking.
-	 */
-	inode_lock(inode);
-	bytes = ll_direct_rw_pages(env, io, rw, inode, pvec);
-	inode_unlock(inode);
-	cl_io_fini(env, io);
-	return (bytes == pvec->ldp_size) ? 0 : (int)bytes;
-}
-
-/*
- * Add bio to back of pending list
- */
-static void loop_add_bio(struct lloop_device *lo, struct bio *bio)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&lo->lo_lock, flags);
-	if (lo->lo_biotail) {
-		lo->lo_biotail->bi_next = bio;
-		lo->lo_biotail = bio;
-	} else {
-		lo->lo_bio = lo->lo_biotail = bio;
-	}
-	spin_unlock_irqrestore(&lo->lo_lock, flags);
-
-	atomic_inc(&lo->lo_pending);
-	if (waitqueue_active(&lo->lo_bh_wait))
-		wake_up(&lo->lo_bh_wait);
-}
-
-/*
- * Grab first pending buffer
- */
-static unsigned int loop_get_bio(struct lloop_device *lo, struct bio **req)
-{
-	struct bio *first;
-	struct bio **bio;
-	unsigned int count = 0;
-	unsigned int page_count = 0;
-	int rw;
-
-	spin_lock_irq(&lo->lo_lock);
-	first = lo->lo_bio;
-	if (unlikely(!first)) {
-		spin_unlock_irq(&lo->lo_lock);
-		return 0;
-	}
-
-	/* TODO: need to split the bio, too bad. */
-	LASSERT(first->bi_vcnt <= LLOOP_MAX_SEGMENTS);
-
-	rw = first->bi_rw;
-	bio = &lo->lo_bio;
-	while (*bio && (*bio)->bi_rw == rw) {
-		CDEBUG(D_INFO, "bio sector %llu size %u count %u vcnt%u\n",
-		       (unsigned long long)(*bio)->bi_iter.bi_sector,
-		       (*bio)->bi_iter.bi_size,
-		       page_count, (*bio)->bi_vcnt);
-		if (page_count + (*bio)->bi_vcnt > LLOOP_MAX_SEGMENTS)
-			break;
-
-		page_count += (*bio)->bi_vcnt;
-		count++;
-		bio = &(*bio)->bi_next;
-	}
-	if (*bio) {
-		/* Some of bios can't be mergeable. */
-		lo->lo_bio = *bio;
-		*bio = NULL;
-	} else {
-		/* Hit the end of queue */
-		lo->lo_biotail = NULL;
-		lo->lo_bio = NULL;
-	}
-	*req = first;
-	spin_unlock_irq(&lo->lo_lock);
-	return count;
-}
-
-static blk_qc_t loop_make_request(struct request_queue *q, struct bio *old_bio)
-{
-	struct lloop_device *lo = q->queuedata;
-	int rw = bio_rw(old_bio);
-	int inactive;
-
-	blk_queue_split(q, &old_bio, q->bio_split);
-
-	if (!lo)
-		goto err;
-
-	CDEBUG(D_INFO, "submit bio sector %llu size %u\n",
-	       (unsigned long long)old_bio->bi_iter.bi_sector,
-	       old_bio->bi_iter.bi_size);
-
-	spin_lock_irq(&lo->lo_lock);
-	inactive = lo->lo_state != LLOOP_BOUND;
-	spin_unlock_irq(&lo->lo_lock);
-	if (inactive)
-		goto err;
-
-	if (rw == WRITE) {
-		if (lo->lo_flags & LO_FLAGS_READ_ONLY)
-			goto err;
-	} else if (rw == READA) {
-		rw = READ;
-	} else if (rw != READ) {
-		CERROR("lloop: unknown command (%x)\n", rw);
-		goto err;
-	}
-	loop_add_bio(lo, old_bio);
-	return BLK_QC_T_NONE;
-err:
-	bio_io_error(old_bio);
-	return BLK_QC_T_NONE;
-}
-
-static inline void loop_handle_bio(struct lloop_device *lo, struct bio *bio)
-{
-	int ret;
-
-	ret = do_bio_lustrebacked(lo, bio);
-	while (bio) {
-		struct bio *tmp = bio->bi_next;
-
-		bio->bi_next = NULL;
-		bio->bi_error = ret;
-		bio_endio(bio);
-		bio = tmp;
-	}
-}
-
-static inline int loop_active(struct lloop_device *lo)
-{
-	return atomic_read(&lo->lo_pending) ||
-		(lo->lo_state == LLOOP_RUNDOWN);
-}
-
-/*
- * worker thread that handles reads/writes to file backed loop devices,
- * to avoid blocking in our make_request_fn.
- */
-static int loop_thread(void *data)
-{
-	struct lloop_device *lo = data;
-	struct bio *bio;
-	unsigned int count;
-	unsigned long times = 0;
-	unsigned long total_count = 0;
-
-	struct lu_env *env;
-	int refcheck;
-	int ret = 0;
-
-	set_user_nice(current, MIN_NICE);
-
-	lo->lo_state = LLOOP_BOUND;
-
-	env = cl_env_get(&refcheck);
-	if (IS_ERR(env)) {
-		ret = PTR_ERR(env);
-		goto out;
-	}
-
-	lo->lo_env = env;
-	memset(&lo->lo_pvec, 0, sizeof(lo->lo_pvec));
-	lo->lo_pvec.ldp_pages   = lo->lo_requests[0].lrd_pages;
-	lo->lo_pvec.ldp_offsets = lo->lo_requests[0].lrd_offsets;
-
-	/*
-	 * up sem, we are running
-	 */
-	up(&lo->lo_sem);
-
-	for (;;) {
-		wait_event(lo->lo_bh_wait, loop_active(lo));
-		if (!atomic_read(&lo->lo_pending)) {
-			int exiting = 0;
-
-			spin_lock_irq(&lo->lo_lock);
-			exiting = (lo->lo_state == LLOOP_RUNDOWN);
-			spin_unlock_irq(&lo->lo_lock);
-			if (exiting)
-				break;
-		}
-
-		bio = NULL;
-		count = loop_get_bio(lo, &bio);
-		if (!count) {
-			CWARN("lloop(minor: %d): missing bio\n", lo->lo_number);
-			continue;
-		}
-
-		total_count += count;
-		if (total_count < count) {     /* overflow */
-			total_count = count;
-			times = 1;
-		} else {
-			times++;
-		}
-		if ((times & 127) == 0) {
-			CDEBUG(D_INFO, "total: %lu, count: %lu, avg: %lu\n",
-			       total_count, times, total_count / times);
-		}
-
-		LASSERT(bio);
-		LASSERT(count <= atomic_read(&lo->lo_pending));
-		loop_handle_bio(lo, bio);
-		atomic_sub(count, &lo->lo_pending);
-	}
-	cl_env_put(env, &refcheck);
-
-out:
-	up(&lo->lo_sem);
-	return ret;
-}
-
-static int loop_set_fd(struct lloop_device *lo, struct file *unused,
-		       struct block_device *bdev, struct file *file)
-{
-	struct inode	 *inode;
-	struct address_space *mapping;
-	int		   lo_flags = 0;
-	int		   error;
-	loff_t		size;
-
-	if (!try_module_get(THIS_MODULE))
-		return -ENODEV;
-
-	error = -EBUSY;
-	if (lo->lo_state != LLOOP_UNBOUND)
-		goto out;
-
-	mapping = file->f_mapping;
-	inode = mapping->host;
-
-	error = -EINVAL;
-	if (!S_ISREG(inode->i_mode) || inode->i_sb->s_magic != LL_SUPER_MAGIC)
-		goto out;
-
-	if (!(file->f_mode & FMODE_WRITE))
-		lo_flags |= LO_FLAGS_READ_ONLY;
-
-	size = get_loop_size(lo, file);
-
-	if ((loff_t)(sector_t)size != size) {
-		error = -EFBIG;
-		goto out;
-	}
-
-	/* remove all pages in cache so as dirty pages not to be existent. */
-	truncate_inode_pages(mapping, 0);
-
-	set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0);
-
-	lo->lo_blocksize = PAGE_SIZE;
-	lo->lo_device = bdev;
-	lo->lo_flags = lo_flags;
-	lo->lo_backing_file = file;
-	lo->lo_sizelimit = 0;
-	lo->old_gfp_mask = mapping_gfp_mask(mapping);
-	mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
-
-	lo->lo_bio = lo->lo_biotail = NULL;
-
-	/*
-	 * set queue make_request_fn, and add limits based on lower level
-	 * device
-	 */
-	blk_queue_make_request(lo->lo_queue, loop_make_request);
-	lo->lo_queue->queuedata = lo;
-
-	/* queue parameters */
-	CLASSERT(PAGE_SIZE < (1 << (sizeof(unsigned short) * 8)));
-	blk_queue_logical_block_size(lo->lo_queue,
-				     (unsigned short)PAGE_SIZE);
-	blk_queue_max_hw_sectors(lo->lo_queue,
-				 LLOOP_MAX_SEGMENTS << (PAGE_SHIFT - 9));
-	blk_queue_max_segments(lo->lo_queue, LLOOP_MAX_SEGMENTS);
-
-	set_capacity(disks[lo->lo_number], size);
-	bd_set_size(bdev, size << 9);
-
-	set_blocksize(bdev, lo->lo_blocksize);
-
-	kthread_run(loop_thread, lo, "lloop%d", lo->lo_number);
-	down(&lo->lo_sem);
-	return 0;
-
-out:
-	/* This is safe: open() is still holding a reference. */
-	module_put(THIS_MODULE);
-	return error;
-}
-
-static int loop_clr_fd(struct lloop_device *lo, struct block_device *bdev,
-		       int count)
-{
-	struct file *filp = lo->lo_backing_file;
-	gfp_t gfp = lo->old_gfp_mask;
-
-	if (lo->lo_state != LLOOP_BOUND)
-		return -ENXIO;
-
-	if (lo->lo_refcnt > count)	/* we needed one fd for the ioctl */
-		return -EBUSY;
-
-	if (!filp)
-		return -EINVAL;
-
-	spin_lock_irq(&lo->lo_lock);
-	lo->lo_state = LLOOP_RUNDOWN;
-	spin_unlock_irq(&lo->lo_lock);
-	wake_up(&lo->lo_bh_wait);
-
-	down(&lo->lo_sem);
-	lo->lo_backing_file = NULL;
-	lo->lo_device = NULL;
-	lo->lo_offset = 0;
-	lo->lo_sizelimit = 0;
-	lo->lo_flags = 0;
-	invalidate_bdev(bdev);
-	set_capacity(disks[lo->lo_number], 0);
-	bd_set_size(bdev, 0);
-	mapping_set_gfp_mask(filp->f_mapping, gfp);
-	lo->lo_state = LLOOP_UNBOUND;
-	fput(filp);
-	/* This is safe: open() is still holding a reference. */
-	module_put(THIS_MODULE);
-	return 0;
-}
-
-static int lo_open(struct block_device *bdev, fmode_t mode)
-{
-	struct lloop_device *lo = bdev->bd_disk->private_data;
-
-	mutex_lock(&lo->lo_ctl_mutex);
-	lo->lo_refcnt++;
-	mutex_unlock(&lo->lo_ctl_mutex);
-
-	return 0;
-}
-
-static void lo_release(struct gendisk *disk, fmode_t mode)
-{
-	struct lloop_device *lo = disk->private_data;
-
-	mutex_lock(&lo->lo_ctl_mutex);
-	--lo->lo_refcnt;
-	mutex_unlock(&lo->lo_ctl_mutex);
-}
-
-/* lloop device node's ioctl function. */
-static int lo_ioctl(struct block_device *bdev, fmode_t mode,
-		    unsigned int cmd, unsigned long arg)
-{
-	struct lloop_device *lo = bdev->bd_disk->private_data;
-	struct inode *inode = NULL;
-	int err = 0;
-
-	mutex_lock(&lloop_mutex);
-	switch (cmd) {
-	case LL_IOC_LLOOP_DETACH: {
-		err = loop_clr_fd(lo, bdev, 2);
-		if (err == 0)
-			blkdev_put(bdev, 0); /* grabbed in LLOOP_ATTACH */
-		break;
-	}
-
-	case LL_IOC_LLOOP_INFO: {
-		struct lu_fid fid;
-
-		if (!lo->lo_backing_file) {
-			err = -ENOENT;
-			break;
-		}
-		if (!inode)
-			inode = file_inode(lo->lo_backing_file);
-		if (lo->lo_state == LLOOP_BOUND)
-			fid = ll_i2info(inode)->lli_fid;
-		else
-			fid_zero(&fid);
-
-		if (copy_to_user((void __user *)arg, &fid, sizeof(fid)))
-			err = -EFAULT;
-		break;
-	}
-
-	default:
-		err = -EINVAL;
-		break;
-	}
-	mutex_unlock(&lloop_mutex);
-
-	return err;
-}
-
-static struct block_device_operations lo_fops = {
-	.owner =	THIS_MODULE,
-	.open =	 lo_open,
-	.release =      lo_release,
-	.ioctl =	lo_ioctl,
-};
-
-/* dynamic iocontrol callback.
- * This callback is registered in lloop_init and will be called by
- * ll_iocontrol_call.
- *
- * This is a llite regular file ioctl function. It takes the responsibility
- * of attaching or detaching a file by a lloop's device number.
- */
-static enum llioc_iter lloop_ioctl(struct inode *unused, struct file *file,
-				   unsigned int cmd, unsigned long arg,
-				   void *magic, int *rcp)
-{
-	struct lloop_device *lo = NULL;
-	struct block_device *bdev = NULL;
-	int err = 0;
-	dev_t dev;
-
-	if (magic != ll_iocontrol_magic)
-		return LLIOC_CONT;
-
-	if (!disks) {
-		err = -ENODEV;
-		goto out1;
-	}
-
-	CWARN("Enter llop_ioctl\n");
-
-	mutex_lock(&lloop_mutex);
-	switch (cmd) {
-	case LL_IOC_LLOOP_ATTACH: {
-		struct lloop_device *lo_free = NULL;
-		int i;
-
-		for (i = 0; i < max_loop; i++, lo = NULL) {
-			lo = &loop_dev[i];
-			if (lo->lo_state == LLOOP_UNBOUND) {
-				if (!lo_free)
-					lo_free = lo;
-				continue;
-			}
-			if (file_inode(lo->lo_backing_file) == file_inode(file))
-				break;
-		}
-		if (lo || !lo_free) {
-			err = -EBUSY;
-			goto out;
-		}
-
-		lo = lo_free;
-		dev = MKDEV(lloop_major, lo->lo_number);
-
-		/* quit if the used pointer is writable */
-		if (put_user((long)old_encode_dev(dev), (long __user *)arg)) {
-			err = -EFAULT;
-			goto out;
-		}
-
-		bdev = blkdev_get_by_dev(dev, file->f_mode, NULL);
-		if (IS_ERR(bdev)) {
-			err = PTR_ERR(bdev);
-			goto out;
-		}
-
-		get_file(file);
-		err = loop_set_fd(lo, NULL, bdev, file);
-		if (err) {
-			fput(file);
-			blkdev_put(bdev, 0);
-		}
-
-		break;
-	}
-
-	case LL_IOC_LLOOP_DETACH_BYDEV: {
-		int minor;
-
-		dev = old_decode_dev(arg);
-		if (MAJOR(dev) != lloop_major) {
-			err = -EINVAL;
-			goto out;
-		}
-
-		minor = MINOR(dev);
-		if (minor > max_loop - 1) {
-			err = -EINVAL;
-			goto out;
-		}
-
-		lo = &loop_dev[minor];
-		if (lo->lo_state != LLOOP_BOUND) {
-			err = -EINVAL;
-			goto out;
-		}
-
-		bdev = lo->lo_device;
-		err = loop_clr_fd(lo, bdev, 1);
-		if (err == 0)
-			blkdev_put(bdev, 0); /* grabbed in LLOOP_ATTACH */
-
-		break;
-	}
-
-	default:
-		err = -EINVAL;
-		break;
-	}
-
-out:
-	mutex_unlock(&lloop_mutex);
-out1:
-	if (rcp)
-		*rcp = err;
-	return LLIOC_STOP;
-}
-
-static int __init lloop_init(void)
-{
-	int	i;
-	unsigned int cmdlist[] = {
-		LL_IOC_LLOOP_ATTACH,
-		LL_IOC_LLOOP_DETACH_BYDEV,
-	};
-
-	if (max_loop < 1 || max_loop > 256) {
-		max_loop = MAX_LOOP_DEFAULT;
-		CWARN("lloop: invalid max_loop (must be between 1 and 256), using default (%u)\n",
-		      max_loop);
-	}
-
-	lloop_major = register_blkdev(0, "lloop");
-	if (lloop_major < 0)
-		return -EIO;
-
-	CDEBUG(D_CONFIG, "registered lloop major %d with %u minors\n",
-	       lloop_major, max_loop);
-
-	ll_iocontrol_magic = ll_iocontrol_register(lloop_ioctl, 2, cmdlist);
-	if (!ll_iocontrol_magic)
-		goto out_mem1;
-
-	loop_dev = kcalloc(max_loop, sizeof(*loop_dev), GFP_KERNEL);
-	if (!loop_dev)
-		goto out_mem1;
-
-	disks = kcalloc(max_loop, sizeof(*disks), GFP_KERNEL);
-	if (!disks)
-		goto out_mem2;
-
-	for (i = 0; i < max_loop; i++) {
-		disks[i] = alloc_disk(1);
-		if (!disks[i])
-			goto out_mem3;
-	}
-
-	mutex_init(&lloop_mutex);
-
-	for (i = 0; i < max_loop; i++) {
-		struct lloop_device *lo = &loop_dev[i];
-		struct gendisk *disk = disks[i];
-
-		lo->lo_queue = blk_alloc_queue(GFP_KERNEL);
-		if (!lo->lo_queue)
-			goto out_mem4;
-
-		mutex_init(&lo->lo_ctl_mutex);
-		sema_init(&lo->lo_sem, 0);
-		init_waitqueue_head(&lo->lo_bh_wait);
-		lo->lo_number = i;
-		spin_lock_init(&lo->lo_lock);
-		disk->major = lloop_major;
-		disk->first_minor = i;
-		disk->fops = &lo_fops;
-		sprintf(disk->disk_name, "lloop%d", i);
-		disk->private_data = lo;
-		disk->queue = lo->lo_queue;
-	}
-
-	/* We cannot fail after we call this, so another loop!*/
-	for (i = 0; i < max_loop; i++)
-		add_disk(disks[i]);
-	return 0;
-
-out_mem4:
-	while (i--)
-		blk_cleanup_queue(loop_dev[i].lo_queue);
-	i = max_loop;
-out_mem3:
-	while (i--)
-		put_disk(disks[i]);
-	kfree(disks);
-out_mem2:
-	kfree(loop_dev);
-out_mem1:
-	unregister_blkdev(lloop_major, "lloop");
-	ll_iocontrol_unregister(ll_iocontrol_magic);
-	CERROR("lloop: ran out of memory\n");
-	return -ENOMEM;
-}
-
-static void lloop_exit(void)
-{
-	int i;
-
-	ll_iocontrol_unregister(ll_iocontrol_magic);
-	for (i = 0; i < max_loop; i++) {
-		del_gendisk(disks[i]);
-		blk_cleanup_queue(loop_dev[i].lo_queue);
-		put_disk(disks[i]);
-	}
-
-	unregister_blkdev(lloop_major, "lloop");
-
-	kfree(disks);
-	kfree(loop_dev);
-}
-
-module_param(max_loop, int, 0444);
-MODULE_PARM_DESC(max_loop, "maximum of lloop_device");
-MODULE_AUTHOR("OpenSFS, Inc. <http://www.lustre.org/>");
-MODULE_DESCRIPTION("Lustre virtual block device");
-MODULE_VERSION(LUSTRE_VERSION_STRING);
-MODULE_LICENSE("GPL");
-
-module_init(lloop_init);
-module_exit(lloop_exit);
-- 
1.7.1

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