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, 844 insertions, 0 deletions

diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
new file mode 100644
index 000000000..35e103f0c
--- /dev/null
+++ b/drivers/md/raid0.c
@@ -0,0 +1,844 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+   raid0.c : Multiple Devices driver for Linux
+	     Copyright (C) 1994-96 Marc ZYNGIER
+	     <zyngier@ufr-info-p7.ibp.fr> or
+	     <maz@gloups.fdn.fr>
+	     Copyright (C) 1999, 2000 Ingo Molnar, Red Hat
+
+   RAID-0 management functions.
+
+*/
+
+#include <linux/blkdev.h>
+#include <linux/seq_file.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/string_choices.h>
+#include <trace/events/block.h>
+#include "md.h"
+#include "raid0.h"
+#include "raid5.h"
+
+static int default_layout = 0;
+module_param(default_layout, int, 0644);
+
+#define UNSUPPORTED_MDDEV_FLAGS		\
+	((1L << MD_HAS_JOURNAL) |	\
+	 (1L << MD_JOURNAL_CLEAN) |	\
+	 (1L << MD_FAILFAST_SUPPORTED) |\
+	 (1L << MD_HAS_PPL) |		\
+	 (1L << MD_HAS_MULTIPLE_PPLS) |	\
+	 (1L << MD_FAILLAST_DEV) |	\
+	 (1L << MD_SERIALIZE_POLICY))
+
+/*
+ * inform the user of the raid configuration
+*/
+static void dump_zones(struct mddev *mddev)
+{
+	int j, k;
+	sector_t zone_size = 0;
+	sector_t zone_start = 0;
+	struct r0conf *conf = mddev->private;
+	int raid_disks = conf->strip_zone[0].nb_dev;
+	pr_debug("md: RAID0 configuration for %s - %d zone%s\n",
+		 mdname(mddev),
+		 conf->nr_strip_zones, str_plural(conf->nr_strip_zones));
+	for (j = 0; j < conf->nr_strip_zones; j++) {
+		char line[200];
+		int len = 0;
+
+		for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
+			len += scnprintf(line+len, 200-len, "%s%pg", k?"/":"",
+				conf->devlist[j * raid_disks + k]->bdev);
+		pr_debug("md: zone%d=[%s]\n", j, line);
+
+		zone_size  = conf->strip_zone[j].zone_end - zone_start;
+		pr_debug("      zone-offset=%10lluKB, device-offset=%10lluKB, size=%10lluKB\n",
+			(unsigned long long)zone_start>>1,
+			(unsigned long long)conf->strip_zone[j].dev_start>>1,
+			(unsigned long long)zone_size>>1);
+		zone_start = conf->strip_zone[j].zone_end;
+	}
+}
+
+static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
+{
+	int i, c, err;
+	sector_t curr_zone_end, sectors;
+	struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev;
+	struct strip_zone *zone;
+	int cnt;
+	struct r0conf *conf = kzalloc_obj(*conf);
+	unsigned int blksize = 512;
+
+	if (!mddev_is_dm(mddev))
+		blksize = queue_logical_block_size(mddev->gendisk->queue);
+
+	*private_conf = ERR_PTR(-ENOMEM);
+	if (!conf)
+		return -ENOMEM;
+	rdev_for_each(rdev1, mddev) {
+		pr_debug("md/raid0:%s: looking at %pg\n",
+			 mdname(mddev),
+			 rdev1->bdev);
+		c = 0;
+
+		/* round size to chunk_size */
+		sectors = rdev1->sectors;
+		sector_div(sectors, mddev->chunk_sectors);
+		rdev1->sectors = sectors * mddev->chunk_sectors;
+
+		if (mddev_is_dm(mddev))
+			blksize = max(blksize, queue_logical_block_size(
+				      rdev1->bdev->bd_disk->queue));
+
+		rdev_for_each(rdev2, mddev) {
+			pr_debug("md/raid0:%s:   comparing %pg(%llu)"
+				 " with %pg(%llu)\n",
+				 mdname(mddev),
+				 rdev1->bdev,
+				 (unsigned long long)rdev1->sectors,
+				 rdev2->bdev,
+				 (unsigned long long)rdev2->sectors);
+			if (rdev2 == rdev1) {
+				pr_debug("md/raid0:%s:   END\n",
+					 mdname(mddev));
+				break;
+			}
+			if (rdev2->sectors == rdev1->sectors) {
+				/*
+				 * Not unique, don't count it as a new
+				 * group
+				 */
+				pr_debug("md/raid0:%s:   EQUAL\n",
+					 mdname(mddev));
+				c = 1;
+				break;
+			}
+			pr_debug("md/raid0:%s:   NOT EQUAL\n",
+				 mdname(mddev));
+		}
+		if (!c) {
+			pr_debug("md/raid0:%s:   ==> UNIQUE\n",
+				 mdname(mddev));
+			conf->nr_strip_zones++;
+			pr_debug("md/raid0:%s: %d zones\n",
+				 mdname(mddev), conf->nr_strip_zones);
+		}
+	}
+	pr_debug("md/raid0:%s: FINAL %d zones\n",
+		 mdname(mddev), conf->nr_strip_zones);
+
+	/*
+	 * now since we have the hard sector sizes, we can make sure
+	 * chunk size is a multiple of that sector size
+	 */
+	if ((mddev->chunk_sectors << 9) % blksize) {
+		pr_warn("md/raid0:%s: chunk_size of %d not multiple of block size %d\n",
+			mdname(mddev),
+			mddev->chunk_sectors << 9, blksize);
+		err = -EINVAL;
+		goto abort;
+	}
+
+	err = -ENOMEM;
+	conf->strip_zone = kvzalloc_objs(struct strip_zone, conf->nr_strip_zones);
+	if (!conf->strip_zone)
+		goto abort;
+	conf->devlist = kvzalloc(array3_size(sizeof(struct md_rdev *),
+					     conf->nr_strip_zones,
+					     mddev->raid_disks),
+				 GFP_KERNEL);
+	if (!conf->devlist)
+		goto abort;
+
+	/* The first zone must contain all devices, so here we check that
+	 * there is a proper alignment of slots to devices and find them all
+	 */
+	zone = &conf->strip_zone[0];
+	cnt = 0;
+	smallest = NULL;
+	dev = conf->devlist;
+	err = -EINVAL;
+	rdev_for_each(rdev1, mddev) {
+		int j = rdev1->raid_disk;
+
+		if (mddev->level == 10) {
+			/* taking over a raid10-n2 array */
+			j /= 2;
+			rdev1->new_raid_disk = j;
+		}
+
+		if (mddev->level == 1) {
+			/* taiking over a raid1 array-
+			 * we have only one active disk
+			 */
+			j = 0;
+			rdev1->new_raid_disk = j;
+		}
+
+		if (j < 0) {
+			pr_warn("md/raid0:%s: remove inactive devices before converting to RAID0\n",
+				mdname(mddev));
+			goto abort;
+		}
+		if (j >= mddev->raid_disks) {
+			pr_warn("md/raid0:%s: bad disk number %d - aborting!\n",
+				mdname(mddev), j);
+			goto abort;
+		}
+		if (dev[j]) {
+			pr_warn("md/raid0:%s: multiple devices for %d - aborting!\n",
+				mdname(mddev), j);
+			goto abort;
+		}
+		dev[j] = rdev1;
+
+		if (!smallest || (rdev1->sectors < smallest->sectors))
+			smallest = rdev1;
+		cnt++;
+	}
+	if (cnt != mddev->raid_disks) {
+		pr_warn("md/raid0:%s: too few disks (%d of %d) - aborting!\n",
+			mdname(mddev), cnt, mddev->raid_disks);
+		goto abort;
+	}
+	zone->nb_dev = cnt;
+	zone->zone_end = smallest->sectors * cnt;
+
+	curr_zone_end = zone->zone_end;
+
+	/* now do the other zones */
+	for (i = 1; i < conf->nr_strip_zones; i++)
+	{
+		int j;
+
+		zone = conf->strip_zone + i;
+		dev = conf->devlist + i * mddev->raid_disks;
+
+		pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i);
+		zone->dev_start = smallest->sectors;
+		smallest = NULL;
+		c = 0;
+
+		for (j=0; j<cnt; j++) {
+			rdev = conf->devlist[j];
+			if (rdev->sectors <= zone->dev_start) {
+				pr_debug("md/raid0:%s: checking %pg ... nope\n",
+					 mdname(mddev),
+					 rdev->bdev);
+				continue;
+			}
+			pr_debug("md/raid0:%s: checking %pg ..."
+				 " contained as device %d\n",
+				 mdname(mddev),
+				 rdev->bdev, c);
+			dev[c] = rdev;
+			c++;
+			if (!smallest || rdev->sectors < smallest->sectors) {
+				smallest = rdev;
+				pr_debug("md/raid0:%s:  (%llu) is smallest!.\n",
+					 mdname(mddev),
+					 (unsigned long long)rdev->sectors);
+			}
+		}
+
+		zone->nb_dev = c;
+		sectors = (smallest->sectors - zone->dev_start) * c;
+		pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n",
+			 mdname(mddev),
+			 zone->nb_dev, (unsigned long long)sectors);
+
+		curr_zone_end += sectors;
+		zone->zone_end = curr_zone_end;
+
+		pr_debug("md/raid0:%s: current zone start: %llu\n",
+			 mdname(mddev),
+			 (unsigned long long)smallest->sectors);
+	}
+
+	if (conf->nr_strip_zones == 1 || conf->strip_zone[1].nb_dev == 1) {
+		conf->layout = RAID0_ORIG_LAYOUT;
+	} else if (mddev->layout == RAID0_ORIG_LAYOUT ||
+		   mddev->layout == RAID0_ALT_MULTIZONE_LAYOUT) {
+		conf->layout = mddev->layout;
+	} else if (default_layout == RAID0_ORIG_LAYOUT ||
+		   default_layout == RAID0_ALT_MULTIZONE_LAYOUT) {
+		conf->layout = default_layout;
+	} else {
+		pr_err("md/raid0:%s: cannot assemble multi-zone RAID0 with default_layout setting\n",
+		       mdname(mddev));
+		pr_err("md/raid0: please set raid0.default_layout to 1 or 2\n");
+		err = -EOPNOTSUPP;
+		goto abort;
+	}
+
+	if (conf->layout == RAID0_ORIG_LAYOUT) {
+		for (i = 1; i < conf->nr_strip_zones; i++) {
+			sector_t first_sector = conf->strip_zone[i-1].zone_end;
+
+			sector_div(first_sector, mddev->chunk_sectors);
+			zone = conf->strip_zone + i;
+			/* disk_shift is first disk index used in the zone */
+			zone->disk_shift = sector_div(first_sector,
+						      zone->nb_dev);
+		}
+	}
+
+	pr_debug("md/raid0:%s: done.\n", mdname(mddev));
+	*private_conf = conf;
+
+	return 0;
+abort:
+	kvfree(conf->strip_zone);
+	kvfree(conf->devlist);
+	kfree(conf);
+	*private_conf = ERR_PTR(err);
+	return err;
+}
+
+/* Find the zone which holds a particular offset
+ * Update *sectorp to be an offset in that zone
+ */
+static struct strip_zone *find_zone(struct r0conf *conf,
+				    sector_t *sectorp)
+{
+	int i;
+	struct strip_zone *z = conf->strip_zone;
+	sector_t sector = *sectorp;
+
+	for (i = 0; i < conf->nr_strip_zones; i++)
+		if (sector < z[i].zone_end) {
+			if (i)
+				*sectorp = sector - z[i-1].zone_end;
+			return z + i;
+		}
+	BUG();
+}
+
+/*
+ * remaps the bio to the target device. we separate two flows.
+ * power 2 flow and a general flow for the sake of performance
+*/
+static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone,
+				sector_t sector, sector_t *sector_offset)
+{
+	unsigned int sect_in_chunk;
+	sector_t chunk;
+	struct r0conf *conf = mddev->private;
+	int raid_disks = conf->strip_zone[0].nb_dev;
+	unsigned int chunk_sects = mddev->chunk_sectors;
+
+	if (is_power_of_2(chunk_sects)) {
+		int chunksect_bits = ffz(~chunk_sects);
+		/* find the sector offset inside the chunk */
+		sect_in_chunk  = sector & (chunk_sects - 1);
+		sector >>= chunksect_bits;
+		/* chunk in zone */
+		chunk = *sector_offset;
+		/* quotient is the chunk in real device*/
+		sector_div(chunk, zone->nb_dev << chunksect_bits);
+	} else{
+		sect_in_chunk = sector_div(sector, chunk_sects);
+		chunk = *sector_offset;
+		sector_div(chunk, chunk_sects * zone->nb_dev);
+	}
+	/*
+	*  position the bio over the real device
+	*  real sector = chunk in device + starting of zone
+	*	+ the position in the chunk
+	*/
+	*sector_offset = (chunk * chunk_sects) + sect_in_chunk;
+	return conf->devlist[(zone - conf->strip_zone)*raid_disks
+			     + sector_div(sector, zone->nb_dev)];
+}
+
+static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks)
+{
+	sector_t array_sectors = 0;
+	struct md_rdev *rdev;
+
+	WARN_ONCE(sectors || raid_disks,
+		  "%s does not support generic reshape\n", __func__);
+
+	rdev_for_each(rdev, mddev)
+		array_sectors += (rdev->sectors &
+				  ~(sector_t)(mddev->chunk_sectors-1));
+
+	return array_sectors;
+}
+
+static void raid0_free(struct mddev *mddev, void *priv)
+{
+	struct r0conf *conf = priv;
+
+	kvfree(conf->strip_zone);
+	kvfree(conf->devlist);
+	kfree(conf);
+}
+
+static int raid0_set_limits(struct mddev *mddev)
+{
+	struct queue_limits lim;
+	int err;
+
+	md_init_stacking_limits(&lim);
+	lim.features |= BLK_FEAT_NOWAIT;
+	lim.max_hw_sectors = mddev->chunk_sectors;
+	lim.max_write_zeroes_sectors = mddev->chunk_sectors;
+	lim.max_hw_wzeroes_unmap_sectors = mddev->chunk_sectors;
+	lim.logical_block_size = mddev->logical_block_size;
+	lim.io_min = mddev->chunk_sectors << 9;
+	lim.io_opt = lim.io_min * mddev->raid_disks;
+	lim.chunk_sectors = mddev->chunk_sectors;
+	lim.features |= BLK_FEAT_ATOMIC_WRITES;
+	lim.features |= BLK_FEAT_PCI_P2PDMA;
+	err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY);
+	if (err)
+		return err;
+	return queue_limits_set(mddev->gendisk->queue, &lim);
+}
+
+static int raid0_run(struct mddev *mddev)
+{
+	struct r0conf *conf;
+	int ret;
+
+	if (mddev->chunk_sectors == 0) {
+		pr_warn("md/raid0:%s: chunk size must be set.\n", mdname(mddev));
+		return -EINVAL;
+	}
+	if (md_check_no_bitmap(mddev))
+		return -EINVAL;
+
+	if (!mddev_is_dm(mddev)) {
+		ret = raid0_set_limits(mddev);
+		if (ret)
+			return ret;
+	}
+
+	/* if private is not null, we are here after takeover */
+	if (mddev->private == NULL) {
+		ret = create_strip_zones(mddev, &conf);
+		if (ret < 0)
+			return ret;
+		mddev->private = conf;
+	}
+	conf = mddev->private;
+
+	/* calculate array device size */
+	md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));
+
+	pr_debug("md/raid0:%s: md_size is %llu sectors.\n",
+		 mdname(mddev),
+		 (unsigned long long)mddev->array_sectors);
+
+	dump_zones(mddev);
+
+	return md_integrity_register(mddev);
+}
+
+/*
+ * Convert disk_index to the disk order in which it is read/written.
+ *  For example, if we have 4 disks, they are numbered 0,1,2,3. If we
+ *  write the disks starting at disk 3, then the read/write order would
+ *  be disk 3, then 0, then 1, and then disk 2 and we want map_disk_shift()
+ *  to map the disks as follows 0,1,2,3 => 1,2,3,0. So disk 0 would map
+ *  to 1, 1 to 2, 2 to 3, and 3 to 0. That way we can compare disks in
+ *  that 'output' space to understand the read/write disk ordering.
+ */
+static int map_disk_shift(int disk_index, int num_disks, int disk_shift)
+{
+	return ((disk_index + num_disks - disk_shift) % num_disks);
+}
+
+static void raid0_handle_discard(struct mddev *mddev, struct bio *bio)
+{
+	struct r0conf *conf = mddev->private;
+	struct strip_zone *zone;
+	sector_t start = bio->bi_iter.bi_sector;
+	sector_t end;
+	unsigned int stripe_size;
+	sector_t first_stripe_index, last_stripe_index;
+	sector_t start_disk_offset;
+	unsigned int start_disk_index;
+	sector_t end_disk_offset;
+	unsigned int end_disk_index;
+	unsigned int disk;
+	sector_t orig_start, orig_end;
+
+	orig_start = start;
+	zone = find_zone(conf, &start);
+
+	if (bio_end_sector(bio) > zone->zone_end) {
+		bio = bio_submit_split_bioset(bio,
+				zone->zone_end - bio->bi_iter.bi_sector,
+				&mddev->bio_set);
+		if (!bio)
+			return;
+
+		end = zone->zone_end;
+	} else {
+		end = bio_end_sector(bio);
+	}
+
+	orig_end = end;
+	if (zone != conf->strip_zone)
+		end = end - zone[-1].zone_end;
+
+	/* Now start and end is the offset in zone */
+	stripe_size = zone->nb_dev * mddev->chunk_sectors;
+
+	first_stripe_index = start;
+	sector_div(first_stripe_index, stripe_size);
+	last_stripe_index = end;
+	sector_div(last_stripe_index, stripe_size);
+
+	/* In the first zone the original and alternate layouts are the same */
+	if ((conf->layout == RAID0_ORIG_LAYOUT) && (zone != conf->strip_zone)) {
+		sector_div(orig_start, mddev->chunk_sectors);
+		start_disk_index = sector_div(orig_start, zone->nb_dev);
+		start_disk_index = map_disk_shift(start_disk_index,
+						  zone->nb_dev,
+						  zone->disk_shift);
+		sector_div(orig_end, mddev->chunk_sectors);
+		end_disk_index = sector_div(orig_end, zone->nb_dev);
+		end_disk_index = map_disk_shift(end_disk_index,
+						zone->nb_dev, zone->disk_shift);
+	} else {
+		start_disk_index = (int)(start - first_stripe_index * stripe_size) /
+			mddev->chunk_sectors;
+		end_disk_index = (int)(end - last_stripe_index * stripe_size) /
+			mddev->chunk_sectors;
+	}
+	start_disk_offset = ((int)(start - first_stripe_index * stripe_size) %
+		mddev->chunk_sectors) +
+		first_stripe_index * mddev->chunk_sectors;
+	end_disk_offset = ((int)(end - last_stripe_index * stripe_size) %
+		mddev->chunk_sectors) +
+		last_stripe_index * mddev->chunk_sectors;
+
+	for (disk = 0; disk < zone->nb_dev; disk++) {
+		sector_t dev_start, dev_end;
+		struct md_rdev *rdev;
+		int compare_disk;
+
+		compare_disk = map_disk_shift(disk, zone->nb_dev,
+					      zone->disk_shift);
+
+		if (compare_disk < start_disk_index)
+			dev_start = (first_stripe_index + 1) *
+				mddev->chunk_sectors;
+		else if (compare_disk > start_disk_index)
+			dev_start = first_stripe_index * mddev->chunk_sectors;
+		else
+			dev_start = start_disk_offset;
+
+		if (compare_disk < end_disk_index)
+			dev_end = (last_stripe_index + 1) * mddev->chunk_sectors;
+		else if (compare_disk > end_disk_index)
+			dev_end = last_stripe_index * mddev->chunk_sectors;
+		else
+			dev_end = end_disk_offset;
+
+		if (dev_end <= dev_start)
+			continue;
+
+		rdev = conf->devlist[(zone - conf->strip_zone) *
+			conf->strip_zone[0].nb_dev + disk];
+		md_submit_discard_bio(mddev, rdev, bio,
+			dev_start + zone->dev_start + rdev->data_offset,
+			dev_end - dev_start);
+	}
+	bio_endio(bio);
+}
+
+static void raid0_map_submit_bio(struct mddev *mddev, struct bio *bio)
+{
+	struct r0conf *conf = mddev->private;
+	struct strip_zone *zone;
+	struct md_rdev *tmp_dev;
+	sector_t bio_sector = bio->bi_iter.bi_sector;
+	sector_t sector = bio_sector;
+
+	md_account_bio(mddev, &bio);
+
+	zone = find_zone(mddev->private, &sector);
+	switch (conf->layout) {
+	case RAID0_ORIG_LAYOUT:
+		tmp_dev = map_sector(mddev, zone, bio_sector, &sector);
+		break;
+	case RAID0_ALT_MULTIZONE_LAYOUT:
+		tmp_dev = map_sector(mddev, zone, sector, &sector);
+		break;
+	default:
+		WARN(1, "md/raid0:%s: Invalid layout\n", mdname(mddev));
+		bio_io_error(bio);
+		return;
+	}
+
+	if (unlikely(is_rdev_broken(tmp_dev))) {
+		bio_io_error(bio);
+		md_error(mddev, tmp_dev);
+		return;
+	}
+
+	bio_set_dev(bio, tmp_dev->bdev);
+	bio->bi_iter.bi_sector = sector + zone->dev_start +
+		tmp_dev->data_offset;
+	mddev_trace_remap(mddev, bio, bio_sector);
+	mddev_check_write_zeroes(mddev, bio);
+	submit_bio_noacct(bio);
+}
+
+static bool raid0_make_request(struct mddev *mddev, struct bio *bio)
+{
+	sector_t sector;
+	unsigned chunk_sects;
+	unsigned sectors;
+
+	if (unlikely(bio->bi_opf & REQ_PREFLUSH)
+	    && md_flush_request(mddev, bio))
+		return true;
+
+	if (unlikely((bio_op(bio) == REQ_OP_DISCARD))) {
+		raid0_handle_discard(mddev, bio);
+		return true;
+	}
+
+	sector = bio->bi_iter.bi_sector;
+	chunk_sects = mddev->chunk_sectors;
+
+	sectors = chunk_sects -
+		(likely(is_power_of_2(chunk_sects))
+		 ? (sector & (chunk_sects-1))
+		 : sector_div(sector, chunk_sects));
+
+	if (sectors < bio_sectors(bio)) {
+		bio = bio_submit_split_bioset(bio, sectors,
+					      &mddev->bio_set);
+		if (!bio)
+			return true;
+	}
+
+	raid0_map_submit_bio(mddev, bio);
+	return true;
+}
+
+static void raid0_status(struct seq_file *seq, struct mddev *mddev)
+{
+	seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2);
+	return;
+}
+
+static void raid0_error(struct mddev *mddev, struct md_rdev *rdev)
+{
+	if (!test_and_set_bit(MD_BROKEN, &mddev->flags)) {
+		char *md_name = mdname(mddev);
+
+		pr_crit("md/raid0%s: Disk failure on %pg detected, failing array.\n",
+			md_name, rdev->bdev);
+	}
+}
+
+static void *raid0_takeover_raid45(struct mddev *mddev)
+{
+	struct md_rdev *rdev;
+	struct r0conf *priv_conf;
+
+	if (mddev->degraded != 1) {
+		pr_warn("md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
+			mdname(mddev),
+			mddev->degraded);
+		return ERR_PTR(-EINVAL);
+	}
+
+	rdev_for_each(rdev, mddev) {
+		/* check slot number for a disk */
+		if (rdev->raid_disk == mddev->raid_disks-1) {
+			pr_warn("md/raid0:%s: raid5 must have missing parity disk!\n",
+				mdname(mddev));
+			return ERR_PTR(-EINVAL);
+		}
+		rdev->sectors = mddev->dev_sectors;
+	}
+
+	/* Set new parameters */
+	mddev->new_level = 0;
+	mddev->new_layout = 0;
+	mddev->new_chunk_sectors = mddev->chunk_sectors;
+	mddev->raid_disks--;
+	mddev->delta_disks = -1;
+	/* make sure it will be not marked as dirty */
+	mddev->resync_offset = MaxSector;
+	mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
+
+	create_strip_zones(mddev, &priv_conf);
+
+	return priv_conf;
+}
+
+static void *raid0_takeover_raid10(struct mddev *mddev)
+{
+	struct r0conf *priv_conf;
+
+	/* Check layout:
+	 *  - far_copies must be 1
+	 *  - near_copies must be 2
+	 *  - disks number must be even
+	 *  - all mirrors must be already degraded
+	 */
+	if (mddev->layout != ((1 << 8) + 2)) {
+		pr_warn("md/raid0:%s:: Raid0 cannot takeover layout: 0x%x\n",
+			mdname(mddev),
+			mddev->layout);
+		return ERR_PTR(-EINVAL);
+	}
+	if (mddev->raid_disks & 1) {
+		pr_warn("md/raid0:%s: Raid0 cannot takeover Raid10 with odd disk number.\n",
+			mdname(mddev));
+		return ERR_PTR(-EINVAL);
+	}
+	if (mddev->degraded != (mddev->raid_disks>>1)) {
+		pr_warn("md/raid0:%s: All mirrors must be already degraded!\n",
+			mdname(mddev));
+		return ERR_PTR(-EINVAL);
+	}
+
+	/* Set new parameters */
+	mddev->new_level = 0;
+	mddev->new_layout = 0;
+	mddev->new_chunk_sectors = mddev->chunk_sectors;
+	mddev->delta_disks = - mddev->raid_disks / 2;
+	mddev->raid_disks += mddev->delta_disks;
+	mddev->degraded = 0;
+	/* make sure it will be not marked as dirty */
+	mddev->resync_offset = MaxSector;
+	mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
+
+	create_strip_zones(mddev, &priv_conf);
+	return priv_conf;
+}
+
+static void *raid0_takeover_raid1(struct mddev *mddev)
+{
+	struct r0conf *priv_conf;
+	int chunksect;
+
+	/* Check layout:
+	 *  - (N - 1) mirror drives must be already faulty
+	 */
+	if ((mddev->raid_disks - 1) != mddev->degraded) {
+		pr_err("md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n",
+		       mdname(mddev));
+		return ERR_PTR(-EINVAL);
+	}
+
+	/*
+	 * a raid1 doesn't have the notion of chunk size, so
+	 * figure out the largest suitable size we can use.
+	 */
+	chunksect = 64 * 2; /* 64K by default */
+
+	/* The array must be an exact multiple of chunksize */
+	while (chunksect && (mddev->array_sectors & (chunksect - 1)))
+		chunksect >>= 1;
+
+	if ((chunksect << 9) < PAGE_SIZE)
+		/* array size does not allow a suitable chunk size */
+		return ERR_PTR(-EINVAL);
+
+	/* Set new parameters */
+	mddev->new_level = 0;
+	mddev->new_layout = 0;
+	mddev->new_chunk_sectors = chunksect;
+	mddev->chunk_sectors = chunksect;
+	mddev->delta_disks = 1 - mddev->raid_disks;
+	mddev->raid_disks = 1;
+	/* make sure it will be not marked as dirty */
+	mddev->resync_offset = MaxSector;
+	mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
+
+	create_strip_zones(mddev, &priv_conf);
+	return priv_conf;
+}
+
+static void *raid0_takeover(struct mddev *mddev)
+{
+	/* raid0 can take over:
+	 *  raid4 - if all data disks are active.
+	 *  raid5 - providing it is Raid4 layout and one disk is faulty
+	 *  raid10 - assuming we have all necessary active disks
+	 *  raid1 - with (N -1) mirror drives faulty
+	 */
+
+	if (mddev->bitmap) {
+		pr_warn("md/raid0: %s: cannot takeover array with bitmap\n",
+			mdname(mddev));
+		return ERR_PTR(-EBUSY);
+	}
+	if (mddev->level == 4)
+		return raid0_takeover_raid45(mddev);
+
+	if (mddev->level == 5) {
+		if (mddev->layout == ALGORITHM_PARITY_N)
+			return raid0_takeover_raid45(mddev);
+
+		pr_warn("md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
+			mdname(mddev), ALGORITHM_PARITY_N);
+	}
+
+	if (mddev->level == 10)
+		return raid0_takeover_raid10(mddev);
+
+	if (mddev->level == 1)
+		return raid0_takeover_raid1(mddev);
+
+	pr_warn("Takeover from raid%i to raid0 not supported\n",
+		mddev->level);
+
+	return ERR_PTR(-EINVAL);
+}
+
+static void raid0_quiesce(struct mddev *mddev, int quiesce)
+{
+}
+
+static struct md_personality raid0_personality=
+{
+	.head = {
+		.type	= MD_PERSONALITY,
+		.id	= ID_RAID0,
+		.name	= "raid0",
+		.owner	= THIS_MODULE,
+	},
+
+	.make_request	= raid0_make_request,
+	.run		= raid0_run,
+	.free		= raid0_free,
+	.status		= raid0_status,
+	.size		= raid0_size,
+	.takeover	= raid0_takeover,
+	.quiesce	= raid0_quiesce,
+	.error_handler	= raid0_error,
+};
+
+static int __init raid0_init(void)
+{
+	return register_md_submodule(&raid0_personality.head);
+}
+
+static void __exit raid0_exit(void)
+{
+	unregister_md_submodule(&raid0_personality.head);
+}
+
+module_init(raid0_init);
+module_exit(raid0_exit);
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("RAID0 (striping) personality for MD");
+MODULE_ALIAS("md-personality-2"); /* RAID0 */
+MODULE_ALIAS("md-raid0");
+MODULE_ALIAS("md-level-0");