1 files changed, 105 insertions, 66 deletions

diff --git a/drivers/md/dm-switch.c b/drivers/md/dm-switch.c
index ff9ac4be4721..50a52ca50b34 100644
--- a/drivers/md/dm-switch.c
+++ b/drivers/md/dm-switch.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2010-2012 by Dell Inc.  All rights reserved.
  * Copyright (C) 2011-2013 Red Hat, Inc.
@@ -38,9 +39,9 @@ struct switch_path {
 struct switch_ctx {
 	struct dm_target *ti;
 
-	unsigned nr_paths;		/* Number of paths in path_list. */
+	unsigned int nr_paths;		/* Number of paths in path_list. */
 
-	unsigned region_size;		/* Region size in 512-byte sectors */
+	unsigned int region_size;		/* Region size in 512-byte sectors */
 	unsigned long nr_regions;	/* Number of regions making up the device */
 	signed char region_size_bits;	/* log2 of region_size or -1 */
 
@@ -53,16 +54,15 @@ struct switch_ctx {
 	/*
 	 * Array of dm devices to switch between.
 	 */
-	struct switch_path path_list[0];
+	struct switch_path path_list[];
 };
 
-static struct switch_ctx *alloc_switch_ctx(struct dm_target *ti, unsigned nr_paths,
-					   unsigned region_size)
+static struct switch_ctx *alloc_switch_ctx(struct dm_target *ti, unsigned int nr_paths,
+					   unsigned int region_size)
 {
 	struct switch_ctx *sctx;
 
-	sctx = kzalloc(sizeof(struct switch_ctx) + nr_paths * sizeof(struct switch_path),
-		       GFP_KERNEL);
+	sctx = kzalloc(struct_size(sctx, path_list, nr_paths), GFP_KERNEL);
 	if (!sctx)
 		return NULL;
 
@@ -74,7 +74,7 @@ static struct switch_ctx *alloc_switch_ctx(struct dm_target *ti, unsigned nr_pat
 	return sctx;
 }
 
-static int alloc_region_table(struct dm_target *ti, unsigned nr_paths)
+static int alloc_region_table(struct dm_target *ti, unsigned int nr_paths)
 {
 	struct switch_ctx *sctx = ti->private;
 	sector_t nr_regions = ti->len;
@@ -99,11 +99,11 @@ static int alloc_region_table(struct dm_target *ti, unsigned nr_paths)
 	if (sector_div(nr_regions, sctx->region_size))
 		nr_regions++;
 
-	sctx->nr_regions = nr_regions;
-	if (sctx->nr_regions != nr_regions || sctx->nr_regions >= ULONG_MAX) {
+	if (nr_regions >= ULONG_MAX) {
 		ti->error = "Region table too large";
 		return -EINVAL;
 	}
+	sctx->nr_regions = nr_regions;
 
 	nr_slots = nr_regions;
 	if (sector_div(nr_slots, sctx->region_entries_per_slot))
@@ -114,7 +114,8 @@ static int alloc_region_table(struct dm_target *ti, unsigned nr_paths)
 		return -EINVAL;
 	}
 
-	sctx->region_table = vmalloc(nr_slots * sizeof(region_table_slot_t));
+	sctx->region_table = vmalloc_array(nr_slots,
+					   sizeof(region_table_slot_t));
 	if (!sctx->region_table) {
 		ti->error = "Cannot allocate region table";
 		return -ENOMEM;
@@ -124,7 +125,7 @@ static int alloc_region_table(struct dm_target *ti, unsigned nr_paths)
 }
 
 static void switch_get_position(struct switch_ctx *sctx, unsigned long region_nr,
-				unsigned long *region_index, unsigned *bit)
+				unsigned long *region_index, unsigned int *bit)
 {
 	if (sctx->region_entries_per_slot_bits >= 0) {
 		*region_index = region_nr >> sctx->region_entries_per_slot_bits;
@@ -137,13 +138,23 @@ static void switch_get_position(struct switch_ctx *sctx, unsigned long region_nr
 	*bit *= sctx->region_table_entry_bits;
 }
 
+static unsigned int switch_region_table_read(struct switch_ctx *sctx, unsigned long region_nr)
+{
+	unsigned long region_index;
+	unsigned int bit;
+
+	switch_get_position(sctx, region_nr, &region_index, &bit);
+
+	return (READ_ONCE(sctx->region_table[region_index]) >> bit) &
+		((1 << sctx->region_table_entry_bits) - 1);
+}
+
 /*
  * Find which path to use at given offset.
  */
-static unsigned switch_get_path_nr(struct switch_ctx *sctx, sector_t offset)
+static unsigned int switch_get_path_nr(struct switch_ctx *sctx, sector_t offset)
 {
-	unsigned long region_index;
-	unsigned bit, path_nr;
+	unsigned int path_nr;
 	sector_t p;
 
 	p = offset;
@@ -152,9 +163,7 @@ static unsigned switch_get_path_nr(struct switch_ctx *sctx, sector_t offset)
 	else
 		sector_div(p, sctx->region_size);
 
-	switch_get_position(sctx, p, &region_index, &bit);
-	path_nr = (ACCESS_ONCE(sctx->region_table[region_index]) >> bit) &
-	       ((1 << sctx->region_table_entry_bits) - 1);
+	path_nr = switch_region_table_read(sctx, p);
 
 	/* This can only happen if the processor uses non-atomic stores. */
 	if (unlikely(path_nr >= sctx->nr_paths))
@@ -164,10 +173,10 @@ static unsigned switch_get_path_nr(struct switch_ctx *sctx, sector_t offset)
 }
 
 static void switch_region_table_write(struct switch_ctx *sctx, unsigned long region_nr,
-				      unsigned value)
+				      unsigned int value)
 {
 	unsigned long region_index;
-	unsigned bit;
+	unsigned int bit;
 	region_table_slot_t pte;
 
 	switch_get_position(sctx, region_nr, &region_index, &bit);
@@ -183,7 +192,7 @@ static void switch_region_table_write(struct switch_ctx *sctx, unsigned long reg
  */
 static void initialise_region_table(struct switch_ctx *sctx)
 {
-	unsigned path_nr = 0;
+	unsigned int path_nr = 0;
 	unsigned long region_nr;
 
 	for (region_nr = 0; region_nr < sctx->nr_regions; region_nr++) {
@@ -241,9 +250,9 @@ static void switch_dtr(struct dm_target *ti)
  * Optional args are to allow for future extension: currently this
  * parameter must be 0.
  */
-static int switch_ctr(struct dm_target *ti, unsigned argc, char **argv)
+static int switch_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 {
-	static struct dm_arg _args[] = {
+	static const struct dm_arg _args[] = {
 		{1, (KMALLOC_MAX_SIZE - sizeof(struct switch_ctx)) / sizeof(struct switch_path), "Invalid number of paths"},
 		{1, UINT_MAX, "Invalid region size"},
 		{0, 0, "Invalid number of optional args"},
@@ -251,7 +260,7 @@ static int switch_ctr(struct dm_target *ti, unsigned argc, char **argv)
 
 	struct switch_ctx *sctx;
 	struct dm_arg_set as;
-	unsigned nr_paths, region_size, nr_optional_args;
+	unsigned int nr_paths, region_size, nr_optional_args;
 	int r;
 
 	as.argc = argc;
@@ -311,11 +320,11 @@ error:
 static int switch_map(struct dm_target *ti, struct bio *bio)
 {
 	struct switch_ctx *sctx = ti->private;
-	sector_t offset = dm_target_offset(ti, bio->bi_sector);
-	unsigned path_nr = switch_get_path_nr(sctx, offset);
+	sector_t offset = dm_target_offset(ti, bio->bi_iter.bi_sector);
+	unsigned int path_nr = switch_get_path_nr(sctx, offset);
 
-	bio->bi_bdev = sctx->path_list[path_nr].dmdev->bdev;
-	bio->bi_sector = sctx->path_list[path_nr].start + offset;
+	bio_set_dev(bio, sctx->path_list[path_nr].dmdev->bdev);
+	bio->bi_iter.bi_sector = sctx->path_list[path_nr].start + offset;
 
 	return DM_MAPIO_REMAPPED;
 }
@@ -363,15 +372,60 @@ static __always_inline unsigned long parse_hex(const char **string)
 }
 
 static int process_set_region_mappings(struct switch_ctx *sctx,
-			     unsigned argc, char **argv)
+				       unsigned int argc, char **argv)
 {
-	unsigned i;
+	unsigned int i;
 	unsigned long region_index = 0;
 
 	for (i = 1; i < argc; i++) {
 		unsigned long path_nr;
 		const char *string = argv[i];
 
+		if ((*string & 0xdf) == 'R') {
+			unsigned long cycle_length, num_write;
+
+			string++;
+			if (unlikely(*string == ',')) {
+				DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
+				return -EINVAL;
+			}
+			cycle_length = parse_hex(&string);
+			if (unlikely(*string != ',')) {
+				DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
+				return -EINVAL;
+			}
+			string++;
+			if (unlikely(!*string)) {
+				DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
+				return -EINVAL;
+			}
+			num_write = parse_hex(&string);
+			if (unlikely(*string)) {
+				DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
+				return -EINVAL;
+			}
+
+			if (unlikely(!cycle_length) || unlikely(cycle_length - 1 > region_index)) {
+				DMWARN("invalid set_region_mappings cycle length: %lu > %lu",
+				       cycle_length - 1, region_index);
+				return -EINVAL;
+			}
+			if (unlikely(region_index + num_write < region_index) ||
+			    unlikely(region_index + num_write >= sctx->nr_regions)) {
+				DMWARN("invalid set_region_mappings region number: %lu + %lu >= %lu",
+				       region_index, num_write, sctx->nr_regions);
+				return -EINVAL;
+			}
+
+			while (num_write--) {
+				region_index++;
+				path_nr = switch_region_table_read(sctx, region_index - cycle_length);
+				switch_region_table_write(sctx, region_index, path_nr);
+			}
+
+			continue;
+		}
+
 		if (*string == ':')
 			region_index++;
 		else {
@@ -413,7 +467,8 @@ static int process_set_region_mappings(struct switch_ctx *sctx,
  *
  * Only set_region_mappings is supported.
  */
-static int switch_message(struct dm_target *ti, unsigned argc, char **argv)
+static int switch_message(struct dm_target *ti, unsigned int argc, char **argv,
+			  char *result, unsigned int maxlen)
 {
 	static DEFINE_MUTEX(message_mutex);
 
@@ -433,10 +488,10 @@ static int switch_message(struct dm_target *ti, unsigned argc, char **argv)
 }
 
 static void switch_status(struct dm_target *ti, status_type_t type,
-			  unsigned status_flags, char *result, unsigned maxlen)
+			  unsigned int status_flags, char *result, unsigned int maxlen)
 {
 	struct switch_ctx *sctx = ti->private;
-	unsigned sz = 0;
+	unsigned int sz = 0;
 	int path_nr;
 
 	switch (type) {
@@ -450,6 +505,10 @@ static void switch_status(struct dm_target *ti, status_type_t type,
 			DMEMIT(" %s %llu", sctx->path_list[path_nr].dmdev->name,
 			       (unsigned long long)sctx->path_list[path_nr].start);
 		break;
+
+	case STATUSTYPE_IMA:
+		result[0] = '\0';
+		break;
 	}
 }
 
@@ -458,27 +517,24 @@ static void switch_status(struct dm_target *ti, status_type_t type,
  *
  * Passthrough all ioctls to the path for sector 0
  */
-static int switch_ioctl(struct dm_target *ti, unsigned cmd,
-			unsigned long arg)
+static int switch_prepare_ioctl(struct dm_target *ti, struct block_device **bdev,
+				unsigned int cmd, unsigned long arg,
+				bool *forward)
 {
 	struct switch_ctx *sctx = ti->private;
-	struct block_device *bdev;
-	fmode_t mode;
-	unsigned path_nr;
-	int r = 0;
+	unsigned int path_nr;
 
 	path_nr = switch_get_path_nr(sctx, 0);
 
-	bdev = sctx->path_list[path_nr].dmdev->bdev;
-	mode = sctx->path_list[path_nr].dmdev->mode;
+	*bdev = sctx->path_list[path_nr].dmdev->bdev;
 
 	/*
 	 * Only pass ioctls through if the device sizes match exactly.
 	 */
-	if (ti->len + sctx->path_list[path_nr].start != i_size_read(bdev->bd_inode) >> SECTOR_SHIFT)
-		r = scsi_verify_blk_ioctl(NULL, cmd);
-
-	return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg);
+	if (ti->len + sctx->path_list[path_nr].start !=
+	    bdev_nr_sectors((*bdev)))
+		return 1;
+	return 0;
 }
 
 static int switch_iterate_devices(struct dm_target *ti,
@@ -500,35 +556,18 @@ static int switch_iterate_devices(struct dm_target *ti,
 
 static struct target_type switch_target = {
 	.name = "switch",
-	.version = {1, 0, 0},
+	.version = {1, 1, 0},
+	.features = DM_TARGET_NOWAIT,
 	.module = THIS_MODULE,
 	.ctr = switch_ctr,
 	.dtr = switch_dtr,
 	.map = switch_map,
 	.message = switch_message,
 	.status = switch_status,
-	.ioctl = switch_ioctl,
+	.prepare_ioctl = switch_prepare_ioctl,
 	.iterate_devices = switch_iterate_devices,
 };
-
-static int __init dm_switch_init(void)
-{
-	int r;
-
-	r = dm_register_target(&switch_target);
-	if (r < 0)
-		DMERR("dm_register_target() failed %d", r);
-
-	return r;
-}
-
-static void __exit dm_switch_exit(void)
-{
-	dm_unregister_target(&switch_target);
-}
-
-module_init(dm_switch_init);
-module_exit(dm_switch_exit);
+module_dm(switch);
 
 MODULE_DESCRIPTION(DM_NAME " dynamic path switching target");
 MODULE_AUTHOR("Kevin D. O'Kelley <Kevin_OKelley@dell.com>");