dm-buffered: fix arguments

Fix arguments so that they can be specified in any order - just like in
other targets.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

---
 drivers/md/dm-buffered-target.c |   79 +++++++++++++---------------------------
 1 file changed, 26 insertions(+), 53 deletions(-)

Index: linux-2.6/drivers/md/dm-buffered-target.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-buffered-target.c
+++ linux-2.6/drivers/md/dm-buffered-target.c
@@ -17,8 +17,7 @@
 
 #define DM_MSG_PREFIX "buffered"
 
-#define DEFAULT_BUFFERED_BLOCK_SIZE	(SECTOR_SIZE <<  3) /* 4KiB */
-#define MAX_BUFFERED_BLOCK_SIZE		(SECTOR_SIZE << 13) /* 4MiB */
+#define DEFAULT_BUFFERED_BLOCK_SIZE	(SECTOR_SIZE << 3) /* 4KiB */
 
 enum stats { S_BUFFER_SPLITS, S_PREFLUSHS, S_FUA, S_SYNCS, S_READS,
 	     S_PREFETCHED_READS, S_PREFETCHED_WRITES, S_END, };
@@ -38,7 +37,6 @@ struct buffered_c {
 	unsigned int block_shift;
 	unsigned int buffer_size;
 	unsigned int buffer_size_set:1;
-	unsigned int buffer_size_default:1;
 	unsigned int discard:1;
 	unsigned int discard_set:1;
 	unsigned int discard_passdown:1;
@@ -367,8 +365,8 @@ static int buffered_ctr(struct dm_target
 	struct buffered_c *bc;
 	int i, r;
 
-	if (argc < 2 || argc > 7) {
-		ti->error = "Requires 2 - 7 arguments";
+	if (argc < 2) {
+		ti->error = "Requires at least 2 arguments";
 		return -EINVAL;
 	}
 
@@ -387,60 +385,37 @@ static int buffered_ctr(struct dm_target
 		goto bad;
 	}
 
-	if (argc > 2) {
-		if (!strcasecmp(argv[2], "-")) {
-			bc->buffer_size_default = true;
-			bc->buffer_size = DEFAULT_BUFFERED_BLOCK_SIZE;
-		} else {
-			bc->buffer_size_set = true;
-			r = (kstrtouint(argv[2], 10, &bc->buffer_size) ||
-			     !is_power_of_2(bc->buffer_size) ||
-			     bc->buffer_size < SECTOR_SIZE ||
-			     bc->buffer_size > MAX_BUFFERED_BLOCK_SIZE) ? -EINVAL : 0;
-			if (r) {
+	for (i = 2; i < argc; i++) {
+		const char *arg = argv[i];
+		char dummy;
+		if (sscanf(arg, "block_size:%u%c", &bc->buffer_size, &dummy) == 1) {
+			if (!is_power_of_2(bc->buffer_size) ||
+			    bc->buffer_size < SECTOR_SIZE) {
 				ti->error = "Invalid block size";
+				r = -EINVAL;
 				goto bad;
 			}
-		}
-	}
-
-	if (argc > 3) {
-		bc->discard_set = 1;
-
-		if (!strcasecmp(argv[3], "no_discard")) {
+			bc->buffer_size_set = 1;
+		} else if (!strcmp(arg, "no_discard")) {
 			bc->discard = 0;
-		} else if (!strcasecmp(argv[3], "discard")) {
+			bc->discard_set = 1;
+		} else if (!strcmp(arg, "discard")) {
 			bc->discard = 1;
-		} else {
-			ti->error = "Invalid discard parameter";
-			r = -EINVAL;
-			goto bad;
-		}
-	}
-
-	if (argc > 4) {
-		bc->discard_passdown_set = 1;
-
-		if (!strcasecmp(argv[4], "no_discard_passdown")) {
+			bc->discard_set = 1;
+		} else if (!strcmp(arg, "no_discard_passdown")) {
 			bc->discard_passdown = 0;
-		} else if (!strcasecmp(argv[4], "discard_passdown")) {
+			bc->write_zeroes_set = 1;
+		} else if (!strcmp(arg, "discard_passdown")) {
 			bc->discard_passdown = 1;
-		} else {
-			ti->error = "Invalid discard passdown parameter";
-			r = -EINVAL;
-			goto bad;
-		}
-	}
-
-	if (argc > 5) {
-		bc->write_zeroes_set = 1;
-
-		if (!strcasecmp(argv[5], "no_write_zeroes")) {
+			bc->write_zeroes_set = 1;
+		} else if (!strcmp(arg, "no_write_zeroes")) {
 			bc->write_zeroes = 0;
-		} else if (!strcasecmp(argv[5], "write_zeroes")) {
+			bc->write_zeroes_set = 1;
+		} else if (!strcmp(arg, "write_zeroes")) {
 			bc->write_zeroes = 1;
+			bc->write_zeroes_set = 1;
 		} else {
-			ti->error = "Invalid write zeroes parameter";
+			ti->error = "Invalid argument";
 			r = -EINVAL;
 			goto bad;
 		}
@@ -565,10 +540,8 @@ static void buffered_status(struct dm_ta
 	switch (type) {
 	case STATUSTYPE_TABLE:
 		DMEMIT("%s %llu", bc->dev->name, (u64)bc->start);
-		if (bc->buffer_size_default)
-			DMEMIT(" -");
 		if (bc->buffer_size_set)
-			DMEMIT(" %u", bc->buffer_size);
+			DMEMIT(" block_size:%u", bc->buffer_size);
 		if (bc->discard_set)
 			DMEMIT(" %s", bc->discard ? "discard" : "no_discard");
 		if (bc->discard_passdown_set)
@@ -646,7 +619,7 @@ static void buffered_io_hints(struct dm_
 	blk_limits_io_min(limits, limits->logical_block_size);
 	blk_limits_io_opt(limits, bc->buffer_size);
 	if (ti->num_write_zeroes_bios)
-		limits->max_write_zeroes_sectors = min(ti->len, to_sector(MAX_BUFFERED_BLOCK_SIZE));
+		limits->max_write_zeroes_sectors = UINT_MAX;
 }
 
 static struct target_type buffered_target = {