[PATCH] block: partitions: Replace pp_buf with struct seq_buf

[Kees Cook <kees@kernel.org>]

In preparation for removing the strlcat API[1], replace the char *pp_buf
with a struct seq_buf, which tracks the current write position and
remaining space internally. This allows for:

- Direct use of seq_buf_printf() in place of snprintf()+strlcat()
  pairs, eliminating local tmp buffers throughout.
- Adjacent strlcat() calls that build strings piece-by-piece
  (e.g., strlcat("["); strlcat(name); strlcat("]")) to be collapsed
  into single seq_buf_printf() calls.
- Simpler call sites: seq_buf_puts() takes only the buffer and string,
  with no need to pass PAGE_SIZE at every call.

The backing buffer allocation is unchanged (__get_free_page), and the
output path uses seq_buf_str() to NUL-terminate before passing to
printk().

Link: https://github.com/KSPP/linux/issues/370 [1]
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Josh Law <objecting@objecting.org>
Signed-off-by: Kees Cook <kees@kernel.org>
---
I couldn't help myself. Here's the full patch, as I suggested in
https://lore.kernel.org/lkml/202603201230.74BBFFABAD@keescook/
There are plenty more like this to do...
---
 block/partitions/check.h   |  8 ++---
 block/partitions/core.c    | 20 ++++++------
 block/partitions/acorn.c   | 32 ++++++++----------
 block/partitions/aix.c     | 21 +++++-------
 block/partitions/amiga.c   | 35 +++++++++-----------
 block/partitions/atari.c   | 12 +++----
 block/partitions/cmdline.c |  6 ++--
 block/partitions/efi.c     |  2 +-
 block/partitions/ibm.c     | 27 ++++++---------
 block/partitions/karma.c   |  2 +-
 block/partitions/ldm.c     |  4 +--
 block/partitions/mac.c     |  4 +--
 block/partitions/msdos.c   | 67 +++++++++++++-------------------------
 block/partitions/of.c      |  6 ++--
 block/partitions/osf.c     |  2 +-
 block/partitions/sgi.c     |  2 +-
 block/partitions/sun.c     |  2 +-
 block/partitions/sysv68.c  |  9 ++---
 block/partitions/ultrix.c  |  2 +-
 19 files changed, 106 insertions(+), 157 deletions(-)

diff --git a/block/partitions/check.h b/block/partitions/check.h
index e5c1c61eb353..b0997467b61a 100644
--- a/block/partitions/check.h
+++ b/block/partitions/check.h
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 #include <linux/pagemap.h>
 #include <linux/blkdev.h>
+#include <linux/seq_buf.h>
 #include "../blk.h"
 
 /*
@@ -20,7 +21,7 @@ struct parsed_partitions {
 	int next;
 	int limit;
 	bool access_beyond_eod;
-	char *pp_buf;
+	struct seq_buf pp_buf;
 };
 
 typedef struct {
@@ -37,12 +38,9 @@ static inline void
 put_partition(struct parsed_partitions *p, int n, sector_t from, sector_t size)
 {
 	if (n < p->limit) {
-		char tmp[1 + BDEVNAME_SIZE + 10 + 1];
-
 		p->parts[n].from = from;
 		p->parts[n].size = size;
-		snprintf(tmp, sizeof(tmp), " %s%d", p->name, n);
-		strlcat(p->pp_buf, tmp, PAGE_SIZE);
+		seq_buf_printf(&p->pp_buf, " %s%d", p->name, n);
 	}
 }
 
diff --git a/block/partitions/core.c b/block/partitions/core.c
index 740228750aaf..3b5928836c69 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -123,16 +123,16 @@ static struct parsed_partitions *check_partition(struct gendisk *hd)
 	state = allocate_partitions(hd);
 	if (!state)
 		return NULL;
-	state->pp_buf = (char *)__get_free_page(GFP_KERNEL);
-	if (!state->pp_buf) {
+	state->pp_buf.buffer = (char *)__get_free_page(GFP_KERNEL);
+	if (!state->pp_buf.buffer) {
 		free_partitions(state);
 		return NULL;
 	}
-	state->pp_buf[0] = '\0';
+	seq_buf_init(&state->pp_buf, state->pp_buf.buffer, PAGE_SIZE);
 
 	state->disk = hd;
 	strscpy(state->name, hd->disk_name);
-	snprintf(state->pp_buf, PAGE_SIZE, " %s:", state->name);
+	seq_buf_printf(&state->pp_buf, " %s:", state->name);
 	if (isdigit(state->name[strlen(state->name)-1]))
 		sprintf(state->name, "p");
 
@@ -151,9 +151,9 @@ static struct parsed_partitions *check_partition(struct gendisk *hd)
 
 	}
 	if (res > 0) {
-		printk(KERN_INFO "%s", state->pp_buf);
+		printk(KERN_INFO "%s", seq_buf_str(&state->pp_buf));
 
-		free_page((unsigned long)state->pp_buf);
+		free_page((unsigned long)state->pp_buf.buffer);
 		return state;
 	}
 	if (state->access_beyond_eod)
@@ -164,12 +164,12 @@ static struct parsed_partitions *check_partition(struct gendisk *hd)
 	if (err)
 		res = err;
 	if (res) {
-		strlcat(state->pp_buf,
-			" unable to read partition table\n", PAGE_SIZE);
-		printk(KERN_INFO "%s", state->pp_buf);
+		seq_buf_puts(&state->pp_buf,
+			     " unable to read partition table\n");
+		printk(KERN_INFO "%s", seq_buf_str(&state->pp_buf));
 	}
 
-	free_page((unsigned long)state->pp_buf);
+	free_page((unsigned long)state->pp_buf.buffer);
 	free_partitions(state);
 	return ERR_PTR(res);
 }
diff --git a/block/partitions/acorn.c b/block/partitions/acorn.c
index d2fc122d7426..9f7389f174d0 100644
--- a/block/partitions/acorn.c
+++ b/block/partitions/acorn.c
@@ -40,9 +40,7 @@ adfs_partition(struct parsed_partitions *state, char *name, char *data,
 		   (le32_to_cpu(dr->disc_size) >> 9);
 
 	if (name) {
-		strlcat(state->pp_buf, " [", PAGE_SIZE);
-		strlcat(state->pp_buf, name, PAGE_SIZE);
-		strlcat(state->pp_buf, "]", PAGE_SIZE);
+		seq_buf_printf(&state->pp_buf, " [%s]", name);
 	}
 	put_partition(state, slot, first_sector, nr_sects);
 	return dr;
@@ -78,14 +76,14 @@ static int riscix_partition(struct parsed_partitions *state,
 	if (!rr)
 		return -1;
 
-	strlcat(state->pp_buf, " [RISCiX]", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, " [RISCiX]");
 
 
 	if (rr->magic == RISCIX_MAGIC) {
 		unsigned long size = nr_sects > 2 ? 2 : nr_sects;
 		int part;
 
-		strlcat(state->pp_buf, " <", PAGE_SIZE);
+		seq_buf_puts(&state->pp_buf, " <");
 
 		put_partition(state, slot++, first_sect, size);
 		for (part = 0; part < 8; part++) {
@@ -94,13 +92,11 @@ static int riscix_partition(struct parsed_partitions *state,
 				put_partition(state, slot++,
 					le32_to_cpu(rr->part[part].start),
 					le32_to_cpu(rr->part[part].length));
-				strlcat(state->pp_buf, "(", PAGE_SIZE);
-				strlcat(state->pp_buf, rr->part[part].name, PAGE_SIZE);
-				strlcat(state->pp_buf, ")", PAGE_SIZE);
+				seq_buf_printf(&state->pp_buf, "(%s)", rr->part[part].name);
 			}
 		}
 
-		strlcat(state->pp_buf, " >\n", PAGE_SIZE);
+		seq_buf_puts(&state->pp_buf, " >\n");
 	} else {
 		put_partition(state, slot++, first_sect, nr_sects);
 	}
@@ -130,7 +126,7 @@ static int linux_partition(struct parsed_partitions *state,
 	struct linux_part *linuxp;
 	unsigned long size = nr_sects > 2 ? 2 : nr_sects;
 
-	strlcat(state->pp_buf, " [Linux]", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, " [Linux]");
 
 	put_partition(state, slot++, first_sect, size);
 
@@ -138,7 +134,7 @@ static int linux_partition(struct parsed_partitions *state,
 	if (!linuxp)
 		return -1;
 
-	strlcat(state->pp_buf, " <", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, " <");
 	while (linuxp->magic == cpu_to_le32(LINUX_NATIVE_MAGIC) ||
 	       linuxp->magic == cpu_to_le32(LINUX_SWAP_MAGIC)) {
 		if (slot == state->limit)
@@ -148,7 +144,7 @@ static int linux_partition(struct parsed_partitions *state,
 				 le32_to_cpu(linuxp->nr_sects));
 		linuxp ++;
 	}
-	strlcat(state->pp_buf, " >", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, " >");
 
 	put_dev_sector(sect);
 	return slot;
@@ -293,7 +289,7 @@ int adfspart_check_ADFS(struct parsed_partitions *state)
 			break;
 		}
 	}
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 	return 1;
 }
 #endif
@@ -366,7 +362,7 @@ int adfspart_check_ICS(struct parsed_partitions *state)
 		return 0;
 	}
 
-	strlcat(state->pp_buf, " [ICS]", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, " [ICS]");
 
 	for (slot = 1, p = (const struct ics_part *)data; p->size; p++) {
 		u32 start = le32_to_cpu(p->start);
@@ -400,7 +396,7 @@ int adfspart_check_ICS(struct parsed_partitions *state)
 	}
 
 	put_dev_sector(sect);
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 	return 1;
 }
 #endif
@@ -460,7 +456,7 @@ int adfspart_check_POWERTEC(struct parsed_partitions *state)
 		return 0;
 	}
 
-	strlcat(state->pp_buf, " [POWERTEC]", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, " [POWERTEC]");
 
 	for (i = 0, p = (const struct ptec_part *)data; i < 12; i++, p++) {
 		u32 start = le32_to_cpu(p->start);
@@ -471,7 +467,7 @@ int adfspart_check_POWERTEC(struct parsed_partitions *state)
 	}
 
 	put_dev_sector(sect);
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 	return 1;
 }
 #endif
@@ -542,7 +538,7 @@ int adfspart_check_EESOX(struct parsed_partitions *state)
 
 		size = get_capacity(state->disk);
 		put_partition(state, slot++, start, size - start);
-		strlcat(state->pp_buf, "\n", PAGE_SIZE);
+		seq_buf_puts(&state->pp_buf, "\n");
 	}
 
 	return i ? 1 : 0;
diff --git a/block/partitions/aix.c b/block/partitions/aix.c
index a886cefbefbb..29b8f4cebb63 100644
--- a/block/partitions/aix.c
+++ b/block/partitions/aix.c
@@ -173,24 +173,22 @@ int aix_partition(struct parsed_partitions *state)
 	if (d) {
 		struct lvm_rec *p = (struct lvm_rec *)d;
 		u16 lvm_version = be16_to_cpu(p->version);
-		char tmp[64];
 
 		if (lvm_version == 1) {
 			int pp_size_log2 = be16_to_cpu(p->pp_size);
 
 			pp_bytes_size = 1 << pp_size_log2;
 			pp_blocks_size = pp_bytes_size / 512;
-			snprintf(tmp, sizeof(tmp),
-				" AIX LVM header version %u found\n",
-				lvm_version);
+			seq_buf_printf(&state->pp_buf,
+				       " AIX LVM header version %u found\n",
+				       lvm_version);
 			vgda_len = be32_to_cpu(p->vgda_len);
 			vgda_sector = be32_to_cpu(p->vgda_psn[0]);
 		} else {
-			snprintf(tmp, sizeof(tmp),
-				" unsupported AIX LVM version %d found\n",
-				lvm_version);
+			seq_buf_printf(&state->pp_buf,
+				       " unsupported AIX LVM version %d found\n",
+				       lvm_version);
 		}
-		strlcat(state->pp_buf, tmp, PAGE_SIZE);
 		put_dev_sector(sect);
 	}
 	if (vgda_sector && (d = read_part_sector(state, vgda_sector, &sect))) {
@@ -251,14 +249,11 @@ int aix_partition(struct parsed_partitions *state)
 				continue;
 			}
 			if (lp_ix == lvip[lv_ix].pps_per_lv) {
-				char tmp[70];
-
 				put_partition(state, lv_ix + 1,
 				  (i + 1 - lp_ix) * pp_blocks_size + psn_part1,
 				  lvip[lv_ix].pps_per_lv * pp_blocks_size);
-				snprintf(tmp, sizeof(tmp), " <%s>\n",
-					 n[lv_ix].name);
-				strlcat(state->pp_buf, tmp, PAGE_SIZE);
+				seq_buf_printf(&state->pp_buf, " <%s>\n",
+					       n[lv_ix].name);
 				lvip[lv_ix].lv_is_contiguous = 1;
 				ret = 1;
 				next_lp_ix = 1;
diff --git a/block/partitions/amiga.c b/block/partitions/amiga.c
index 506921095412..8325046a14eb 100644
--- a/block/partitions/amiga.c
+++ b/block/partitions/amiga.c
@@ -81,13 +81,8 @@ int amiga_partition(struct parsed_partitions *state)
 	/* blksize is blocks per 512 byte standard block */
 	blksize = be32_to_cpu( rdb->rdb_BlockBytes ) / 512;
 
-	{
-		char tmp[7 + 10 + 1 + 1];
-
-		/* Be more informative */
-		snprintf(tmp, sizeof(tmp), " RDSK (%d)", blksize * 512);
-		strlcat(state->pp_buf, tmp, PAGE_SIZE);
-	}
+	/* Be more informative */
+	seq_buf_printf(&state->pp_buf, " RDSK (%d)", blksize * 512);
 	blk = be32_to_cpu(rdb->rdb_PartitionList);
 	put_dev_sector(sect);
 	for (part = 1; (s32) blk>0 && part<=16; part++, put_dev_sector(sect)) {
@@ -179,27 +174,27 @@ int amiga_partition(struct parsed_partitions *state)
 		{
 			/* Be even more informative to aid mounting */
 			char dostype[4];
-			char tmp[42];
 
 			__be32 *dt = (__be32 *)dostype;
 			*dt = pb->pb_Environment[16];
 			if (dostype[3] < ' ')
-				snprintf(tmp, sizeof(tmp), " (%c%c%c^%c)",
-					dostype[0], dostype[1],
-					dostype[2], dostype[3] + '@' );
+				seq_buf_printf(&state->pp_buf,
+					       " (%c%c%c^%c)",
+					       dostype[0], dostype[1],
+					       dostype[2],
+					       dostype[3] + '@');
 			else
-				snprintf(tmp, sizeof(tmp), " (%c%c%c%c)",
-					dostype[0], dostype[1],
-					dostype[2], dostype[3]);
-			strlcat(state->pp_buf, tmp, PAGE_SIZE);
-			snprintf(tmp, sizeof(tmp), "(res %d spb %d)",
-				be32_to_cpu(pb->pb_Environment[6]),
-				be32_to_cpu(pb->pb_Environment[4]));
-			strlcat(state->pp_buf, tmp, PAGE_SIZE);
+				seq_buf_printf(&state->pp_buf,
+					       " (%c%c%c%c)",
+					       dostype[0], dostype[1],
+					       dostype[2], dostype[3]);
+			seq_buf_printf(&state->pp_buf, "(res %d spb %d)",
+				       be32_to_cpu(pb->pb_Environment[6]),
+				       be32_to_cpu(pb->pb_Environment[4]));
 		}
 		res = 1;
 	}
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 
 rdb_done:
 	return res;
diff --git a/block/partitions/atari.c b/block/partitions/atari.c
index 9655c728262a..2438d1448f38 100644
--- a/block/partitions/atari.c
+++ b/block/partitions/atari.c
@@ -70,7 +70,7 @@ int atari_partition(struct parsed_partitions *state)
 	}
 
 	pi = &rs->part[0];
-	strlcat(state->pp_buf, " AHDI", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, " AHDI");
 	for (slot = 1; pi < &rs->part[4] && slot < state->limit; slot++, pi++) {
 		struct rootsector *xrs;
 		Sector sect2;
@@ -89,7 +89,7 @@ int atari_partition(struct parsed_partitions *state)
 #ifdef ICD_PARTS
 		part_fmt = 1;
 #endif
-		strlcat(state->pp_buf, " XGM<", PAGE_SIZE);
+		seq_buf_puts(&state->pp_buf, " XGM<");
 		partsect = extensect = be32_to_cpu(pi->st);
 		while (1) {
 			xrs = read_part_sector(state, partsect, &sect2);
@@ -128,14 +128,14 @@ int atari_partition(struct parsed_partitions *state)
 				break;
 			}
 		}
-		strlcat(state->pp_buf, " >", PAGE_SIZE);
+		seq_buf_puts(&state->pp_buf, " >");
 	}
 #ifdef ICD_PARTS
 	if ( part_fmt!=1 ) { /* no extended partitions -> test ICD-format */
 		pi = &rs->icdpart[0];
 		/* sanity check: no ICD format if first partition invalid */
 		if (OK_id(pi->id)) {
-			strlcat(state->pp_buf, " ICD<", PAGE_SIZE);
+			seq_buf_puts(&state->pp_buf, " ICD<");
 			for (; pi < &rs->icdpart[8] && slot < state->limit; slot++, pi++) {
 				/* accept only GEM,BGM,RAW,LNX,SWP partitions */
 				if (!((pi->flg & 1) && OK_id(pi->id)))
@@ -144,13 +144,13 @@ int atari_partition(struct parsed_partitions *state)
 						be32_to_cpu(pi->st),
 						be32_to_cpu(pi->siz));
 			}
-			strlcat(state->pp_buf, " >", PAGE_SIZE);
+			seq_buf_puts(&state->pp_buf, " >");
 		}
 	}
 #endif
 	put_dev_sector(sect);
 
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 
 	return 1;
 }
diff --git a/block/partitions/cmdline.c b/block/partitions/cmdline.c
index a2b1870c3fd4..4fd52ed154b4 100644
--- a/block/partitions/cmdline.c
+++ b/block/partitions/cmdline.c
@@ -229,7 +229,6 @@ static int add_part(int slot, struct cmdline_subpart *subpart,
 		struct parsed_partitions *state)
 {
 	struct partition_meta_info *info;
-	char tmp[sizeof(info->volname) + 4];
 
 	if (slot >= state->limit)
 		return 1;
@@ -244,8 +243,7 @@ static int add_part(int slot, struct cmdline_subpart *subpart,
 
 	strscpy(info->volname, subpart->name, sizeof(info->volname));
 
-	snprintf(tmp, sizeof(tmp), "(%s)", info->volname);
-	strlcat(state->pp_buf, tmp, PAGE_SIZE);
+	seq_buf_printf(&state->pp_buf, "(%s)", info->volname);
 
 	state->parts[slot].has_info = true;
 
@@ -379,7 +377,7 @@ int cmdline_partition(struct parsed_partitions *state)
 	cmdline_parts_set(parts, disk_size, state);
 	cmdline_parts_verifier(1, state);
 
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 
 	return 1;
 }
diff --git a/block/partitions/efi.c b/block/partitions/efi.c
index 75474fb3848e..9865d59093fa 100644
--- a/block/partitions/efi.c
+++ b/block/partitions/efi.c
@@ -751,6 +751,6 @@ int efi_partition(struct parsed_partitions *state)
 	}
 	kfree(ptes);
 	kfree(gpt);
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 	return 1;
 }
diff --git a/block/partitions/ibm.c b/block/partitions/ibm.c
index 9311ad5fb95d..54047e722a9d 100644
--- a/block/partitions/ibm.c
+++ b/block/partitions/ibm.c
@@ -173,15 +173,13 @@ static int find_vol1_partitions(struct parsed_partitions *state,
 {
 	sector_t blk;
 	int counter;
-	char tmp[64];
 	Sector sect;
 	unsigned char *data;
 	loff_t offset, size;
 	struct vtoc_format1_label f1;
 	int secperblk;
 
-	snprintf(tmp, sizeof(tmp), "VOL1/%8s:", name);
-	strlcat(state->pp_buf, tmp, PAGE_SIZE);
+	seq_buf_printf(&state->pp_buf, "VOL1/%8s:", name);
 	/*
 	 * get start of VTOC from the disk label and then search for format1
 	 * and format8 labels
@@ -219,7 +217,7 @@ static int find_vol1_partitions(struct parsed_partitions *state,
 		blk++;
 		data = read_part_sector(state, blk * secperblk, &sect);
 	}
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 
 	if (!data)
 		return -1;
@@ -237,11 +235,9 @@ static int find_lnx1_partitions(struct parsed_partitions *state,
 				dasd_information2_t *info)
 {
 	loff_t offset, geo_size, size;
-	char tmp[64];
 	int secperblk;
 
-	snprintf(tmp, sizeof(tmp), "LNX1/%8s:", name);
-	strlcat(state->pp_buf, tmp, PAGE_SIZE);
+	seq_buf_printf(&state->pp_buf, "LNX1/%8s:", name);
 	secperblk = blocksize >> 9;
 	if (label->lnx.ldl_version == 0xf2) {
 		size = label->lnx.formatted_blocks * secperblk;
@@ -258,7 +254,7 @@ static int find_lnx1_partitions(struct parsed_partitions *state,
 		size = nr_sectors;
 		if (size != geo_size) {
 			if (!info) {
-				strlcat(state->pp_buf, "\n", PAGE_SIZE);
+				seq_buf_puts(&state->pp_buf, "\n");
 				return 1;
 			}
 			if (!strcmp(info->type, "ECKD"))
@@ -270,7 +266,7 @@ static int find_lnx1_partitions(struct parsed_partitions *state,
 	/* first and only partition starts in the first block after the label */
 	offset = labelsect + secperblk;
 	put_partition(state, 1, offset, size - offset);
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 	return 1;
 }
 
@@ -282,7 +278,6 @@ static int find_cms1_partitions(struct parsed_partitions *state,
 				sector_t labelsect)
 {
 	loff_t offset, size;
-	char tmp[64];
 	int secperblk;
 
 	/*
@@ -291,14 +286,12 @@ static int find_cms1_partitions(struct parsed_partitions *state,
 	blocksize = label->cms.block_size;
 	secperblk = blocksize >> 9;
 	if (label->cms.disk_offset != 0) {
-		snprintf(tmp, sizeof(tmp), "CMS1/%8s(MDSK):", name);
-		strlcat(state->pp_buf, tmp, PAGE_SIZE);
+		seq_buf_printf(&state->pp_buf, "CMS1/%8s(MDSK):", name);
 		/* disk is reserved minidisk */
 		offset = label->cms.disk_offset * secperblk;
 		size = (label->cms.block_count - 1) * secperblk;
 	} else {
-		snprintf(tmp, sizeof(tmp), "CMS1/%8s:", name);
-		strlcat(state->pp_buf, tmp, PAGE_SIZE);
+		seq_buf_printf(&state->pp_buf, "CMS1/%8s:", name);
 		/*
 		 * Special case for FBA devices:
 		 * If an FBA device is CMS formatted with blocksize > 512 byte
@@ -314,7 +307,7 @@ static int find_cms1_partitions(struct parsed_partitions *state,
 	}
 
 	put_partition(state, 1, offset, size-offset);
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 	return 1;
 }
 
@@ -391,11 +384,11 @@ int ibm_partition(struct parsed_partitions *state)
 		 */
 		res = 1;
 		if (info->format == DASD_FORMAT_LDL) {
-			strlcat(state->pp_buf, "(nonl)", PAGE_SIZE);
+			seq_buf_puts(&state->pp_buf, "(nonl)");
 			size = nr_sectors;
 			offset = (info->label_block + 1) * (blocksize >> 9);
 			put_partition(state, 1, offset, size-offset);
-			strlcat(state->pp_buf, "\n", PAGE_SIZE);
+			seq_buf_puts(&state->pp_buf, "\n");
 		}
 	} else
 		res = 0;
diff --git a/block/partitions/karma.c b/block/partitions/karma.c
index 4d93512f4bd4..a4e3c5050177 100644
--- a/block/partitions/karma.c
+++ b/block/partitions/karma.c
@@ -53,7 +53,7 @@ int karma_partition(struct parsed_partitions *state)
 		}
 		slot++;
 	}
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 	put_dev_sector(sect);
 	return 1;
 }
diff --git a/block/partitions/ldm.c b/block/partitions/ldm.c
index 776b4ad95091..c0bdcae58a3e 100644
--- a/block/partitions/ldm.c
+++ b/block/partitions/ldm.c
@@ -582,7 +582,7 @@ static bool ldm_create_data_partitions (struct parsed_partitions *pp,
 		return false;
 	}
 
-	strlcat(pp->pp_buf, " [LDM]", PAGE_SIZE);
+	seq_buf_puts(&pp->pp_buf, " [LDM]");
 
 	/* Create the data partitions */
 	list_for_each (item, &ldb->v_part) {
@@ -597,7 +597,7 @@ static bool ldm_create_data_partitions (struct parsed_partitions *pp,
 		part_num++;
 	}
 
-	strlcat(pp->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&pp->pp_buf, "\n");
 	return true;
 }
 
diff --git a/block/partitions/mac.c b/block/partitions/mac.c
index b02530d98629..df03ca428e15 100644
--- a/block/partitions/mac.c
+++ b/block/partitions/mac.c
@@ -86,7 +86,7 @@ int mac_partition(struct parsed_partitions *state)
 	if (blocks_in_map >= state->limit)
 		blocks_in_map = state->limit - 1;
 
-	strlcat(state->pp_buf, " [mac]", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, " [mac]");
 	for (slot = 1; slot <= blocks_in_map; ++slot) {
 		int pos = slot * secsize;
 		put_dev_sector(sect);
@@ -152,6 +152,6 @@ int mac_partition(struct parsed_partitions *state)
 #endif
 
 	put_dev_sector(sect);
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 	return 1;
 }
diff --git a/block/partitions/msdos.c b/block/partitions/msdos.c
index 073be78ba0b0..200ea53ea6a2 100644
--- a/block/partitions/msdos.c
+++ b/block/partitions/msdos.c
@@ -263,18 +263,11 @@ static void parse_solaris_x86(struct parsed_partitions *state,
 		put_dev_sector(sect);
 		return;
 	}
-	{
-		char tmp[1 + BDEVNAME_SIZE + 10 + 11 + 1];
-
-		snprintf(tmp, sizeof(tmp), " %s%d: <solaris:", state->name, origin);
-		strlcat(state->pp_buf, tmp, PAGE_SIZE);
-	}
+	seq_buf_printf(&state->pp_buf, " %s%d: <solaris:", state->name, origin);
 	if (le32_to_cpu(v->v_version) != 1) {
-		char tmp[64];
-
-		snprintf(tmp, sizeof(tmp), "  cannot handle version %d vtoc>\n",
-			 le32_to_cpu(v->v_version));
-		strlcat(state->pp_buf, tmp, PAGE_SIZE);
+		seq_buf_printf(&state->pp_buf,
+			       "  cannot handle version %d vtoc>\n",
+			       le32_to_cpu(v->v_version));
 		put_dev_sector(sect);
 		return;
 	}
@@ -282,12 +275,10 @@ static void parse_solaris_x86(struct parsed_partitions *state,
 	max_nparts = le16_to_cpu(v->v_nparts) > 8 ? SOLARIS_X86_NUMSLICE : 8;
 	for (i = 0; i < max_nparts && state->next < state->limit; i++) {
 		struct solaris_x86_slice *s = &v->v_slice[i];
-		char tmp[3 + 10 + 1 + 1];
 
 		if (s->s_size == 0)
 			continue;
-		snprintf(tmp, sizeof(tmp), " [s%d]", i);
-		strlcat(state->pp_buf, tmp, PAGE_SIZE);
+		seq_buf_printf(&state->pp_buf, " [s%d]", i);
 		/* solaris partitions are relative to current MS-DOS
 		 * one; must add the offset of the current partition */
 		put_partition(state, state->next++,
@@ -295,7 +286,7 @@ static void parse_solaris_x86(struct parsed_partitions *state,
 				 le32_to_cpu(s->s_size));
 	}
 	put_dev_sector(sect);
-	strlcat(state->pp_buf, " >\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, " >\n");
 #endif
 }
 
@@ -359,7 +350,6 @@ static void parse_bsd(struct parsed_partitions *state,
 	Sector sect;
 	struct bsd_disklabel *l;
 	struct bsd_partition *p;
-	char tmp[64];
 
 	l = read_part_sector(state, offset + 1, &sect);
 	if (!l)
@@ -369,8 +359,7 @@ static void parse_bsd(struct parsed_partitions *state,
 		return;
 	}
 
-	snprintf(tmp, sizeof(tmp), " %s%d: <%s:", state->name, origin, flavour);
-	strlcat(state->pp_buf, tmp, PAGE_SIZE);
+	seq_buf_printf(&state->pp_buf, " %s%d: <%s:", state->name, origin, flavour);
 
 	if (le16_to_cpu(l->d_npartitions) < max_partitions)
 		max_partitions = le16_to_cpu(l->d_npartitions);
@@ -391,18 +380,16 @@ static void parse_bsd(struct parsed_partitions *state,
 			/* full parent partition, we have it already */
 			continue;
 		if (offset > bsd_start || offset+size < bsd_start+bsd_size) {
-			strlcat(state->pp_buf, "bad subpartition - ignored\n", PAGE_SIZE);
+			seq_buf_puts(&state->pp_buf, "bad subpartition - ignored\n");
 			continue;
 		}
 		put_partition(state, state->next++, bsd_start, bsd_size);
 	}
 	put_dev_sector(sect);
-	if (le16_to_cpu(l->d_npartitions) > max_partitions) {
-		snprintf(tmp, sizeof(tmp), " (ignored %d more)",
-			 le16_to_cpu(l->d_npartitions) - max_partitions);
-		strlcat(state->pp_buf, tmp, PAGE_SIZE);
-	}
-	strlcat(state->pp_buf, " >\n", PAGE_SIZE);
+	if (le16_to_cpu(l->d_npartitions) > max_partitions)
+		seq_buf_printf(&state->pp_buf, " (ignored %d more)",
+			       le16_to_cpu(l->d_npartitions) - max_partitions);
+	seq_buf_puts(&state->pp_buf, " >\n");
 }
 #endif
 
@@ -496,12 +483,7 @@ static void parse_unixware(struct parsed_partitions *state,
 		put_dev_sector(sect);
 		return;
 	}
-	{
-		char tmp[1 + BDEVNAME_SIZE + 10 + 12 + 1];
-
-		snprintf(tmp, sizeof(tmp), " %s%d: <unixware:", state->name, origin);
-		strlcat(state->pp_buf, tmp, PAGE_SIZE);
-	}
+	seq_buf_printf(&state->pp_buf, " %s%d: <unixware:", state->name, origin);
 	p = &l->vtoc.v_slice[1];
 	/* I omit the 0th slice as it is the same as whole disk. */
 	while (p - &l->vtoc.v_slice[0] < UNIXWARE_NUMSLICE) {
@@ -515,7 +497,7 @@ static void parse_unixware(struct parsed_partitions *state,
 		p++;
 	}
 	put_dev_sector(sect);
-	strlcat(state->pp_buf, " >\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, " >\n");
 #endif
 }
 
@@ -546,10 +528,7 @@ static void parse_minix(struct parsed_partitions *state,
 	 * the normal boot sector. */
 	if (msdos_magic_present(data + 510) &&
 	    p->sys_ind == MINIX_PARTITION) { /* subpartition table present */
-		char tmp[1 + BDEVNAME_SIZE + 10 + 9 + 1];
-
-		snprintf(tmp, sizeof(tmp), " %s%d: <minix:", state->name, origin);
-		strlcat(state->pp_buf, tmp, PAGE_SIZE);
+		seq_buf_printf(&state->pp_buf, " %s%d: <minix:", state->name, origin);
 		for (i = 0; i < MINIX_NR_SUBPARTITIONS; i++, p++) {
 			if (state->next == state->limit)
 				break;
@@ -558,7 +537,7 @@ static void parse_minix(struct parsed_partitions *state,
 				put_partition(state, state->next++,
 					      start_sect(p), nr_sects(p));
 		}
-		strlcat(state->pp_buf, " >\n", PAGE_SIZE);
+		seq_buf_puts(&state->pp_buf, " >\n");
 	}
 	put_dev_sector(sect);
 #endif /* CONFIG_MINIX_SUBPARTITION */
@@ -602,7 +581,7 @@ int msdos_partition(struct parsed_partitions *state)
 #ifdef CONFIG_AIX_PARTITION
 		return aix_partition(state);
 #else
-		strlcat(state->pp_buf, " [AIX]", PAGE_SIZE);
+		seq_buf_puts(&state->pp_buf, " [AIX]");
 		return 0;
 #endif
 	}
@@ -629,7 +608,7 @@ int msdos_partition(struct parsed_partitions *state)
 			fb = (struct fat_boot_sector *) data;
 			if (slot == 1 && fb->reserved && fb->fats
 				&& fat_valid_media(fb->media)) {
-				strlcat(state->pp_buf, "\n", PAGE_SIZE);
+				seq_buf_puts(&state->pp_buf, "\n");
 				put_dev_sector(sect);
 				return 1;
 			} else {
@@ -678,9 +657,9 @@ int msdos_partition(struct parsed_partitions *state)
 			n = min(size, max(sector_size, n));
 			put_partition(state, slot, start, n);
 
-			strlcat(state->pp_buf, " <", PAGE_SIZE);
+			seq_buf_puts(&state->pp_buf, " <");
 			parse_extended(state, start, size, disksig);
-			strlcat(state->pp_buf, " >", PAGE_SIZE);
+			seq_buf_puts(&state->pp_buf, " >");
 			continue;
 		}
 		put_partition(state, slot, start, size);
@@ -688,12 +667,12 @@ int msdos_partition(struct parsed_partitions *state)
 		if (p->sys_ind == LINUX_RAID_PARTITION)
 			state->parts[slot].flags = ADDPART_FLAG_RAID;
 		if (p->sys_ind == DM6_PARTITION)
-			strlcat(state->pp_buf, "[DM]", PAGE_SIZE);
+			seq_buf_puts(&state->pp_buf, "[DM]");
 		if (p->sys_ind == EZD_PARTITION)
-			strlcat(state->pp_buf, "[EZD]", PAGE_SIZE);
+			seq_buf_puts(&state->pp_buf, "[EZD]");
 	}
 
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 
 	/* second pass - output for each on a separate line */
 	p = (struct msdos_partition *) (0x1be + data);
diff --git a/block/partitions/of.c b/block/partitions/of.c
index 4e760fdffb3f..c22b60661098 100644
--- a/block/partitions/of.c
+++ b/block/partitions/of.c
@@ -36,7 +36,6 @@ static void add_of_partition(struct parsed_partitions *state, int slot,
 			     struct device_node *np)
 {
 	struct partition_meta_info *info;
-	char tmp[sizeof(info->volname) + 4];
 	const char *partname;
 	int len;
 
@@ -63,8 +62,7 @@ static void add_of_partition(struct parsed_partitions *state, int slot,
 		partname = of_get_property(np, "name", &len);
 	strscpy(info->volname, partname, sizeof(info->volname));
 
-	snprintf(tmp, sizeof(tmp), "(%s)", info->volname);
-	strlcat(state->pp_buf, tmp, PAGE_SIZE);
+	seq_buf_printf(&state->pp_buf, "(%s)", info->volname);
 }
 
 int of_partition(struct parsed_partitions *state)
@@ -104,7 +102,7 @@ int of_partition(struct parsed_partitions *state)
 		slot++;
 	}
 
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 
 	return 1;
 }
diff --git a/block/partitions/osf.c b/block/partitions/osf.c
index 84560d0765ed..2a692584dba9 100644
--- a/block/partitions/osf.c
+++ b/block/partitions/osf.c
@@ -81,7 +81,7 @@ int osf_partition(struct parsed_partitions *state)
 				le32_to_cpu(partition->p_size));
 		slot++;
 	}
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 	put_dev_sector(sect);
 	return 1;
 }
diff --git a/block/partitions/sgi.c b/block/partitions/sgi.c
index b5ecddd5181a..2383ca63cd66 100644
--- a/block/partitions/sgi.c
+++ b/block/partitions/sgi.c
@@ -79,7 +79,7 @@ int sgi_partition(struct parsed_partitions *state)
 		}
 		slot++;
 	}
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 	put_dev_sector(sect);
 	return 1;
 }
diff --git a/block/partitions/sun.c b/block/partitions/sun.c
index 2419af76120f..92c645fcd2e0 100644
--- a/block/partitions/sun.c
+++ b/block/partitions/sun.c
@@ -121,7 +121,7 @@ int sun_partition(struct parsed_partitions *state)
 		}
 		slot++;
 	}
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 	put_dev_sector(sect);
 	return 1;
 }
diff --git a/block/partitions/sysv68.c b/block/partitions/sysv68.c
index 6f6257fd4eb4..470e0f9de7be 100644
--- a/block/partitions/sysv68.c
+++ b/block/partitions/sysv68.c
@@ -54,7 +54,6 @@ int sysv68_partition(struct parsed_partitions *state)
 	unsigned char *data;
 	struct dkblk0 *b;
 	struct slice *slice;
-	char tmp[64];
 
 	data = read_part_sector(state, 0, &sect);
 	if (!data)
@@ -74,8 +73,7 @@ int sysv68_partition(struct parsed_partitions *state)
 		return -1;
 
 	slices -= 1; /* last slice is the whole disk */
-	snprintf(tmp, sizeof(tmp), "sysV68: %s(s%u)", state->name, slices);
-	strlcat(state->pp_buf, tmp, PAGE_SIZE);
+	seq_buf_printf(&state->pp_buf, "sysV68: %s(s%u)", state->name, slices);
 	slice = (struct slice *)data;
 	for (i = 0; i < slices; i++, slice++) {
 		if (slot == state->limit)
@@ -84,12 +82,11 @@ int sysv68_partition(struct parsed_partitions *state)
 			put_partition(state, slot,
 				be32_to_cpu(slice->blkoff),
 				be32_to_cpu(slice->nblocks));
-			snprintf(tmp, sizeof(tmp), "(s%u)", i);
-			strlcat(state->pp_buf, tmp, PAGE_SIZE);
+			seq_buf_printf(&state->pp_buf, "(s%u)", i);
 		}
 		slot++;
 	}
-	strlcat(state->pp_buf, "\n", PAGE_SIZE);
+	seq_buf_puts(&state->pp_buf, "\n");
 	put_dev_sector(sect);
 	return 1;
 }
diff --git a/block/partitions/ultrix.c b/block/partitions/ultrix.c
index 4aaa81043ca0..b4b9ddc57a5d 100644
--- a/block/partitions/ultrix.c
+++ b/block/partitions/ultrix.c
@@ -39,7 +39,7 @@ int ultrix_partition(struct parsed_partitions *state)
 					      label->pt_part[i].pi_blkoff,
 					      label->pt_part[i].pi_nblocks);
 		put_dev_sector(sect);
-		strlcat(state->pp_buf, "\n", PAGE_SIZE);
+		seq_buf_puts(&state->pp_buf, "\n");
 		return 1;
 	} else {
 		put_dev_sector(sect);
-- 
2.34.1