Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted

Pull I3C updates from Alexandre Belloni:
 "A new driver this cycle, for the AMD AXI I3C controller.

  There are also new features such as IBI wakeup support, SETAASA device
  discovery and ACPI support for the the DAA methods, meaning we can now
  communicate with the SPD devices on DDR5 modules.

  New driver:
   - AMD AXI I3C master controller

  Subsystem:
   - I3C Common Command Code (CCC) handling improvements, especially
     around GET CCCs
   - SETAASA device discovery support
   - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
     well as I2C devices on I3C bus
   - IBI-based wakeup support

  Drivers:
   - dw: SETAASA support
   - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
     controller support, PIO queue management support for HCI v1.2
   - renesas: improve suspend to RAM support, add runtime PM support"

* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
  i3c: dw: reduce do_daa time if there's no client
  i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
  i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
  i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
  i3c: dw: rename "pclk" to "apb" to match dt-binding
  i3c: dw: make struct dw_i3c_cmd smaller
  i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
  i3c: renesas: Don't register devices when ENTDAA times out
  i3c: master: dw-i3c-master: fix OD timing for first broadcast
  i3c: mipi-i3c-hci: Advertise IBI wakeup capability
  i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
  i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
  i3c: master: Reject IBI requests from non-IBI-capable devices
  i3c: master: Add helper to query bus wakeup requirements
  i3c: master: Report wakeup events for IBIs
  i3c: master: Support IBI-based wakeup capability
  i3c: master: Fix potential UAF in i3c_device_match()
  i3c: master: Fix potential UAF in i3c_device_uevent()
  i3c: Make dev->desc locking assumptions explicit
  i3c: master: Fix use-after-free of master->this
  ...

7 files changed, 807 insertions, 0 deletions

diff --git a/fs/qnx4/Kconfig b/fs/qnx4/Kconfig
new file mode 100644
index 000000000..a2eb826e7
--- /dev/null
+++ b/fs/qnx4/Kconfig
@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config QNX4FS_FS
+	tristate "QNX4 file system support (read only)"
+	depends on BLOCK
+	select BUFFER_HEAD
+	help
+	  This is the file system used by the real-time operating systems
+	  QNX 4 and QNX 6 (the latter is also called QNX RTP).
+	  Further information is available at <http://www.qnx.com/>.
+	  Say Y if you intend to mount QNX hard disks or floppies.
+
+	  To compile this file system support as a module, choose M here: the
+	  module will be called qnx4.
+
+	  If you don't know whether you need it, then you don't need it:
+	  answer N.
diff --git a/fs/qnx4/Makefile b/fs/qnx4/Makefile
new file mode 100644
index 000000000..42d4fc263
--- /dev/null
+++ b/fs/qnx4/Makefile
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for the linux qnx4-filesystem routines.
+#
+
+obj-$(CONFIG_QNX4FS_FS) += qnx4.o
+
+qnx4-objs := inode.o dir.o namei.o bitmap.o
diff --git a/fs/qnx4/bitmap.c b/fs/qnx4/bitmap.c
new file mode 100644
index 000000000..163afc4ba
--- /dev/null
+++ b/fs/qnx4/bitmap.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * QNX4 file system, Linux implementation.
+ *
+ * Version : 0.2.1
+ *
+ * Using parts of the xiafs filesystem.
+ *
+ * History :
+ *
+ * 28-05-1998 by Richard Frowijn : first release.
+ * 20-06-1998 by Frank Denis : basic optimisations.
+ * 25-06-1998 by Frank Denis : qnx4_is_free, qnx4_set_bitmap, qnx4_bmap .
+ * 28-06-1998 by Frank Denis : qnx4_free_inode (to be fixed) .
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/bitops.h>
+#include "qnx4.h"
+
+unsigned long qnx4_count_free_blocks(struct super_block *sb)
+{
+	int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
+	int total = 0;
+	int total_free = 0;
+	int offset = 0;
+	int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size);
+	struct buffer_head *bh;
+
+	while (total < size) {
+		int bytes = min(size - total, QNX4_BLOCK_SIZE);
+
+		if ((bh = sb_bread(sb, start + offset)) == NULL) {
+			printk(KERN_ERR "qnx4: I/O error in counting free blocks\n");
+			break;
+		}
+		total_free += bytes * BITS_PER_BYTE -
+				memweight(bh->b_data, bytes);
+		brelse(bh);
+		total += bytes;
+		offset++;
+	}
+
+	return total_free;
+}
diff --git a/fs/qnx4/dir.c b/fs/qnx4/dir.c
new file mode 100644
index 000000000..a9038d231
--- /dev/null
+++ b/fs/qnx4/dir.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * QNX4 file system, Linux implementation.
+ *
+ * Version : 0.2.1
+ *
+ * Using parts of the xiafs filesystem.
+ *
+ * History :
+ *
+ * 28-05-1998 by Richard Frowijn : first release.
+ * 20-06-1998 by Frank Denis : Linux 2.1.99+ & dcache support.
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/filelock.h>
+#include "qnx4.h"
+
+static int qnx4_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct inode *inode = file_inode(file);
+	unsigned int offset;
+	struct buffer_head *bh;
+	unsigned long blknum;
+	int ix, ino;
+	int size;
+
+	QNX4DEBUG((KERN_INFO "qnx4_readdir:i_size = %ld\n", (long) inode->i_size));
+	QNX4DEBUG((KERN_INFO "pos                 = %ld\n", (long) ctx->pos));
+
+	while (ctx->pos < inode->i_size) {
+		blknum = qnx4_block_map(inode, ctx->pos >> QNX4_BLOCK_SIZE_BITS);
+		bh = sb_bread(inode->i_sb, blknum);
+		if (bh == NULL) {
+			printk(KERN_ERR "qnx4_readdir: bread failed (%ld)\n", blknum);
+			return 0;
+		}
+		ix = (ctx->pos >> QNX4_DIR_ENTRY_SIZE_BITS) % QNX4_INODES_PER_BLOCK;
+		for (; ix < QNX4_INODES_PER_BLOCK; ix++, ctx->pos += QNX4_DIR_ENTRY_SIZE) {
+			union qnx4_directory_entry *de;
+			const char *fname;
+
+			offset = ix * QNX4_DIR_ENTRY_SIZE;
+			de = (union qnx4_directory_entry *) (bh->b_data + offset);
+
+			fname = get_entry_fname(de, &size);
+			if (!fname)
+				continue;
+
+			if (!(de->de_status & QNX4_FILE_LINK)) {
+				ino = blknum * QNX4_INODES_PER_BLOCK + ix - 1;
+			} else {
+				ino = ( le32_to_cpu(de->link.dl_inode_blk) - 1 ) *
+					QNX4_INODES_PER_BLOCK +
+					de->link.dl_inode_ndx;
+			}
+
+			QNX4DEBUG((KERN_INFO "qnx4_readdir:%.*s\n", size, fname));
+			if (!dir_emit(ctx, fname, size, ino, DT_UNKNOWN)) {
+				brelse(bh);
+				return 0;
+			}
+		}
+		brelse(bh);
+	}
+	return 0;
+}
+
+const struct file_operations qnx4_dir_operations =
+{
+	.llseek		= generic_file_llseek,
+	.read		= generic_read_dir,
+	.iterate_shared	= qnx4_readdir,
+	.fsync		= simple_fsync,
+	.setlease	= generic_setlease,
+};
+
+const struct inode_operations qnx4_dir_inode_operations =
+{
+	.lookup		= qnx4_lookup,
+};
diff --git a/fs/qnx4/inode.c b/fs/qnx4/inode.c
new file mode 100644
index 000000000..42fcd500f
--- /dev/null
+++ b/fs/qnx4/inode.c
@@ -0,0 +1,436 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * QNX4 file system, Linux implementation.
+ *
+ * Version : 0.2.1
+ *
+ * Using parts of the xiafs filesystem.
+ *
+ * History :
+ *
+ * 01-06-1998 by Richard Frowijn : first release.
+ * 20-06-1998 by Frank Denis : Linux 2.1.99+ support, boot signature, misc.
+ * 30-06-1998 by Frank Denis : first step to write inodes.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/highuid.h>
+#include <linux/pagemap.h>
+#include <linux/buffer_head.h>
+#include <linux/writeback.h>
+#include <linux/statfs.h>
+#include <linux/fs_context.h>
+#include "qnx4.h"
+
+#define QNX4_VERSION  4
+#define QNX4_BMNAME   ".bitmap"
+
+static const struct super_operations qnx4_sops;
+
+static struct inode *qnx4_alloc_inode(struct super_block *sb);
+static void qnx4_free_inode(struct inode *inode);
+static int qnx4_statfs(struct dentry *, struct kstatfs *);
+static int qnx4_get_tree(struct fs_context *fc);
+
+static const struct super_operations qnx4_sops =
+{
+	.alloc_inode	= qnx4_alloc_inode,
+	.free_inode	= qnx4_free_inode,
+	.statfs		= qnx4_statfs,
+};
+
+static int qnx4_reconfigure(struct fs_context *fc)
+{
+	struct super_block *sb = fc->root->d_sb;
+	struct qnx4_sb_info *qs;
+
+	sync_filesystem(sb);
+	qs = qnx4_sb(sb);
+	qs->Version = QNX4_VERSION;
+	fc->sb_flags |= SB_RDONLY;
+	return 0;
+}
+
+static const struct fs_context_operations qnx4_context_opts = {
+	.get_tree	= qnx4_get_tree,
+	.reconfigure	= qnx4_reconfigure,
+};
+
+static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
+{
+	unsigned long phys;
+
+	QNX4DEBUG((KERN_INFO "qnx4: qnx4_get_block inode=[%llu] iblock=[%ld]\n", inode->i_ino, iblock));
+
+	phys = qnx4_block_map( inode, iblock );
+	if ( phys ) {
+		// logical block is before EOF
+		map_bh(bh, inode->i_sb, phys);
+	}
+	return 0;
+}
+
+static inline u32 try_extent(qnx4_xtnt_t *extent, u32 *offset)
+{
+	u32 size = le32_to_cpu(extent->xtnt_size);
+	if (*offset < size)
+		return le32_to_cpu(extent->xtnt_blk) + *offset - 1;
+	*offset -= size;
+	return 0;
+}
+
+unsigned long qnx4_block_map( struct inode *inode, long iblock )
+{
+	int ix;
+	long i_xblk;
+	struct buffer_head *bh = NULL;
+	struct qnx4_xblk *xblk = NULL;
+	struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
+	u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
+	u32 offset = iblock;
+	u32 block = try_extent(&qnx4_inode->di_first_xtnt, &offset);
+
+	if (block) {
+		// iblock is in the first extent. This is easy.
+	} else {
+		// iblock is beyond first extent. We have to follow the extent chain.
+		i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
+		ix = 0;
+		while ( --nxtnt > 0 ) {
+			if ( ix == 0 ) {
+				// read next xtnt block.
+				bh = sb_bread(inode->i_sb, i_xblk - 1);
+				if ( !bh ) {
+					QNX4DEBUG((KERN_ERR "qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
+					return -EIO;
+				}
+				xblk = (struct qnx4_xblk*)bh->b_data;
+				if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
+					QNX4DEBUG((KERN_ERR "qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
+					return -EIO;
+				}
+			}
+			block = try_extent(&xblk->xblk_xtnts[ix], &offset);
+			if (block) {
+				// got it!
+				break;
+			}
+			if ( ++ix >= xblk->xblk_num_xtnts ) {
+				i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
+				ix = 0;
+				brelse( bh );
+				bh = NULL;
+			}
+		}
+		if ( bh )
+			brelse( bh );
+	}
+
+	QNX4DEBUG((KERN_INFO "qnx4: mapping block %ld of inode %llu = %ld\n", iblock, inode->i_ino, block));
+	return block;
+}
+
+static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct super_block *sb = dentry->d_sb;
+	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
+
+	buf->f_type    = sb->s_magic;
+	buf->f_bsize   = sb->s_blocksize;
+	buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
+	buf->f_bfree   = qnx4_count_free_blocks(sb);
+	buf->f_bavail  = buf->f_bfree;
+	buf->f_namelen = QNX4_NAME_MAX;
+	buf->f_fsid    = u64_to_fsid(id);
+
+	return 0;
+}
+
+/*
+ * Check the root directory of the filesystem to make sure
+ * it really _is_ a qnx4 filesystem, and to check the size
+ * of the directory entry.
+ */
+static const char *qnx4_checkroot(struct super_block *sb,
+				  struct qnx4_super_block *s)
+{
+	struct buffer_head *bh;
+	struct qnx4_inode_entry *rootdir;
+	int rd, rl;
+	int i, j;
+
+	if (s->RootDir.di_fname[0] != '/' || s->RootDir.di_fname[1] != '\0')
+		return "no qnx4 filesystem (no root dir).";
+	QNX4DEBUG((KERN_NOTICE "QNX4 filesystem found on dev %s.\n", sb->s_id));
+	rd = le32_to_cpu(s->RootDir.di_first_xtnt.xtnt_blk) - 1;
+	rl = le32_to_cpu(s->RootDir.di_first_xtnt.xtnt_size);
+	for (j = 0; j < rl; j++) {
+		bh = sb_bread(sb, rd + j);	/* root dir, first block */
+		if (bh == NULL)
+			return "unable to read root entry.";
+		rootdir = (struct qnx4_inode_entry *) bh->b_data;
+		for (i = 0; i < QNX4_INODES_PER_BLOCK; i++, rootdir++) {
+			QNX4DEBUG((KERN_INFO "rootdir entry found : [%s]\n", rootdir->di_fname));
+			if (strcmp(rootdir->di_fname, QNX4_BMNAME) != 0)
+				continue;
+			qnx4_sb(sb)->BitMap = kmemdup(rootdir,
+						      sizeof(struct qnx4_inode_entry),
+						      GFP_KERNEL);
+			brelse(bh);
+			if (!qnx4_sb(sb)->BitMap)
+				return "not enough memory for bitmap inode";
+			/* keep bitmap inode known */
+			return NULL;
+		}
+		brelse(bh);
+	}
+	return "bitmap file not found.";
+}
+
+static int qnx4_fill_super(struct super_block *s, struct fs_context *fc)
+{
+	struct buffer_head *bh;
+	struct inode *root;
+	const char *errmsg;
+	struct qnx4_sb_info *qs;
+	int silent = fc->sb_flags & SB_SILENT;
+
+	qs = kzalloc_obj(struct qnx4_sb_info);
+	if (!qs)
+		return -ENOMEM;
+	s->s_fs_info = qs;
+
+	if (!sb_set_blocksize(s, QNX4_BLOCK_SIZE))
+		return -EINVAL;
+
+	s->s_op = &qnx4_sops;
+	s->s_magic = QNX4_SUPER_MAGIC;
+	s->s_flags |= SB_RDONLY;	/* Yup, read-only yet */
+	s->s_time_min = 0;
+	s->s_time_max = U32_MAX;
+
+	/* Check the superblock signature. Since the qnx4 code is
+	   dangerous, we should leave as quickly as possible
+	   if we don't belong here... */
+	bh = sb_bread(s, 1);
+	if (!bh) {
+		printk(KERN_ERR "qnx4: unable to read the superblock\n");
+		return -EINVAL;
+	}
+
+ 	/* check before allocating dentries, inodes, .. */
+	errmsg = qnx4_checkroot(s, (struct qnx4_super_block *) bh->b_data);
+	brelse(bh);
+	if (errmsg != NULL) {
+		if (!silent)
+			printk(KERN_ERR "qnx4: %s\n", errmsg);
+		return -EINVAL;
+	}
+
+ 	/* does root not have inode number QNX4_ROOT_INO ?? */
+	root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
+	if (IS_ERR(root)) {
+		printk(KERN_ERR "qnx4: get inode failed\n");
+		return PTR_ERR(root);
+ 	}
+
+ 	s->s_root = d_make_root(root);
+ 	if (s->s_root == NULL)
+ 		return -ENOMEM;
+
+	return 0;
+}
+
+static int qnx4_get_tree(struct fs_context *fc)
+{
+	return get_tree_bdev(fc, qnx4_fill_super);
+}
+
+static int qnx4_init_fs_context(struct fs_context *fc)
+{
+	fc->ops = &qnx4_context_opts;
+
+	return 0;
+}
+
+static void qnx4_kill_sb(struct super_block *sb)
+{
+	struct qnx4_sb_info *qs = qnx4_sb(sb);
+	kill_block_super(sb);
+	if (qs) {
+		kfree(qs->BitMap);
+		kfree(qs);
+	}
+}
+
+static int qnx4_read_folio(struct file *file, struct folio *folio)
+{
+	return block_read_full_folio(folio, qnx4_get_block);
+}
+
+static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
+{
+	return generic_block_bmap(mapping,block,qnx4_get_block);
+}
+
+static const struct address_space_operations qnx4_aops = {
+	.read_folio	= qnx4_read_folio,
+	.bmap		= qnx4_bmap
+};
+
+struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
+{
+	struct buffer_head *bh;
+	struct qnx4_inode_entry *raw_inode;
+	int block;
+	struct qnx4_inode_entry *qnx4_inode;
+	struct inode *inode;
+
+	inode = iget_locked(sb, ino);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	if (!(inode_state_read_once(inode) & I_NEW))
+		return inode;
+
+	qnx4_inode = qnx4_raw_inode(inode);
+	inode->i_mode = 0;
+
+	QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
+	if (!ino) {
+		printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
+				"out of range\n",
+		       sb->s_id, ino);
+		iget_failed(inode);
+		return ERR_PTR(-EIO);
+	}
+	block = ino / QNX4_INODES_PER_BLOCK;
+
+	if (!(bh = sb_bread(sb, block))) {
+		printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
+		       "%s\n", sb->s_id);
+		iget_failed(inode);
+		return ERR_PTR(-EIO);
+	}
+	raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
+	    (ino % QNX4_INODES_PER_BLOCK);
+
+	inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
+	i_uid_write(inode, (uid_t)le16_to_cpu(raw_inode->di_uid));
+	i_gid_write(inode, (gid_t)le16_to_cpu(raw_inode->di_gid));
+	set_nlink(inode, le16_to_cpu(raw_inode->di_nlink));
+	inode->i_size    = le32_to_cpu(raw_inode->di_size);
+	inode_set_mtime(inode, le32_to_cpu(raw_inode->di_mtime), 0);
+	inode_set_atime(inode, le32_to_cpu(raw_inode->di_atime), 0);
+	inode_set_ctime(inode, le32_to_cpu(raw_inode->di_ctime), 0);
+	inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
+
+	memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
+	if (S_ISREG(inode->i_mode)) {
+		inode->i_fop = &generic_ro_fops;
+		inode->i_mapping->a_ops = &qnx4_aops;
+		qnx4_i(inode)->mmu_private = inode->i_size;
+	} else if (S_ISDIR(inode->i_mode)) {
+		inode->i_op = &qnx4_dir_inode_operations;
+		inode->i_fop = &qnx4_dir_operations;
+	} else if (S_ISLNK(inode->i_mode)) {
+		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
+		inode->i_mapping->a_ops = &qnx4_aops;
+		qnx4_i(inode)->mmu_private = inode->i_size;
+	} else {
+		printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
+			ino, sb->s_id);
+		iget_failed(inode);
+		brelse(bh);
+		return ERR_PTR(-EIO);
+	}
+	brelse(bh);
+	unlock_new_inode(inode);
+	return inode;
+}
+
+static struct kmem_cache *qnx4_inode_cachep;
+
+static struct inode *qnx4_alloc_inode(struct super_block *sb)
+{
+	struct qnx4_inode_info *ei;
+	ei = alloc_inode_sb(sb, qnx4_inode_cachep, GFP_KERNEL);
+	if (!ei)
+		return NULL;
+	return &ei->vfs_inode;
+}
+
+static void qnx4_free_inode(struct inode *inode)
+{
+	kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
+}
+
+static void init_once(void *foo)
+{
+	struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
+
+	inode_init_once(&ei->vfs_inode);
+}
+
+static int init_inodecache(void)
+{
+	qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
+					     sizeof(struct qnx4_inode_info),
+					     0, (SLAB_RECLAIM_ACCOUNT|
+						SLAB_ACCOUNT),
+					     init_once);
+	if (qnx4_inode_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+static void destroy_inodecache(void)
+{
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(qnx4_inode_cachep);
+}
+
+static struct file_system_type qnx4_fs_type = {
+	.owner			= THIS_MODULE,
+	.name			= "qnx4",
+	.kill_sb		= qnx4_kill_sb,
+	.fs_flags		= FS_REQUIRES_DEV,
+	.init_fs_context	= qnx4_init_fs_context,
+};
+MODULE_ALIAS_FS("qnx4");
+
+static int __init init_qnx4_fs(void)
+{
+	int err;
+
+	err = init_inodecache();
+	if (err)
+		return err;
+
+	err = register_filesystem(&qnx4_fs_type);
+	if (err) {
+		destroy_inodecache();
+		return err;
+	}
+
+	printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
+	return 0;
+}
+
+static void __exit exit_qnx4_fs(void)
+{
+	unregister_filesystem(&qnx4_fs_type);
+	destroy_inodecache();
+}
+
+module_init(init_qnx4_fs)
+module_exit(exit_qnx4_fs)
+MODULE_DESCRIPTION("QNX4 file system");
+MODULE_LICENSE("GPL");
+
diff --git a/fs/qnx4/namei.c b/fs/qnx4/namei.c
new file mode 100644
index 000000000..bb8db6550
--- /dev/null
+++ b/fs/qnx4/namei.c
@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: GPL-2.0
+/* 
+ * QNX4 file system, Linux implementation.
+ * 
+ * Version : 0.2.1
+ * 
+ * Using parts of the xiafs filesystem.
+ * 
+ * History :
+ * 
+ * 01-06-1998 by Richard Frowijn : first release.
+ * 21-06-1998 by Frank Denis : dcache support, fixed error codes.
+ * 04-07-1998 by Frank Denis : first step for rmdir/unlink.
+ */
+
+#include <linux/buffer_head.h>
+#include "qnx4.h"
+
+
+/*
+ * check if the filename is correct. For some obscure reason, qnx writes a
+ * new file twice in the directory entry, first with all possible options at 0
+ * and for a second time the way it is, they want us not to access the qnx
+ * filesystem when whe are using linux.
+ */
+static int qnx4_match(int len, const char *name,
+		      struct buffer_head *bh, unsigned long *offset)
+{
+	union qnx4_directory_entry *de;
+	const char *fname;
+	int fnamelen;
+
+	if (bh == NULL) {
+		printk(KERN_WARNING "qnx4: matching unassigned buffer !\n");
+		return 0;
+	}
+	de = (union qnx4_directory_entry *) (bh->b_data + *offset);
+	*offset += QNX4_DIR_ENTRY_SIZE;
+
+	fname = get_entry_fname(de, &fnamelen);
+	if (!fname || len != fnamelen)
+		return 0;
+
+	if (strncmp(name, fname, len) == 0)
+		return 1;
+
+	return 0;
+}
+
+static struct buffer_head *qnx4_find_entry(int len, struct inode *dir,
+	   const char *name, struct qnx4_inode_entry **res_dir, int *ino)
+{
+	unsigned long block, offset, blkofs;
+	struct buffer_head *bh;
+
+	*res_dir = NULL;
+	bh = NULL;
+	block = offset = blkofs = 0;
+	while (blkofs * QNX4_BLOCK_SIZE + offset < dir->i_size) {
+		if (!bh) {
+			block = qnx4_block_map(dir, blkofs);
+			if (block)
+				bh = sb_bread(dir->i_sb, block);
+			if (!bh) {
+				blkofs++;
+				continue;
+			}
+		}
+		*res_dir = (struct qnx4_inode_entry *) (bh->b_data + offset);
+		if (qnx4_match(len, name, bh, &offset)) {
+			*ino = block * QNX4_INODES_PER_BLOCK +
+			    (offset / QNX4_DIR_ENTRY_SIZE) - 1;
+			return bh;
+		}
+		if (offset < bh->b_size) {
+			continue;
+		}
+		brelse(bh);
+		bh = NULL;
+		offset = 0;
+		blkofs++;
+	}
+	brelse(bh);
+	*res_dir = NULL;
+	return NULL;
+}
+
+struct dentry * qnx4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
+{
+	int ino;
+	struct qnx4_inode_entry *de;
+	struct qnx4_link_info *lnk;
+	struct buffer_head *bh;
+	const char *name = dentry->d_name.name;
+	int len = dentry->d_name.len;
+	struct inode *foundinode = NULL;
+
+	if (!(bh = qnx4_find_entry(len, dir, name, &de, &ino)))
+		goto out;
+	/* The entry is linked, let's get the real info */
+	if ((de->di_status & QNX4_FILE_LINK) == QNX4_FILE_LINK) {
+		lnk = (struct qnx4_link_info *) de;
+		ino = (le32_to_cpu(lnk->dl_inode_blk) - 1) *
+                    QNX4_INODES_PER_BLOCK +
+		    lnk->dl_inode_ndx;
+	}
+	brelse(bh);
+
+	foundinode = qnx4_iget(dir->i_sb, ino);
+	if (IS_ERR(foundinode))
+		QNX4DEBUG((KERN_ERR "qnx4: lookup->iget -> error %ld\n",
+			   PTR_ERR(foundinode)));
+out:
+	return d_splice_alias(foundinode, dentry);
+}
diff --git a/fs/qnx4/qnx4.h b/fs/qnx4/qnx4.h
new file mode 100644
index 000000000..5c2b1fb6b
--- /dev/null
+++ b/fs/qnx4/qnx4.h
@@ -0,0 +1,106 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/fs.h>
+#include <linux/qnx4_fs.h>
+
+#define QNX4_DEBUG 0
+
+#if QNX4_DEBUG
+#define QNX4DEBUG(X) printk X
+#else
+#define QNX4DEBUG(X) (void) 0
+#endif
+
+struct qnx4_sb_info {
+	unsigned int		Version;	/* may be useful */
+	struct qnx4_inode_entry	*BitMap;	/* useful */
+};
+
+struct qnx4_inode_info {
+	struct qnx4_inode_entry raw;
+	loff_t mmu_private;
+	struct inode vfs_inode;
+};
+
+extern struct inode *qnx4_iget(struct super_block *, unsigned long);
+extern struct dentry *qnx4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags);
+extern unsigned long qnx4_count_free_blocks(struct super_block *sb);
+extern unsigned long qnx4_block_map(struct inode *inode, long iblock);
+
+extern const struct inode_operations qnx4_dir_inode_operations;
+extern const struct file_operations qnx4_dir_operations;
+extern int qnx4_is_free(struct super_block *sb, long block);
+
+static inline struct qnx4_sb_info *qnx4_sb(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
+static inline struct qnx4_inode_info *qnx4_i(struct inode *inode)
+{
+	return container_of(inode, struct qnx4_inode_info, vfs_inode);
+}
+
+static inline struct qnx4_inode_entry *qnx4_raw_inode(struct inode *inode)
+{
+	return &qnx4_i(inode)->raw;
+}
+
+/*
+ * A qnx4 directory entry is an inode entry or link info
+ * depending on the status field in the last byte. The
+ * first byte is where the name start either way, and a
+ * zero means it's empty.
+ *
+ * Also, due to a bug in gcc, we don't want to use the
+ * real (differently sized) name arrays in the inode and
+ * link entries, but always the 'de_name[]' one in the
+ * fake struct entry.
+ *
+ * See
+ *
+ *   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578#c6
+ *
+ * for details, but basically gcc will take the size of the
+ * 'name' array from one of the used union entries randomly.
+ *
+ * This use of 'de_name[]' (48 bytes) avoids the false positive
+ * warnings that would happen if gcc decides to use 'inode.di_name'
+ * (16 bytes) even when the pointer and size were to come from
+ * 'link.dl_name' (48 bytes).
+ *
+ * In all cases the actual name pointer itself is the same, it's
+ * only the gcc internal 'what is the size of this field' logic
+ * that can get confused.
+ */
+union qnx4_directory_entry {
+	struct {
+		const char de_name[48];
+		u8 de_pad[15];
+		u8 de_status;
+	};
+	struct qnx4_inode_entry inode;
+	struct qnx4_link_info link;
+};
+
+static inline const char *get_entry_fname(union qnx4_directory_entry *de,
+					  int *size)
+{
+	/* Make sure the status byte is in the same place for all structs. */
+	BUILD_BUG_ON(offsetof(struct qnx4_inode_entry, di_status) !=
+			offsetof(struct qnx4_link_info, dl_status));
+	BUILD_BUG_ON(offsetof(struct qnx4_inode_entry, di_status) !=
+			offsetof(union qnx4_directory_entry, de_status));
+
+	if (!de->de_name[0])
+		return NULL;
+	if (!(de->de_status & (QNX4_FILE_USED|QNX4_FILE_LINK)))
+		return NULL;
+	if (!(de->de_status & QNX4_FILE_LINK))
+		*size = sizeof(de->inode.di_fname);
+	else
+		*size = sizeof(de->link.dl_fname);
+
+	*size = strnlen(de->de_name, *size);
+
+	return de->de_name;
+}