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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
| commit | 4352b8aee98005853aa63f57d6377282de17a33f (patch) | |
| tree | 27614d7a9ef05c32d089004e104364ce42324837 /fs/ramfs/inode.c | |
| download | linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip | |
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
...
Diffstat (limited to 'fs/ramfs/inode.c')
| -rw-r--r-- | fs/ramfs/inode.c | 329 |
1 files changed, 329 insertions, 0 deletions
diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c new file mode 100644 index 000000000..0a88ede48 --- /dev/null +++ b/fs/ramfs/inode.c @@ -0,0 +1,329 @@ +/* + * Resizable simple ram filesystem for Linux. + * + * Copyright (C) 2000 Linus Torvalds. + * 2000 Transmeta Corp. + * + * Usage limits added by David Gibson, Linuxcare Australia. + * This file is released under the GPL. + */ + +/* + * NOTE! This filesystem is probably most useful + * not as a real filesystem, but as an example of + * how virtual filesystems can be written. + * + * It doesn't get much simpler than this. Consider + * that this file implements the full semantics of + * a POSIX-compliant read-write filesystem. + * + * Note in particular how the filesystem does not + * need to implement any data structures of its own + * to keep track of the virtual data: using the VFS + * caches is sufficient. + */ + +#include <linux/fs.h> +#include <linux/pagemap.h> +#include <linux/highmem.h> +#include <linux/time.h> +#include <linux/init.h> +#include <linux/string.h> +#include <linux/backing-dev.h> +#include <linux/ramfs.h> +#include <linux/sched.h> +#include <linux/parser.h> +#include <linux/magic.h> +#include <linux/slab.h> +#include <linux/uaccess.h> +#include <linux/fs_context.h> +#include <linux/fs_parser.h> +#include <linux/seq_file.h> +#include "internal.h" + +struct ramfs_mount_opts { + umode_t mode; +}; + +struct ramfs_fs_info { + struct ramfs_mount_opts mount_opts; +}; + +#define RAMFS_DEFAULT_MODE 0755 + +static const struct super_operations ramfs_ops; +static const struct inode_operations ramfs_dir_inode_operations; + +struct inode *ramfs_get_inode(struct super_block *sb, + const struct inode *dir, umode_t mode, dev_t dev) +{ + struct inode * inode = new_inode(sb); + + if (inode) { + inode->i_ino = get_next_ino(); + inode_init_owner(&nop_mnt_idmap, inode, dir, mode); + inode->i_mapping->a_ops = &ram_aops; + mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER); + mapping_set_unevictable(inode->i_mapping); + simple_inode_init_ts(inode); + switch (mode & S_IFMT) { + default: + init_special_inode(inode, mode, dev); + break; + case S_IFREG: + inode->i_op = &ramfs_file_inode_operations; + inode->i_fop = &ramfs_file_operations; + break; + case S_IFDIR: + inode->i_op = &ramfs_dir_inode_operations; + inode->i_fop = &simple_dir_operations; + + /* directory inodes start off with i_nlink == 2 (for "." entry) */ + inc_nlink(inode); + break; + case S_IFLNK: + inode->i_op = &page_symlink_inode_operations; + inode_nohighmem(inode); + break; + } + } + return inode; +} + +/* + * File creation. Allocate an inode, and we're done.. + */ +/* SMP-safe */ +static int +ramfs_mknod(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, umode_t mode, dev_t dev) +{ + struct inode * inode = ramfs_get_inode(dir->i_sb, dir, mode, dev); + int error = -ENOSPC; + + if (inode) { + error = security_inode_init_security(inode, dir, + &dentry->d_name, NULL, + NULL); + if (error) { + iput(inode); + goto out; + } + + d_make_persistent(dentry, inode); + error = 0; + inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); + } +out: + return error; +} + +static struct dentry *ramfs_mkdir(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, umode_t mode) +{ + int retval = ramfs_mknod(&nop_mnt_idmap, dir, dentry, mode, 0); + if (!retval) + inc_nlink(dir); + return ERR_PTR(retval); +} + +static int ramfs_create(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, umode_t mode) +{ + return ramfs_mknod(&nop_mnt_idmap, dir, dentry, mode | S_IFREG, 0); +} + +static int ramfs_symlink(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, const char *symname) +{ + struct inode *inode; + int error = -ENOSPC; + + inode = ramfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0); + if (inode) { + int l = strlen(symname)+1; + + error = security_inode_init_security(inode, dir, + &dentry->d_name, NULL, + NULL); + if (error) { + iput(inode); + goto out; + } + + error = page_symlink(inode, symname, l); + if (!error) { + d_make_persistent(dentry, inode); + inode_set_mtime_to_ts(dir, + inode_set_ctime_current(dir)); + } else + iput(inode); + } +out: + return error; +} + +static int ramfs_tmpfile(struct mnt_idmap *idmap, + struct inode *dir, struct file *file, umode_t mode) +{ + struct inode *inode; + int error; + + inode = ramfs_get_inode(dir->i_sb, dir, mode, 0); + if (!inode) + return -ENOSPC; + + error = security_inode_init_security(inode, dir, + &file_dentry(file)->d_name, NULL, + NULL); + if (error) { + iput(inode); + goto out; + } + + d_tmpfile(file, inode); +out: + return finish_open_simple(file, error); +} + +static const struct inode_operations ramfs_dir_inode_operations = { + .create = ramfs_create, + .lookup = simple_lookup, + .link = simple_link, + .unlink = simple_unlink, + .symlink = ramfs_symlink, + .mkdir = ramfs_mkdir, + .rmdir = simple_rmdir, + .mknod = ramfs_mknod, + .rename = simple_rename, + .tmpfile = ramfs_tmpfile, +}; + +/* + * Display the mount options in /proc/mounts. + */ +static int ramfs_show_options(struct seq_file *m, struct dentry *root) +{ + struct ramfs_fs_info *fsi = root->d_sb->s_fs_info; + + if (fsi->mount_opts.mode != RAMFS_DEFAULT_MODE) + seq_printf(m, ",mode=%o", fsi->mount_opts.mode); + return 0; +} + +static const struct super_operations ramfs_ops = { + .statfs = simple_statfs, + .drop_inode = inode_just_drop, + .show_options = ramfs_show_options, +}; + +enum ramfs_param { + Opt_mode, +}; + +const struct fs_parameter_spec ramfs_fs_parameters[] = { + fsparam_u32oct("mode", Opt_mode), + {} +}; + +static int ramfs_parse_param(struct fs_context *fc, struct fs_parameter *param) +{ + struct fs_parse_result result; + struct ramfs_fs_info *fsi = fc->s_fs_info; + int opt; + + opt = fs_parse(fc, ramfs_fs_parameters, param, &result); + if (opt == -ENOPARAM) { + opt = vfs_parse_fs_param_source(fc, param); + if (opt != -ENOPARAM) + return opt; + /* + * We might like to report bad mount options here; + * but traditionally ramfs has ignored all mount options, + * and as it is used as a !CONFIG_SHMEM simple substitute + * for tmpfs, better continue to ignore other mount options. + */ + return 0; + } + if (opt < 0) + return opt; + + switch (opt) { + case Opt_mode: + fsi->mount_opts.mode = result.uint_32 & S_IALLUGO; + break; + } + + return 0; +} + +static int ramfs_fill_super(struct super_block *sb, struct fs_context *fc) +{ + struct ramfs_fs_info *fsi = sb->s_fs_info; + struct inode *inode; + + sb->s_maxbytes = MAX_LFS_FILESIZE; + sb->s_blocksize = PAGE_SIZE; + sb->s_blocksize_bits = PAGE_SHIFT; + sb->s_magic = RAMFS_MAGIC; + sb->s_op = &ramfs_ops; + sb->s_d_flags = DCACHE_DONTCACHE; + sb->s_time_gran = 1; + + inode = ramfs_get_inode(sb, NULL, S_IFDIR | fsi->mount_opts.mode, 0); + sb->s_root = d_make_root(inode); + if (!sb->s_root) + return -ENOMEM; + + return 0; +} + +static int ramfs_get_tree(struct fs_context *fc) +{ + return get_tree_nodev(fc, ramfs_fill_super); +} + +static void ramfs_free_fc(struct fs_context *fc) +{ + kfree(fc->s_fs_info); +} + +static const struct fs_context_operations ramfs_context_ops = { + .free = ramfs_free_fc, + .parse_param = ramfs_parse_param, + .get_tree = ramfs_get_tree, +}; + +int ramfs_init_fs_context(struct fs_context *fc) +{ + struct ramfs_fs_info *fsi; + + fsi = kzalloc_obj(*fsi); + if (!fsi) + return -ENOMEM; + + fsi->mount_opts.mode = RAMFS_DEFAULT_MODE; + fc->s_fs_info = fsi; + fc->ops = &ramfs_context_ops; + return 0; +} + +void ramfs_kill_sb(struct super_block *sb) +{ + kfree(sb->s_fs_info); + kill_anon_super(sb); +} + +static struct file_system_type ramfs_fs_type = { + .name = "ramfs", + .init_fs_context = ramfs_init_fs_context, + .parameters = ramfs_fs_parameters, + .kill_sb = ramfs_kill_sb, + .fs_flags = FS_USERNS_MOUNT, +}; + +static int __init init_ramfs_fs(void) +{ + return register_filesystem(&ramfs_fs_type); +} +fs_initcall(init_ramfs_fs); |
