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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 /*
  *  file.c - part of debugfs, a tiny little debug file system
  *
  *  Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
  *  Copyright (C) 2004 IBM Inc.
  *
  *  debugfs is for people to use instead of /proc or /sys.
  *  See Documentation/filesystems/ for more details.
  */
 
 #include <linux/module.h>
 #include <linux/fs.h>
 #include <linux/seq_file.h>
 #include <linux/pagemap.h>
 #include <linux/debugfs.h>
 #include <linux/io.h>
 #include <linux/slab.h>
 #include <linux/atomic.h>
 #include <linux/device.h>
 #include <linux/pm_runtime.h>
 #include <linux/poll.h>
 #include <linux/security.h>
 
 #include "internal.h"
 
 struct poll_table_struct;
 
 static ssize_t default_read_file(struct file *file, char __user *buf,
                  size_t count, loff_t *ppos)
 {
     return 0;
 }
 
 static ssize_t default_write_file(struct file *file, const char __user *buf,
                    size_t count, loff_t *ppos)
 {
     return count;
 }
 
 const struct file_operations debugfs_noop_file_operations = {
     .read =     default_read_file,
     .write =    default_write_file,
     .open =     simple_open,
     .llseek =   noop_llseek,
 };
 
 #define F_DENTRY(filp) ((filp)->f_path.dentry)
 
 const struct file_operations *debugfs_real_fops(const struct file *filp)
 {
     struct debugfs_fsdata *fsd = F_DENTRY(filp)->d_fsdata;
 
     if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) {
         /*
          * Urgh, we've been called w/o a protecting
          * debugfs_file_get().
          */
         WARN_ON(1);
         return NULL;
     }
 
     return fsd->real_fops;
 }
 EXPORT_SYMBOL_GPL(debugfs_real_fops);
 
 /**
  * debugfs_file_get - mark the beginning of file data access
  * @dentry: the dentry object whose data is being accessed.
  *
  * Up to a matching call to debugfs_file_put(), any successive call
  * into the file removing functions debugfs_remove() and
  * debugfs_remove_recursive() will block. Since associated private
  * file data may only get freed after a successful return of any of
  * the removal functions, you may safely access it after a successful
  * call to debugfs_file_get() without worrying about lifetime issues.
  *
  * If -%EIO is returned, the file has already been removed and thus,
  * it is not safe to access any of its data. If, on the other hand,
  * it is allowed to access the file data, zero is returned.
  */
 int debugfs_file_get(struct dentry *dentry)
 {
     struct debugfs_fsdata *fsd;
     void *d_fsd;
 
     d_fsd = READ_ONCE(dentry->d_fsdata);
     if (!((unsigned long)d_fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) {
         fsd = d_fsd;
     } else {
         fsd = kmalloc(sizeof(*fsd), GFP_KERNEL);
         if (!fsd)
             return -ENOMEM;
 
         fsd->real_fops = (void *)((unsigned long)d_fsd &
                     ~DEBUGFS_FSDATA_IS_REAL_FOPS_BIT);
         refcount_set(&fsd->active_users, 1);
         init_completion(&fsd->active_users_drained);
         if (cmpxchg(&dentry->d_fsdata, d_fsd, fsd) != d_fsd) {
             kfree(fsd);
             fsd = READ_ONCE(dentry->d_fsdata);
         }
     }
 
     /*
      * In case of a successful cmpxchg() above, this check is
      * strictly necessary and must follow it, see the comment in
      * __debugfs_remove_file().
      * OTOH, if the cmpxchg() hasn't been executed or wasn't
      * successful, this serves the purpose of not starving
      * removers.
      */
     if (d_unlinked(dentry))
         return -EIO;
 
     if (!refcount_inc_not_zero(&fsd->active_users))
         return -EIO;
 
     return 0;
 }
 EXPORT_SYMBOL_GPL(debugfs_file_get);
 
 /**
  * debugfs_file_put - mark the end of file data access
  * @dentry: the dentry object formerly passed to
  *          debugfs_file_get().
  *
  * Allow any ongoing concurrent call into debugfs_remove() or
  * debugfs_remove_recursive() blocked by a former call to
  * debugfs_file_get() to proceed and return to its caller.
  */
 void debugfs_file_put(struct dentry *dentry)
 {
     struct debugfs_fsdata *fsd = READ_ONCE(dentry->d_fsdata);
 
     if (refcount_dec_and_test(&fsd->active_users))
         complete(&fsd->active_users_drained);
 }
 EXPORT_SYMBOL_GPL(debugfs_file_put);
 
 /*
  * Only permit access to world-readable files when the kernel is locked down.
  * We also need to exclude any file that has ways to write or alter it as root
  * can bypass the permissions check.
  */
 static int debugfs_locked_down(struct inode *inode,
                    struct file *filp,
                    const struct file_operations *real_fops)
 {
     if ((inode->i_mode & 07777 & ~0444) == 0 &&
         !(filp->f_mode & FMODE_WRITE) &&
         !real_fops->unlocked_ioctl &&
         !real_fops->compat_ioctl &&
         !real_fops->mmap)
         return 0;
 
     if (security_locked_down(LOCKDOWN_DEBUGFS))
         return -EPERM;
 
     return 0;
 }
 
 static int open_proxy_open(struct inode *inode, struct file *filp)
 {
     struct dentry *dentry = F_DENTRY(filp);
     const struct file_operations *real_fops = NULL;
     int r;
 
     r = debugfs_file_get(dentry);
     if (r)
         return r == -EIO ? -ENOENT : r;
 
     real_fops = debugfs_real_fops(filp);
 
     r = debugfs_locked_down(inode, filp, real_fops);
     if (r)
         goto out;
 
     if (!fops_get(real_fops)) {
 #ifdef CONFIG_MODULES
         if (real_fops->owner &&
             real_fops->owner->state == MODULE_STATE_GOING) {
             r = -ENXIO;
             goto out;
         }
 #endif
 
         /* Huh? Module did not clean up after itself at exit? */
         WARN(1, "debugfs file owner did not clean up at exit: %pd",
             dentry);
         r = -ENXIO;
         goto out;
     }
     replace_fops(filp, real_fops);
 
     if (real_fops->open)
         r = real_fops->open(inode, filp);
 
 out:
     debugfs_file_put(dentry);
     return r;
 }
 
 const struct file_operations debugfs_open_proxy_file_operations = {
     .open = open_proxy_open,
 };
 
 #define PROTO(args...) args
 #define ARGS(args...) args
 
 #define FULL_PROXY_FUNC(name, ret_type, filp, proto, args)      \
 static ret_type full_proxy_ ## name(proto)              \
 {                                   \
     struct dentry *dentry = F_DENTRY(filp);         \
     const struct file_operations *real_fops;            \
     ret_type r;                         \
                                     \
     r = debugfs_file_get(dentry);                   \
     if (unlikely(r))                        \
         return r;                       \
     real_fops = debugfs_real_fops(filp);                \
     r = real_fops->name(args);                  \
     debugfs_file_put(dentry);                   \
     return r;                           \
 }
 
 FULL_PROXY_FUNC(llseek, loff_t, filp,
         PROTO(struct file *filp, loff_t offset, int whence),
         ARGS(filp, offset, whence));
 
 FULL_PROXY_FUNC(read, ssize_t, filp,
         PROTO(struct file *filp, char __user *buf, size_t size,
             loff_t *ppos),
         ARGS(filp, buf, size, ppos));
 
 FULL_PROXY_FUNC(write, ssize_t, filp,
         PROTO(struct file *filp, const char __user *buf, size_t size,
             loff_t *ppos),
         ARGS(filp, buf, size, ppos));
 
 FULL_PROXY_FUNC(unlocked_ioctl, long, filp,
         PROTO(struct file *filp, unsigned int cmd, unsigned long arg),
         ARGS(filp, cmd, arg));
 
 static __poll_t full_proxy_poll(struct file *filp,
                 struct poll_table_struct *wait)
 {
     struct dentry *dentry = F_DENTRY(filp);
     __poll_t r = 0;
     const struct file_operations *real_fops;
 
     if (debugfs_file_get(dentry))
         return EPOLLHUP;
 
     real_fops = debugfs_real_fops(filp);
     r = real_fops->poll(filp, wait);
     debugfs_file_put(dentry);
     return r;
 }
 
 static int full_proxy_release(struct inode *inode, struct file *filp)
 {
     const struct dentry *dentry = F_DENTRY(filp);
     const struct file_operations *real_fops = debugfs_real_fops(filp);
     const struct file_operations *proxy_fops = filp->f_op;
     int r = 0;
 
     /*
      * We must not protect this against removal races here: the
      * original releaser should be called unconditionally in order
      * not to leak any resources. Releasers must not assume that
      * ->i_private is still being meaningful here.
      */
     if (real_fops->release)
         r = real_fops->release(inode, filp);
 
     replace_fops(filp, d_inode(dentry)->i_fop);
     kfree(proxy_fops);
     fops_put(real_fops);
     return r;
 }
 
 static void __full_proxy_fops_init(struct file_operations *proxy_fops,
                 const struct file_operations *real_fops)
 {
     proxy_fops->release = full_proxy_release;
     if (real_fops->llseek)
         proxy_fops->llseek = full_proxy_llseek;
     if (real_fops->read)
         proxy_fops->read = full_proxy_read;
     if (real_fops->write)
         proxy_fops->write = full_proxy_write;
     if (real_fops->poll)
         proxy_fops->poll = full_proxy_poll;
     if (real_fops->unlocked_ioctl)
         proxy_fops->unlocked_ioctl = full_proxy_unlocked_ioctl;
 }
 
 static int full_proxy_open(struct inode *inode, struct file *filp)
 {
     struct dentry *dentry = F_DENTRY(filp);
     const struct file_operations *real_fops = NULL;
     struct file_operations *proxy_fops = NULL;
     int r;
 
     r = debugfs_file_get(dentry);
     if (r)
         return r == -EIO ? -ENOENT : r;
 
     real_fops = debugfs_real_fops(filp);
 
     r = debugfs_locked_down(inode, filp, real_fops);
     if (r)
         goto out;
 
     if (!fops_get(real_fops)) {
 #ifdef CONFIG_MODULES
         if (real_fops->owner &&
             real_fops->owner->state == MODULE_STATE_GOING) {
             r = -ENXIO;
             goto out;
         }
 #endif
 
         /* Huh? Module did not cleanup after itself at exit? */
         WARN(1, "debugfs file owner did not clean up at exit: %pd",
             dentry);
         r = -ENXIO;
         goto out;
     }
 
     proxy_fops = kzalloc(sizeof(*proxy_fops), GFP_KERNEL);
     if (!proxy_fops) {
         r = -ENOMEM;
         goto free_proxy;
     }
     __full_proxy_fops_init(proxy_fops, real_fops);
     replace_fops(filp, proxy_fops);
 
     if (real_fops->open) {
         r = real_fops->open(inode, filp);
         if (r) {
             replace_fops(filp, d_inode(dentry)->i_fop);
             goto free_proxy;
         } else if (filp->f_op != proxy_fops) {
             /* No protection against file removal anymore. */
             WARN(1, "debugfs file owner replaced proxy fops: %pd",
                 dentry);
             goto free_proxy;
         }
     }
 
     goto out;
 free_proxy:
     kfree(proxy_fops);
     fops_put(real_fops);
 out:
     debugfs_file_put(dentry);
     return r;
 }
 
 const struct file_operations debugfs_full_proxy_file_operations = {
     .open = full_proxy_open,
 };
 
 ssize_t debugfs_attr_read(struct file *file, char __user *buf,
             size_t len, loff_t *ppos)
 {
     struct dentry *dentry = F_DENTRY(file);
     ssize_t ret;
 
     ret = debugfs_file_get(dentry);
     if (unlikely(ret))
         return ret;
     ret = simple_attr_read(file, buf, len, ppos);
     debugfs_file_put(dentry);
     return ret;
 }
 EXPORT_SYMBOL_GPL(debugfs_attr_read);
 
 ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
              size_t len, loff_t *ppos)
 {
     struct dentry *dentry = F_DENTRY(file);
     ssize_t ret;
 
     ret = debugfs_file_get(dentry);
     if (unlikely(ret))
         return ret;
     ret = simple_attr_write(file, buf, len, ppos);
     debugfs_file_put(dentry);
     return ret;
 }
 EXPORT_SYMBOL_GPL(debugfs_attr_write);
 
 static struct dentry *debugfs_create_mode_unsafe(const char *name, umode_t mode,
                     struct dentry *parent, void *value,
                     const struct file_operations *fops,
                     const struct file_operations *fops_ro,
                     const struct file_operations *fops_wo)
 {
     /* if there are no write bits set, make read only */
     if (!(mode & S_IWUGO))
         return debugfs_create_file_unsafe(name, mode, parent, value,
                         fops_ro);
     /* if there are no read bits set, make write only */
     if (!(mode & S_IRUGO))
         return debugfs_create_file_unsafe(name, mode, parent, value,
                         fops_wo);
 
     return debugfs_create_file_unsafe(name, mode, parent, value, fops);
 }
 
 static int debugfs_u8_set(void *data, u64 val)
 {
     *(u8 *)data = val;
     return 0;
 }
 static int debugfs_u8_get(void *data, u64 *val)
 {
     *val = *(u8 *)data;
     return 0;
 }
 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
 
 /**
  * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
  * @name: a pointer to a string containing the name of the file to create.
  * @mode: the permission that the file should have
  * @parent: a pointer to the parent dentry for this file.  This should be a
  *          directory dentry if set.  If this parameter is %NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @value: a pointer to the variable that the file should read to and write
  *         from.
  *
  * This function creates a file in debugfs with the given name that
  * contains the value of the variable @value.  If the @mode variable is so
  * set, it can be read from, and written to.
  */
 void debugfs_create_u8(const char *name, umode_t mode, struct dentry *parent,
                u8 *value)
 {
     debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u8,
                    &fops_u8_ro, &fops_u8_wo);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_u8);
 
 static int debugfs_u16_set(void *data, u64 val)
 {
     *(u16 *)data = val;
     return 0;
 }
 static int debugfs_u16_get(void *data, u64 *val)
 {
     *val = *(u16 *)data;
     return 0;
 }
 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
 
 /**
  * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
  * @name: a pointer to a string containing the name of the file to create.
  * @mode: the permission that the file should have
  * @parent: a pointer to the parent dentry for this file.  This should be a
  *          directory dentry if set.  If this parameter is %NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @value: a pointer to the variable that the file should read to and write
  *         from.
  *
  * This function creates a file in debugfs with the given name that
  * contains the value of the variable @value.  If the @mode variable is so
  * set, it can be read from, and written to.
  */
 void debugfs_create_u16(const char *name, umode_t mode, struct dentry *parent,
             u16 *value)
 {
     debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u16,
                    &fops_u16_ro, &fops_u16_wo);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_u16);
 
 static int debugfs_u32_set(void *data, u64 val)
 {
     *(u32 *)data = val;
     return 0;
 }
 static int debugfs_u32_get(void *data, u64 *val)
 {
     *val = *(u32 *)data;
     return 0;
 }
 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
 
 /**
  * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
  * @name: a pointer to a string containing the name of the file to create.
  * @mode: the permission that the file should have
  * @parent: a pointer to the parent dentry for this file.  This should be a
  *          directory dentry if set.  If this parameter is %NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @value: a pointer to the variable that the file should read to and write
  *         from.
  *
  * This function creates a file in debugfs with the given name that
  * contains the value of the variable @value.  If the @mode variable is so
  * set, it can be read from, and written to.
  */
 void debugfs_create_u32(const char *name, umode_t mode, struct dentry *parent,
             u32 *value)
 {
     debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u32,
                    &fops_u32_ro, &fops_u32_wo);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_u32);
 
 static int debugfs_u64_set(void *data, u64 val)
 {
     *(u64 *)data = val;
     return 0;
 }
 
 static int debugfs_u64_get(void *data, u64 *val)
 {
     *val = *(u64 *)data;
     return 0;
 }
 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
 
 /**
  * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
  * @name: a pointer to a string containing the name of the file to create.
  * @mode: the permission that the file should have
  * @parent: a pointer to the parent dentry for this file.  This should be a
  *          directory dentry if set.  If this parameter is %NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @value: a pointer to the variable that the file should read to and write
  *         from.
  *
  * This function creates a file in debugfs with the given name that
  * contains the value of the variable @value.  If the @mode variable is so
  * set, it can be read from, and written to.
  */
 void debugfs_create_u64(const char *name, umode_t mode, struct dentry *parent,
             u64 *value)
 {
     debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u64,
                    &fops_u64_ro, &fops_u64_wo);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_u64);
 
 static int debugfs_ulong_set(void *data, u64 val)
 {
     *(unsigned long *)data = val;
     return 0;
 }
 
 static int debugfs_ulong_get(void *data, u64 *val)
 {
     *val = *(unsigned long *)data;
     return 0;
 }
 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set,
             "%llu\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");
 
 /**
  * debugfs_create_ulong - create a debugfs file that is used to read and write
  * an unsigned long value.
  * @name: a pointer to a string containing the name of the file to create.
  * @mode: the permission that the file should have
  * @parent: a pointer to the parent dentry for this file.  This should be a
  *          directory dentry if set.  If this parameter is %NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @value: a pointer to the variable that the file should read to and write
  *         from.
  *
  * This function creates a file in debugfs with the given name that
  * contains the value of the variable @value.  If the @mode variable is so
  * set, it can be read from, and written to.
  */
 void debugfs_create_ulong(const char *name, umode_t mode, struct dentry *parent,
               unsigned long *value)
 {
     debugfs_create_mode_unsafe(name, mode, parent, value, &fops_ulong,
                    &fops_ulong_ro, &fops_ulong_wo);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_ulong);
 
 DEFINE_DEBUGFS_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
 
 DEFINE_DEBUGFS_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set,
             "0x%04llx\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");
 
 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set,
             "0x%08llx\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
 
 DEFINE_DEBUGFS_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set,
             "0x%016llx\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n");
 
 /*
  * debugfs_create_x{8,16,32,64} - create a debugfs file that is used to read and write an unsigned {8,16,32,64}-bit value
  *
  * These functions are exactly the same as the above functions (but use a hex
  * output for the decimal challenged). For details look at the above unsigned
  * decimal functions.
  */
 
 /**
  * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
  * @name: a pointer to a string containing the name of the file to create.
  * @mode: the permission that the file should have
  * @parent: a pointer to the parent dentry for this file.  This should be a
  *          directory dentry if set.  If this parameter is %NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @value: a pointer to the variable that the file should read to and write
  *         from.
  */
 void debugfs_create_x8(const char *name, umode_t mode, struct dentry *parent,
                u8 *value)
 {
     debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x8,
                    &fops_x8_ro, &fops_x8_wo);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_x8);
 
 /**
  * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value
  * @name: a pointer to a string containing the name of the file to create.
  * @mode: the permission that the file should have
  * @parent: a pointer to the parent dentry for this file.  This should be a
  *          directory dentry if set.  If this parameter is %NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @value: a pointer to the variable that the file should read to and write
  *         from.
  */
 void debugfs_create_x16(const char *name, umode_t mode, struct dentry *parent,
             u16 *value)
 {
     debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x16,
                    &fops_x16_ro, &fops_x16_wo);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_x16);
 
 /**
  * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value
  * @name: a pointer to a string containing the name of the file to create.
  * @mode: the permission that the file should have
  * @parent: a pointer to the parent dentry for this file.  This should be a
  *          directory dentry if set.  If this parameter is %NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @value: a pointer to the variable that the file should read to and write
  *         from.
  */
 void debugfs_create_x32(const char *name, umode_t mode, struct dentry *parent,
             u32 *value)
 {
     debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x32,
                    &fops_x32_ro, &fops_x32_wo);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_x32);
 
 /**
  * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value
  * @name: a pointer to a string containing the name of the file to create.
  * @mode: the permission that the file should have
  * @parent: a pointer to the parent dentry for this file.  This should be a
  *          directory dentry if set.  If this parameter is %NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @value: a pointer to the variable that the file should read to and write
  *         from.
  */
 void debugfs_create_x64(const char *name, umode_t mode, struct dentry *parent,
             u64 *value)
 {
     debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x64,
                    &fops_x64_ro, &fops_x64_wo);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_x64);
 
 
 static int debugfs_size_t_set(void *data, u64 val)
 {
     *(size_t *)data = val;
     return 0;
 }
 static int debugfs_size_t_get(void *data, u64 *val)
 {
     *val = *(size_t *)data;
     return 0;
 }
 DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
             "%llu\n"); /* %llu and %zu are more or less the same */
 DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_ro, debugfs_size_t_get, NULL, "%llu\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu\n");
 
 /**
  * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
  * @name: a pointer to a string containing the name of the file to create.
  * @mode: the permission that the file should have
  * @parent: a pointer to the parent dentry for this file.  This should be a
  *          directory dentry if set.  If this parameter is %NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @value: a pointer to the variable that the file should read to and write
  *         from.
  */
 void debugfs_create_size_t(const char *name, umode_t mode,
                struct dentry *parent, size_t *value)
 {
     debugfs_create_mode_unsafe(name, mode, parent, value, &fops_size_t,
                    &fops_size_t_ro, &fops_size_t_wo);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_size_t);
 
 static int debugfs_atomic_t_set(void *data, u64 val)
 {
     atomic_set((atomic_t *)data, val);
     return 0;
 }
 static int debugfs_atomic_t_get(void *data, u64 *val)
 {
     *val = atomic_read((atomic_t *)data);
     return 0;
 }
 DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
             debugfs_atomic_t_set, "%lld\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_ro, debugfs_atomic_t_get, NULL,
             "%lld\n");
 DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_wo, NULL, debugfs_atomic_t_set,
             "%lld\n");
 
 /**
  * debugfs_create_atomic_t - create a debugfs file that is used to read and
  * write an atomic_t value
  * @name: a pointer to a string containing the name of the file to create.
  * @mode: the permission that the file should have
  * @parent: a pointer to the parent dentry for this file.  This should be a
  *          directory dentry if set.  If this parameter is %NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @value: a pointer to the variable that the file should read to and write
  *         from.
  */
 void debugfs_create_atomic_t(const char *name, umode_t mode,
                  struct dentry *parent, atomic_t *value)
 {
     debugfs_create_mode_unsafe(name, mode, parent, value, &fops_atomic_t,
                    &fops_atomic_t_ro, &fops_atomic_t_wo);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);
 
 ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
                    size_t count, loff_t *ppos)
 {
     char buf[2];
     bool val;
     int r;
     struct dentry *dentry = F_DENTRY(file);
 
     r = debugfs_file_get(dentry);
     if (unlikely(r))
         return r;
     val = *(bool *)file->private_data;
     debugfs_file_put(dentry);
 
     if (val)
         buf[0] = 'Y';
     else
         buf[0] = 'N';
     buf[1] = '\n';
     return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
 }
 EXPORT_SYMBOL_GPL(debugfs_read_file_bool);
 
 ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
                 size_t count, loff_t *ppos)
 {
     bool bv;
     int r;
     bool *val = file->private_data;
     struct dentry *dentry = F_DENTRY(file);
 
     r = kstrtobool_from_user(user_buf, count, &bv);
     if (!r) {
         r = debugfs_file_get(dentry);
         if (unlikely(r))
             return r;
         *val = bv;
         debugfs_file_put(dentry);
     }
 
     return count;
 }
 EXPORT_SYMBOL_GPL(debugfs_write_file_bool);
 
 static const struct file_operations fops_bool = {
     .read =     debugfs_read_file_bool,
     .write =    debugfs_write_file_bool,
     .open =     simple_open,
     .llseek =   default_llseek,
 };
 
 static const struct file_operations fops_bool_ro = {
     .read =     debugfs_read_file_bool,
     .open =     simple_open,
     .llseek =   default_llseek,
 };
 
 static const struct file_operations fops_bool_wo = {
     .write =    debugfs_write_file_bool,
     .open =     simple_open,
     .llseek =   default_llseek,
 };
 
 /**
  * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
  * @name: a pointer to a string containing the name of the file to create.
  * @mode: the permission that the file should have
  * @parent: a pointer to the parent dentry for this file.  This should be a
  *          directory dentry if set.  If this parameter is %NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @value: a pointer to the variable that the file should read to and write
  *         from.
  *
  * This function creates a file in debugfs with the given name that
  * contains the value of the variable @value.  If the @mode variable is so
  * set, it can be read from, and written to.
  */
 void debugfs_create_bool(const char *name, umode_t mode, struct dentry *parent,
              bool *value)
 {
     debugfs_create_mode_unsafe(name, mode, parent, value, &fops_bool,
                    &fops_bool_ro, &fops_bool_wo);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_bool);
 
 ssize_t debugfs_read_file_str(struct file *file, char __user *user_buf,
                   size_t count, loff_t *ppos)
 {
     struct dentry *dentry = F_DENTRY(file);
     char *str, *copy = NULL;
     int copy_len, len;
     ssize_t ret;
 
     ret = debugfs_file_get(dentry);
     if (unlikely(ret))
         return ret;
 
     str = *(char **)file->private_data;
     len = strlen(str) + 1;
     copy = kmalloc(len, GFP_KERNEL);
     if (!copy) {
         debugfs_file_put(dentry);
         return -ENOMEM;
     }
 
     copy_len = strscpy(copy, str, len);
     debugfs_file_put(dentry);
     if (copy_len < 0) {
         kfree(copy);
         return copy_len;
     }
 
     copy[copy_len] = '\n';
 
     ret = simple_read_from_buffer(user_buf, count, ppos, copy, len);
     kfree(copy);
 
     return ret;
 }
 
 static ssize_t debugfs_write_file_str(struct file *file, const char __user *user_buf,
                       size_t count, loff_t *ppos)
 {
     /* This is really only for read-only strings */
     return -EINVAL;
 }
 
 static const struct file_operations fops_str = {
     .read =     debugfs_read_file_str,
     .write =    debugfs_write_file_str,
     .open =     simple_open,
     .llseek =   default_llseek,
 };
 
 static const struct file_operations fops_str_ro = {
     .read =     debugfs_read_file_str,
     .open =     simple_open,
     .llseek =   default_llseek,
 };
 
 static const struct file_operations fops_str_wo = {
     .write =    debugfs_write_file_str,
     .open =     simple_open,
     .llseek =   default_llseek,
 };
 
 /**
  * debugfs_create_str - create a debugfs file that is used to read and write a string value
  * @name: a pointer to a string containing the name of the file to create.
  * @mode: the permission that the file should have
  * @parent: a pointer to the parent dentry for this file.  This should be a
  *          directory dentry if set.  If this parameter is %NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @value: a pointer to the variable that the file should read to and write
  *         from.
  *
  * This function creates a file in debugfs with the given name that
  * contains the value of the variable @value.  If the @mode variable is so
  * set, it can be read from, and written to.
  *
  * This function will return a pointer to a dentry if it succeeds.  This
  * pointer must be passed to the debugfs_remove() function when the file is
  * to be removed (no automatic cleanup happens if your module is unloaded,
  * you are responsible here.)  If an error occurs, ERR_PTR(-ERROR) will be
  * returned.
  *
  * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will
  * be returned.
  */
 void debugfs_create_str(const char *name, umode_t mode,
             struct dentry *parent, char **value)
 {
     debugfs_create_mode_unsafe(name, mode, parent, value, &fops_str,
                    &fops_str_ro, &fops_str_wo);
 }
 
 static ssize_t read_file_blob(struct file *file, char __user *user_buf,
                   size_t count, loff_t *ppos)
 {
     struct debugfs_blob_wrapper *blob = file->private_data;
     struct dentry *dentry = F_DENTRY(file);
     ssize_t r;
 
     r = debugfs_file_get(dentry);
     if (unlikely(r))
         return r;
     r = simple_read_from_buffer(user_buf, count, ppos, blob->data,
                 blob->size);
     debugfs_file_put(dentry);
     return r;
 }
 
 static const struct file_operations fops_blob = {
     .read =     read_file_blob,
     .open =     simple_open,
     .llseek =   default_llseek,
 };
 
 /**
  * debugfs_create_blob - create a debugfs file that is used to read a binary blob
  * @name: a pointer to a string containing the name of the file to create.
  * @mode: the read permission that the file should have (other permissions are
  *    masked out)
  * @parent: a pointer to the parent dentry for this file.  This should be a
  *          directory dentry if set.  If this parameter is %NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
  *        to the blob data and the size of the data.
  *
  * This function creates a file in debugfs with the given name that exports
  * @blob->data as a binary blob. If the @mode variable is so set it can be
  * read from. Writing is not supported.
  *
  * This function will return a pointer to a dentry if it succeeds.  This
  * pointer must be passed to the debugfs_remove() function when the file is
  * to be removed (no automatic cleanup happens if your module is unloaded,
  * you are responsible here.)  If an error occurs, ERR_PTR(-ERROR) will be
  * returned.
  *
  * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will
  * be returned.
  */
 struct dentry *debugfs_create_blob(const char *name, umode_t mode,
                    struct dentry *parent,
                    struct debugfs_blob_wrapper *blob)
 {
     return debugfs_create_file_unsafe(name, mode & 0444, parent, blob, &fops_blob);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_blob);
 
 static size_t u32_format_array(char *buf, size_t bufsize,
                    u32 *array, int array_size)
 {
     size_t ret = 0;
 
     while (--array_size >= 0) {
         size_t len;
         char term = array_size ? ' ' : '\n';
 
         len = snprintf(buf, bufsize, "%u%c", *array++, term);
         ret += len;
 
         buf += len;
         bufsize -= len;
     }
     return ret;
 }
 
 static int u32_array_open(struct inode *inode, struct file *file)
 {
     struct debugfs_u32_array *data = inode->i_private;
     int size, elements = data->n_elements;
     char *buf;
 
     /*
      * Max size:
      *  - 10 digits + ' '/'\n' = 11 bytes per number
      *  - terminating NUL character
      */
     size = elements*11;
     buf = kmalloc(size+1, GFP_KERNEL);
     if (!buf)
         return -ENOMEM;
     buf[size] = 0;
 
     file->private_data = buf;
     u32_format_array(buf, size, data->array, data->n_elements);
 
     return nonseekable_open(inode, file);
 }
 
 static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
                   loff_t *ppos)
 {
     size_t size = strlen(file->private_data);
 
     return simple_read_from_buffer(buf, len, ppos,
                     file->private_data, size);
 }
 
 static int u32_array_release(struct inode *inode, struct file *file)
 {
     kfree(file->private_data);
 
     return 0;
 }
 
 static const struct file_operations u32_array_fops = {
     .owner   = THIS_MODULE,
     .open    = u32_array_open,
     .release = u32_array_release,
     .read    = u32_array_read,
     .llseek  = no_llseek,
 };
 
 /**
  * debugfs_create_u32_array - create a debugfs file that is used to read u32
  * array.
  * @name: a pointer to a string containing the name of the file to create.
  * @mode: the permission that the file should have.
  * @parent: a pointer to the parent dentry for this file.  This should be a
  *          directory dentry if set.  If this parameter is %NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @array: wrapper struct containing data pointer and size of the array.
  *
  * This function creates a file in debugfs with the given name that exports
  * @array as data. If the @mode variable is so set it can be read from.
  * Writing is not supported. Seek within the file is also not supported.
  * Once array is created its size can not be changed.
  */
 void debugfs_create_u32_array(const char *name, umode_t mode,
                   struct dentry *parent,
                   struct debugfs_u32_array *array)
 {
     debugfs_create_file_unsafe(name, mode, parent, array, &u32_array_fops);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
 
 #ifdef CONFIG_HAS_IOMEM
 
 /*
  * The regset32 stuff is used to print 32-bit registers using the
  * seq_file utilities. We offer printing a register set in an already-opened
  * sequential file or create a debugfs file that only prints a regset32.
  */
 
 /**
  * debugfs_print_regs32 - use seq_print to describe a set of registers
  * @s: the seq_file structure being used to generate output
  * @regs: an array if struct debugfs_reg32 structures
  * @nregs: the length of the above array
  * @base: the base address to be used in reading the registers
  * @prefix: a string to be prefixed to every output line
  *
  * This function outputs a text block describing the current values of
  * some 32-bit hardware registers. It is meant to be used within debugfs
  * files based on seq_file that need to show registers, intermixed with other
  * information. The prefix argument may be used to specify a leading string,
  * because some peripherals have several blocks of identical registers,
  * for example configuration of dma channels
  */
 void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
               int nregs, void __iomem *base, char *prefix)
 {
     int i;
 
     for (i = 0; i < nregs; i++, regs++) {
         if (prefix)
             seq_printf(s, "%s", prefix);
         seq_printf(s, "%s = 0x%08x\n", regs->name,
                readl(base + regs->offset));
         if (seq_has_overflowed(s))
             break;
     }
 }
 EXPORT_SYMBOL_GPL(debugfs_print_regs32);
 
 static int debugfs_show_regset32(struct seq_file *s, void *data)
 {
     struct debugfs_regset32 *regset = s->private;
 
     if (regset->dev)
         pm_runtime_get_sync(regset->dev);
 
     debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
 
     if (regset->dev)
         pm_runtime_put(regset->dev);
 
     return 0;
 }
 
 static int debugfs_open_regset32(struct inode *inode, struct file *file)
 {
     return single_open(file, debugfs_show_regset32, inode->i_private);
 }
 
 static const struct file_operations fops_regset32 = {
     .open =     debugfs_open_regset32,
     .read =     seq_read,
     .llseek =   seq_lseek,
     .release =  single_release,
 };
 
 /**
  * debugfs_create_regset32 - create a debugfs file that returns register values
  * @name: a pointer to a string containing the name of the file to create.
  * @mode: the permission that the file should have
  * @parent: a pointer to the parent dentry for this file.  This should be a
  *          directory dentry if set.  If this parameter is %NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @regset: a pointer to a struct debugfs_regset32, which contains a pointer
  *          to an array of register definitions, the array size and the base
  *          address where the register bank is to be found.
  *
  * This function creates a file in debugfs with the given name that reports
  * the names and values of a set of 32-bit registers. If the @mode variable
  * is so set it can be read from. Writing is not supported.
  */
 void debugfs_create_regset32(const char *name, umode_t mode,
                  struct dentry *parent,
                  struct debugfs_regset32 *regset)
 {
     debugfs_create_file(name, mode, parent, regset, &fops_regset32);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_regset32);
 
 #endif /* CONFIG_HAS_IOMEM */
 
 struct debugfs_devm_entry {
     int (*read)(struct seq_file *seq, void *data);
     struct device *dev;
 };
 
 static int debugfs_devm_entry_open(struct inode *inode, struct file *f)
 {
     struct debugfs_devm_entry *entry = inode->i_private;
 
     return single_open(f, entry->read, entry->dev);
 }
 
 static const struct file_operations debugfs_devm_entry_ops = {
     .owner = THIS_MODULE,
     .open = debugfs_devm_entry_open,
     .release = single_release,
     .read = seq_read,
     .llseek = seq_lseek
 };
 
 /**
  * debugfs_create_devm_seqfile - create a debugfs file that is bound to device.
  *
  * @dev: device related to this debugfs file.
  * @name: name of the debugfs file.
  * @parent: a pointer to the parent dentry for this file.  This should be a
  *  directory dentry if set.  If this parameter is %NULL, then the
  *  file will be created in the root of the debugfs filesystem.
  * @read_fn: function pointer called to print the seq_file content.
  */
 void debugfs_create_devm_seqfile(struct device *dev, const char *name,
                  struct dentry *parent,
                  int (*read_fn)(struct seq_file *s, void *data))
 {
     struct debugfs_devm_entry *entry;
 
     if (IS_ERR(parent))
         return;
 
     entry = devm_kzalloc(dev, sizeof(*entry), GFP_KERNEL);
     if (!entry)
         return;
 
     entry->read = read_fn;
     entry->dev = dev;
 
     debugfs_create_file(name, S_IRUGO, parent, entry,
                 &debugfs_devm_entry_ops);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile);

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