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LU-8066 llite: move /proc/fs/lustre/llite/checksum_pages to sysfs
[fs/lustre-release.git] / lustre / llite / lproc_llite.c
index b44e077..66d0f11 100644 (file)
@@ -23,7 +23,7 @@
  * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
- * Copyright (c) 2012, 2015, Intel Corporation.
+ * Copyright (c) 2012, 2017, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
@@ -36,7 +36,7 @@
 #ifdef HAVE_UIDGID_HEADER
 # include <linux/uidgid.h>
 #endif
-#include <lustre_param.h>
+#include <uapi/linux/lustre/lustre_param.h>
 #include <lprocfs_status.h>
 #include <obd_support.h>
 
 #include "vvp_internal.h"
 
 struct proc_dir_entry *proc_lustre_fs_root;
+static struct kobject *llite_kobj;
+
+int llite_tunables_register(void)
+{
+       int rc = 0;
+
+       proc_lustre_fs_root = lprocfs_register("llite", proc_lustre_root,
+                                              NULL, NULL);
+       if (IS_ERR(proc_lustre_fs_root)) {
+               rc = PTR_ERR(proc_lustre_fs_root);
+               CERROR("cannot register '/proc/fs/lustre/llite': rc = %d\n",
+                      rc);
+               proc_lustre_fs_root = NULL;
+               return rc;
+       }
+
+       llite_kobj = class_setup_tunables("llite");
+       if (IS_ERR(llite_kobj)) {
+               rc = PTR_ERR(llite_kobj);
+               llite_kobj = NULL;
+       }
+
+       return rc;
+}
+
+void llite_tunables_unregister(void)
+{
+       if (llite_kobj)
+               kobject_put(llite_kobj);
+
+       lprocfs_remove(&proc_lustre_fs_root);
+}
 
 #ifdef CONFIG_PROC_FS
 /* /proc/lustre/llite mount point registration */
 static const struct file_operations ll_rw_extents_stats_fops;
 static const struct file_operations ll_rw_extents_stats_pp_fops;
 static const struct file_operations ll_rw_offset_stats_fops;
+static __s64 ll_stats_pid_write(const char __user *buf, size_t len);
 
-static int ll_blksize_seq_show(struct seq_file *m, void *v)
+static ssize_t blocksize_show(struct kobject *kobj, struct attribute *attr,
+                             char *buf)
 {
-       struct super_block *sb = m->private;
+       struct ll_sb_info *sbi = container_of(kobj, struct ll_sb_info,
+                                             ll_kset.kobj);
        struct obd_statfs osfs;
        int rc;
 
-       LASSERT(sb != NULL);
-       rc = ll_statfs_internal(sb, &osfs,
-                               cfs_time_shift_64(-OBD_STATFS_CACHE_SECONDS),
-                               OBD_STATFS_NODELAY);
-       if (!rc)
-               seq_printf(m, "%u\n", osfs.os_bsize);
-       return rc;
+       rc = ll_statfs_internal(sbi, &osfs, OBD_STATFS_NODELAY);
+       if (rc)
+               return rc;
+
+       return sprintf(buf, "%u\n", osfs.os_bsize);
 }
-LPROC_SEQ_FOPS_RO(ll_blksize);
+LUSTRE_RO_ATTR(blocksize);
 
-static int ll_kbytestotal_seq_show(struct seq_file *m, void *v)
+static int ll_stat_blksize_seq_show(struct seq_file *m, void *v)
 {
-       struct super_block *sb = m->private;
-       struct obd_statfs osfs;
+       struct ll_sb_info *sbi = ll_s2sbi((struct super_block *)m->private);
+
+       seq_printf(m, "%u\n", sbi->ll_stat_blksize);
+
+       return 0;
+}
+
+static ssize_t ll_stat_blksize_seq_write(struct file *file,
+                                        const char __user *buffer,
+                                        size_t count, loff_t *off)
+{
+       struct seq_file *m = file->private_data;
+       struct ll_sb_info *sbi = ll_s2sbi((struct super_block *)m->private);
+       unsigned int val;
        int rc;
 
-       LASSERT(sb != NULL);
-       rc = ll_statfs_internal(sb, &osfs,
-                               cfs_time_shift_64(-OBD_STATFS_CACHE_SECONDS),
-                               OBD_STATFS_NODELAY);
-       if (!rc) {
-               __u32 blk_size = osfs.os_bsize >> 10;
-               __u64 result = osfs.os_blocks;
+       rc = kstrtouint_from_user(buffer, count, 0, &val);
+       if (rc)
+               return rc;
 
-               while (blk_size >>= 1)
-                       result <<= 1;
+       if (val != 0 && (val < PAGE_SIZE || (val & (val - 1))) != 0)
+               return -ERANGE;
 
-               seq_printf(m, "%llu\n", result);
-       }
-       return rc;
+       sbi->ll_stat_blksize = val;
+
+       return count;
 }
-LPROC_SEQ_FOPS_RO(ll_kbytestotal);
+LPROC_SEQ_FOPS(ll_stat_blksize);
 
-static int ll_kbytesfree_seq_show(struct seq_file *m, void *v)
+static ssize_t kbytestotal_show(struct kobject *kobj, struct attribute *attr,
+                               char *buf)
 {
-       struct super_block *sb = m->private;
+       struct ll_sb_info *sbi = container_of(kobj, struct ll_sb_info,
+                                             ll_kset.kobj);
        struct obd_statfs osfs;
+       u32 blk_size;
+       u64 result;
        int rc;
 
-       LASSERT(sb != NULL);
-       rc = ll_statfs_internal(sb, &osfs,
-                               cfs_time_shift_64(-OBD_STATFS_CACHE_SECONDS),
-                               OBD_STATFS_NODELAY);
-       if (!rc) {
-               __u32 blk_size = osfs.os_bsize >> 10;
-               __u64 result = osfs.os_bfree;
+       rc = ll_statfs_internal(sbi, &osfs, OBD_STATFS_NODELAY);
+       if (rc)
+               return rc;
 
-               while (blk_size >>= 1)
-                       result <<= 1;
+       blk_size = osfs.os_bsize >> 10;
+       result = osfs.os_blocks;
 
-               seq_printf(m, "%llu\n", result);
-       }
-       return rc;
+       while (blk_size >>= 1)
+               result <<= 1;
+
+       return sprintf(buf, "%llu\n", result);
 }
-LPROC_SEQ_FOPS_RO(ll_kbytesfree);
+LUSTRE_RO_ATTR(kbytestotal);
 
-static int ll_kbytesavail_seq_show(struct seq_file *m, void *v)
+static ssize_t kbytesfree_show(struct kobject *kobj, struct attribute *attr,
+                              char *buf)
 {
-       struct super_block *sb = m->private;
+       struct ll_sb_info *sbi = container_of(kobj, struct ll_sb_info,
+                                             ll_kset.kobj);
        struct obd_statfs osfs;
+       u32 blk_size;
+       u64 result;
        int rc;
 
-       LASSERT(sb != NULL);
-       rc = ll_statfs_internal(sb, &osfs,
-                               cfs_time_shift_64(-OBD_STATFS_CACHE_SECONDS),
-                               OBD_STATFS_NODELAY);
-       if (!rc) {
-               __u32 blk_size = osfs.os_bsize >> 10;
-               __u64 result = osfs.os_bavail;
+       rc = ll_statfs_internal(sbi, &osfs, OBD_STATFS_NODELAY);
+       if (rc)
+               return rc;
 
-               while (blk_size >>= 1)
-                       result <<= 1;
+       blk_size = osfs.os_bsize >> 10;
+       result = osfs.os_bfree;
 
-               seq_printf(m, "%llu\n", result);
-       }
-       return rc;
+       while (blk_size >>= 1)
+               result <<= 1;
+
+       return sprintf(buf, "%llu\n", result);
 }
-LPROC_SEQ_FOPS_RO(ll_kbytesavail);
+LUSTRE_RO_ATTR(kbytesfree);
 
-static int ll_filestotal_seq_show(struct seq_file *m, void *v)
+static ssize_t kbytesavail_show(struct kobject *kobj, struct attribute *attr,
+                               char *buf)
 {
-       struct super_block *sb = m->private;
+       struct ll_sb_info *sbi = container_of(kobj, struct ll_sb_info,
+                                             ll_kset.kobj);
        struct obd_statfs osfs;
+       u32 blk_size;
+       u64 result;
        int rc;
 
-       LASSERT(sb != NULL);
-       rc = ll_statfs_internal(sb, &osfs,
-                               cfs_time_shift_64(-OBD_STATFS_CACHE_SECONDS),
-                               OBD_STATFS_NODELAY);
-       if (!rc)
-               seq_printf(m, "%llu\n", osfs.os_files);
-       return rc;
+       rc = ll_statfs_internal(sbi, &osfs, OBD_STATFS_NODELAY);
+       if (rc)
+               return rc;
+
+       blk_size = osfs.os_bsize >> 10;
+       result = osfs.os_bavail;
+
+       while (blk_size >>= 1)
+               result <<= 1;
+
+       return sprintf(buf, "%llu\n", result);
 }
-LPROC_SEQ_FOPS_RO(ll_filestotal);
+LUSTRE_RO_ATTR(kbytesavail);
 
-static int ll_filesfree_seq_show(struct seq_file *m, void *v)
+static ssize_t filestotal_show(struct kobject *kobj, struct attribute *attr,
+                              char *buf)
 {
-       struct super_block *sb = m->private;
+       struct ll_sb_info *sbi = container_of(kobj, struct ll_sb_info,
+                                             ll_kset.kobj);
        struct obd_statfs osfs;
        int rc;
 
-       LASSERT(sb != NULL);
-       rc = ll_statfs_internal(sb, &osfs,
-                               cfs_time_shift_64(-OBD_STATFS_CACHE_SECONDS),
-                               OBD_STATFS_NODELAY);
-       if (!rc)
-               seq_printf(m, "%llu\n", osfs.os_ffree);
-       return rc;
+       rc = ll_statfs_internal(sbi, &osfs, OBD_STATFS_NODELAY);
+       if (rc)
+               return rc;
+
+       return sprintf(buf, "%llu\n", osfs.os_files);
 }
-LPROC_SEQ_FOPS_RO(ll_filesfree);
+LUSTRE_RO_ATTR(filestotal);
 
-static int ll_client_type_seq_show(struct seq_file *m, void *v)
+static ssize_t filesfree_show(struct kobject *kobj, struct attribute *attr,
+                             char *buf)
 {
-       struct ll_sb_info *sbi = ll_s2sbi((struct super_block *)m->private);
+       struct ll_sb_info *sbi = container_of(kobj, struct ll_sb_info,
+                                             ll_kset.kobj);
+       struct obd_statfs osfs;
+       int rc;
 
-       LASSERT(sbi != NULL);
+       rc = ll_statfs_internal(sbi, &osfs, OBD_STATFS_NODELAY);
+       if (rc)
+               return rc;
 
-       seq_puts(m, "local client\n");
-       return 0;
+       return sprintf(buf, "%llu\n", osfs.os_ffree);
 }
-LPROC_SEQ_FOPS_RO(ll_client_type);
+LUSTRE_RO_ATTR(filesfree);
 
-static int ll_fstype_seq_show(struct seq_file *m, void *v)
+static ssize_t client_type_show(struct kobject *kobj, struct attribute *attr,
+                               char *buf)
 {
-       struct super_block *sb = m->private;
+       return sprintf(buf, "local client\n");
+}
+LUSTRE_RO_ATTR(client_type);
 
-       LASSERT(sb != NULL);
-       seq_printf(m, "%s\n", sb->s_type->name);
-       return 0;
+static ssize_t fstype_show(struct kobject *kobj, struct attribute *attr,
+                          char *buf)
+{
+       return sprintf(buf, "lustre\n");
 }
-LPROC_SEQ_FOPS_RO(ll_fstype);
+LUSTRE_RO_ATTR(fstype);
 
-static int ll_sb_uuid_seq_show(struct seq_file *m, void *v)
+static ssize_t uuid_show(struct kobject *kobj, struct attribute *attr,
+                        char *buf)
 {
-       struct super_block *sb = m->private;
+       struct ll_sb_info *sbi = container_of(kobj, struct ll_sb_info,
+                                             ll_kset.kobj);
 
-       LASSERT(sb != NULL);
-       seq_printf(m, "%s\n", ll_s2sbi(sb)->ll_sb_uuid.uuid);
-       return 0;
+       return sprintf(buf, "%s\n", sbi->ll_sb_uuid.uuid);
 }
-LPROC_SEQ_FOPS_RO(ll_sb_uuid);
+LUSTRE_RO_ATTR(uuid);
 
 static int ll_xattr_cache_seq_show(struct seq_file *m, void *v)
 {
@@ -213,20 +273,18 @@ static ssize_t ll_xattr_cache_seq_write(struct file *file,
 {
        struct seq_file *m = file->private_data;
        struct ll_sb_info *sbi = ll_s2sbi((struct super_block *)m->private);
-       __s64 val;
+       bool val;
        int rc;
 
-       rc = lprocfs_str_to_s64(buffer, count, &val);
+       rc = kstrtobool_from_user(buffer, count, &val);
        if (rc)
                return rc;
 
-       if (val != 0 && val != 1)
-               return -ERANGE;
-
-       if (val == 1 && !(sbi->ll_flags & LL_SBI_XATTR_CACHE))
+       if (val && !(sbi->ll_flags & LL_SBI_XATTR_CACHE))
                return -ENOTSUPP;
 
        sbi->ll_xattr_cache_enabled = val;
+       sbi->ll_xattr_cache_set = 1;
 
        return count;
 }
@@ -522,44 +580,47 @@ out:
 }
 LPROC_SEQ_FOPS(ll_max_cached_mb);
 
-static int ll_checksum_seq_show(struct seq_file *m, void *v)
+static ssize_t checksum_pages_show(struct kobject *kobj, struct attribute *attr,
+                                  char *buf)
 {
-       struct super_block *sb = m->private;
-       struct ll_sb_info *sbi = ll_s2sbi(sb);
+       struct ll_sb_info *sbi = container_of(kobj, struct ll_sb_info,
+                                             ll_kset.kobj);
 
-       seq_printf(m, "%u\n", (sbi->ll_flags & LL_SBI_CHECKSUM) ? 1 : 0);
-       return 0;
+       return sprintf(buf, "%u\n", (sbi->ll_flags & LL_SBI_CHECKSUM) ? 1 : 0);
 }
 
-static ssize_t ll_checksum_seq_write(struct file *file,
-                                    const char __user *buffer,
-                                    size_t count, loff_t *off)
+static ssize_t checksum_pages_store(struct kobject *kobj,
+                                   struct attribute *attr,
+                                   const char *buffer,
+                                   size_t count)
 {
-       struct seq_file *m = file->private_data;
-       struct ll_sb_info *sbi = ll_s2sbi((struct super_block *)m->private);
+       struct ll_sb_info *sbi = container_of(kobj, struct ll_sb_info,
+                                             ll_kset.kobj);
+       bool val;
+       int tmp;
        int rc;
-       __s64 val;
 
        if (!sbi->ll_dt_exp)
                /* Not set up yet */
                return -EAGAIN;
 
-       rc = lprocfs_str_to_s64(buffer, count, &val);
+       rc = kstrtobool(buffer, &val);
        if (rc)
                return rc;
        if (val)
                sbi->ll_flags |= LL_SBI_CHECKSUM;
        else
                sbi->ll_flags &= ~LL_SBI_CHECKSUM;
+       tmp = val;
 
        rc = obd_set_info_async(NULL, sbi->ll_dt_exp, sizeof(KEY_CHECKSUM),
-                               KEY_CHECKSUM, sizeof(val), &val, NULL);
+                               KEY_CHECKSUM, sizeof(tmp), &tmp, NULL);
        if (rc)
                CWARN("Failed to set OSC checksum flags: %d\n", rc);
 
        return count;
 }
-LPROC_SEQ_FOPS(ll_checksum);
+LUSTRE_RW_ATTR(checksum_pages);
 
 static int ll_rd_track_id(struct seq_file *m, enum stats_track_type type)
 {
@@ -580,14 +641,12 @@ static int ll_wr_track_id(const char __user *buffer, unsigned long count,
                          void *data, enum stats_track_type type)
 {
        struct super_block *sb = data;
+       unsigned int pid;
        int rc;
-       __s64 pid;
 
-       rc = lprocfs_str_to_s64(buffer, count, &pid);
+       rc = kstrtouint_from_user(buffer, count, 0, &pid);
        if (rc)
                return rc;
-       if (pid > INT_MAX || pid < 0)
-               return -ERANGE;
 
        ll_s2sbi(sb)->ll_stats_track_id = pid;
        if (pid == 0)
@@ -640,6 +699,42 @@ static ssize_t ll_track_gid_seq_write(struct file *file,
 }
 LPROC_SEQ_FOPS(ll_track_gid);
 
+static ssize_t statahead_running_max_show(struct kobject *kobj,
+                                         struct attribute *attr,
+                                         char *buf)
+{
+       struct ll_sb_info *sbi = container_of(kobj, struct ll_sb_info,
+                                             ll_kset.kobj);
+
+       return snprintf(buf, 16, "%u\n", sbi->ll_sa_running_max);
+}
+
+static ssize_t statahead_running_max_store(struct kobject *kobj,
+                                          struct attribute *attr,
+                                          const char *buffer,
+                                          size_t count)
+{
+       struct ll_sb_info *sbi = container_of(kobj, struct ll_sb_info,
+                                             ll_kset.kobj);
+       unsigned long val;
+       int rc;
+
+       rc = kstrtoul(buffer, 0, &val);
+       if (rc)
+               return rc;
+
+       if (val <= LL_SA_RUNNING_MAX) {
+               sbi->ll_sa_running_max = val;
+               return count;
+       }
+
+       CERROR("Bad statahead_running_max value %lu. Valid values "
+              "are in the range [0, %d]\n", val, LL_SA_RUNNING_MAX);
+
+       return -ERANGE;
+}
+LUSTRE_RW_ATTR(statahead_running_max);
+
 static int ll_statahead_max_seq_show(struct seq_file *m, void *v)
 {
        struct super_block *sb = m->private;
@@ -655,17 +750,17 @@ static ssize_t ll_statahead_max_seq_write(struct file *file,
 {
        struct seq_file *m = file->private_data;
        struct ll_sb_info *sbi = ll_s2sbi((struct super_block *)m->private);
+       unsigned int val;
        int rc;
-       __s64 val;
 
-       rc = lprocfs_str_to_s64(buffer, count, &val);
+       rc = kstrtouint_from_user(buffer, count, 0, &val);
        if (rc)
                return rc;
 
-       if (val >= 0 && val <= LL_SA_RPC_MAX)
+       if (val <= LL_SA_RPC_MAX)
                sbi->ll_sa_max = val;
        else
-               CERROR("Bad statahead_max value %lld. Valid values are in "
+               CERROR("Bad statahead_max value %u. Valid values are in "
                       "the range [0, %d]\n", val, LL_SA_RPC_MAX);
 
        return count;
@@ -688,10 +783,10 @@ static ssize_t ll_statahead_agl_seq_write(struct file *file,
 {
        struct seq_file *m = file->private_data;
        struct ll_sb_info *sbi = ll_s2sbi((struct super_block *)m->private);
+       bool val;
        int rc;
-       __s64 val;
 
-       rc = lprocfs_str_to_s64(buffer, count, &val);
+       rc = kstrtobool_from_user(buffer, count, &val);
        if (rc)
                return rc;
 
@@ -735,10 +830,10 @@ static ssize_t ll_lazystatfs_seq_write(struct file *file,
 {
        struct seq_file *m = file->private_data;
        struct ll_sb_info *sbi = ll_s2sbi((struct super_block *)m->private);
+       bool val;
        int rc;
-       __s64 val;
 
-       rc = lprocfs_str_to_s64(buffer, count, &val);
+       rc = kstrtobool_from_user(buffer, count, &val);
        if (rc)
                return rc;
 
@@ -816,17 +911,15 @@ static ssize_t ll_default_easize_seq_write(struct file *file,
        struct seq_file *seq = file->private_data;
        struct super_block *sb = (struct super_block *)seq->private;
        struct ll_sb_info *sbi = ll_s2sbi(sb);
-       __s64 val;
+       unsigned int val;
        int rc;
 
        if (count == 0)
                return 0;
 
-       rc = lprocfs_str_to_s64(buffer, count, &val);
+       rc = kstrtouint_from_user(buffer, count, 0, &val);
        if (rc)
                return rc;
-       if (val < 0 || val > INT_MAX)
-               return -ERANGE;
 
        rc = ll_set_default_mdsize(sbi, val);
        if (rc)
@@ -860,6 +953,39 @@ static int ll_sbi_flags_seq_show(struct seq_file *m, void *v)
 }
 LPROC_SEQ_FOPS_RO(ll_sbi_flags);
 
+static int ll_tiny_write_seq_show(struct seq_file *m, void *v)
+{
+       struct super_block *sb = m->private;
+       struct ll_sb_info *sbi = ll_s2sbi(sb);
+
+       seq_printf(m, "%u\n", !!(sbi->ll_flags & LL_SBI_TINY_WRITE));
+       return 0;
+}
+
+static ssize_t ll_tiny_write_seq_write(
+       struct file *file, const char __user *buffer, size_t count, loff_t *off)
+{
+       struct seq_file *m = file->private_data;
+       struct super_block *sb = m->private;
+       struct ll_sb_info *sbi = ll_s2sbi(sb);
+       bool val;
+       int rc;
+
+       rc = kstrtobool_from_user(buffer, count, &val);
+       if (rc)
+               return rc;
+
+       spin_lock(&sbi->ll_lock);
+       if (val)
+               sbi->ll_flags |= LL_SBI_TINY_WRITE;
+       else
+               sbi->ll_flags &= ~LL_SBI_TINY_WRITE;
+       spin_unlock(&sbi->ll_lock);
+
+       return count;
+}
+LPROC_SEQ_FOPS(ll_tiny_write);
+
 static int ll_fast_read_seq_show(struct seq_file *m, void *v)
 {
        struct super_block *sb = m->private;
@@ -876,15 +1002,15 @@ ll_fast_read_seq_write(struct file *file, const char __user *buffer,
        struct seq_file *m = file->private_data;
        struct super_block *sb = m->private;
        struct ll_sb_info *sbi = ll_s2sbi(sb);
+       bool val;
        int rc;
-       __s64 val;
 
-       rc = lprocfs_str_to_s64(buffer, count, &val);
+       rc = kstrtobool_from_user(buffer, count, &val);
        if (rc)
                return rc;
 
        spin_lock(&sbi->ll_lock);
-       if (val == 1)
+       if (val)
                sbi->ll_flags |= LL_SBI_FAST_READ;
        else
                sbi->ll_flags &= ~LL_SBI_FAST_READ;
@@ -894,6 +1020,39 @@ ll_fast_read_seq_write(struct file *file, const char __user *buffer,
 }
 LPROC_SEQ_FOPS(ll_fast_read);
 
+static int ll_pio_seq_show(struct seq_file *m, void *v)
+{
+       struct super_block *sb = m->private;
+       struct ll_sb_info *sbi = ll_s2sbi(sb);
+
+       seq_printf(m, "%u\n", !!(sbi->ll_flags & LL_SBI_PIO));
+       return 0;
+}
+
+static ssize_t ll_pio_seq_write(struct file *file, const char __user *buffer,
+                               size_t count, loff_t *off)
+{
+       struct seq_file *m = file->private_data;
+       struct super_block *sb = m->private;
+       struct ll_sb_info *sbi = ll_s2sbi(sb);
+       bool val;
+       int rc;
+
+       rc = kstrtobool_from_user(buffer, count, &val);
+       if (rc)
+               return rc;
+
+       spin_lock(&sbi->ll_lock);
+       if (val)
+               sbi->ll_flags |= LL_SBI_PIO;
+       else
+               sbi->ll_flags &= ~LL_SBI_PIO;
+       spin_unlock(&sbi->ll_lock);
+
+       return count;
+}
+LPROC_SEQ_FOPS(ll_pio);
+
 static int ll_unstable_stats_seq_show(struct seq_file *m, void *v)
 {
        struct super_block      *sb    = m->private;
@@ -919,8 +1078,8 @@ static ssize_t ll_unstable_stats_seq_write(struct file *file,
        struct seq_file *seq = file->private_data;
        struct ll_sb_info *sbi = ll_s2sbi((struct super_block *)seq->private);
        char kernbuf[128];
+       bool val;
        int rc;
-       __s64 val;
 
        if (count == 0)
                return 0;
@@ -933,13 +1092,13 @@ static ssize_t ll_unstable_stats_seq_write(struct file *file,
 
        buffer += lprocfs_find_named_value(kernbuf, "unstable_check:", &count) -
                  kernbuf;
-       rc = lprocfs_str_to_s64(buffer, count, &val);
+       rc = kstrtobool_from_user(buffer, count, &val);
        if (rc < 0)
                return rc;
 
        /* borrow lru lock to set the value */
        spin_lock(&sbi->ll_cache->ccc_lru_lock);
-       sbi->ll_cache->ccc_unstable_check = !!val;
+       sbi->ll_cache->ccc_unstable_check = val;
        spin_unlock(&sbi->ll_cache->ccc_lru_lock);
 
        return count;
@@ -1013,26 +1172,10 @@ static ssize_t ll_nosquash_nids_seq_write(struct file *file,
 LPROC_SEQ_FOPS(ll_nosquash_nids);
 
 struct lprocfs_vars lprocfs_llite_obd_vars[] = {
-       { .name =       "uuid",
-         .fops =       &ll_sb_uuid_fops                        },
-       { .name =       "fstype",
-         .fops =       &ll_fstype_fops                         },
        { .name =       "site",
          .fops =       &ll_site_stats_fops                     },
-       { .name =       "blocksize",
-         .fops =       &ll_blksize_fops                        },
-       { .name =       "kbytestotal",
-         .fops =       &ll_kbytestotal_fops                    },
-       { .name =       "kbytesfree",
-         .fops =       &ll_kbytesfree_fops                     },
-       { .name =       "kbytesavail",
-         .fops =       &ll_kbytesavail_fops                    },
-       { .name =       "filestotal",
-         .fops =       &ll_filestotal_fops                     },
-       { .name =       "filesfree",
-         .fops =       &ll_filesfree_fops                      },
-       { .name =       "client_type",
-         .fops =       &ll_client_type_fops                    },
+       { .name =       "stat_blocksize",
+         .fops =       &ll_stat_blksize_fops                   },
        { .name =       "max_read_ahead_mb",
          .fops =       &ll_max_readahead_mb_fops               },
        { .name =       "max_read_ahead_per_file_mb",
@@ -1041,8 +1184,6 @@ struct lprocfs_vars lprocfs_llite_obd_vars[] = {
          .fops =       &ll_max_read_ahead_whole_mb_fops        },
        { .name =       "max_cached_mb",
          .fops =       &ll_max_cached_mb_fops                  },
-       { .name =       "checksum_pages",
-         .fops =       &ll_checksum_fops                       },
        { .name =       "stats_track_pid",
          .fops =       &ll_track_pid_fops                      },
        { .name =       "stats_track_ppid",
@@ -1071,13 +1212,45 @@ struct lprocfs_vars lprocfs_llite_obd_vars[] = {
          .fops =       &ll_root_squash_fops                    },
        { .name =       "nosquash_nids",
          .fops =       &ll_nosquash_nids_fops                  },
-       { .name =       "fast_read",
-         .fops =       &ll_fast_read_fops,                     },
+       { .name =       "fast_read",
+         .fops =       &ll_fast_read_fops,                     },
+       { .name =       "pio",
+         .fops =       &ll_pio_fops,                           },
+       { .name =       "tiny_write",
+         .fops =       &ll_tiny_write_fops,                    },
        { NULL }
 };
 
 #define MAX_STRING_SIZE 128
 
+static struct attribute *llite_attrs[] = {
+       &lustre_attr_blocksize.attr,
+       &lustre_attr_kbytestotal.attr,
+       &lustre_attr_kbytesfree.attr,
+       &lustre_attr_kbytesavail.attr,
+       &lustre_attr_filestotal.attr,
+       &lustre_attr_filesfree.attr,
+       &lustre_attr_client_type.attr,
+       &lustre_attr_fstype.attr,
+       &lustre_attr_uuid.attr,
+       &lustre_attr_checksum_pages.attr,
+       &lustre_attr_statahead_running_max.attr,
+       NULL,
+};
+
+static void llite_kobj_release(struct kobject *kobj)
+{
+       struct ll_sb_info *sbi = container_of(kobj, struct ll_sb_info,
+                                             ll_kset.kobj);
+       complete(&sbi->ll_kobj_unregister);
+}
+
+static struct kobj_type llite_ktype = {
+       .default_attrs  = llite_attrs,
+       .sysfs_ops      = &lustre_sysfs_ops,
+       .release        = llite_kobj_release,
+};
+
 static const struct llite_file_opcode {
         __u32       opcode;
         __u32       type;
@@ -1166,38 +1339,21 @@ static const char *ra_stat_string[] = {
 LPROC_SEQ_FOPS_RO_TYPE(llite, name);
 LPROC_SEQ_FOPS_RO_TYPE(llite, uuid);
 
-int lprocfs_register_mountpoint(struct proc_dir_entry *parent,
-                                struct super_block *sb, char *osc, char *mdc)
+int ll_debugfs_register_super(struct super_block *sb, const char *name)
 {
-       struct lprocfs_vars lvars[2];
        struct lustre_sb_info *lsi = s2lsi(sb);
        struct ll_sb_info *sbi = ll_s2sbi(sb);
-       struct obd_device *obd;
-       struct proc_dir_entry *dir;
-       char name[MAX_STRING_SIZE + 1], *ptr;
-       int err, id, len, rc;
-       ENTRY;
+       struct lprocfs_vars lvars[2];
+       int err, id, rc;
 
+       ENTRY;
        memset(lvars, 0, sizeof(lvars));
-
-       name[MAX_STRING_SIZE] = '\0';
        lvars[0].name = name;
 
        LASSERT(sbi != NULL);
-       LASSERT(mdc != NULL);
-       LASSERT(osc != NULL);
-
-       /* Get fsname */
-       len = strlen(lsi->lsi_lmd->lmd_profile);
-       ptr = strrchr(lsi->lsi_lmd->lmd_profile, '-');
-       if (ptr && (strcmp(ptr, "-client") == 0))
-               len -= 7;
 
-       /* Mount info */
-       snprintf(name, MAX_STRING_SIZE, "%.*s-%p", len,
-                lsi->lsi_lmd->lmd_profile, sb);
-
-       sbi->ll_proc_root = lprocfs_register(name, parent, NULL, NULL);
+       sbi->ll_proc_root = lprocfs_register(name, proc_lustre_fs_root,
+                                            NULL, NULL);
        if (IS_ERR(sbi->ll_proc_root)) {
                err = PTR_ERR(sbi->ll_proc_root);
                sbi->ll_proc_root = NULL;
@@ -1209,88 +1365,108 @@ int lprocfs_register_mountpoint(struct proc_dir_entry *parent,
        if (rc)
                CWARN("Error adding the dump_page_cache file\n");
 
-        rc = lprocfs_seq_create(sbi->ll_proc_root, "extents_stats", 0644,
-                                &ll_rw_extents_stats_fops, sbi);
-        if (rc)
-                CWARN("Error adding the extent_stats file\n");
-
-        rc = lprocfs_seq_create(sbi->ll_proc_root, "extents_stats_per_process",
-                                0644, &ll_rw_extents_stats_pp_fops, sbi);
-        if (rc)
-                CWARN("Error adding the extents_stats_per_process file\n");
-
-        rc = lprocfs_seq_create(sbi->ll_proc_root, "offset_stats", 0644,
-                                &ll_rw_offset_stats_fops, sbi);
-        if (rc)
-                CWARN("Error adding the offset_stats file\n");
-
-        /* File operations stats */
-        sbi->ll_stats = lprocfs_alloc_stats(LPROC_LL_FILE_OPCODES,
-                                            LPROCFS_STATS_FLAG_NONE);
-        if (sbi->ll_stats == NULL)
-                GOTO(out, err = -ENOMEM);
-        /* do counter init */
-        for (id = 0; id < LPROC_LL_FILE_OPCODES; id++) {
-                __u32 type = llite_opcode_table[id].type;
-                void *ptr = NULL;
-                if (type & LPROCFS_TYPE_REGS)
-                        ptr = "regs";
-                else if (type & LPROCFS_TYPE_BYTES)
-                        ptr = "bytes";
-                else if (type & LPROCFS_TYPE_PAGES)
-                        ptr = "pages";
-                lprocfs_counter_init(sbi->ll_stats,
-                                     llite_opcode_table[id].opcode,
-                                     (type & LPROCFS_CNTR_AVGMINMAX),
-                                     llite_opcode_table[id].opname, ptr);
-        }
-        err = lprocfs_register_stats(sbi->ll_proc_root, "stats", sbi->ll_stats);
-        if (err)
-                GOTO(out, err);
+       rc = lprocfs_seq_create(sbi->ll_proc_root, "extents_stats", 0644,
+                               &ll_rw_extents_stats_fops, sbi);
+       if (rc)
+               CWARN("Error adding the extent_stats file\n");
 
-        sbi->ll_ra_stats = lprocfs_alloc_stats(ARRAY_SIZE(ra_stat_string),
-                                               LPROCFS_STATS_FLAG_NONE);
-        if (sbi->ll_ra_stats == NULL)
-                GOTO(out, err = -ENOMEM);
+       rc = lprocfs_seq_create(sbi->ll_proc_root, "extents_stats_per_process",
+                               0644, &ll_rw_extents_stats_pp_fops, sbi);
+       if (rc)
+               CWARN("Error adding the extents_stats_per_process file\n");
 
-        for (id = 0; id < ARRAY_SIZE(ra_stat_string); id++)
-                lprocfs_counter_init(sbi->ll_ra_stats, id, 0,
-                                     ra_stat_string[id], "pages");
-        err = lprocfs_register_stats(sbi->ll_proc_root, "read_ahead_stats",
-                                     sbi->ll_ra_stats);
-        if (err)
-                GOTO(out, err);
+       rc = lprocfs_seq_create(sbi->ll_proc_root, "offset_stats", 0644,
+                               &ll_rw_offset_stats_fops, sbi);
+       if (rc)
+               CWARN("Error adding the offset_stats file\n");
+
+       /* File operations stats */
+       sbi->ll_stats = lprocfs_alloc_stats(LPROC_LL_FILE_OPCODES,
+                                           LPROCFS_STATS_FLAG_NONE);
+       if (sbi->ll_stats == NULL)
+               GOTO(out_proc, err = -ENOMEM);
+
+       /* do counter init */
+       for (id = 0; id < LPROC_LL_FILE_OPCODES; id++) {
+               __u32 type = llite_opcode_table[id].type;
+               void *ptr = NULL;
+               if (type & LPROCFS_TYPE_REGS)
+                       ptr = "regs";
+               else if (type & LPROCFS_TYPE_BYTES)
+                       ptr = "bytes";
+               else if (type & LPROCFS_TYPE_PAGES)
+                       ptr = "pages";
+               lprocfs_counter_init(sbi->ll_stats,
+                                    llite_opcode_table[id].opcode,
+                                    (type & LPROCFS_CNTR_AVGMINMAX),
+                                    llite_opcode_table[id].opname, ptr);
+       }
 
+       err = lprocfs_register_stats(sbi->ll_proc_root, "stats", sbi->ll_stats);
+       if (err)
+               GOTO(out_stats, err);
+
+       sbi->ll_ra_stats = lprocfs_alloc_stats(ARRAY_SIZE(ra_stat_string),
+                                              LPROCFS_STATS_FLAG_NONE);
+       if (sbi->ll_ra_stats == NULL)
+               GOTO(out_stats, err = -ENOMEM);
+
+       for (id = 0; id < ARRAY_SIZE(ra_stat_string); id++)
+               lprocfs_counter_init(sbi->ll_ra_stats, id, 0,
+                                    ra_stat_string[id], "pages");
+       err = lprocfs_register_stats(sbi->ll_proc_root, "read_ahead_stats",
+                                    sbi->ll_ra_stats);
+       if (err)
+               GOTO(out_ra_stats, err);
 
        err = lprocfs_add_vars(sbi->ll_proc_root, lprocfs_llite_obd_vars, sb);
        if (err)
-               GOTO(out, err);
+               GOTO(out_ra_stats, err);
 
-       /* MDC info */
-       obd = class_name2obd(mdc);
+       /* Yes we also register sysfs mount kset here as well */
+       sbi->ll_kset.kobj.parent = llite_kobj;
+       sbi->ll_kset.kobj.ktype = &llite_ktype;
+       init_completion(&sbi->ll_kobj_unregister);
+       err = kobject_set_name(&sbi->ll_kset.kobj, "%s", name);
+       if (err)
+               GOTO(out_ra_stats, err);
 
-       LASSERT(obd != NULL);
-       LASSERT(obd->obd_magic == OBD_DEVICE_MAGIC);
-       LASSERT(obd->obd_type->typ_name != NULL);
+       err = kset_register(&sbi->ll_kset);
+       if (err)
+               GOTO(out_ra_stats, err);
 
-       dir = proc_mkdir(obd->obd_type->typ_name, sbi->ll_proc_root);
-       if (dir == NULL)
-               GOTO(out, err = -ENOMEM);
+       lsi->lsi_kobj = kobject_get(&sbi->ll_kset.kobj);
 
-       snprintf(name, MAX_STRING_SIZE, "common_name");
-       lvars[0].fops = &llite_name_fops;
-       err = lprocfs_add_vars(dir, lvars, obd);
-       if (err)
-               GOTO(out, err);
+       RETURN(0);
+out_ra_stats:
+       lprocfs_free_stats(&sbi->ll_ra_stats);
+out_stats:
+       lprocfs_free_stats(&sbi->ll_stats);
+out_proc:
+       lprocfs_remove(&sbi->ll_proc_root);
 
-       snprintf(name, MAX_STRING_SIZE, "uuid");
-       lvars[0].fops = &llite_uuid_fops;
-       err = lprocfs_add_vars(dir, lvars, obd);
-       if (err)
-               GOTO(out, err);
+       RETURN(err);
+}
+
+int lprocfs_ll_register_obd(struct super_block *sb, const char *obdname)
+{
+       struct lprocfs_vars lvars[2];
+       struct ll_sb_info *sbi = ll_s2sbi(sb);
+       struct obd_device *obd;
+       struct proc_dir_entry *dir;
+       char name[MAX_STRING_SIZE + 1];
+       int err;
+       ENTRY;
+
+       memset(lvars, 0, sizeof(lvars));
+
+       name[MAX_STRING_SIZE] = '\0';
+       lvars[0].name = name;
+
+       LASSERT(sbi != NULL);
+       LASSERT(obdname != NULL);
 
-       /* OSC */
-       obd = class_name2obd(osc);
+       obd = class_name2obd(obdname);
 
        LASSERT(obd != NULL);
        LASSERT(obd->obd_magic == OBD_DEVICE_MAGIC);
@@ -1309,6 +1485,9 @@ int lprocfs_register_mountpoint(struct proc_dir_entry *parent,
        snprintf(name, MAX_STRING_SIZE, "uuid");
        lvars[0].fops = &llite_uuid_fops;
        err = lprocfs_add_vars(dir, lvars, obd);
+       if (err)
+               GOTO(out, err);
+
 out:
        if (err) {
                lprocfs_remove(&sbi->ll_proc_root);
@@ -1318,8 +1497,16 @@ out:
        RETURN(err);
 }
 
-void lprocfs_unregister_mountpoint(struct ll_sb_info *sbi)
+void ll_debugfs_unregister_super(struct super_block *sb)
 {
+       struct lustre_sb_info *lsi = s2lsi(sb);
+       struct ll_sb_info *sbi = ll_s2sbi(sb);
+
+       kobject_put(lsi->lsi_kobj);
+
+       kset_unregister(&sbi->ll_kset);
+       wait_for_completion(&sbi->ll_kobj_unregister);
+
         if (sbi->ll_proc_root) {
                 lprocfs_remove(&sbi->ll_proc_root);
                 lprocfs_free_stats(&sbi->ll_ra_stats);
@@ -1372,19 +1559,19 @@ static void ll_display_extents_info(struct ll_rw_extents_info *io_extents,
 
 static int ll_rw_extents_stats_pp_seq_show(struct seq_file *seq, void *v)
 {
-        struct timeval now;
-        struct ll_sb_info *sbi = seq->private;
-        struct ll_rw_extents_info *io_extents = &sbi->ll_rw_extents_info;
+       struct timespec64 now;
+       struct ll_sb_info *sbi = seq->private;
+       struct ll_rw_extents_info *io_extents = &sbi->ll_rw_extents_info;
        int k;
 
-       do_gettimeofday(&now);
+       ktime_get_real_ts64(&now);
 
        if (!sbi->ll_rw_stats_on) {
-               seq_puts(seq, "disabled\n write anything in this file to activate, then 0 or \[D/d]isabled\" to deactivate\n");
-                return 0;
-        }
-        seq_printf(seq, "snapshot_time:         %lu.%lu (secs.usecs)\n",
-                   now.tv_sec, now.tv_usec);
+               seq_puts(seq, "disabled\n write anything to this file to activate, then '0' or 'disable' to deactivate\n");
+               return 0;
+       }
+       seq_printf(seq, "snapshot_time:         %llu.%09lu (secs.nsecs)\n",
+                  (s64)now.tv_sec, now.tv_nsec);
         seq_printf(seq, "%15s %19s       | %20s\n", " ", "read", "write");
         seq_printf(seq, "%13s   %14s %4s %4s  | %14s %4s %4s\n",
                    "extents", "calls", "%", "cum%",
@@ -1410,27 +1597,12 @@ static ssize_t ll_rw_extents_stats_pp_seq_write(struct file *file,
        struct ll_sb_info *sbi = seq->private;
        struct ll_rw_extents_info *io_extents = &sbi->ll_rw_extents_info;
        int i;
-       __s64 value = 1;
-       int rc = 0;
+       __s64 value;
 
        if (len == 0)
                return -EINVAL;
 
-       rc = lprocfs_str_to_s64(buf, len, &value);
-       if (rc < 0 && len < 16) {
-               char kernbuf[16];
-
-               if (copy_from_user(kernbuf, buf, len))
-                       return -EFAULT;
-               kernbuf[len] = 0;
-
-               if (kernbuf[len - 1] == '\n')
-                       kernbuf[len - 1] = 0;
-
-               if (strcmp(kernbuf, "disabled") == 0 ||
-                   strcmp(kernbuf, "Disabled") == 0)
-                       value = 0;
-       }
+       value = ll_stats_pid_write(buf, len);
 
        if (value == 0)
                sbi->ll_rw_stats_on = 0;
@@ -1451,18 +1623,18 @@ LPROC_SEQ_FOPS(ll_rw_extents_stats_pp);
 
 static int ll_rw_extents_stats_seq_show(struct seq_file *seq, void *v)
 {
-       struct timeval now;
+       struct timespec64 now;
        struct ll_sb_info *sbi = seq->private;
        struct ll_rw_extents_info *io_extents = &sbi->ll_rw_extents_info;
 
-       do_gettimeofday(&now);
+       ktime_get_real_ts64(&now);
 
        if (!sbi->ll_rw_stats_on) {
-               seq_puts(seq, "disabled\n write anything in this file to activate, then 0 or \"[D/d]isabled\" to deactivate\n");
+               seq_puts(seq, "disabled\n write anything to this file to activate, then '0' or 'disable' to deactivate\n");
                return 0;
        }
-       seq_printf(seq, "snapshot_time:         %lu.%lu (secs.usecs)\n",
-                  now.tv_sec, now.tv_usec);
+       seq_printf(seq, "snapshot_time:         %llu.%09lu (secs.nsecs)\n",
+                  (s64)now.tv_sec, now.tv_nsec);
 
        seq_printf(seq, "%15s %19s       | %20s\n", " ", "read", "write");
        seq_printf(seq, "%13s   %14s %4s %4s  | %14s %4s %4s\n",
@@ -1483,27 +1655,12 @@ static ssize_t ll_rw_extents_stats_seq_write(struct file *file,
        struct ll_sb_info *sbi = seq->private;
        struct ll_rw_extents_info *io_extents = &sbi->ll_rw_extents_info;
        int i;
-       __s64 value = 1;
-       int rc = 0;
+       __s64 value;
 
        if (len == 0)
                return -EINVAL;
 
-       rc = lprocfs_str_to_s64(buf, len, &value);
-       if (rc < 0 && len < 16) {
-               char kernbuf[16];
-
-               if (copy_from_user(kernbuf, buf, len))
-                       return -EFAULT;
-               kernbuf[len] = 0;
-
-               if (kernbuf[len - 1] == '\n')
-                       kernbuf[len - 1] = 0;
-
-               if (strcmp(kernbuf, "disabled") == 0 ||
-                   strcmp(kernbuf, "Disabled") == 0)
-                       value = 0;
-       }
+       value = ll_stats_pid_write(buf, len);
 
        if (value == 0)
                sbi->ll_rw_stats_on = 0;
@@ -1627,31 +1784,31 @@ void ll_rw_stats_tally(struct ll_sb_info *sbi, pid_t pid,
 
 static int ll_rw_offset_stats_seq_show(struct seq_file *seq, void *v)
 {
-        struct timeval now;
-        struct ll_sb_info *sbi = seq->private;
-        struct ll_rw_process_info *offset = sbi->ll_rw_offset_info;
-        struct ll_rw_process_info *process = sbi->ll_rw_process_info;
+       struct timespec64 now;
+       struct ll_sb_info *sbi = seq->private;
+       struct ll_rw_process_info *offset = sbi->ll_rw_offset_info;
+       struct ll_rw_process_info *process = sbi->ll_rw_process_info;
        int i;
 
-       do_gettimeofday(&now);
+       ktime_get_real_ts64(&now);
 
        if (!sbi->ll_rw_stats_on) {
-               seq_puts(seq, "disabled\n write anything in this file to activate, then 0 or \"[D/d]isabled\" to deactivate\n");
+               seq_puts(seq, "disabled\n write anything to this file to activate, then '0' or 'disable' to deactivate\n");
                return 0;
        }
        spin_lock(&sbi->ll_process_lock);
 
-        seq_printf(seq, "snapshot_time:         %lu.%lu (secs.usecs)\n",
-                   now.tv_sec, now.tv_usec);
-        seq_printf(seq, "%3s %10s %14s %14s %17s %17s %14s\n",
-                   "R/W", "PID", "RANGE START", "RANGE END",
-                   "SMALLEST EXTENT", "LARGEST EXTENT", "OFFSET");
+       seq_printf(seq, "snapshot_time:         %llu.%09lu (secs.nsecs)\n",
+                  (s64)now.tv_sec, now.tv_nsec);
+       seq_printf(seq, "%3s %10s %14s %14s %17s %17s %14s\n",
+                  "R/W", "PID", "RANGE START", "RANGE END",
+                  "SMALLEST EXTENT", "LARGEST EXTENT", "OFFSET");
 
        /* We stored the discontiguous offsets here; print them first */
        for (i = 0; i < LL_OFFSET_HIST_MAX; i++) {
                if (offset[i].rw_pid != 0)
                        seq_printf(seq,
-                                  "%3c %10d %14Lu %14Lu %17lu %17lu %14Lu",
+                                 "%3c %10d %14llu %14llu %17lu %17lu %14llu\n",
                                   offset[i].rw_op == READ ? 'R' : 'W',
                                   offset[i].rw_pid,
                                   offset[i].rw_range_start,
@@ -1665,7 +1822,7 @@ static int ll_rw_offset_stats_seq_show(struct seq_file *seq, void *v)
        for (i = 0; i < LL_PROCESS_HIST_MAX; i++) {
                if (process[i].rw_pid != 0)
                        seq_printf(seq,
-                                  "%3c %10d %14Lu %14Lu %17lu %17lu %14Lu",
+                                 "%3c %10d %14llu %14llu %17lu %17lu %14llu\n",
                                   process[i].rw_op == READ ? 'R' : 'W',
                                   process[i].rw_pid,
                                   process[i].rw_range_start,
@@ -1687,28 +1844,12 @@ static ssize_t ll_rw_offset_stats_seq_write(struct file *file,
        struct ll_sb_info *sbi = seq->private;
        struct ll_rw_process_info *process_info = sbi->ll_rw_process_info;
        struct ll_rw_process_info *offset_info = sbi->ll_rw_offset_info;
-       __s64 value = 1;
-       int rc = 0;
+       __s64 value;
 
        if (len == 0)
                return -EINVAL;
 
-       rc = lprocfs_str_to_s64(buf, len, &value);
-
-       if (rc < 0 && len < 16) {
-               char kernbuf[16];
-
-               if (copy_from_user(kernbuf, buf, len))
-                       return -EFAULT;
-               kernbuf[len] = 0;
-
-               if (kernbuf[len - 1] == '\n')
-                       kernbuf[len - 1] = 0;
-
-               if (strcmp(kernbuf, "disabled") == 0 ||
-                   strcmp(kernbuf, "Disabled") == 0)
-                       value = 0;
-       }
+       value = ll_stats_pid_write(buf, len);
 
        if (value == 0)
                sbi->ll_rw_stats_on = 0;
@@ -1727,5 +1868,41 @@ static ssize_t ll_rw_offset_stats_seq_write(struct file *file,
        return len;
 }
 
+/**
+ * ll_stats_pid_write() - Determine if stats collection should be enabled
+ * @buf: Buffer containing the data written
+ * @len: Number of bytes in the buffer
+ *
+ * Several proc files begin collecting stats when a value is written, and stop
+ * collecting when either '0' or 'disable' is written. This function checks the
+ * written value to see if collection should be enabled or disabled.
+ *
+ * Return: If '0' or 'disable' is provided, 0 is returned. If the text
+ * equivalent of a number is written, that number is returned. Otherwise,
+ * 1 is returned. Non-zero return values indicate collection should be enabled.
+ */
+static __s64 ll_stats_pid_write(const char __user *buf, size_t len)
+{
+       unsigned long long value = 1;
+       int rc;
+       char kernbuf[16];
+
+       rc = kstrtoull_from_user(buf, len, 0, &value);
+       if (rc < 0 && len < sizeof(kernbuf)) {
+
+               if (copy_from_user(kernbuf, buf, len))
+                       return -EFAULT;
+               kernbuf[len] = 0;
+
+               if (kernbuf[len - 1] == '\n')
+                       kernbuf[len - 1] = 0;
+
+               if (strncasecmp(kernbuf, "disable", 7) == 0)
+                       value = 0;
+       }
+
+       return value;
+}
+
 LPROC_SEQ_FOPS(ll_rw_offset_stats);
 #endif /* CONFIG_PROC_FS */