ocfs2/dlm: Cleanup dlmdebug.c

Remove struct debug_buffer in dlmdebug.c/h.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>

2 files changed, 66 insertions, 117 deletions

diff --git a/fs/ocfs2/dlm/dlmdebug.c b/fs/ocfs2/dlm/dlmdebug.c
index 272ec8631a51..77199ca4409a 100644
--- a/fs/ocfs2/dlm/dlmdebug.c
+++ b/fs/ocfs2/dlm/dlmdebug.c
@@ -370,92 +370,46 @@ static void dlm_debug_get(struct dlm_debug_ctxt *dc)
         kref_get(&dc->debug_refcnt);
 }
 
-static struct debug_buffer *debug_buffer_allocate(void)
+static int debug_release(struct inode *inode, struct file *file)
 {
-        struct debug_buffer *db = NULL;
-
-        db = kzalloc(sizeof(struct debug_buffer), GFP_KERNEL);
-        if (!db)
-                goto bail;
-
-        db->len = PAGE_SIZE;
-        db->buf = kmalloc(db->len, GFP_KERNEL);
-        if (!db->buf)
-                goto bail;
-
-        return db;
-bail:
-        kfree(db);
-        return NULL;
-}
-
-static ssize_t debug_buffer_read(struct file *file, char __user *buf,
-                                 size_t nbytes, loff_t *ppos)
-{
-        struct debug_buffer *db = file->private_data;
-
-        return simple_read_from_buffer(buf, nbytes, ppos, db->buf, db->len);
-}
-
-static loff_t debug_buffer_llseek(struct file *file, loff_t off, int whence)
-{
-        struct debug_buffer *db = file->private_data;
-        loff_t new = -1;
-
-        switch (whence) {
-        case 0:
-                new = off;
-                break;
-        case 1:
-                new = file->f_pos + off;
-                break;
-        }
-
-        if (new < 0 || new > db->len)
-                return -EINVAL;
-
-        return (file->f_pos = new);
+        free_page((unsigned long)file->private_data);
+        return 0;
 }
 
-static int debug_buffer_release(struct inode *inode, struct file *file)
+static ssize_t debug_read(struct file *file, char __user *buf,
+                          size_t nbytes, loff_t *ppos)
 {
-        struct debug_buffer *db = file->private_data;
-
-        if (db)
-                kfree(db->buf);
-        kfree(db);
-
-        return 0;
+        return simple_read_from_buffer(buf, nbytes, ppos, file->private_data,
+                                       i_size_read(file->f_mapping->host));
 }
 /* end - util funcs */
 
 /* begin - purge list funcs */
-static int debug_purgelist_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
+static int debug_purgelist_print(struct dlm_ctxt *dlm, char *buf, int len)
 {
         struct dlm_lock_resource *res;
         int out = 0;
         unsigned long total = 0;
 
-        out += snprintf(db->buf + out, db->len - out,
+        out += snprintf(buf + out, len - out,
                         "Dumping Purgelist for Domain: %s\n", dlm->name);
 
         spin_lock(&dlm->spinlock);
         list_for_each_entry(res, &dlm->purge_list, purge) {
                 ++total;
-                if (db->len - out < 100)
+                if (len - out < 100)
                         continue;
                 spin_lock(&res->spinlock);
                 out += stringify_lockname(res->lockname.name,
                                           res->lockname.len,
-                                          db->buf + out, db->len - out);
-                out += snprintf(db->buf + out, db->len - out, "\t%ld\n",
+                                          buf + out, len - out);
+                out += snprintf(buf + out, len - out, "\t%ld\n",
                                 (jiffies - res->last_used)/HZ);
                 spin_unlock(&res->spinlock);
         }
         spin_unlock(&dlm->spinlock);
 
-        out += snprintf(db->buf + out, db->len - out,
-                        "Total on list: %ld\n", total);
+        out += snprintf(buf + out, len - out, "Total on list: %ld\n", total);
 
         return out;
 }
@@ -463,15 +417,15 @@ static int debug_purgelist_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
 static int debug_purgelist_open(struct inode *inode, struct file *file)
 {
         struct dlm_ctxt *dlm = inode->i_private;
-        struct debug_buffer *db;
+        char *buf = NULL;
 
-        db = debug_buffer_allocate();
-        if (!db)
+        buf = (char *) get_zeroed_page(GFP_NOFS);
+        if (!buf)
                 goto bail;
 
-        db->len = debug_purgelist_print(dlm, db);
+        i_size_write(inode, debug_purgelist_print(dlm, buf, PAGE_SIZE - 1));
 
-        file->private_data = db;
+        file->private_data = buf;
 
         return 0;
 bail:
@@ -480,14 +434,14 @@ bail:
 
 static const struct file_operations debug_purgelist_fops = {
         .open =         debug_purgelist_open,
-        .release =      debug_buffer_release,
-        .read =         debug_buffer_read,
-        .llseek =       debug_buffer_llseek,
+        .release =      debug_release,
+        .read =         debug_read,
+        .llseek =       generic_file_llseek,
 };
 /* end - purge list funcs */
 
 /* begin - debug mle funcs */
-static int debug_mle_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
+static int debug_mle_print(struct dlm_ctxt *dlm, char *buf, int len)
 {
         struct dlm_master_list_entry *mle;
         struct hlist_head *bucket;
@@ -495,7 +449,7 @@ static int debug_mle_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
         int i, out = 0;
         unsigned long total = 0, longest = 0, bucket_count = 0;
 
-        out += snprintf(db->buf + out, db->len - out,
+        out += snprintf(buf + out, len - out,
                         "Dumping MLEs for Domain: %s\n", dlm->name);
 
         spin_lock(&dlm->master_lock);
@@ -506,16 +460,16 @@ static int debug_mle_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
                                           master_hash_node);
                         ++total;
                         ++bucket_count;
-                        if (db->len - out < 200)
+                        if (len - out < 200)
                                 continue;
-                        out += dump_mle(mle, db->buf + out, db->len - out);
+                        out += dump_mle(mle, buf + out, len - out);
                 }
                 longest = max(longest, bucket_count);
                 bucket_count = 0;
         }
         spin_unlock(&dlm->master_lock);
 
-        out += snprintf(db->buf + out, db->len - out,
+        out += snprintf(buf + out, len - out,
                         "Total: %ld, Longest: %ld\n", total, longest);
         return out;
 }
@@ -523,15 +477,15 @@ static int debug_mle_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
 static int debug_mle_open(struct inode *inode, struct file *file)
 {
         struct dlm_ctxt *dlm = inode->i_private;
-        struct debug_buffer *db;
+        char *buf = NULL;
 
-        db = debug_buffer_allocate();
-        if (!db)
+        buf = (char *) get_zeroed_page(GFP_NOFS);
+        if (!buf)
                 goto bail;
 
-        db->len = debug_mle_print(dlm, db);
+        i_size_write(inode, debug_mle_print(dlm, buf, PAGE_SIZE - 1));
 
-        file->private_data = db;
+        file->private_data = buf;
 
         return 0;
 bail:
@@ -540,9 +494,9 @@ bail:
 
 static const struct file_operations debug_mle_fops = {
         .open =         debug_mle_open,
-        .release =      debug_buffer_release,
-        .read =         debug_buffer_read,
-        .llseek =       debug_buffer_llseek,
+        .release =      debug_release,
+        .read =         debug_read,
+        .llseek =       generic_file_llseek,
 };
 
 /* end - debug mle funcs */
@@ -757,7 +711,7 @@ static const struct file_operations debug_lockres_fops = {
 /* end - debug lockres funcs */
 
 /* begin - debug state funcs */
-static int debug_state_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
+static int debug_state_print(struct dlm_ctxt *dlm, char *buf, int len)
 {
         int out = 0;
         struct dlm_reco_node_data *node;
@@ -781,35 +735,35 @@ static int debug_state_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
         }
 
         /* Domain: xxxxxxxxxx  Key: 0xdfbac769 */
-        out += snprintf(db->buf + out, db->len - out,
+        out += snprintf(buf + out, len - out,
                         "Domain: %s  Key: 0x%08x  Protocol: %d.%d\n",
                         dlm->name, dlm->key, dlm->dlm_locking_proto.pv_major,
                         dlm->dlm_locking_proto.pv_minor);
 
         /* Thread Pid: xxx  Node: xxx  State: xxxxx */
-        out += snprintf(db->buf + out, db->len - out,
+        out += snprintf(buf + out, len - out,
                         "Thread Pid: %d  Node: %d  State: %s\n",
                         dlm->dlm_thread_task->pid, dlm->node_num, state);
 
         /* Number of Joins: xxx  Joining Node: xxx */
-        out += snprintf(db->buf + out, db->len - out,
+        out += snprintf(buf + out, len - out,
                         "Number of Joins: %d  Joining Node: %d\n",
                         dlm->num_joins, dlm->joining_node);
 
         /* Domain Map: xx xx xx */
-        out += snprintf(db->buf + out, db->len - out, "Domain Map: ");
+        out += snprintf(buf + out, len - out, "Domain Map: ");
         out += stringify_nodemap(dlm->domain_map, O2NM_MAX_NODES,
-                                 db->buf + out, db->len - out);
-        out += snprintf(db->buf + out, db->len - out, "\n");
+                                 buf + out, len - out);
+        out += snprintf(buf + out, len - out, "\n");
 
         /* Live Map: xx xx xx */
-        out += snprintf(db->buf + out, db->len - out, "Live Map: ");
+        out += snprintf(buf + out, len - out, "Live Map: ");
         out += stringify_nodemap(dlm->live_nodes_map, O2NM_MAX_NODES,
-                                 db->buf + out, db->len - out);
-        out += snprintf(db->buf + out, db->len - out, "\n");
+                                 buf + out, len - out);
+        out += snprintf(buf + out, len - out, "\n");
 
         /* Lock Resources: xxx (xxx) */
-        out += snprintf(db->buf + out, db->len - out,
+        out += snprintf(buf + out, len - out,
                         "Lock Resources: %d (%d)\n",
                         atomic_read(&dlm->res_cur_count),
                         atomic_read(&dlm->res_tot_count));
@@ -821,29 +775,29 @@ static int debug_state_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
                 cur_mles += atomic_read(&dlm->mle_cur_count[i]);
 
         /* MLEs: xxx (xxx) */
-        out += snprintf(db->buf + out, db->len - out,
+        out += snprintf(buf + out, len - out,
                         "MLEs: %d (%d)\n", cur_mles, tot_mles);
 
         /*  Blocking: xxx (xxx) */
-        out += snprintf(db->buf + out, db->len - out,
+        out += snprintf(buf + out, len - out,
                         "  Blocking: %d (%d)\n",
                         atomic_read(&dlm->mle_cur_count[DLM_MLE_BLOCK]),
                         atomic_read(&dlm->mle_tot_count[DLM_MLE_BLOCK]));
 
         /*  Mastery: xxx (xxx) */
-        out += snprintf(db->buf + out, db->len - out,
+        out += snprintf(buf + out, len - out,
                         "  Mastery: %d (%d)\n",
                         atomic_read(&dlm->mle_cur_count[DLM_MLE_MASTER]),
                         atomic_read(&dlm->mle_tot_count[DLM_MLE_MASTER]));
 
         /*  Migration: xxx (xxx) */
-        out += snprintf(db->buf + out, db->len - out,
+        out += snprintf(buf + out, len - out,
                         "  Migration: %d (%d)\n",
                         atomic_read(&dlm->mle_cur_count[DLM_MLE_MIGRATION]),
                         atomic_read(&dlm->mle_tot_count[DLM_MLE_MIGRATION]));
 
         /* Lists: Dirty=Empty  Purge=InUse  PendingASTs=Empty  ... */
-        out += snprintf(db->buf + out, db->len - out,
+        out += snprintf(buf + out, len - out,
                         "Lists: Dirty=%s  Purge=%s  PendingASTs=%s  "
                         "PendingBASTs=%s\n",
                         (list_empty(&dlm->dirty_list) ? "Empty" : "InUse"),
@@ -852,12 +806,12 @@ static int debug_state_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
                         (list_empty(&dlm->pending_basts) ? "Empty" : "InUse"));
 
         /* Purge Count: xxx  Refs: xxx */
-        out += snprintf(db->buf + out, db->len - out,
+        out += snprintf(buf + out, len - out,
                         "Purge Count: %d  Refs: %d\n", dlm->purge_count,
                         atomic_read(&dlm->dlm_refs.refcount));
 
         /* Dead Node: xxx */
-        out += snprintf(db->buf + out, db->len - out,
+        out += snprintf(buf + out, len - out,
                         "Dead Node: %d\n", dlm->reco.dead_node);
 
         /* What about DLM_RECO_STATE_FINALIZE? */
@@ -867,19 +821,19 @@ static int debug_state_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
                 state = "INACTIVE";
 
         /* Recovery Pid: xxxx  Master: xxx  State: xxxx */
-        out += snprintf(db->buf + out, db->len - out,
+        out += snprintf(buf + out, len - out,
                         "Recovery Pid: %d  Master: %d  State: %s\n",
                         dlm->dlm_reco_thread_task->pid,
                         dlm->reco.new_master, state);
 
         /* Recovery Map: xx xx */
-        out += snprintf(db->buf + out, db->len - out, "Recovery Map: ");
+        out += snprintf(buf + out, len - out, "Recovery Map: ");
         out += stringify_nodemap(dlm->recovery_map, O2NM_MAX_NODES,
-                                 db->buf + out, db->len - out);
-        out += snprintf(db->buf + out, db->len - out, "\n");
+                                 buf + out, len - out);
+        out += snprintf(buf + out, len - out, "\n");
 
         /* Recovery Node State: */
-        out += snprintf(db->buf + out, db->len - out, "Recovery Node State:\n");
+        out += snprintf(buf + out, len - out, "Recovery Node State:\n");
         list_for_each_entry(node, &dlm->reco.node_data, list) {
                 switch (node->state) {
                 case DLM_RECO_NODE_DATA_INIT:
@@ -907,7 +861,7 @@ static int debug_state_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
                         state = "BAD";
                         break;
                 }
-                out += snprintf(db->buf + out, db->len - out, "\t%u - %s\n",
+                out += snprintf(buf + out, len - out, "\t%u - %s\n",
                                 node->node_num, state);
         }
 
@@ -919,15 +873,15 @@ static int debug_state_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
 static int debug_state_open(struct inode *inode, struct file *file)
 {
         struct dlm_ctxt *dlm = inode->i_private;
-        struct debug_buffer *db = NULL;
+        char *buf = NULL;
 
-        db = debug_buffer_allocate();
-        if (!db)
+        buf = (char *) get_zeroed_page(GFP_NOFS);
+        if (!buf)
                 goto bail;
 
-        db->len = debug_state_print(dlm, db);
+        i_size_write(inode, debug_state_print(dlm, buf, PAGE_SIZE - 1));
 
-        file->private_data = db;
+        file->private_data = buf;
 
         return 0;
 bail:
@@ -936,9 +890,9 @@ bail:
 
 static const struct file_operations debug_state_fops = {
         .open =         debug_state_open,
-        .release =      debug_buffer_release,
-        .read =         debug_buffer_read,
-        .llseek =       debug_buffer_llseek,
+        .release =      debug_release,
+        .read =         debug_read,
+        .llseek =       generic_file_llseek,
 };
 /* end  - debug state funcs */
 
diff --git a/fs/ocfs2/dlm/dlmdebug.h b/fs/ocfs2/dlm/dlmdebug.h
index 8c686d22f9c7..1f27c4812d1a 100644
--- a/fs/ocfs2/dlm/dlmdebug.h
+++ b/fs/ocfs2/dlm/dlmdebug.h
@@ -37,11 +37,6 @@ struct dlm_debug_ctxt {
         struct dentry *debug_purgelist_dentry;
 };
 
-struct debug_buffer {
-        int len;
-        char *buf;
-};
-
 struct debug_lockres {
         int dl_len;
         char *dl_buf;