[PATCH 1/5] procfs: factor out a few helpers

[jeffm]

From: Jeff Mahoney <je...@suse.com>

In order to make the following series easier to review, this patch
factors out a few helpers:
- proc_fill_cache_entry: proc_fill_cache that takes an entry instead of
  an entry, a name, and a name length
- pident_lookup_task: proc_pident_lookup that takes a task, allowing the
  caller to do the task validation
- pid_entry_match_dentry: the comparison between a dentry's name and
  a pid_entry

Signed-off-by: Jeff Mahoney <je...@suse.com>
---
 fs/proc/base.c | 60 ++++++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 40 insertions(+), 20 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 9298324325ed..e9876a89a5ad 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2453,19 +2453,28 @@ static int proc_pident_instantiate(struct inode *dir,
        return -ENOENT;
 }
 
-static struct dentry *proc_pident_lookup(struct inode *dir, 
-                                        struct dentry *dentry,
-                                        const struct pid_entry *ents,
-                                        unsigned int nents)
+static bool proc_fill_cache_entry(struct file *file, struct dir_context *ctx,
+                                 const struct pid_entry *entry,
+                                 struct task_struct *task)
 {
-       int error;
-       struct task_struct *task = get_proc_task(dir);
-       const struct pid_entry *p, *last;
+       return proc_fill_cache(file, ctx, entry->name, entry->len,
+                              proc_pident_instantiate, task, entry);
+}
 
-       error = -ENOENT;
+static bool pid_entry_match_dentry(const struct pid_entry *entry,
+                                  const struct dentry *dentry)
+{
+       if (entry->len != dentry->d_name.len)
+               return false;
+       return !memcmp(dentry->d_name.name, entry->name, entry->len);
+}
 
-       if (!task)
-               goto out_no_task;
+static int proc_pident_lookup_task(struct inode *dir, struct dentry *dentry,
+                                  const struct pid_entry *ents,
+                                  unsigned int nents,
+                                  struct task_struct *task)
+{
+       const struct pid_entry *p, *last;
 
        /*
         * Yes, it does not scale. And it should not. Don't add
@@ -2473,18 +2482,30 @@ static struct dentry *proc_pident_lookup(struct inode 
*dir,
         */
        last = &ents[nents];
        for (p = ents; p < last; p++) {
-               if (p->len != dentry->d_name.len)
-                       continue;
-               if (!memcmp(dentry->d_name.name, p->name, p->len))
+               if (pid_entry_match_dentry(p, dentry))
                        break;
        }
        if (p >= last)
-               goto out;
+               return -ENOENT;
+
+       return proc_pident_instantiate(dir, dentry, task, p);
+}
+
+static struct dentry *proc_pident_lookup(struct inode *dir,
+                                        struct dentry *dentry,
+                                        const struct pid_entry *ents,
+                                        unsigned int nents)
+{
+       struct task_struct *task;
+       int error = -ENOENT;
+
+       task = get_proc_task(dir);
+       if (task) {
+               error = proc_pident_lookup_task(dir, dentry, ents,
+                                               nents, task);
+               put_task_struct(task);
+       }
 
-       error = proc_pident_instantiate(dir, dentry, task, p);
-out:
-       put_task_struct(task);
-out_no_task:
        return ERR_PTR(error);
 }
 
@@ -2504,8 +2525,7 @@ static int proc_pident_readdir(struct file *file, struct 
dir_context *ctx,
                goto out;
 
        for (p = ents + (ctx->pos - 2); p < ents + nents; p++) {
-               if (!proc_fill_cache(file, ctx, p->name, p->len,
-                               proc_pident_instantiate, task, p))
+               if (!proc_fill_cache_entry(file, ctx, p, task))
                        break;
                ctx->pos++;
        }
-- 
2.12.3