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

jeffm
2018-04-24T02:21:21Z

From: Jeff Mahoney <jeffm@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 <jeffm@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