procfs: switch instantiate_t to d_splice_alias()

... and get rid of pointless struct inode *dir argument of those,
while we are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

4 files changed, 65 insertions, 79 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 6e0875505898..de22c2002b38 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1878,8 +1878,8 @@ bool proc_fill_cache(struct file *file, struct dir_context *ctx,
         struct dentry *child, *dir = file->f_path.dentry;
         struct qstr qname = QSTR_INIT(name, len);
         struct inode *inode;
-        unsigned type;
-        ino_t ino;
+        unsigned type = DT_UNKNOWN;
+        ino_t ino = 1;
 
         child = d_hash_and_lookup(dir, &qname);
         if (!child) {
@@ -1888,22 +1888,23 @@ bool proc_fill_cache(struct file *file, struct dir_context *ctx,
                 if (IS_ERR(child))
                         goto end_instantiate;
                 if (d_in_lookup(child)) {
-                        int err = instantiate(d_inode(dir), child, task, ptr);
+                        struct dentry *res;
+                        res = instantiate(child, task, ptr);
                         d_lookup_done(child);
-                        if (err < 0) {
-                                dput(child);
+                        if (IS_ERR(res))
                                 goto end_instantiate;
+                        if (unlikely(res)) {
+                                dput(child);
+                                child = res;
                         }
                 }
         }
         inode = d_inode(child);
         ino = inode->i_ino;
         type = inode->i_mode >> 12;
+end_instantiate:
         dput(child);
         return dir_emit(ctx, name, len, ino, type);
-
-end_instantiate:
-        return dir_emit(ctx, name, len, 1, DT_UNKNOWN);
 }
 
 /*
@@ -2065,19 +2066,19 @@ static const struct inode_operations proc_map_files_link_inode_operations = {
         .setattr        = proc_setattr,
 };
 
-static int
-proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
+static struct dentry *
+proc_map_files_instantiate(struct dentry *dentry,
                            struct task_struct *task, const void *ptr)
 {
         fmode_t mode = (fmode_t)(unsigned long)ptr;
         struct proc_inode *ei;
         struct inode *inode;
 
-        inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK |
+        inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK |
                                     ((mode & FMODE_READ ) ? S_IRUSR : 0) |
                                     ((mode & FMODE_WRITE) ? S_IWUSR : 0));
         if (!inode)
-                return -ENOENT;
+                return ERR_PTR(-ENOENT);
 
         ei = PROC_I(inode);
         ei->op.proc_get_link = map_files_get_link;
@@ -2086,9 +2087,7 @@ proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
         inode->i_size = 64;
 
         d_set_d_op(dentry, &tid_map_files_dentry_operations);
-        d_add(dentry, inode);
-
-        return 0;
+        return d_splice_alias(inode, dentry);
 }
 
 static struct dentry *proc_map_files_lookup(struct inode *dir,
@@ -2097,19 +2096,19 @@ static struct dentry *proc_map_files_lookup(struct inode *dir,
         unsigned long vm_start, vm_end;
         struct vm_area_struct *vma;
         struct task_struct *task;
-        int result;
+        struct dentry *result;
         struct mm_struct *mm;
 
-        result = -ENOENT;
+        result = ERR_PTR(-ENOENT);
         task = get_proc_task(dir);
         if (!task)
                 goto out;
 
-        result = -EACCES;
+        result = ERR_PTR(-EACCES);
         if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
                 goto out_put_task;
 
-        result = -ENOENT;
+        result = ERR_PTR(-ENOENT);
         if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
                 goto out_put_task;
 
@@ -2123,7 +2122,7 @@ static struct dentry *proc_map_files_lookup(struct inode *dir,
                 goto out_no_vma;
 
         if (vma->vm_file)
-                result = proc_map_files_instantiate(dir, dentry, task,
+                result = proc_map_files_instantiate(dentry, task,
                                 (void *)(unsigned long)vma->vm_file->f_mode);
 
 out_no_vma:
@@ -2132,7 +2131,7 @@ out_no_vma:
 out_put_task:
         put_task_struct(task);
 out:
-        return ERR_PTR(result);
+        return result;
 }
 
 static const struct inode_operations proc_map_files_inode_operations = {
@@ -2433,16 +2432,16 @@ static const struct file_operations proc_pid_set_timerslack_ns_operations = {
         .release        = single_release,
 };
 
-static int proc_pident_instantiate(struct inode *dir,
-        struct dentry *dentry, struct task_struct *task, const void *ptr)
+static struct dentry *proc_pident_instantiate(struct dentry *dentry,
+        struct task_struct *task, const void *ptr)
 {
         const struct pid_entry *p = ptr;
         struct inode *inode;
         struct proc_inode *ei;
 
-        inode = proc_pid_make_inode(dir->i_sb, task, p->mode);
+        inode = proc_pid_make_inode(dentry->d_sb, task, p->mode);
         if (!inode)
-                return -ENOENT;
+                return ERR_PTR(-ENOENT);
 
         ei = PROC_I(inode);
         if (S_ISDIR(inode->i_mode))
@@ -2454,8 +2453,7 @@ static int proc_pident_instantiate(struct inode *dir,
         ei->op = p->op;
         pid_update_inode(task, inode);
         d_set_d_op(dentry, &pid_dentry_operations);
-        d_add(dentry, inode);
-        return 0;
+        return d_splice_alias(inode, dentry);
 }
 
 static struct dentry *proc_pident_lookup(struct inode *dir, 
@@ -2463,11 +2461,9 @@ static struct dentry *proc_pident_lookup(struct inode *dir,
                                          const struct pid_entry *ents,
                                          unsigned int nents)
 {
-        int error;
         struct task_struct *task = get_proc_task(dir);
         const struct pid_entry *p, *last;
-
-        error = -ENOENT;
+        struct dentry *res = ERR_PTR(-ENOENT);
 
         if (!task)
                 goto out_no_task;
@@ -2486,11 +2482,11 @@ static struct dentry *proc_pident_lookup(struct inode *dir,
         if (p >= last)
                 goto out;
 
-        error = proc_pident_instantiate(dir, dentry, task, p);
+        res = proc_pident_instantiate(dentry, task, p);
 out:
         put_task_struct(task);
 out_no_task:
-        return ERR_PTR(error);
+        return res;
 }
 
 static int proc_pident_readdir(struct file *file, struct dir_context *ctx,
@@ -3133,15 +3129,14 @@ void proc_flush_task(struct task_struct *task)
         }
 }
 
-static int proc_pid_instantiate(struct inode *dir,
-                                   struct dentry * dentry,
+static struct dentry *proc_pid_instantiate(struct dentry * dentry,
                                    struct task_struct *task, const void *ptr)
 {
         struct inode *inode;
 
-        inode = proc_pid_make_inode(dir->i_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
+        inode = proc_pid_make_inode(dentry->d_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
         if (!inode)
-                return -ENOENT;
+                return ERR_PTR(-ENOENT);
 
         inode->i_op = &proc_tgid_base_inode_operations;
         inode->i_fop = &proc_tgid_base_operations;
@@ -3151,16 +3146,15 @@ static int proc_pid_instantiate(struct inode *dir,
         pid_update_inode(task, inode);
 
         d_set_d_op(dentry, &pid_dentry_operations);
-        d_add(dentry, inode);
-        return 0;
+        return d_splice_alias(inode, dentry);
 }
 
 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
 {
-        int result = -ENOENT;
         struct task_struct *task;
         unsigned tgid;
         struct pid_namespace *ns;
+        struct dentry *result = ERR_PTR(-ENOENT);
 
         tgid = name_to_int(&dentry->d_name);
         if (tgid == ~0U)
@@ -3175,10 +3169,10 @@ struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsign
         if (!task)
                 goto out;
 
-        result = proc_pid_instantiate(dir, dentry, task, NULL);
+        result = proc_pid_instantiate(dentry, task, NULL);
         put_task_struct(task);
 out:
-        return ERR_PTR(result);
+        return result;
 }
 
 /*
@@ -3426,13 +3420,13 @@ static const struct inode_operations proc_tid_base_inode_operations = {
         .setattr        = proc_setattr,
 };
 
-static int proc_task_instantiate(struct inode *dir,
-        struct dentry *dentry, struct task_struct *task, const void *ptr)
+static struct dentry *proc_task_instantiate(struct dentry *dentry,
+        struct task_struct *task, const void *ptr)
 {
         struct inode *inode;
-        inode = proc_pid_make_inode(dir->i_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
+        inode = proc_pid_make_inode(dentry->d_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
         if (!inode)
-                return -ENOENT;
+                return ERR_PTR(-ENOENT);
 
         inode->i_op = &proc_tid_base_inode_operations;
         inode->i_fop = &proc_tid_base_operations;
@@ -3442,17 +3436,16 @@ static int proc_task_instantiate(struct inode *dir,
         pid_update_inode(task, inode);
 
         d_set_d_op(dentry, &pid_dentry_operations);
-        d_add(dentry, inode);
-        return 0;
+        return d_splice_alias(inode, dentry);
 }
 
 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
 {
-        int result = -ENOENT;
         struct task_struct *task;
         struct task_struct *leader = get_proc_task(dir);
         unsigned tid;
         struct pid_namespace *ns;
+        struct dentry *result = ERR_PTR(-ENOENT);
 
         if (!leader)
                 goto out_no_task;
@@ -3472,13 +3465,13 @@ static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry
         if (!same_thread_group(leader, task))
                 goto out_drop_task;
 
-        result = proc_task_instantiate(dir, dentry, task, NULL);
+        result = proc_task_instantiate(dentry, task, NULL);
 out_drop_task:
         put_task_struct(task);
 out:
         put_task_struct(leader);
 out_no_task:
-        return ERR_PTR(result);
+        return result;
 }
 
 /*
diff --git a/fs/proc/fd.c b/fs/proc/fd.c
index f5de22a9e9e0..05b9893e9a22 100644
--- a/fs/proc/fd.c
+++ b/fs/proc/fd.c
@@ -179,17 +179,16 @@ struct fd_data {
         unsigned fd;
 };
 
-static int
-proc_fd_instantiate(struct inode *dir, struct dentry *dentry,
-                    struct task_struct *task, const void *ptr)
+static struct dentry *proc_fd_instantiate(struct dentry *dentry,
+        struct task_struct *task, const void *ptr)
 {
         const struct fd_data *data = ptr;
         struct proc_inode *ei;
         struct inode *inode;
 
-        inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK);
+        inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK);
         if (!inode)
-                return -ENOENT;
+                return ERR_PTR(-ENOENT);
 
         ei = PROC_I(inode);
         ei->fd = data->fd;
@@ -201,8 +200,7 @@ proc_fd_instantiate(struct inode *dir, struct dentry *dentry,
         tid_fd_update_inode(task, inode, data->mode);
 
         d_set_d_op(dentry, &tid_fd_dentry_operations);
-        d_add(dentry, inode);
-        return 0;
+        return d_splice_alias(inode, dentry);
 }
 
 static struct dentry *proc_lookupfd_common(struct inode *dir,
@@ -210,8 +208,8 @@ static struct dentry *proc_lookupfd_common(struct inode *dir,
                                            instantiate_t instantiate)
 {
         struct task_struct *task = get_proc_task(dir);
-        int result = -ENOENT;
         struct fd_data data = {.fd = name_to_int(&dentry->d_name)};
+        struct dentry *result = ERR_PTR(-ENOENT);
 
         if (!task)
                 goto out_no_task;
@@ -220,11 +218,11 @@ static struct dentry *proc_lookupfd_common(struct inode *dir,
         if (!tid_fd_mode(task, data.fd, &data.mode))
                 goto out;
 
-        result = instantiate(dir, dentry, task, &data);
+        result = instantiate(dentry, task, &data);
 out:
         put_task_struct(task);
 out_no_task:
-        return ERR_PTR(result);
+        return result;
 }
 
 static int proc_readfd_common(struct file *file, struct dir_context *ctx,
@@ -320,17 +318,16 @@ const struct inode_operations proc_fd_inode_operations = {
         .setattr        = proc_setattr,
 };
 
-static int
-proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry,
-                        struct task_struct *task, const void *ptr)
+static struct dentry *proc_fdinfo_instantiate(struct dentry *dentry,
+        struct task_struct *task, const void *ptr)
 {
         const struct fd_data *data = ptr;
         struct proc_inode *ei;
         struct inode *inode;
 
-        inode = proc_pid_make_inode(dir->i_sb, task, S_IFREG | S_IRUSR);
+        inode = proc_pid_make_inode(dentry->d_sb, task, S_IFREG | S_IRUSR);
         if (!inode)
-                return -ENOENT;
+                return ERR_PTR(-ENOENT);
 
         ei = PROC_I(inode);
         ei->fd = data->fd;
@@ -339,8 +336,7 @@ proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry,
         tid_fd_update_inode(task, inode, 0);
 
         d_set_d_op(dentry, &tid_fd_dentry_operations);
-        d_add(dentry, inode);
-        return 0;
+        return d_splice_alias(inode, dentry);
 }
 
 static struct dentry *
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 04a455b9ae69..275b062e58af 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -154,7 +154,7 @@ extern struct dentry *proc_pid_lookup(struct inode *, struct dentry *, unsigned
 extern loff_t mem_lseek(struct file *, loff_t, int);
 
 /* Lookups */
-typedef int instantiate_t(struct inode *, struct dentry *,
+typedef struct dentry *instantiate_t(struct dentry *,
                                      struct task_struct *, const void *);
 extern bool proc_fill_cache(struct file *, struct dir_context *, const char *, int,
                            instantiate_t, struct task_struct *, const void *);
diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index ad1adce6541d..dd2b35f78b09 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -87,16 +87,16 @@ static const struct inode_operations proc_ns_link_inode_operations = {
         .setattr        = proc_setattr,
 };
 
-static int proc_ns_instantiate(struct inode *dir,
-        struct dentry *dentry, struct task_struct *task, const void *ptr)
+static struct dentry *proc_ns_instantiate(struct dentry *dentry,
+        struct task_struct *task, const void *ptr)
 {
         const struct proc_ns_operations *ns_ops = ptr;
         struct inode *inode;
         struct proc_inode *ei;
 
-        inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK | S_IRWXUGO);
+        inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK | S_IRWXUGO);
         if (!inode)
-                return -ENOENT;
+                return ERR_PTR(-ENOENT);
 
         ei = PROC_I(inode);
         inode->i_op = &proc_ns_link_inode_operations;
@@ -104,8 +104,7 @@ static int proc_ns_instantiate(struct inode *dir,
         pid_update_inode(task, inode);
 
         d_set_d_op(dentry, &pid_dentry_operations);
-        d_add(dentry, inode);
-        return 0;
+        return d_splice_alias(inode, dentry);
 }
 
 static int proc_ns_dir_readdir(struct file *file, struct dir_context *ctx)
@@ -144,12 +143,10 @@ const struct file_operations proc_ns_dir_operations = {
 static struct dentry *proc_ns_dir_lookup(struct inode *dir,
                                 struct dentry *dentry, unsigned int flags)
 {
-        int error;
         struct task_struct *task = get_proc_task(dir);
         const struct proc_ns_operations **entry, **last;
         unsigned int len = dentry->d_name.len;
-
-        error = -ENOENT;
+        struct dentry *res = ERR_PTR(-ENOENT);
 
         if (!task)
                 goto out_no_task;
@@ -164,11 +161,11 @@ static struct dentry *proc_ns_dir_lookup(struct inode *dir,
         if (entry == last)
                 goto out;
 
-        error = proc_ns_instantiate(dir, dentry, task, *entry);
+        res = proc_ns_instantiate(dentry, task, *entry);
 out:
         put_task_struct(task);
 out_no_task:
-        return ERR_PTR(error);
+        return res;
 }
 
 const struct inode_operations proc_ns_dir_inode_operations = {