From 8fd3395ec9051a52828fcca2328cb50a69dea8ef Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Wed, 31 Jul 2024 11:49:04 -0400
Subject: get rid of ...lookup...fdget_rcu() family

Once upon a time, predecessors of those used to do file lookup
without bumping a refcount, provided that caller held rcu_read_lock()
across the lookup and whatever it wanted to read from the struct
file found.  When struct file allocation switched to SLAB_TYPESAFE_BY_RCU,
that stopped being feasible and these primitives started to bump the
file refcount for lookup result, requiring the caller to call fput()
afterwards.

But that turned them pointless - e.g.
	rcu_read_lock();
	file = lookup_fdget_rcu(fd);
	rcu_read_unlock();
is equivalent to
	file = fget_raw(fd);
and all callers of lookup_fdget_rcu() are of that form.  Similarly,
task_lookup_fdget_rcu() calls can be replaced with calling fget_task().
task_lookup_next_fdget_rcu() doesn't have direct counterparts, but
its callers would be happier if we replaced it with an analogue that
deals with RCU internally.

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 kernel/bpf/task_iter.c | 6 +-----
 kernel/kcmp.c          | 4 +---
 2 files changed, 2 insertions(+), 8 deletions(-)

(limited to 'kernel')

diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
index 02aa9db8d796..7fe602ca74a0 100644
--- a/kernel/bpf/task_iter.c
+++ b/kernel/bpf/task_iter.c
@@ -5,7 +5,6 @@
 #include <linux/namei.h>
 #include <linux/pid_namespace.h>
 #include <linux/fs.h>
-#include <linux/fdtable.h>
 #include <linux/filter.h>
 #include <linux/bpf_mem_alloc.h>
 #include <linux/btf_ids.h>
@@ -286,17 +285,14 @@ again:
 			curr_fd = 0;
 	}
 
-	rcu_read_lock();
-	f = task_lookup_next_fdget_rcu(curr_task, &curr_fd);
+	f = fget_task_next(curr_task, &curr_fd);
 	if (f) {
 		/* set info->fd */
 		info->fd = curr_fd;
-		rcu_read_unlock();
 		return f;
 	}
 
 	/* the current task is done, go to the next task */
-	rcu_read_unlock();
 	put_task_struct(curr_task);
 
 	if (info->common.type == BPF_TASK_ITER_TID) {
diff --git a/kernel/kcmp.c b/kernel/kcmp.c
index b0639f21041f..2c596851f8a9 100644
--- a/kernel/kcmp.c
+++ b/kernel/kcmp.c
@@ -63,9 +63,7 @@ get_file_raw_ptr(struct task_struct *task, unsigned int idx)
 {
 	struct file *file;
 
-	rcu_read_lock();
-	file = task_lookup_fdget_rcu(task, idx);
-	rcu_read_unlock();
+	file = fget_task(task, idx);
 	if (file)
 		fput(file);
 
-- 
cgit v1.2.3


From be5498cac2ddb112c5bd7433d5e834a1a2493427 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 2 Jun 2024 23:58:44 -0400
Subject: remove pointless includes of <linux/fdtable.h>

some of those used to be needed, some had been cargo-culted for
no reason...

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 kernel/bpf/bpf_inode_storage.c | 1 -
 kernel/bpf/bpf_task_storage.c  | 1 -
 kernel/bpf/token.c             | 1 -
 kernel/exit.c                  | 1 -
 kernel/module/dups.c           | 1 -
 kernel/module/kmod.c           | 1 -
 kernel/umh.c                   | 1 -
 7 files changed, 7 deletions(-)

(limited to 'kernel')

diff --git a/kernel/bpf/bpf_inode_storage.c b/kernel/bpf/bpf_inode_storage.c
index 29da6d3838f6..e16e79f8cd6d 100644
--- a/kernel/bpf/bpf_inode_storage.c
+++ b/kernel/bpf/bpf_inode_storage.c
@@ -16,7 +16,6 @@
 #include <uapi/linux/btf.h>
 #include <linux/bpf_lsm.h>
 #include <linux/btf_ids.h>
-#include <linux/fdtable.h>
 #include <linux/rcupdate_trace.h>
 
 DEFINE_BPF_STORAGE_CACHE(inode_cache);
diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c
index adf6dfe0ba68..1eb9852a9f8e 100644
--- a/kernel/bpf/bpf_task_storage.c
+++ b/kernel/bpf/bpf_task_storage.c
@@ -16,7 +16,6 @@
 #include <linux/filter.h>
 #include <uapi/linux/btf.h>
 #include <linux/btf_ids.h>
-#include <linux/fdtable.h>
 #include <linux/rcupdate_trace.h>
 
 DEFINE_BPF_STORAGE_CACHE(task_cache);
diff --git a/kernel/bpf/token.c b/kernel/bpf/token.c
index dcbec1a0dfb3..26057aa13503 100644
--- a/kernel/bpf/token.c
+++ b/kernel/bpf/token.c
@@ -1,6 +1,5 @@
 #include <linux/bpf.h>
 #include <linux/vmalloc.h>
-#include <linux/fdtable.h>
 #include <linux/file.h>
 #include <linux/fs.h>
 #include <linux/kernel.h>
diff --git a/kernel/exit.c b/kernel/exit.c
index 619f0014c33b..1dcddfe537ee 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -25,7 +25,6 @@
 #include <linux/acct.h>
 #include <linux/tsacct_kern.h>
 #include <linux/file.h>
-#include <linux/fdtable.h>
 #include <linux/freezer.h>
 #include <linux/binfmts.h>
 #include <linux/nsproxy.h>
diff --git a/kernel/module/dups.c b/kernel/module/dups.c
index 9a92f2f8c9d3..bd2149fbe117 100644
--- a/kernel/module/dups.c
+++ b/kernel/module/dups.c
@@ -18,7 +18,6 @@
 #include <linux/completion.h>
 #include <linux/cred.h>
 #include <linux/file.h>
-#include <linux/fdtable.h>
 #include <linux/workqueue.h>
 #include <linux/security.h>
 #include <linux/mount.h>
diff --git a/kernel/module/kmod.c b/kernel/module/kmod.c
index 0800d9891692..25f253812512 100644
--- a/kernel/module/kmod.c
+++ b/kernel/module/kmod.c
@@ -15,7 +15,6 @@
 #include <linux/completion.h>
 #include <linux/cred.h>
 #include <linux/file.h>
-#include <linux/fdtable.h>
 #include <linux/workqueue.h>
 #include <linux/security.h>
 #include <linux/mount.h>
diff --git a/kernel/umh.c b/kernel/umh.c
index ff1f13a27d29..be9234270777 100644
--- a/kernel/umh.c
+++ b/kernel/umh.c
@@ -13,7 +13,6 @@
 #include <linux/completion.h>
 #include <linux/cred.h>
 #include <linux/file.h>
-#include <linux/fdtable.h>
 #include <linux/fs_struct.h>
 #include <linux/workqueue.h>
 #include <linux/security.h>
-- 
cgit v1.2.3