All of lore.kernel.org
 help / color / mirror / Atom feed
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	Marc Zyngier <maz@kernel.org>
Subject: [RFC PATCH 13/27] ep_loop_check_proc(): saner calling conventions
Date: Sun,  4 Oct 2020 03:39:15 +0100	[thread overview]
Message-ID: <20201004023929.2740074-13-viro@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20201004023929.2740074-1-viro@ZenIV.linux.org.uk>

From: Al Viro <viro@zeniv.linux.org.uk>

1) 'cookie' argument is unused; kill it.
2) 'priv' one is always an epoll struct file, and we only care
about its associated struct eventpoll; pass that instead.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/eventpoll.c | 38 ++++++++++++++++----------------------
 1 file changed, 16 insertions(+), 22 deletions(-)

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 6b1990b8b9a0..e971e3ace557 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1845,19 +1845,14 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
  *                      result in excessive stack usage).
  *
  * @priv: Pointer to the epoll file to be currently checked.
- * @cookie: Original cookie for this call. This is the top-of-the-chain epoll
- *          data structure pointer.
- * @call_nests: Current dept of the @ep_call_nested() call stack.
+ * @depth: Current depth of the path being checked.
  *
  * Returns: Returns zero if adding the epoll @file inside current epoll
  *          structure @ep does not violate the constraints, or -1 otherwise.
  */
-static int ep_loop_check_proc(void *priv, void *cookie, int depth)
+static int ep_loop_check_proc(struct eventpoll *ep, int depth)
 {
 	int error = 0;
-	struct file *file = priv;
-	struct eventpoll *ep = file->private_data;
-	struct eventpoll *ep_tovisit;
 	struct rb_node *rbp;
 	struct epitem *epi;
 
@@ -1866,15 +1861,14 @@ static int ep_loop_check_proc(void *priv, void *cookie, int depth)
 	for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) {
 		epi = rb_entry(rbp, struct epitem, rbn);
 		if (unlikely(is_file_epoll(epi->ffd.file))) {
+			struct eventpoll *ep_tovisit;
 			ep_tovisit = epi->ffd.file->private_data;
 			if (ep_tovisit->gen == loop_check_gen)
 				continue;
-			if (ep_tovisit == inserting_into || depth > EP_MAX_NESTS) {
+			if (ep_tovisit == inserting_into || depth > EP_MAX_NESTS)
 				error = -1;
-			} else {
-				error = ep_loop_check_proc(epi->ffd.file, ep_tovisit,
-						   depth + 1);
-			}
+			else
+				error = ep_loop_check_proc(ep_tovisit, depth + 1);
 			if (error != 0)
 				break;
 		} else {
@@ -1899,20 +1893,20 @@ static int ep_loop_check_proc(void *priv, void *cookie, int depth)
 }
 
 /**
- * ep_loop_check - Performs a check to verify that adding an epoll file (@file)
- *                 another epoll file (represented by @ep) does not create
+ * ep_loop_check - Performs a check to verify that adding an epoll file (@to)
+ *                 into another epoll file (represented by @from) does not create
  *                 closed loops or too deep chains.
  *
- * @ep: Pointer to the epoll private data structure.
- * @file: Pointer to the epoll file to be checked.
+ * @from: Pointer to the epoll we are inserting into.
+ * @to: Pointer to the epoll to be inserted.
  *
- * Returns: Returns zero if adding the epoll @file inside current epoll
- *          structure @ep does not violate the constraints, or -1 otherwise.
+ * Returns: Returns zero if adding the epoll @to inside the epoll @from
+ * does not violate the constraints, or -1 otherwise.
  */
-static int ep_loop_check(struct eventpoll *ep, struct file *file)
+static int ep_loop_check(struct eventpoll *ep, struct eventpoll *to)
 {
 	inserting_into = ep;
-	return ep_loop_check_proc(file, ep, 0);
+	return ep_loop_check_proc(to, 0);
 }
 
 static void clear_tfile_check_list(void)
@@ -2086,8 +2080,9 @@ int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds,
 			loop_check_gen++;
 			full_check = 1;
 			if (is_file_epoll(tf.file)) {
+				tep = tf.file->private_data;
 				error = -ELOOP;
-				if (ep_loop_check(ep, tf.file) != 0)
+				if (ep_loop_check(ep, tep) != 0)
 					goto error_tgt_fput;
 			} else {
 				get_file(tf.file);
@@ -2098,7 +2093,6 @@ int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds,
 			if (error)
 				goto error_tgt_fput;
 			if (is_file_epoll(tf.file)) {
-				tep = tf.file->private_data;
 				error = epoll_mutex_lock(&tep->mtx, 1, nonblock);
 				if (error) {
 					mutex_unlock(&ep->mtx);
-- 
2.11.0


  parent reply	other threads:[~2020-10-04  2:39 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-04  2:36 [RFC][PATCHSET] epoll cleanups Al Viro
2020-10-04  2:39 ` [RFC PATCH 01/27] epoll: switch epitem->pwqlist to single-linked list Al Viro
2020-10-04  2:39   ` [RFC PATCH 02/27] epoll: get rid of epitem->nwait Al Viro
2020-10-04  2:39   ` [RFC PATCH 03/27] untangling ep_call_nested(): get rid of useless arguments Al Viro
2020-10-04  2:39   ` [RFC PATCH 04/27] untangling ep_call_nested(): it's all serialized on epmutex Al Viro
2020-10-04  2:39   ` [RFC PATCH 05/27] untangling ep_call_nested(): take pushing cookie into a helper Al Viro
2020-10-04  2:39   ` [RFC PATCH 06/27] untangling ep_call_nested(): move push/pop of cookie into the callbacks Al Viro
2020-10-04  2:39   ` [RFC PATCH 07/27] untangling ep_call_nested(): and there was much rejoicing Al Viro
2020-10-04  2:39   ` [RFC PATCH 08/27] reverse_path_check_proc(): sane arguments Al Viro
2020-10-04  2:39   ` [RFC PATCH 09/27] reverse_path_check_proc(): don't bother with cookies Al Viro
2020-10-04  2:39   ` [RFC PATCH 10/27] clean reverse_path_check_proc() a bit Al Viro
2020-10-04  2:39   ` [RFC PATCH 11/27] ep_loop_check_proc(): lift pushing the cookie into callers Al Viro
2020-10-04  2:39   ` [RFC PATCH 12/27] get rid of ep_push_nested() Al Viro
2020-10-04  2:39   ` Al Viro [this message]
2020-10-04  2:39   ` [RFC PATCH 14/27] ep_scan_ready_list(): prepare to splitup Al Viro
2020-10-04  2:39   ` [RFC PATCH 15/27] lift the calls of ep_read_events_proc() into the callers Al Viro
2020-10-04  2:39   ` [RFC PATCH 16/27] lift the calls of ep_send_events_proc() " Al Viro
2020-10-04  2:39   ` [RFC PATCH 17/27] ep_send_events_proc(): fold into the caller Al Viro
2020-10-04  2:39   ` [RFC PATCH 18/27] lift locking/unlocking ep->mtx out of ep_{start,done}_scan() Al Viro
2020-10-04  2:39   ` [RFC PATCH 19/27] ep_insert(): don't open-code ep_remove() on failure exits Al Viro
2020-10-04  2:39   ` [RFC PATCH 20/27] ep_insert(): we only need tep->mtx around the insertion itself Al Viro
2020-10-04 12:56     ` [ep_insert()] 9ee1cc5666: WARNING:possible_recursive_locking_detected kernel test robot
2020-10-04 14:17       ` Al Viro
2020-10-04 14:27         ` Al Viro
2020-10-04  2:39   ` [RFC PATCH 21/27] take the common part of ep_eventpoll_poll() and ep_item_poll() into helper Al Viro
2020-10-04  2:39   ` [RFC PATCH 22/27] fold ep_read_events_proc() into the only caller Al Viro
2020-10-04  2:39   ` [RFC PATCH 23/27] ep_insert(): move creation of wakeup source past the fl_ep_links insertion Al Viro
2020-10-04  2:39   ` [RFC PATCH 24/27] convert ->f_ep_links/->fllink to hlist Al Viro
2020-10-04  2:39   ` [RFC PATCH 25/27] lift rcu_read_lock() into reverse_path_check() Al Viro
2020-10-04  2:39   ` [RFC PATCH 26/27] epoll: massage the check list insertion Al Viro
2020-10-04  2:39   ` [RFC PATCH 27/27] epoll: take epitem list out of struct file Al Viro
2020-10-05 20:37     ` Qian Cai
2020-10-05 20:49       ` Al Viro
2020-10-04  2:49 ` [RFC][PATCHSET] epoll cleanups Al Viro
2020-10-04 12:13 ` Matthew Wilcox
2020-10-04 14:15   ` Al Viro
2020-10-04 18:08 ` Linus Torvalds
2020-10-04 20:05   ` Al Viro

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201004023929.2740074-13-viro@ZenIV.linux.org.uk \
    --to=viro@zeniv.linux.org.uk \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=maz@kernel.org \
    --cc=torvalds@linux-foundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.