All of lore.kernel.org
 help / color / mirror / Atom feed
From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
	linux-block@vger.kernel.org,
	Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Subject: [PATCH 6/9] loop: move loop_ctl_mutex locking into loop_add
Date: Wed, 23 Jun 2021 16:59:05 +0200	[thread overview]
Message-ID: <20210623145908.92973-7-hch@lst.de> (raw)
In-Reply-To: <20210623145908.92973-1-hch@lst.de>

Move acquiring and releasing loop_ctl_mutex from the callers into
loop_add.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
 drivers/block/loop.c | 37 +++++++++++++------------------------
 1 file changed, 13 insertions(+), 24 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index d55526c355e1..01d393a60b37 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -2079,9 +2079,12 @@ static int loop_add(int i)
 	lo = kzalloc(sizeof(*lo), GFP_KERNEL);
 	if (!lo)
 		goto out;
-
 	lo->lo_state = Lo_unbound;
 
+	err = mutex_lock_killable(&loop_ctl_mutex);
+	if (err)
+		goto out_free_dev;
+
 	/* allocate id, if @id >= 0, we're requesting that specific id */
 	if (i >= 0) {
 		err = idr_alloc(&loop_index_idr, lo, i, i + 1, GFP_KERNEL);
@@ -2091,7 +2094,7 @@ static int loop_add(int i)
 		err = idr_alloc(&loop_index_idr, lo, 0, 0, GFP_KERNEL);
 	}
 	if (err < 0)
-		goto out_free_dev;
+		goto out_unlock;
 	i = err;
 
 	err = -ENOMEM;
@@ -2157,12 +2160,15 @@ static int loop_add(int i)
 	disk->queue		= lo->lo_queue;
 	sprintf(disk->disk_name, "loop%d", i);
 	add_disk(disk);
-	return lo->lo_number;
+	mutex_unlock(&loop_ctl_mutex);
+	return i;
 
 out_cleanup_tags:
 	blk_mq_free_tag_set(&lo->tag_set);
 out_free_idr:
 	idr_remove(&loop_index_idr, i);
+out_unlock:
+	mutex_unlock(&loop_ctl_mutex);
 out_free_dev:
 	kfree(lo);
 out:
@@ -2222,22 +2228,7 @@ static void loop_probe(dev_t dev)
 
 	if (max_loop && idx >= max_loop)
 		return;
-
-	mutex_lock(&loop_ctl_mutex);
 	loop_add(idx);
-	mutex_unlock(&loop_ctl_mutex);
-}
-
-static int loop_control_add(int idx)
-{
-	int ret;
-		
-	ret = mutex_lock_killable(&loop_ctl_mutex);
-	if (ret)
-		return ret;
-	ret = loop_add(idx);
-	mutex_unlock(&loop_ctl_mutex);
-	return ret;
 }
 
 static int loop_control_remove(int idx)
@@ -2281,11 +2272,11 @@ static int loop_control_get_free(int idx)
 	if (ret)
 		return ret;
 	ret = loop_lookup(&lo, -1);
-	if (ret < 0)
-		ret = loop_add(-1);
 	mutex_unlock(&loop_ctl_mutex);
 
-	return ret;
+	if (ret >= 0)
+		return ret;
+	return loop_add(-1);
 }
 
 static long loop_control_ioctl(struct file *file, unsigned int cmd,
@@ -2293,7 +2284,7 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd,
 {
 	switch (cmd) {
 	case LOOP_CTL_ADD:
-		return loop_control_add(parm);
+		return loop_add(parm);
 	case LOOP_CTL_REMOVE:
 		return loop_control_remove(parm);
 	case LOOP_CTL_GET_FREE:
@@ -2374,10 +2365,8 @@ static int __init loop_init(void)
 	}
 
 	/* pre-create number of devices given by config or max_loop */
-	mutex_lock(&loop_ctl_mutex);
 	for (i = 0; i < nr; i++)
 		loop_add(i);
-	mutex_unlock(&loop_ctl_mutex);
 
 	printk(KERN_INFO "loop: module loaded\n");
 	return 0;
-- 
2.30.2


  parent reply	other threads:[~2021-06-23 15:03 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-23 14:58 loop cleanups v2 Christoph Hellwig
2021-06-23 14:59 ` [PATCH 1/9] loop: reorder loop_exit Christoph Hellwig
2021-06-23 14:59 ` [PATCH 2/9] loop: reduce loop_ctl_mutex coverage in loop_exit Christoph Hellwig
2021-06-23 14:59 ` [PATCH 3/9] loop: remove the l argument to loop_add Christoph Hellwig
2021-06-23 14:59 ` [PATCH 4/9] loop: don't call loop_lookup before adding a loop device Christoph Hellwig
2021-06-23 14:59 ` [PATCH 5/9] loop: split loop_control_ioctl Christoph Hellwig
2021-06-23 14:59 ` Christoph Hellwig [this message]
2021-06-23 14:59 ` [PATCH 7/9] loop: don't allow deleting an unspecified loop device Christoph Hellwig
2021-06-23 14:59 ` [PATCH 8/9] loop: split loop_lookup Christoph Hellwig
2021-06-23 14:59 ` [PATCH 9/9] loop: rewrite loop_exit using idr_for_each_entry Christoph Hellwig
2021-06-24  2:45 ` loop cleanups v2 Jens Axboe
  -- strict thread matches above, loose matches on Subject: below --
2021-06-21 10:15 loop cleanups Christoph Hellwig
2021-06-21 10:15 ` [PATCH 6/9] loop: move loop_ctl_mutex locking into loop_add Christoph Hellwig
2021-06-21 20:16   ` Chaitanya Kulkarni

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=20210623145908.92973-7-hch@lst.de \
    --to=hch@lst.de \
    --cc=axboe@kernel.dk \
    --cc=chaitanya.kulkarni@wdc.com \
    --cc=linux-block@vger.kernel.org \
    --cc=penguin-kernel@i-love.sakura.ne.jp \
    /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.