From: NeilBrown <neilb@suse.de>
To: linux-raid@vger.kernel.org
Subject: [md PATCH 17/26] md: remove mddev_lock() from md_attr_show()
Date: Wed, 04 Feb 2015 08:42:29 +1100 [thread overview]
Message-ID: <20150203214229.3448.46056.stgit@notabene.brown> (raw)
In-Reply-To: <20150203213948.3448.80258.stgit@notabene.brown>
Most attributes can be read safely without any locking.
A race might lead to a slightly out-dated value, but nothing wrong.
We already have locking in some places where needed.
All that remains is can_clear_show(), behind_writes_used_show()
and action_show() which are easily fixed.
Signed-off-by: NeilBrown <neilb@suse.de>
---
drivers/md/bitmap.c | 13 ++++++++++---
drivers/md/md.c | 23 ++++++++++-------------
2 files changed, 20 insertions(+), 16 deletions(-)
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 3424b1915fc4..3a5767968ba0 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -2211,11 +2211,13 @@ __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
static ssize_t can_clear_show(struct mddev *mddev, char *page)
{
int len;
+ spin_lock(&mddev->lock);
if (mddev->bitmap)
len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
"false" : "true"));
else
len = sprintf(page, "\n");
+ spin_unlock(&mddev->lock);
return len;
}
@@ -2240,10 +2242,15 @@ __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
static ssize_t
behind_writes_used_show(struct mddev *mddev, char *page)
{
+ ssize_t ret;
+ spin_lock(&mddev->lock);
if (mddev->bitmap == NULL)
- return sprintf(page, "0\n");
- return sprintf(page, "%lu\n",
- mddev->bitmap->behind_writes_used);
+ ret = sprintf(page, "0\n");
+ else
+ ret = sprintf(page, "%lu\n",
+ mddev->bitmap->behind_writes_used);
+ spin_unlock(&mddev->lock);
+ return ret;
}
static ssize_t
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 4caa414fe6a3..b7f48238a92d 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4042,20 +4042,21 @@ static ssize_t
action_show(struct mddev *mddev, char *page)
{
char *type = "idle";
- if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
+ unsigned long recovery = mddev->recovery;
+ if (test_bit(MD_RECOVERY_FROZEN, &recovery))
type = "frozen";
- else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
- (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))) {
- if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
+ else if (test_bit(MD_RECOVERY_RUNNING, &recovery) ||
+ (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &recovery))) {
+ if (test_bit(MD_RECOVERY_RESHAPE, &recovery))
type = "reshape";
- else if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
- if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
+ else if (test_bit(MD_RECOVERY_SYNC, &recovery)) {
+ if (!test_bit(MD_RECOVERY_REQUESTED, &recovery))
type = "resync";
- else if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
+ else if (test_bit(MD_RECOVERY_CHECK, &recovery))
type = "check";
else
type = "repair";
- } else if (test_bit(MD_RECOVERY_RECOVER, &mddev->recovery))
+ } else if (test_bit(MD_RECOVERY_RECOVER, &recovery))
type = "recover";
}
return sprintf(page, "%s\n", type);
@@ -4572,11 +4573,7 @@ md_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
mddev_get(mddev);
spin_unlock(&all_mddevs_lock);
- rv = mddev_lock(mddev);
- if (!rv) {
- rv = entry->show(mddev, page);
- mddev_unlock(mddev);
- }
+ rv = entry->show(mddev, page);
mddev_put(mddev);
return rv;
}
next prev parent reply other threads:[~2015-02-03 21:42 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-03 21:42 [md PATCH 00/26] Pending md patches NeilBrown
2015-02-03 21:42 ` [md PATCH 04/26] md/raid5: need_this_block: start simplifying the last two conditions NeilBrown
2015-02-03 21:42 ` [md PATCH 06/26] md: rename mddev->write_lock to mddev->lock NeilBrown
2015-02-03 21:42 ` [md PATCH 02/26] md/raid5: separate large if clause out of fetch_block() NeilBrown
2015-02-03 21:42 ` [md PATCH 01/26] md: do_release_stripe(): No need to call md_wakeup_thread() twice NeilBrown
2015-02-03 21:42 ` [md PATCH 03/26] md/raid5: separate out the easy conditions in need_this_block NeilBrown
2015-02-03 21:42 ` [md PATCH 05/26] md/raid5: need_this_block: tidy/fix last condition NeilBrown
2015-02-03 21:42 ` [md PATCH 12/26] md: level_store: group all important changes into one place NeilBrown
2015-02-03 21:42 ` [md PATCH 10/26] md: split detach operation out from ->stop NeilBrown
2015-02-03 21:42 ` [md PATCH 13/26] md: protect ->pers changes with mddev->lock NeilBrown
2015-02-03 21:42 ` [md PATCH 14/26] md/bitmap: protect clearing of ->bitmap by mddev->lock NeilBrown
2015-02-03 21:42 ` [md PATCH 16/26] md/raid5: use ->lock to protect accessing raid5 sysfs attributes NeilBrown
2015-02-03 21:42 ` [md PATCH 19/26] md: remove unnecessary 'buf' from get_bitmap_file NeilBrown
2015-02-03 21:42 ` [md PATCH 07/26] md: make ->congested robust against personality changes NeilBrown
2015-02-03 21:42 ` [md PATCH 11/26] md: rename ->stop to ->free NeilBrown
2015-02-03 21:42 ` NeilBrown [this message]
2015-02-03 21:42 ` [md PATCH 09/26] md/linear: remove rcu protections in favour of suspend/resume NeilBrown
2015-02-03 21:42 ` [md PATCH 15/26] md: remove need for mddev_lock() in md_seq_show() NeilBrown
2015-02-03 21:42 ` [md PATCH 08/26] md: make merge_bvec_fn more robust in face of personality changes NeilBrown
2015-02-03 21:42 ` [md PATCH 20/26] md: tidy up set_bitmap_file NeilBrown
2015-02-03 21:42 ` [md PATCH 18/26] md: remove mddev_lock from rdev_attr_show() NeilBrown
2015-02-03 21:42 ` [md PATCH 23/26] md: use mddev->lock to protect updates to resync_{min, max} NeilBrown
2015-02-03 21:42 ` [md PATCH 24/26] md: move mddev_lock and related to md.h NeilBrown
2015-02-03 21:42 ` [md PATCH 25/26] md: make reconfig_mutex optional for writes to md sysfs files NeilBrown
2015-02-03 21:42 ` [md PATCH 22/26] md: minor cleanup in safe_delay_store NeilBrown
2015-02-03 21:42 ` [md PATCH 21/26] md: move GET_BITMAP_FILE ioctl out from mddev_lock NeilBrown
2015-02-03 21:42 ` [md PATCH 26/26] md: wakeup thread upon rdev_dec_pending() NeilBrown
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=20150203214229.3448.46056.stgit@notabene.brown \
--to=neilb@suse.de \
--cc=linux-raid@vger.kernel.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).