From: Alasdair G Kergon <agk@redhat.com>
To: Joe Thornber <ejt@redhat.com>
Cc: dm-devel@redhat.com
Subject: Re: [PATCH 8/8] [dm-cache] cache target
Date: Tue, 12 Feb 2013 16:40:40 +0000 [thread overview]
Message-ID: <20130212164040.GI3228@agk-dp.fab.redhat.com> (raw)
In-Reply-To: <20130212152733.GH12499@agk-dp.fab.redhat.com>
On Tue, Feb 12, 2013 at 03:27:33PM +0000, Alasdair G Kergon wrote:
> updated code taken from the all-caches branch of
> git://github.com/jthornber/linux-2.6
File: dm-cache-policy.c
> #include "dm.h"
> #include <linux/list.h>
Already pulled in via dm.h
> static struct dm_cache_policy_type *__get_policy(const char *name)
> {
> struct dm_cache_policy_type *t = __find_policy(name);
>
> if (!t) {
Could we move this up a level and avoid the inverted unlock/lock
(which only seems to confuse automated lock analysis)?
__find_policy(); if not found, request_module and __find_policy again ?
> spin_unlock(®ister_lock);
> request_module("dm-cache-%s", name);
> spin_lock(®ister_lock);
> t = __find_policy(name);
> }
> int dm_cache_policy_register(struct dm_cache_policy_type *type)
> {
> int r;
>
> /* One size fits all for now */
> if (type->hint_size != 0 && type->hint_size != 4)
This should never happen unless coding error or corruption => DMWARN?
> return -EINVAL;
> void dm_cache_policy_destroy(struct dm_cache_policy *p)
> {
> struct dm_cache_policy_type *t = p->private;
>
> put_policy(t);
module_put should be AFTER destroy or the code could get unloaded while destroy
is still running?
[Still to check the ref counting is sufficient: to understand why this is
a bit simpler than dm-path-selector which also handles modules plugging into
modules and went through a few iterations fixing ref problems]
> p->destroy(p);
> }
Alasdair
next prev parent reply other threads:[~2013-02-12 16:40 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-13 20:19 Another cache target Joe Thornber
2012-12-13 20:19 ` [PATCH 1/8] [persistent-data] Fix a bug in btree_del, and another bug that was compensating for it Joe Thornber
2012-12-13 20:19 ` [PATCH 2/8] [persistent-data] dm_btree_walk Joe Thornber
2012-12-13 20:19 ` [PATCH 3/8] [persistent-data] tweak an error message Joe Thornber
2012-12-13 20:19 ` [PATCH 4/8] [dm-bio-prison] Change the bio-prison interface so the memory for the cells is passed in Joe Thornber
2013-01-14 10:02 ` Alasdair G Kergon
2013-01-14 14:06 ` thornber
2013-01-14 14:22 ` Alasdair G Kergon
2013-01-21 23:32 ` Alasdair G Kergon
2013-01-22 11:31 ` thornber
2013-01-22 12:10 ` Alasdair G Kergon
2012-12-13 20:19 ` [PATCH 5/8] [dm-thin] Fix a race condition between discard bios and ordinary bios Joe Thornber
2012-12-14 15:52 ` Mike Snitzer
2013-01-22 0:03 ` Alasdair G Kergon
2013-01-24 2:35 ` Alasdair G Kergon
2013-01-24 13:23 ` thornber
2013-02-06 0:11 ` Mikulas Patocka
2013-02-07 11:20 ` thornber
2012-12-13 20:19 ` [PATCH 6/8] [persistent-data] Add a transactional array Joe Thornber
2013-01-22 21:18 ` Alasdair G Kergon
2013-01-23 12:07 ` thornber
2013-01-25 20:11 ` Alasdair G Kergon
2013-01-28 13:06 ` thornber
2013-01-28 20:25 ` Alasdair G Kergon
2013-01-28 14:57 ` thornber
2013-01-28 20:22 ` Alasdair G Kergon
2012-12-13 20:19 ` [PATCH 7/8] [persistent-data] transactional bitset Joe Thornber
2013-01-22 21:59 ` Alasdair G Kergon
2012-12-13 20:19 ` [PATCH 8/8] [dm-cache] cache target Joe Thornber
2012-12-14 0:17 ` Darrick J. Wong
2012-12-14 10:09 ` thornber
2013-02-12 15:27 ` Alasdair G Kergon
2013-02-12 16:40 ` Alasdair G Kergon [this message]
2013-02-12 17:29 ` Alasdair G Kergon
2013-02-14 13:57 ` Joe Thornber
2013-02-14 14:05 ` Joe Thornber
2013-02-14 21:06 ` Alasdair G Kergon
2012-12-13 21:57 ` Another " Mike Snitzer
2012-12-14 1:16 ` Darrick J. Wong
2012-12-14 2:19 ` Mike Snitzer
2012-12-14 2:27 ` Mike Snitzer
2012-12-14 2:42 ` Darrick J. Wong
2012-12-14 4:23 ` Mike Snitzer
2012-12-14 2:34 ` Darrick J. Wong
2012-12-14 10:24 ` thornber
2012-12-14 12:11 ` thornber
2012-12-14 21:51 ` Darrick J. Wong
2012-12-15 8:23 ` Joe Thornber
2012-12-18 1:49 ` Darrick J. Wong
2012-12-18 2:31 ` Alasdair G Kergon
2013-01-08 0:19 ` Darrick J. Wong
2013-01-08 13:55 ` thornber
2012-12-22 18:50 ` Mark Hills
2012-12-17 16:54 ` Heinz Mauelshagen
2012-12-18 15:44 ` basic cache policy module fix [was: Re: Another cache target] Mike Snitzer
2012-12-20 1:14 ` Darrick J. Wong
2012-12-20 12:57 ` Heinz Mauelshagen
2012-12-20 13:24 ` Mike Snitzer
2012-12-20 16:10 ` Darrick J. Wong
2012-12-20 17:02 ` Heinz Mauelshagen
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