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blkcg: revert blkcg cleanups series

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This reverts a series committed earlier due to null pointer exception
bug report in [1]. It seems there are edge case interactions that I did
not consider and will need some time to understand what causes the
adverse interactions.

The original series can be found in [2] with a follow up series in [3].

[1] https://www.spinics.net/lists/cgroups/msg20719.html
[2] https://lore.kernel.org/lkml/20180911184137.35897-1-dennisszhou@gmail.com/
[3] https://lore.kernel.org/lkml/20181020185612.51587-1-dennis@kernel.org/

This reverts the following commits:
d459d853c2, b2c3fa5467, 101246ec02, b3b9f24f5f, e2b0989954,
f0fcb3ec89, c839e7a03f, bdc2491708, 74b7c02a9b, 5bf9a1f3b4,
a7b39b4e96, 07b05bcc32, 49f4c2dc2b, 27e6fa996c

Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Dennis Zhou
2018-11-01 17:24:10 -04:00
committed by Jens Axboe
parent 153fcd5f6d
commit b5f2954d30
22 changed files with 226 additions and 421 deletions
Download Patch File Download Diff File Expand all files Collapse all files

48
kernel/cgroup/cgroup.c
View File

@@ -492,7 +492,7 @@ static struct cgroup_subsys_state *cgroup_tryget_css(struct cgroup *cgrp,
}
/**
* cgroup_e_css_by_mask - obtain a cgroup's effective css for the specified ss
* cgroup_e_css - obtain a cgroup's effective css for the specified subsystem
* @cgrp: the cgroup of interest
* @ss: the subsystem of interest (%NULL returns @cgrp->self)
*
@@ -501,8 +501,8 @@ static struct cgroup_subsys_state *cgroup_tryget_css(struct cgroup *cgrp,
* enabled. If @ss is associated with the hierarchy @cgrp is on, this
* function is guaranteed to return non-NULL css.
*/
static struct cgroup_subsys_state *cgroup_e_css_by_mask(struct cgroup *cgrp,
struct cgroup_subsys *ss)
static struct cgroup_subsys_state *cgroup_e_css(struct cgroup *cgrp,
struct cgroup_subsys *ss)
{
lockdep_assert_held(&cgroup_mutex);
@@ -522,35 +522,6 @@ static struct cgroup_subsys_state *cgroup_e_css_by_mask(struct cgroup *cgrp,
return cgroup_css(cgrp, ss);
}
/**
* cgroup_e_css - obtain a cgroup's effective css for the specified subsystem
* @cgrp: the cgroup of interest
* @ss: the subsystem of interest
*
* Find and get the effective css of @cgrp for @ss. The effective css is
* defined as the matching css of the nearest ancestor including self which
* has @ss enabled. If @ss is not mounted on the hierarchy @cgrp is on,
* the root css is returned, so this function always returns a valid css.
*
* The returned css is not guaranteed to be online, and therefore it is the
* callers responsiblity to tryget a reference for it.
*/
struct cgroup_subsys_state *cgroup_e_css(struct cgroup *cgrp,
struct cgroup_subsys *ss)
{
struct cgroup_subsys_state *css;
do {
css = cgroup_css(cgrp, ss);
if (css)
return css;
cgrp = cgroup_parent(cgrp);
} while (cgrp);
return init_css_set.subsys[ss->id];
}
/**
* cgroup_get_e_css - get a cgroup's effective css for the specified subsystem
* @cgrp: the cgroup of interest
@@ -633,11 +604,10 @@ EXPORT_SYMBOL_GPL(of_css);
*
* Should be called under cgroup_[tree_]mutex.
*/
#define for_each_e_css(css, ssid, cgrp) \
for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT; (ssid)++) \
if (!((css) = cgroup_e_css_by_mask(cgrp, \
cgroup_subsys[(ssid)]))) \
; \
#define for_each_e_css(css, ssid, cgrp) \
for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT; (ssid)++) \
if (!((css) = cgroup_e_css(cgrp, cgroup_subsys[(ssid)]))) \
; \
else
/**
@@ -1036,7 +1006,7 @@ static struct css_set *find_existing_css_set(struct css_set *old_cset,
* @ss is in this hierarchy, so we want the
* effective css from @cgrp.
*/
template[i] = cgroup_e_css_by_mask(cgrp, ss);
template[i] = cgroup_e_css(cgrp, ss);
} else {
/*
* @ss is not in this hierarchy, so we don't want
@@ -3053,7 +3023,7 @@ static int cgroup_apply_control(struct cgroup *cgrp)
return ret;
/*
* At this point, cgroup_e_css_by_mask() results reflect the new csses
* At this point, cgroup_e_css() results reflect the new csses
* making the following cgroup_update_dfl_csses() properly update
* css associations of all tasks in the subtree.
*/

4
kernel/trace/blktrace.c
View File

@@ -764,9 +764,9 @@ blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
return NULL;
if (!bio->bi_blkg)
if (!bio->bi_css)
return NULL;
return cgroup_get_kernfs_id(bio_blkcg(bio)->css.cgroup);
return cgroup_get_kernfs_id(bio->bi_css->cgroup);
}
#else
static union kernfs_node_id *