From 451af504df0c62f695a69b83c250486e77c66378 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 13 May 2014 12:16:21 -0400 Subject: cgroup: replace cftype->write_string() with cftype->write() Convert all cftype->write_string() users to the new cftype->write() which maps directly to kernfs write operation and has full access to kernfs and cgroup contexts. The conversions are mostly mechanical. * @css and @cft are accessed using of_css() and of_cft() accessors respectively instead of being specified as arguments. * Should return @nbytes on success instead of 0. * @buf is not trimmed automatically. Trim if necessary. Note that blkcg and netprio don't need this as the parsers already handle whitespaces. cftype->write_string() has no user left after the conversions and removed. While at it, remove unnecessary local variable @p in cgroup_subtree_control_write() and stale comment about CGROUP_LOCAL_BUFFER_SIZE in cgroup_freezer.c. This patch doesn't introduce any visible behavior changes. v2: netprio was missing from conversion. Converted. Signed-off-by: Tejun Heo Acked-by: Aristeu Rozanski Acked-by: Vivek Goyal Acked-by: Li Zefan Cc: Jens Axboe Cc: Johannes Weiner Cc: Michal Hocko Cc: Neil Horman Cc: "David S. Miller" --- kernel/cgroup.c | 38 +++++++++++++++++++------------------- 1 file changed, 19 insertions(+), 19 deletions(-) (limited to 'kernel/cgroup.c') diff --git a/kernel/cgroup.c b/kernel/cgroup.c index a16f91d12f4e..2a88ce7b24b6 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1035,7 +1035,7 @@ static umode_t cgroup_file_mode(const struct cftype *cft) mode |= S_IRUGO; if (cft->write_u64 || cft->write_s64 || cft->write || - cft->write_string || cft->trigger) + cft->trigger) mode |= S_IWUSR; return mode; @@ -2352,20 +2352,21 @@ static int cgroup_procs_write(struct cgroup_subsys_state *css, return attach_task_by_pid(css->cgroup, tgid, true); } -static int cgroup_release_agent_write(struct cgroup_subsys_state *css, - struct cftype *cft, char *buffer) +static ssize_t cgroup_release_agent_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) { - struct cgroup_root *root = css->cgroup->root; + struct cgroup *cgrp = of_css(of)->cgroup; + struct cgroup_root *root = cgrp->root; BUILD_BUG_ON(sizeof(root->release_agent_path) < PATH_MAX); - if (!cgroup_lock_live_group(css->cgroup)) + if (!cgroup_lock_live_group(cgrp)) return -ENODEV; spin_lock(&release_agent_path_lock); - strlcpy(root->release_agent_path, buffer, + strlcpy(root->release_agent_path, strstrip(buf), sizeof(root->release_agent_path)); spin_unlock(&release_agent_path_lock); mutex_unlock(&cgroup_mutex); - return 0; + return nbytes; } static int cgroup_release_agent_show(struct seq_file *seq, void *v) @@ -2530,21 +2531,22 @@ out_finish: } /* change the enabled child controllers for a cgroup in the default hierarchy */ -static int cgroup_subtree_control_write(struct cgroup_subsys_state *dummy_css, - struct cftype *cft, char *buffer) +static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, + loff_t off) { unsigned int enable = 0, disable = 0; - struct cgroup *cgrp = dummy_css->cgroup, *child; + struct cgroup *cgrp = of_css(of)->cgroup, *child; struct cgroup_subsys *ss; - char *tok, *p; + char *tok; int ssid, ret; /* * Parse input - space separated list of subsystem names prefixed * with either + or -. */ - p = buffer; - while ((tok = strsep(&p, " "))) { + buf = strstrip(buf); + while ((tok = strsep(&buf, " "))) { if (tok[0] == '\0') continue; for_each_subsys(ss, ssid) { @@ -2692,7 +2694,7 @@ out_unlock_tree: out_unbreak: kernfs_unbreak_active_protection(cgrp->control_kn); cgroup_put(cgrp); - return ret; + return ret ?: nbytes; err_undo_css: cgrp->child_subsys_mask &= ~enable; @@ -2738,9 +2740,7 @@ static ssize_t cgroup_file_write(struct kernfs_open_file *of, char *buf, css = cgroup_css(cgrp, cft->ss); rcu_read_unlock(); - if (cft->write_string) { - ret = cft->write_string(css, cft, strstrip(buf)); - } else if (cft->write_u64) { + if (cft->write_u64) { unsigned long long v; ret = kstrtoull(buf, 0, &v); if (!ret) @@ -3984,7 +3984,7 @@ static struct cftype cgroup_base_files[] = { .name = "cgroup.subtree_control", .flags = CFTYPE_ONLY_ON_DFL, .seq_show = cgroup_subtree_control_show, - .write_string = cgroup_subtree_control_write, + .write = cgroup_subtree_control_write, }, { .name = "cgroup.populated", @@ -4018,7 +4018,7 @@ static struct cftype cgroup_base_files[] = { .name = "release_agent", .flags = CFTYPE_INSANE | CFTYPE_ONLY_ON_ROOT, .seq_show = cgroup_release_agent_show, - .write_string = cgroup_release_agent_write, + .write = cgroup_release_agent_write, .max_write_len = PATH_MAX - 1, }, { } /* terminate */ -- cgit v1.2.3