cgroup/bfq: revert bfq.weight symlink change

There's some discussion on how to do this the best, and Tejun prefers
that BFQ just create the file itself instead of having cgroups support
a symlink feature.

Hence revert commit 54b7b868e826 and 19e9da9e86c4 for 5.2, and this
can be done properly for 5.3.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
index 59f4690..b3796a4 100644 (file)
--- a/block/bfq-cgroup.c
+++ b/block/bfq-cgroup.c
@@ -1046,8 +1046,7 @@ struct blkcg_policy blkcg_policy_bfq = {
 struct cftype bfq_blkcg_legacy_files[] = {
        {
                .name = "bfq.weight",
-               .link_name = "weight",
-               .flags = CFTYPE_NOT_ON_ROOT | CFTYPE_SYMLINKED,
+               .flags = CFTYPE_NOT_ON_ROOT,
                .seq_show = bfq_io_show_weight,
                .write_u64 = bfq_io_set_weight_legacy,
        },
@@ -1167,8 +1166,7 @@ struct cftype bfq_blkcg_legacy_files[] = {
 struct cftype bfq_blkg_files[] = {
        {
                .name = "bfq.weight",
-               .link_name = "weight",
-               .flags = CFTYPE_NOT_ON_ROOT | CFTYPE_SYMLINKED,
+               .flags = CFTYPE_NOT_ON_ROOT,
                .seq_show = bfq_io_show_weight,
                .write = bfq_io_set_weight,
        },

diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index d71b079..11e215d 100644 (file)
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -106,8 +106,6 @@ enum {
        CFTYPE_WORLD_WRITABLE   = (1 << 4),     /* (DON'T USE FOR NEW FILES) S_IWUGO */
        CFTYPE_DEBUG            = (1 << 5),     /* create when cgroup_debug */
 
-       CFTYPE_SYMLINKED        = (1 << 6),     /* pointed to by symlink too */
-
        /* internal flags, do not use outside cgroup core proper */
        __CFTYPE_ONLY_ON_DFL    = (1 << 16),    /* only on default hierarchy */
        __CFTYPE_NOT_ON_DFL     = (1 << 17),    /* not on default hierarchy */
@@ -545,7 +543,6 @@ struct cftype {
         * end of cftype array.
         */
        char name[MAX_CFTYPE_NAME];
-       char link_name[MAX_CFTYPE_NAME];
        unsigned long private;
 
        /*

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 155048b..426a002 100644 (file)
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -1460,8 +1460,8 @@ struct cgroup *task_cgroup_from_root(struct task_struct *task,
 
 static struct kernfs_syscall_ops cgroup_kf_syscall_ops;
 
-static char *cgroup_fill_name(struct cgroup *cgrp, const struct cftype *cft,
-                             char *buf, bool write_link_name)
+static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft,
+                             char *buf)
 {
        struct cgroup_subsys *ss = cft->ss;
 
@@ -1471,26 +1471,13 @@ static char *cgroup_fill_name(struct cgroup *cgrp, const struct cftype *cft,
 
                snprintf(buf, CGROUP_FILE_NAME_MAX, "%s%s.%s",
                         dbg, cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name,
-                        write_link_name ? cft->link_name : cft->name);
+                        cft->name);
        } else {
-               strscpy(buf, write_link_name ? cft->link_name : cft->name,
-                       CGROUP_FILE_NAME_MAX);
+               strscpy(buf, cft->name, CGROUP_FILE_NAME_MAX);
        }
        return buf;
 }
 
-static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft,
-                             char *buf)
-{
-       return cgroup_fill_name(cgrp, cft, buf, false);
-}
-
-static char *cgroup_link_name(struct cgroup *cgrp, const struct cftype *cft,
-                             char *buf)
-{
-       return cgroup_fill_name(cgrp, cft, buf, true);
-}
-
 /**
  * cgroup_file_mode - deduce file mode of a control file
  * @cft: the control file in question
@@ -1649,9 +1636,6 @@ static void cgroup_rm_file(struct cgroup *cgrp, const struct cftype *cft)
        }
 
        kernfs_remove_by_name(cgrp->kn, cgroup_file_name(cgrp, cft, name));
-       if (cft->flags & CFTYPE_SYMLINKED)
-               kernfs_remove_by_name(cgrp->kn,
-                                     cgroup_link_name(cgrp, cft, name));
 }
 
 /**
@@ -3837,7 +3821,6 @@ static int cgroup_add_file(struct cgroup_subsys_state *css, struct cgroup *cgrp,
 {
        char name[CGROUP_FILE_NAME_MAX];
        struct kernfs_node *kn;
-       struct kernfs_node *kn_link;
        struct lock_class_key *key = NULL;
        int ret;
 
@@ -3868,14 +3851,6 @@ static int cgroup_add_file(struct cgroup_subsys_state *css, struct cgroup *cgrp,
                spin_unlock_irq(&cgroup_file_kn_lock);
        }
 
-       if (cft->flags & CFTYPE_SYMLINKED) {
-               kn_link = kernfs_create_link(cgrp->kn,
-                                            cgroup_link_name(cgrp, cft, name),
-                                            kn);
-               if (IS_ERR(kn_link))
-                       return PTR_ERR(kn_link);
-       }
-
        return 0;
 }