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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 32/43] cgroup_do_mount(): massage calling conventions From: David Howells To: viro@zeniv.linux.org.uk Cc: linux-fsdevel@vger.kernel.org, dhowells@redhat.com, torvalds@linux-foundation.org, ebiederm@xmission.com, linux-security-module@vger.kernel.org Date: Tue, 19 Feb 2019 16:32:44 +0000 Message-ID: <155059396486.12449.1117812894043256835.stgit@warthog.procyon.org.uk> In-Reply-To: <155059366914.12449.4669870128936536848.stgit@warthog.procyon.org.uk> References: <155059366914.12449.4669870128936536848.stgit@warthog.procyon.org.uk> User-Agent: StGit/unknown-version MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Tue, 19 Feb 2019 16:32:50 +0000 (UTC) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP From: Al Viro pass it fs_context instead of fs_type/flags/root triple, have it return int instead of dentry and make it deal with setting fc->root. Signed-off-by: Al Viro --- kernel/cgroup/cgroup-internal.h | 3 +-- kernel/cgroup/cgroup-v1.c | 17 ++++----------- kernel/cgroup/cgroup.c | 45 ++++++++++++++++++++------------------- 3 files changed, 29 insertions(+), 36 deletions(-) diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h index 3c1613a7648c..f7fd54f2973f 100644 --- a/kernel/cgroup/cgroup-internal.h +++ b/kernel/cgroup/cgroup-internal.h @@ -212,8 +212,7 @@ void cgroup_free_root(struct cgroup_root *root); void init_cgroup_root(struct cgroup_fs_context *ctx); int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask); int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask); -struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags, - struct cgroup_root *root, unsigned long magic, +int cgroup_do_mount(struct fs_context *fc, unsigned long magic, struct cgroup_namespace *ns); int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp); diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c index 45a198c63d6e..05f05d773adf 100644 --- a/kernel/cgroup/cgroup-v1.c +++ b/kernel/cgroup/cgroup-v1.c @@ -1141,7 +1141,6 @@ int cgroup1_get_tree(struct fs_context *fc) struct cgroup_fs_context *ctx = cgroup_fc2context(fc); struct cgroup_root *root; struct cgroup_subsys *ss; - struct dentry *dentry; int i, ret; /* Check if the caller has permission to mount. */ @@ -1253,21 +1252,15 @@ int cgroup1_get_tree(struct fs_context *fc) if (ret) return ret; - dentry = cgroup_do_mount(&cgroup_fs_type, fc->sb_flags, root, - CGROUP_SUPER_MAGIC, ns); - if (IS_ERR(dentry)) - return PTR_ERR(dentry); - - if (percpu_ref_is_dying(&root->cgrp.self.refcnt)) { - struct super_block *sb = dentry->d_sb; - dput(dentry); + ret = cgroup_do_mount(fc, CGROUP_SUPER_MAGIC, ns); + if (!ret && percpu_ref_is_dying(&root->cgrp.self.refcnt)) { + struct super_block *sb = fc->root->d_sb; + dput(fc->root); deactivate_locked_super(sb); msleep(10); return restart_syscall(); } - - fc->root = dentry; - return 0; + return ret; } static int __init cgroup1_wq_init(void) diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 57f43f63363a..64360a46d4df 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -2036,43 +2036,48 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask) return ret; } -struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags, - struct cgroup_root *root, unsigned long magic, - struct cgroup_namespace *ns) +int cgroup_do_mount(struct fs_context *fc, unsigned long magic, + struct cgroup_namespace *ns) { - struct dentry *dentry; + struct cgroup_fs_context *ctx = cgroup_fc2context(fc); bool new_sb = false; + int ret = 0; - dentry = kernfs_mount(fs_type, flags, root->kf_root, magic, &new_sb); + fc->root = kernfs_mount(fc->fs_type, fc->sb_flags, ctx->root->kf_root, + magic, &new_sb); + if (IS_ERR(fc->root)) + ret = PTR_ERR(fc->root); /* * In non-init cgroup namespace, instead of root cgroup's dentry, * we return the dentry corresponding to the cgroupns->root_cgrp. */ - if (!IS_ERR(dentry) && ns != &init_cgroup_ns) { + if (!ret && ns != &init_cgroup_ns) { struct dentry *nsdentry; - struct super_block *sb = dentry->d_sb; + struct super_block *sb = fc->root->d_sb; struct cgroup *cgrp; mutex_lock(&cgroup_mutex); spin_lock_irq(&css_set_lock); - cgrp = cset_cgroup_from_root(ns->root_cset, root); + cgrp = cset_cgroup_from_root(ns->root_cset, ctx->root); spin_unlock_irq(&css_set_lock); mutex_unlock(&cgroup_mutex); nsdentry = kernfs_node_dentry(cgrp->kn, sb); - dput(dentry); - if (IS_ERR(nsdentry)) + dput(fc->root); + fc->root = nsdentry; + if (IS_ERR(nsdentry)) { + ret = PTR_ERR(nsdentry); deactivate_locked_super(sb); - dentry = nsdentry; + } } if (!new_sb) - cgroup_put(&root->cgrp); + cgroup_put(&ctx->root->cgrp); - return dentry; + return ret; } /* @@ -2091,7 +2096,7 @@ static int cgroup_get_tree(struct fs_context *fc) { struct cgroup_namespace *ns = current->nsproxy->cgroup_ns; struct cgroup_fs_context *ctx = cgroup_fc2context(fc); - struct dentry *root; + int ret; /* Check if the caller has permission to mount. */ if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) @@ -2101,14 +2106,10 @@ static int cgroup_get_tree(struct fs_context *fc) cgroup_get_live(&cgrp_dfl_root.cgrp); ctx->root = &cgrp_dfl_root; - root = cgroup_do_mount(&cgroup2_fs_type, fc->sb_flags, &cgrp_dfl_root, - CGROUP2_SUPER_MAGIC, ns); - if (IS_ERR(root)) - return PTR_ERR(root); - - apply_cgroup_root_flags(ctx->flags); - fc->root = root; - return 0; + ret = cgroup_do_mount(fc, CGROUP2_SUPER_MAGIC, ns); + if (!ret) + apply_cgroup_root_flags(ctx->flags); + return ret; } static const struct fs_context_operations cgroup_fs_context_ops = {