Let's inline all low-level helpers and use likely()/unlikely() to help
the compiler along.
Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
---
fs/mnt_idmapping.c | 145 -----------------------------------------
include/linux/mnt_idmapping.h | 147 +++++++++++++++++++++++++++++++++++++++---
kernel/user_namespace.c | 2 +
3 files changed, 141 insertions(+), 153 deletions(-)
diff --git a/fs/mnt_idmapping.c b/fs/mnt_idmapping.c
index 5c7e1db8fef8..ba1f752b6fa7 100644
--- a/fs/mnt_idmapping.c
+++ b/fs/mnt_idmapping.c
@@ -10,13 +10,6 @@
#include "internal.h"
-/*
- * Outside of this file vfs{g,u}id_t are always created from k{g,u}id_t,
- * never from raw values. These are just internal helpers.
- */
-#define VFSUIDT_INIT_RAW(val) (vfsuid_t){ val }
-#define VFSGIDT_INIT_RAW(val) (vfsgid_t){ val }
-
/*
* Carries the initial idmapping of 0:0:4294967295 which is an identity
* mapping. This means that {g,u}id 0 is mapped to {g,u}id 0, {g,u}id 1 is
@@ -36,144 +29,6 @@ struct mnt_idmap invalid_mnt_idmap = {
};
EXPORT_SYMBOL_GPL(invalid_mnt_idmap);
-/**
- * make_vfsuid - map a filesystem kuid according to an idmapping
- * @idmap: the mount's idmapping
- * @fs_userns: the filesystem's idmapping
- * @kuid : kuid to be mapped
- *
- * Take a @kuid and remap it from @fs_userns into @idmap. Use this
- * function when preparing a @kuid to be reported to userspace.
- *
- * If initial_idmapping() determines that this is not an idmapped mount
- * we can simply return @kuid unchanged.
- * If initial_idmapping() tells us that the filesystem is not mounted with an
- * idmapping we know the value of @kuid won't change when calling
- * from_kuid() so we can simply retrieve the value via __kuid_val()
- * directly.
- *
- * Return: @kuid mapped according to @idmap.
- * If @kuid has no mapping in either @idmap or @fs_userns INVALID_UID is
- * returned.
- */
-
-vfsuid_t make_vfsuid(struct mnt_idmap *idmap,
- struct user_namespace *fs_userns,
- kuid_t kuid)
-{
- uid_t uid;
-
- if (idmap == &nop_mnt_idmap)
- return VFSUIDT_INIT(kuid);
- if (idmap == &invalid_mnt_idmap)
- return INVALID_VFSUID;
- if (initial_idmapping(fs_userns))
- uid = __kuid_val(kuid);
- else
- uid = from_kuid(fs_userns, kuid);
- if (uid == (uid_t)-1)
- return INVALID_VFSUID;
- return VFSUIDT_INIT_RAW(map_id_down(&idmap->uid_map, uid));
-}
-EXPORT_SYMBOL_GPL(make_vfsuid);
-
-/**
- * make_vfsgid - map a filesystem kgid according to an idmapping
- * @idmap: the mount's idmapping
- * @fs_userns: the filesystem's idmapping
- * @kgid : kgid to be mapped
- *
- * Take a @kgid and remap it from @fs_userns into @idmap. Use this
- * function when preparing a @kgid to be reported to userspace.
- *
- * If initial_idmapping() determines that this is not an idmapped mount
- * we can simply return @kgid unchanged.
- * If initial_idmapping() tells us that the filesystem is not mounted with an
- * idmapping we know the value of @kgid won't change when calling
- * from_kgid() so we can simply retrieve the value via __kgid_val()
- * directly.
- *
- * Return: @kgid mapped according to @idmap.
- * If @kgid has no mapping in either @idmap or @fs_userns INVALID_GID is
- * returned.
- */
-vfsgid_t make_vfsgid(struct mnt_idmap *idmap,
- struct user_namespace *fs_userns, kgid_t kgid)
-{
- gid_t gid;
-
- if (idmap == &nop_mnt_idmap)
- return VFSGIDT_INIT(kgid);
- if (idmap == &invalid_mnt_idmap)
- return INVALID_VFSGID;
- if (initial_idmapping(fs_userns))
- gid = __kgid_val(kgid);
- else
- gid = from_kgid(fs_userns, kgid);
- if (gid == (gid_t)-1)
- return INVALID_VFSGID;
- return VFSGIDT_INIT_RAW(map_id_down(&idmap->gid_map, gid));
-}
-EXPORT_SYMBOL_GPL(make_vfsgid);
-
-/**
- * from_vfsuid - map a vfsuid into the filesystem idmapping
- * @idmap: the mount's idmapping
- * @fs_userns: the filesystem's idmapping
- * @vfsuid : vfsuid to be mapped
- *
- * Map @vfsuid into the filesystem idmapping. This function has to be used in
- * order to e.g. write @vfsuid to inode->i_uid.
- *
- * Return: @vfsuid mapped into the filesystem idmapping
- */
-kuid_t from_vfsuid(struct mnt_idmap *idmap,
- struct user_namespace *fs_userns, vfsuid_t vfsuid)
-{
- uid_t uid;
-
- if (idmap == &nop_mnt_idmap)
- return AS_KUIDT(vfsuid);
- if (idmap == &invalid_mnt_idmap)
- return INVALID_UID;
- uid = map_id_up(&idmap->uid_map, __vfsuid_val(vfsuid));
- if (uid == (uid_t)-1)
- return INVALID_UID;
- if (initial_idmapping(fs_userns))
- return KUIDT_INIT(uid);
- return make_kuid(fs_userns, uid);
-}
-EXPORT_SYMBOL_GPL(from_vfsuid);
-
-/**
- * from_vfsgid - map a vfsgid into the filesystem idmapping
- * @idmap: the mount's idmapping
- * @fs_userns: the filesystem's idmapping
- * @vfsgid : vfsgid to be mapped
- *
- * Map @vfsgid into the filesystem idmapping. This function has to be used in
- * order to e.g. write @vfsgid to inode->i_gid.
- *
- * Return: @vfsgid mapped into the filesystem idmapping
- */
-kgid_t from_vfsgid(struct mnt_idmap *idmap,
- struct user_namespace *fs_userns, vfsgid_t vfsgid)
-{
- gid_t gid;
-
- if (idmap == &nop_mnt_idmap)
- return AS_KGIDT(vfsgid);
- if (idmap == &invalid_mnt_idmap)
- return INVALID_GID;
- gid = map_id_up(&idmap->gid_map, __vfsgid_val(vfsgid));
- if (gid == (gid_t)-1)
- return INVALID_GID;
- if (initial_idmapping(fs_userns))
- return KGIDT_INIT(gid);
- return make_kgid(fs_userns, gid);
-}
-EXPORT_SYMBOL_GPL(from_vfsgid);
-
#ifdef CONFIG_MULTIUSER
/**
* vfsgid_in_group_p() - check whether a vfsuid matches the caller's groups
diff --git a/include/linux/mnt_idmapping.h b/include/linux/mnt_idmapping.h
index 4410672c2828..e6fb905c39bd 100644
--- a/include/linux/mnt_idmapping.h
+++ b/include/linux/mnt_idmapping.h
@@ -140,22 +140,153 @@ static inline bool vfsgid_eq_kgid(vfsgid_t vfsgid, kgid_t kgid)
#define AS_KUIDT(val) (kuid_t){ __vfsuid_val(val) }
#define AS_KGIDT(val) (kgid_t){ __vfsgid_val(val) }
+/*
+ * Outside of this file vfs{g,u}id_t are always created from k{g,u}id_t,
+ * never from raw values. These are just internal helpers.
+ */
+#define VFSUIDT_INIT_RAW(val) (vfsuid_t){ val }
+#define VFSGIDT_INIT_RAW(val) (vfsgid_t){ val }
+
int vfsgid_in_group_p(vfsgid_t vfsgid);
struct mnt_idmap *mnt_idmap_get(struct mnt_idmap *idmap);
void mnt_idmap_put(struct mnt_idmap *idmap);
-vfsuid_t make_vfsuid(struct mnt_idmap *idmap,
- struct user_namespace *fs_userns, kuid_t kuid);
+/**
+ * make_vfsuid - map a filesystem kuid according to an idmapping
+ * @idmap: the mount's idmapping
+ * @fs_userns: the filesystem's idmapping
+ * @kuid : kuid to be mapped
+ *
+ * Take a @kuid and remap it from @fs_userns into @idmap. Use this
+ * function when preparing a @kuid to be reported to userspace.
+ *
+ * If initial_idmapping() determines that this is not an idmapped mount
+ * we can simply return @kuid unchanged.
+ * If initial_idmapping() tells us that the filesystem is not mounted with an
+ * idmapping we know the value of @kuid won't change when calling
+ * from_kuid() so we can simply retrieve the value via __kuid_val()
+ * directly.
+ *
+ * Return: @kuid mapped according to @idmap.
+ * If @kuid has no mapping in either @idmap or @fs_userns INVALID_UID is
+ * returned.
+ */
+static inline vfsuid_t make_vfsuid(struct mnt_idmap *idmap,
+ struct user_namespace *fs_userns,
+ kuid_t kuid)
+{
+ uid_t uid;
+
+ if (likely(idmap == &nop_mnt_idmap))
+ return VFSUIDT_INIT(kuid);
+ if (unlikely(idmap == &invalid_mnt_idmap))
+ return INVALID_VFSUID;
+ if (likely(initial_idmapping(fs_userns)))
+ uid = __kuid_val(kuid);
+ else
+ uid = from_kuid(fs_userns, kuid);
+ if (unlikely(uid == (uid_t)-1))
+ return INVALID_VFSUID;
+ return VFSUIDT_INIT_RAW(map_id_down(&idmap->uid_map, uid));
+}
-vfsgid_t make_vfsgid(struct mnt_idmap *idmap,
- struct user_namespace *fs_userns, kgid_t kgid);
+/**
+ * make_vfsgid - map a filesystem kgid according to an idmapping
+ * @idmap: the mount's idmapping
+ * @fs_userns: the filesystem's idmapping
+ * @kgid : kgid to be mapped
+ *
+ * Take a @kgid and remap it from @fs_userns into @idmap. Use this
+ * function when preparing a @kgid to be reported to userspace.
+ *
+ * If initial_idmapping() determines that this is not an idmapped mount
+ * we can simply return @kgid unchanged.
+ * If initial_idmapping() tells us that the filesystem is not mounted with an
+ * idmapping we know the value of @kgid won't change when calling
+ * from_kgid() so we can simply retrieve the value via __kgid_val()
+ * directly.
+ *
+ * Return: @kgid mapped according to @idmap.
+ * If @kgid has no mapping in either @idmap or @fs_userns INVALID_GID is
+ * returned.
+ */
+static inline vfsgid_t make_vfsgid(struct mnt_idmap *idmap,
+ struct user_namespace *fs_userns,
+ kgid_t kgid)
+{
+ gid_t gid;
+
+ if (likely(idmap == &nop_mnt_idmap))
+ return VFSGIDT_INIT(kgid);
+ if (unlikely(idmap == &invalid_mnt_idmap))
+ return INVALID_VFSGID;
+ if (likely(initial_idmapping(fs_userns)))
+ gid = __kgid_val(kgid);
+ else
+ gid = from_kgid(fs_userns, kgid);
+ if (unlikely(gid == (gid_t)-1))
+ return INVALID_VFSGID;
+ return VFSGIDT_INIT_RAW(map_id_down(&idmap->gid_map, gid));
+}
-kuid_t from_vfsuid(struct mnt_idmap *idmap,
- struct user_namespace *fs_userns, vfsuid_t vfsuid);
+/**
+ * from_vfsuid - map a vfsuid into the filesystem idmapping
+ * @idmap: the mount's idmapping
+ * @fs_userns: the filesystem's idmapping
+ * @vfsuid : vfsuid to be mapped
+ *
+ * Map @vfsuid into the filesystem idmapping. This function has to be used in
+ * order to e.g. write @vfsuid to inode->i_uid.
+ *
+ * Return: @vfsuid mapped into the filesystem idmapping
+ */
+static inline kuid_t from_vfsuid(struct mnt_idmap *idmap,
+ struct user_namespace *fs_userns,
+ vfsuid_t vfsuid)
+{
+ uid_t uid;
+
+ if (likely(idmap == &nop_mnt_idmap))
+ return AS_KUIDT(vfsuid);
+ if (unlikely(idmap == &invalid_mnt_idmap))
+ return INVALID_UID;
+ uid = map_id_up(&idmap->uid_map, __vfsuid_val(vfsuid));
+ if (unlikely(uid == (uid_t)-1))
+ return INVALID_UID;
+ if (likely(initial_idmapping(fs_userns)))
+ return KUIDT_INIT(uid);
+ return make_kuid(fs_userns, uid);
+}
-kgid_t from_vfsgid(struct mnt_idmap *idmap,
- struct user_namespace *fs_userns, vfsgid_t vfsgid);
+/**
+ * from_vfsgid - map a vfsgid into the filesystem idmapping
+ * @idmap: the mount's idmapping
+ * @fs_userns: the filesystem's idmapping
+ * @vfsgid : vfsgid to be mapped
+ *
+ * Map @vfsgid into the filesystem idmapping. This function has to be used in
+ * order to e.g. write @vfsgid to inode->i_gid.
+ *
+ * Return: @vfsgid mapped into the filesystem idmapping
+ */
+static inline kgid_t from_vfsgid(struct mnt_idmap *idmap,
+ struct user_namespace *fs_userns,
+ vfsgid_t vfsgid)
+{
+ gid_t gid;
+
+ if (likely(idmap == &nop_mnt_idmap))
+ return AS_KGIDT(vfsgid);
+ if (unlikely(idmap == &invalid_mnt_idmap))
+ return INVALID_GID;
+ gid = map_id_up(&idmap->gid_map, __vfsgid_val(vfsgid));
+ if (unlikely(gid == (gid_t)-1))
+ return INVALID_GID;
+ if (likely(initial_idmapping(fs_userns)))
+ return KGIDT_INIT(gid);
+ return make_kgid(fs_userns, gid);
+}
/**
* vfsuid_has_fsmapping - check whether a vfsuid maps into the filesystem
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 682f40d5632d..693c62587571 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -336,6 +336,7 @@ u32 map_id_down(struct uid_gid_map *map, u32 id)
{
return map_id_range_down(map, id, 1);
}
+EXPORT_SYMBOL_GPL(map_id_down);
/*
* map_id_up_base - Find idmap via binary search in static extent array.
@@ -402,6 +403,7 @@ u32 map_id_up(struct uid_gid_map *map, u32 id)
{
return map_id_range_up(map, id, 1);
}
+EXPORT_SYMBOL_GPL(map_id_up);
/**
* make_kuid - Map a user-namespace uid pair into a kuid.
--
2.47.2
