staging: lustre: opencode cfs_cap_{raise, lower, raised}
authorNeilBrown <neilb@suse.com>
Tue, 20 Feb 2018 02:23:37 +0000 (13:23 +1100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 22 Feb 2018 14:03:22 +0000 (15:03 +0100)
Each of these functions is used precisely once, so having
a separate exported function seems like overkill.

cfs_cap_raised() is trivial - one line.
cfs_cap_raise() and cfs_cap_lower() are used as a pair
which is more effectively implemented with
override_cred() / revert_creds().

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/staging/lustre/include/linux/libcfs/curproc.h
drivers/staging/lustre/lnet/libcfs/linux/linux-curproc.c
drivers/staging/lustre/lustre/obdclass/llog.c

index cdc549e..51f2179 100644 (file)
@@ -66,9 +66,6 @@ typedef u32 cfs_cap_t;
                         BIT(CAP_SYS_BOOT) |    \
                         BIT(CAP_SYS_RESOURCE))
 
-void cfs_cap_raise(cfs_cap_t cap);
-void cfs_cap_lower(cfs_cap_t cap);
-int cfs_cap_raised(cfs_cap_t cap);
 cfs_cap_t cfs_curproc_cap_pack(void);
 
 /* __LIBCFS_CURPROC_H__ */
index 1d8949f..6b75c5c 100644 (file)
  * for Linux kernel.
  */
 
-void cfs_cap_raise(cfs_cap_t cap)
-{
-       struct cred *cred;
-
-       cred = prepare_creds();
-       if (cred) {
-               cap_raise(cred->cap_effective, cap);
-               commit_creds(cred);
-       }
-}
-EXPORT_SYMBOL(cfs_cap_raise);
-
-void cfs_cap_lower(cfs_cap_t cap)
-{
-       struct cred *cred;
-
-       cred = prepare_creds();
-       if (cred) {
-               cap_lower(cred->cap_effective, cap);
-               commit_creds(cred);
-       }
-}
-EXPORT_SYMBOL(cfs_cap_lower);
-
-int cfs_cap_raised(cfs_cap_t cap)
-{
-       return cap_raised(current_cap(), cap);
-}
-EXPORT_SYMBOL(cfs_cap_raised);
-
 static void cfs_kernel_cap_pack(kernel_cap_t kcap, cfs_cap_t *cap)
 {
        /* XXX lost high byte */
index aa48b3d..934f067 100644 (file)
@@ -466,7 +466,7 @@ int llog_open(const struct lu_env *env, struct llog_ctxt *ctxt,
              struct llog_handle **lgh, struct llog_logid *logid,
              char *name, enum llog_open_param open_param)
 {
-       int      raised;
+       const struct cred *old_cred = NULL;
        int      rc;
 
        LASSERT(ctxt);
@@ -483,12 +483,18 @@ int llog_open(const struct lu_env *env, struct llog_ctxt *ctxt,
        (*lgh)->lgh_ctxt = ctxt;
        (*lgh)->lgh_logops = ctxt->loc_logops;
 
-       raised = cfs_cap_raised(CAP_SYS_RESOURCE);
-       if (!raised)
-               cfs_cap_raise(CAP_SYS_RESOURCE);
+       if (cap_raised(current_cap(), CAP_SYS_RESOURCE)) {
+               struct cred *cred = prepare_creds();
+
+               if (cred) {
+                       cap_raise(cred->cap_effective, CAP_SYS_RESOURCE);
+                       old_cred = override_creds(cred);
+               }
+       }
        rc = ctxt->loc_logops->lop_open(env, *lgh, logid, name, open_param);
-       if (!raised)
-               cfs_cap_lower(CAP_SYS_RESOURCE);
+       if (old_cred)
+               revert_creds(old_cred);
+
        if (rc) {
                llog_free_handle(*lgh);
                *lgh = NULL;