dm: fix redundant IO accounting for bios that need splitting

[linux-2.6-microblaze.git] / kernel / cred.c

diff --git a/kernel/cred.c b/kernel/cred.c
index ecf0365..21f4a97 100644 (file)
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -19,6 +19,7 @@
 #include <linux/security.h>
 #include <linux/binfmts.h>
 #include <linux/cn_proc.h>
+#include <linux/uidgid.h>
 
 #if 0
 #define kdebug(FMT, ...)                                               \
@@ -194,11 +195,12 @@ const struct cred *get_task_cred(struct task_struct *task)
        do {
                cred = __task_cred((task));
                BUG_ON(!cred);
-       } while (!atomic_inc_not_zero(&((struct cred *)cred)->usage));
+       } while (!get_cred_rcu(cred));
 
        rcu_read_unlock();
        return cred;
 }
+EXPORT_SYMBOL(get_task_cred);
 
 /*
  * Allocate blank credentials, such that the credentials can be filled in at a
@@ -564,6 +566,60 @@ void revert_creds(const struct cred *old)
 }
 EXPORT_SYMBOL(revert_creds);
 
+/**
+ * cred_fscmp - Compare two credentials with respect to filesystem access.
+ * @a: The first credential
+ * @b: The second credential
+ *
+ * cred_cmp() will return zero if both credentials have the same
+ * fsuid, fsgid, and supplementary groups.  That is, if they will both
+ * provide the same access to files based on mode/uid/gid.
+ * If the credentials are different, then either -1 or 1 will
+ * be returned depending on whether @a comes before or after @b
+ * respectively in an arbitrary, but stable, ordering of credentials.
+ *
+ * Return: -1, 0, or 1 depending on comparison
+ */
+int cred_fscmp(const struct cred *a, const struct cred *b)
+{
+       struct group_info *ga, *gb;
+       int g;
+
+       if (a == b)
+               return 0;
+       if (uid_lt(a->fsuid, b->fsuid))
+               return -1;
+       if (uid_gt(a->fsuid, b->fsuid))
+               return 1;
+
+       if (gid_lt(a->fsgid, b->fsgid))
+               return -1;
+       if (gid_gt(a->fsgid, b->fsgid))
+               return 1;
+
+       ga = a->group_info;
+       gb = b->group_info;
+       if (ga == gb)
+               return 0;
+       if (ga == NULL)
+               return -1;
+       if (gb == NULL)
+               return 1;
+       if (ga->ngroups < gb->ngroups)
+               return -1;
+       if (ga->ngroups > gb->ngroups)
+               return 1;
+
+       for (g = 0; g < ga->ngroups; g++) {
+               if (gid_lt(ga->gid[g], gb->gid[g]))
+                       return -1;
+               if (gid_gt(ga->gid[g], gb->gid[g]))
+                       return 1;
+       }
+       return 0;
+}
+EXPORT_SYMBOL(cred_fscmp);
+
 /*
  * initialise the credentials stuff
  */