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authorMike Snitzer <snitzer@redhat.com>2013-08-20 23:05:17 +0400
committerMike Snitzer <snitzer@redhat.com>2013-08-23 17:02:14 +0400
commiteb18cba78c2b9250663021e17e1e9cc34630e92a (patch)
treee12eaa9ab3e5fddfd27f7697e7f5b0baf00150e5 /include/linux/math64.h
parentf722063ee01c0060488e1000006405449451cfa0 (diff)
downloadlinux-eb18cba78c2b9250663021e17e1e9cc34630e92a.tar.xz
math64: New separate div64_u64_rem helper
Commit f792685006274a850e6cc0ea9ade275ccdfc90bc ("math64: New div64_u64_rem helper") implemented div64_u64 in terms of div64_u64_rem. But div64_u64_rem was removed because it slowed down div64_u64 (and there were no other users of div64_u64_rem). Device Mapper's I/O statistics support has a need for div64_u64_rem; reintroduce this helper as a separate method that doesn't slow down div64_u64, especially on 32-bit systems. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'include/linux/math64.h')
-rw-r--r--include/linux/math64.h13
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/math64.h b/include/linux/math64.h
index 2913b86eb12a..69ed5f5e9f6e 100644
--- a/include/linux/math64.h
+++ b/include/linux/math64.h
@@ -31,6 +31,15 @@ static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
}
/**
+ * div64_u64_rem - unsigned 64bit divide with 64bit divisor and remainder
+ */
+static inline u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder)
+{
+ *remainder = dividend % divisor;
+ return dividend / divisor;
+}
+
+/**
* div64_u64 - unsigned 64bit divide with 64bit divisor
*/
static inline u64 div64_u64(u64 dividend, u64 divisor)
@@ -63,6 +72,10 @@ static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder);
#endif
+#ifndef div64_u64_rem
+extern u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder);
+#endif
+
#ifndef div64_u64
extern u64 div64_u64(u64 dividend, u64 divisor);
#endif