From: Jeff Layton <jlayton@xxxxxxxxxx>
As Linus points out:
The inode_cmp_iversion{+raw}() functions are pure and utter crap.
Why?
You say that they return 0/negative/positive, but they do so in a
completely broken manner. They return that ternary value as the
sequence number difference in a 's64', which means that if you
actually care about that ternary value, and do the *sane* thing that
the kernel-doc of the function implies is the right thing, you would
do
int cmp = inode_cmp_iversion(inode, old);
if (cmp < 0 ...
and as a result you get code that looks sane, but that doesn't
actually *WORK* right.
Since none of the callers actually care about the ternary value here,
convert the inode_cmp_iversion{+raw} functions to just return a boolean
value (false for matching, true for non-matching).
This matches the existing use of these functions just fine, and makes it
simple to convert them to return a ternary value in the future if we
grow callers that need it.
With this change we can also reimplement inode_cmp_iversion in a simpler
way using inode_peek_iversion.
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
include/linux/iversion.h | 20 ++++++++------------
1 file changed, 8 insertions(+), 12 deletions(-)
diff --git a/include/linux/iversion.h b/include/linux/iversion.h
index 858463fca249..3d2fd06495ec 100644
--- a/include/linux/iversion.h
+++ b/include/linux/iversion.h
@@ -309,13 +309,13 @@ inode_query_iversion(struct inode *inode)
* @inode: inode to check
* @old: old value to check against its i_version
*
- * Compare the current raw i_version counter with a previous one. Returns 0 if
- * they are the same or non-zero if they are different.
+ * Compare the current raw i_version counter with a previous one. Returns false
+ * if they are the same or true if they are different.
*/
-static inline s64
+static inline bool
inode_cmp_iversion_raw(const struct inode *inode, u64 old)
{
- return (s64)inode_peek_iversion_raw(inode) - (s64)old;
+ return inode_peek_iversion_raw(inode) != old;
}
/**
@@ -323,19 +323,15 @@ inode_cmp_iversion_raw(const struct inode *inode, u64 old)
* @inode: inode to check
* @old: old value to check against its i_version
*
- * Compare an i_version counter with a previous one. Returns 0 if they are
- * the same, a positive value if the one in the inode appears newer than @old,
- * and a negative value if @old appears to be newer than the one in the
- * inode.
+ * Compare an i_version counter with a previous one. Returns false if they are
+ * the same, and true if they are different.
*
* Note that we don't need to set the QUERIED flag in this case, as the value
* in the inode is not being recorded for later use.
*/
-
-static inline s64
+static inline bool
inode_cmp_iversion(const struct inode *inode, u64 old)
{
- return (s64)(inode_peek_iversion_raw(inode) & ~I_VERSION_QUERIED) -
- (s64)(old << I_VERSION_QUERIED_SHIFT);
+ return inode_peek_iversion(inode) != old;
}
#endif
--
2.14.3
--
To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
