[PATCH v2 12/42] lockd: Move nlm4svc_set_file_lock_range()

[Chuck Lever <cel@kernel.org>]

From: Chuck Lever <chuck.lever@oracle.com>

Refactor: nlm4svc_set_file_lock_range() is used by both the
client-side and server-side code. Remove the "svc" from the
name and relocate the function to a generic header.

This clean up partly enables the removal of '#include "xdr4.h"'
from fs/lockd/clnt4xdr.c.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/lockd/clnt4xdr.c |  2 +-
 fs/lockd/lockd.h    | 23 +++++++++++++++++++++++
 fs/lockd/xdr4.c     | 13 +------------
 fs/lockd/xdr4.h     |  1 -
 4 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/fs/lockd/clnt4xdr.c b/fs/lockd/clnt4xdr.c
index 61ee5fa6dfa4..c09e67765cac 100644
--- a/fs/lockd/clnt4xdr.c
+++ b/fs/lockd/clnt4xdr.c
@@ -287,7 +287,7 @@ static int decode_nlm4_holder(struct xdr_stream *xdr, struct nlm_res *result)
 	fl->c.flc_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
 	p = xdr_decode_hyper(p, &l_offset);
 	xdr_decode_hyper(p, &l_len);
-	nlm4svc_set_file_lock_range(fl, l_offset, l_len);
+	lockd_set_file_lock_range4(fl, l_offset, l_len);
 	error = 0;
 out:
 	return error;
diff --git a/fs/lockd/lockd.h b/fs/lockd/lockd.h
index 3f44820974cd..c889475a74e0 100644
--- a/fs/lockd/lockd.h
+++ b/fs/lockd/lockd.h
@@ -413,6 +413,29 @@ static inline int nlm_compare_locks(const struct file_lock *fl1,
 	     &&(fl1->c.flc_type  == fl2->c.flc_type || fl2->c.flc_type == F_UNLCK);
 }
 
+/**
+ * lockd_set_file_lock_range4 - set the byte range of a file_lock
+ * @fl: file_lock whose length fields are to be initialized
+ * @off: starting offset of the lock, in bytes
+ * @len: length of the byte range, in bytes, or zero
+ *
+ * NLMv4 uses a (start, length) representation for lock byte ranges,
+ * while the kernel's file_lock uses (start, end). A length of zero
+ * means "lock to end of file."  This function handles the conversion
+ * and also treats arithmetic overflow as "lock to end of file."
+ */
+static inline void
+lockd_set_file_lock_range4(struct file_lock *fl, u64 off, u64 len)
+{
+	s64 end = off + len - 1;
+
+	fl->fl_start = off;
+	if (len == 0 || end < 0)
+		fl->fl_end = OFFSET_MAX;
+	else
+		fl->fl_end = end;
+}
+
 extern const struct lock_manager_operations nlmsvc_lock_operations;
 
 #endif /* _LOCKD_LOCKD_H */
diff --git a/fs/lockd/xdr4.c b/fs/lockd/xdr4.c
index f57d4881d5f1..dbbb2dfcb81b 100644
--- a/fs/lockd/xdr4.c
+++ b/fs/lockd/xdr4.c
@@ -34,17 +34,6 @@ loff_t_to_s64(loff_t offset)
 	return res;
 }
 
-void nlm4svc_set_file_lock_range(struct file_lock *fl, u64 off, u64 len)
-{
-	s64 end = off + len - 1;
-
-	fl->fl_start = off;
-	if (len == 0 || end < 0)
-		fl->fl_end = OFFSET_MAX;
-	else
-		fl->fl_end = end;
-}
-
 /*
  * NLM file handles are defined by specification to be a variable-length
  * XDR opaque no longer than 1024 bytes. However, this implementation
@@ -91,7 +80,7 @@ svcxdr_decode_lock(struct xdr_stream *xdr, struct nlm_lock *lock)
 
 	locks_init_lock(fl);
 	fl->c.flc_type  = F_RDLCK;
-	nlm4svc_set_file_lock_range(fl, lock->lock_start, lock->lock_len);
+	lockd_set_file_lock_range4(fl, lock->lock_start, lock->lock_len);
 	return true;
 }
 
diff --git a/fs/lockd/xdr4.h b/fs/lockd/xdr4.h
index 7be318c0512b..4ddf51a2e0ea 100644
--- a/fs/lockd/xdr4.h
+++ b/fs/lockd/xdr4.h
@@ -15,7 +15,6 @@
 #define	nlm4_fbig		cpu_to_be32(NLM_FBIG)
 #define	nlm4_failed		cpu_to_be32(NLM_FAILED)
 
-void	nlm4svc_set_file_lock_range(struct file_lock *fl, u64 off, u64 len);
 bool	nlm4svc_decode_void(struct svc_rqst *rqstp, struct xdr_stream *xdr);
 bool	nlm4svc_decode_testargs(struct svc_rqst *rqstp, struct xdr_stream *xdr);
 bool	nlm4svc_decode_lockargs(struct svc_rqst *rqstp, struct xdr_stream *xdr);
-- 
2.52.0