nfs: use time64_t internally

The timestamps for the cache are all in boottime seconds, so they
don't overflow 32-bit values, but the use of time_t is deprecated
because it generally does overflow when used with wall-clock time.

There are multiple possible ways of avoiding it:

- leave time_t, which is safe here, but forces others to
  look into this code to determine that it is over and over.

- use a more generic type, like 'int' or 'long', which is known
  to be sufficient here but loses the documentation of referring
  to timestamps

- use ktime_t everywhere, and convert into seconds in the few
  places where we want realtime-seconds. The conversion is
  sometimes expensive, but not more so than the conversion we
  do today.

- use time64_t to clarify that this code is safe. Nothing would
  change for 64-bit architectures, but it is slightly less
  efficient on 32-bit architectures.

Without a clear winner of the three approaches above, this picks
the last one, favouring readability over a small performance
loss on 32-bit architectures.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 5 insertions, 5 deletions

diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
index 5c04ba7d456b..04aa80a2d752 100644
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -166,7 +166,7 @@ static void ip_map_request(struct cache_detail *cd,
 }
 
 static struct ip_map *__ip_map_lookup(struct cache_detail *cd, char *class, struct in6_addr *addr);
-static int __ip_map_update(struct cache_detail *cd, struct ip_map *ipm, struct unix_domain *udom, time_t expiry);
+static int __ip_map_update(struct cache_detail *cd, struct ip_map *ipm, struct unix_domain *udom, time64_t expiry);
 
 static int ip_map_parse(struct cache_detail *cd,
 			  char *mesg, int mlen)
@@ -187,7 +187,7 @@ static int ip_map_parse(struct cache_detail *cd,
 
 	struct ip_map *ipmp;
 	struct auth_domain *dom;
-	time_t expiry;
+	time64_t expiry;
 
 	if (mesg[mlen-1] != '\n')
 		return -EINVAL;
@@ -308,7 +308,7 @@ static inline struct ip_map *ip_map_lookup(struct net *net, char *class,
 }
 
 static int __ip_map_update(struct cache_detail *cd, struct ip_map *ipm,
-		struct unix_domain *udom, time_t expiry)
+		struct unix_domain *udom, time64_t expiry)
 {
 	struct ip_map ip;
 	struct cache_head *ch;
@@ -328,7 +328,7 @@ static int __ip_map_update(struct cache_detail *cd, struct ip_map *ipm,
 }
 
 static inline int ip_map_update(struct net *net, struct ip_map *ipm,
-		struct unix_domain *udom, time_t expiry)
+		struct unix_domain *udom, time64_t expiry)
 {
 	struct sunrpc_net *sn;
 
@@ -491,7 +491,7 @@ static int unix_gid_parse(struct cache_detail *cd,
 	int rv;
 	int i;
 	int err;
-	time_t expiry;
+	time64_t expiry;
 	struct unix_gid ug, *ugp;
 
 	if (mesg[mlen - 1] != '\n')