Commit f559935e authored by Arnd Bergmann's avatar Arnd Bergmann
Browse files

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: default avatarArnd Bergmann <arnd@arndb.de>
parent 294ec5b8

include/linux/sunrpc/cache.h

+23 −19
Original line number Diff line number Diff line
@@ -45,8 +45,8 @@ 
 */

struct cache_head {

	struct hlist_node	cache_list;

	time_t		expiry_time;	/* After time time, don't use the data */

	time_t		last_refresh;   /* If CACHE_PENDING, this is when upcall was

	time64_t	expiry_time;	/* After time time, don't use the data */

	time64_t	last_refresh;   /* If CACHE_PENDING, this is when upcall was

					 * sent, else this is when update was

					 * received, though it is alway set to

					 * be *after* ->flush_time.
@@ -95,22 +95,22 @@ struct cache_detail { 
	/* fields below this comment are for internal use

	 * and should not be touched by cache owners

	 */

	time_t			flush_time;		/* flush all cache items with

	time64_t		flush_time;		/* flush all cache items with

							 * last_refresh at or earlier

							 * than this.  last_refresh

							 * is never set at or earlier

							 * than this.

							 */

	struct list_head	others;

	time_t			nextcheck;

	time64_t		nextcheck;

	int			entries;



	/* fields for communication over channel */

	struct list_head	queue;



	atomic_t		writers;		/* how many time is /channel open */

	time_t			last_close;		/* if no writers, when did last close */

	time_t			last_warn;		/* when we last warned about no writers */

	time64_t		last_close;		/* if no writers, when did last close */

	time64_t		last_warn;		/* when we last warned about no writers */



	union {

		struct proc_dir_entry	*procfs;
@@ -147,18 +147,22 @@ struct cache_deferred_req { 
 * timestamps kept in the cache are expressed in seconds

 * since boot.  This is the best for measuring differences in

 * real time.

 * This reimplemnts ktime_get_boottime_seconds() in a slightly

 * faster but less accurate way. When we end up converting

 * back to wallclock (CLOCK_REALTIME), that error often

 * cancels out during the reverse operation.

 */

static inline time_t seconds_since_boot(void)

static inline time64_t seconds_since_boot(void)

{

	struct timespec boot;

	getboottime(&boot);

	return get_seconds() - boot.tv_sec;

	struct timespec64 boot;

	getboottime64(&boot);

	return ktime_get_real_seconds() - boot.tv_sec;

}



static inline time_t convert_to_wallclock(time_t sinceboot)

static inline time64_t convert_to_wallclock(time64_t sinceboot)

{

	struct timespec boot;

	getboottime(&boot);

	struct timespec64 boot;

	getboottime64(&boot);

	return boot.tv_sec + sinceboot;

}
@@ -273,7 +277,7 @@ static inline int get_uint(char **bpp, unsigned int *anint) 
	return 0;

}



static inline int get_time(char **bpp, time_t *time)

static inline int get_time(char **bpp, time64_t *time)

{

	char buf[50];

	long long ll;
@@ -287,20 +291,20 @@ static inline int get_time(char **bpp, time_t *time) 
	if (kstrtoll(buf, 0, &ll))

		return -EINVAL;



	*time = (time_t)ll;

	*time = ll;

	return 0;

}



static inline time_t get_expiry(char **bpp)

static inline time64_t get_expiry(char **bpp)

{

	time_t rv;

	struct timespec boot;

	time64_t rv;

	struct timespec64 boot;



	if (get_time(bpp, &rv))

		return 0;

	if (rv < 0)

		return 0;

	getboottime(&boot);

	getboottime64(&boot);

	return rv - boot.tv_sec;

}

net/sunrpc/auth_gss/svcauth_gss.c

+1 −1
Original line number Diff line number Diff line
@@ -203,7 +203,7 @@ static int rsi_parse(struct cache_detail *cd, 
	char *ep;

	int len;

	struct rsi rsii, *rsip = NULL;

	time_t expiry;

	time64_t expiry;

	int status = -EINVAL;



	memset(&rsii, 0, sizeof(rsii));

net/sunrpc/cache.c

+8 −8
Original line number Diff line number Diff line
@@ -42,7 +42,7 @@ static bool cache_listeners_exist(struct cache_detail *detail); 


static void cache_init(struct cache_head *h, struct cache_detail *detail)

{

	time_t now = seconds_since_boot();

	time64_t now = seconds_since_boot();

	INIT_HLIST_NODE(&h->cache_list);

	h->flags = 0;

	kref_init(&h->ref);
@@ -139,10 +139,10 @@ EXPORT_SYMBOL_GPL(sunrpc_cache_lookup_rcu); 


static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);



static void cache_fresh_locked(struct cache_head *head, time_t expiry,

static void cache_fresh_locked(struct cache_head *head, time64_t expiry,

			       struct cache_detail *detail)

{

	time_t now = seconds_since_boot();

	time64_t now = seconds_since_boot();

	if (now <= detail->flush_time)

		/* ensure it isn't immediately treated as expired */

		now = detail->flush_time + 1;
@@ -274,7 +274,7 @@ int cache_check(struct cache_detail *detail, 
		    struct cache_head *h, struct cache_req *rqstp)

{

	int rv;

	long refresh_age, age;

	time64_t refresh_age, age;



	/* First decide return status as best we can */

	rv = cache_is_valid(h);
@@ -288,7 +288,7 @@ int cache_check(struct cache_detail *detail, 
			rv = -ENOENT;

	} else if (rv == -EAGAIN ||

		   (h->expiry_time != 0 && age > refresh_age/2)) {

		dprintk("RPC:       Want update, refage=%ld, age=%ld\n",

		dprintk("RPC:       Want update, refage=%lld, age=%lld\n",

				refresh_age, age);

		if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {

			switch (cache_make_upcall(detail, h)) {
@@ -1404,7 +1404,7 @@ static int c_show(struct seq_file *m, void *p) 
		return cd->cache_show(m, cd, NULL);



	ifdebug(CACHE)

		seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",

		seq_printf(m, "# expiry=%lld refcnt=%d flags=%lx\n",

			   convert_to_wallclock(cp->expiry_time),

			   kref_read(&cp->ref), cp->flags);

	cache_get(cp);
@@ -1477,7 +1477,7 @@ static ssize_t read_flush(struct file *file, char __user *buf, 
	char tbuf[22];

	size_t len;



	len = snprintf(tbuf, sizeof(tbuf), "%lu\n",

	len = snprintf(tbuf, sizeof(tbuf), "%llu\n",

			convert_to_wallclock(cd->flush_time));

	return simple_read_from_buffer(buf, count, ppos, tbuf, len);

}
@@ -1488,7 +1488,7 @@ static ssize_t write_flush(struct file *file, const char __user *buf, 
{

	char tbuf[20];

	char *ep;

	time_t now;

	time64_t now;



	if (*ppos || count > sizeof(tbuf)-1)

		return -EINVAL;

net/sunrpc/svcauth_unix.c

+5 −5
Original line number Diff line number Diff line
@@ -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')

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