sgi-xp: base xpc_rsvd_page's timestamp on jiffies

Change XPC's reserved page timestamp to be based on jiffies.

Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 34 insertions, 57 deletions

diff --git a/drivers/misc/sgi-xp/xpc.h b/drivers/misc/sgi-xp/xpc.h
index a3a67485cf8d..56bf5dcc391d 100644
--- a/drivers/misc/sgi-xp/xpc.h
+++ b/drivers/misc/sgi-xp/xpc.h
@@ -115,8 +115,8 @@ struct xpc_rsvd_page {
                 u64 vars_pa;    /* physical address of struct xpc_vars */
                 u64 activate_mq_gpa;    /* global phys address of activate_mq */
         } sn;
-        struct timespec stamp;  /* time when reserved page was setup by XPC */
-        u64 pad2[9];            /* align to last u64 in 2nd 64-byte cacheline */
+        unsigned long stamp;    /* time when reserved page was setup by XPC */
+        u64 pad2[10];           /* align to last u64 in 2nd 64-byte cacheline */
         u64 SAL_nasids_size;    /* SAL: size of each nasid mask in bytes */
 };
 
@@ -125,26 +125,6 @@ struct xpc_rsvd_page {
 #define XPC_SUPPORTS_RP_STAMP(_version) \
                         (_version >= _XPC_VERSION(1, 1))
 
-#define ZERO_STAMP      ((struct timespec){0, 0})
-/*
- * compare stamps - the return value is:
- *
- *      < 0,    if stamp1 < stamp2
- *      = 0,    if stamp1 == stamp2
- *      > 0,    if stamp1 > stamp2
- */
-static inline int
-xpc_compare_stamps(struct timespec *stamp1, struct timespec *stamp2)
-{
-        int ret;
-
-        ret = stamp1->tv_sec - stamp2->tv_sec;
-        if (ret == 0)
-                ret = stamp1->tv_nsec - stamp2->tv_nsec;
-
-        return ret;
-}
-
 /*
  * Define the structures by which XPC variables can be exported to other
  * partitions. (There are two: struct xpc_vars and struct xpc_vars_part)
@@ -492,7 +472,7 @@ struct xpc_partition {
         /* XPC HB infrastructure */
 
         u8 remote_rp_version;   /* version# of partition's rsvd pg */
-        struct timespec remote_rp_stamp; /* time when rsvd pg was initialized */
+        unsigned long remote_rp_stamp; /* time when rsvd pg was initialized */
         u64 remote_rp_pa;       /* phys addr of partition's rsvd pg */
         u64 remote_vars_pa;     /* phys addr of partition's vars */
         u64 remote_vars_part_pa;        /* phys addr of partition's vars part */
diff --git a/drivers/misc/sgi-xp/xpc_main.c b/drivers/misc/sgi-xp/xpc_main.c
index 10dac3652b23..4a6eb3774759 100644
--- a/drivers/misc/sgi-xp/xpc_main.c
+++ b/drivers/misc/sgi-xp/xpc_main.c
@@ -233,7 +233,7 @@ xpc_timeout_partition_disengage_request(unsigned long data)
 {
         struct xpc_partition *part = (struct xpc_partition *)data;
 
-        DBUG_ON(time_before(jiffies, part->disengage_request_timeout));
+        DBUG_ON(time_is_after_jiffies(part->disengage_request_timeout));
 
         (void)xpc_partition_disengaged(part);
 
@@ -262,7 +262,7 @@ xpc_hb_beater(unsigned long dummy)
 {
         xpc_increment_heartbeat();
 
-        if (time_after_eq(jiffies, xpc_hb_check_timeout))
+        if (time_is_before_eq_jiffies(xpc_hb_check_timeout))
                 wake_up_interruptible(&xpc_act_IRQ_wq);
 
         xpc_hb_timer.expires = jiffies + (xpc_hb_interval * HZ);
@@ -312,7 +312,7 @@ xpc_hb_checker(void *ignore)
                         atomic_read(&xpc_act_IRQ_rcvd) - last_IRQ_count);
 
                 /* checking of remote heartbeats is skewed by IRQ handling */
-                if (time_after_eq(jiffies, xpc_hb_check_timeout)) {
+                if (time_is_before_eq_jiffies(xpc_hb_check_timeout)) {
                         dev_dbg(xpc_part, "checking remote heartbeats\n");
                         xpc_check_remote_hb();
 
@@ -344,8 +344,8 @@ xpc_hb_checker(void *ignore)
                 (void)wait_event_interruptible(xpc_act_IRQ_wq,
                                                (last_IRQ_count <
                                                 atomic_read(&xpc_act_IRQ_rcvd)
-                                                || time_after_eq(jiffies,
-                                                        xpc_hb_check_timeout) ||
+                                                || time_is_before_eq_jiffies(
+                                                xpc_hb_check_timeout) ||
                                                 xpc_exiting));
         }
 
@@ -929,7 +929,7 @@ xpc_do_exit(enum xp_retval reason)
                 }
 
                 if (xpc_partition_engaged(-1UL)) {
-                        if (time_after(jiffies, printmsg_time)) {
+                        if (time_is_before_jiffies(printmsg_time)) {
                                 dev_info(xpc_part, "waiting for remote "
                                          "partitions to disengage, timeout in "
                                          "%ld seconds\n",
@@ -964,7 +964,7 @@ xpc_do_exit(enum xp_retval reason)
         DBUG_ON(xpc_any_hbs_allowed() != 0);
 
         /* indicate to others that our reserved page is uninitialized */
-        xpc_rsvd_page->stamp = ZERO_STAMP;
+        xpc_rsvd_page->stamp = 0;
 
         if (reason == xpUnloading) {
                 (void)unregister_die_notifier(&xpc_die_notifier);
@@ -1295,7 +1295,7 @@ xpc_init(void)
         /* initialization was not successful */
 out_4:
         /* indicate to others that our reserved page is uninitialized */
-        xpc_rsvd_page->stamp = ZERO_STAMP;
+        xpc_rsvd_page->stamp = 0;
 
         (void)unregister_die_notifier(&xpc_die_notifier);
         (void)unregister_reboot_notifier(&xpc_reboot_notifier);
diff --git a/drivers/misc/sgi-xp/xpc_partition.c b/drivers/misc/sgi-xp/xpc_partition.c
index 4e14effdeddb..90ec5ca8c9ab 100644
--- a/drivers/misc/sgi-xp/xpc_partition.c
+++ b/drivers/misc/sgi-xp/xpc_partition.c
@@ -152,6 +152,7 @@ xpc_setup_rsvd_page(void)
 {
         struct xpc_rsvd_page *rp;
         u64 rp_pa;
+        unsigned long new_stamp;
 
         /* get the local reserved page's address */
 
@@ -201,7 +202,10 @@ xpc_setup_rsvd_page(void)
          * This signifies to the remote partition that our reserved
          * page is initialized.
          */
-        rp->stamp = CURRENT_TIME;
+        new_stamp = jiffies;
+        if (new_stamp == 0 || new_stamp == rp->stamp)
+                new_stamp++;
+        rp->stamp = new_stamp;
 
         return rp;
 }
@@ -350,18 +354,8 @@ xpc_get_remote_rp(int nasid, u64 *discovered_nasids,
                         discovered_nasids[i] |= remote_part_nasids[i];
         }
 
-        /* check that the partid is valid and is for another partition */
-
-        if (remote_rp->SAL_partid < 0 ||
-            remote_rp->SAL_partid >= xp_max_npartitions) {
-                return xpInvalidPartid;
-        }
-
-        if (remote_rp->SAL_partid == sn_partition_id)
-                return xpLocalPartid;
-
-        /* see if the rest of the reserved page has been set up by XPC */
-        if (timespec_equal(&remote_rp->stamp, &ZERO_STAMP))
+        /* see if the reserved page has been set up by XPC */
+        if (remote_rp->stamp == 0)
                 return xpRsvdPageNotSet;
 
         if (XPC_VERSION_MAJOR(remote_rp->version) !=
@@ -369,8 +363,15 @@ xpc_get_remote_rp(int nasid, u64 *discovered_nasids,
                 return xpBadVersion;
         }
 
-        if (remote_rp->max_npartitions <= sn_partition_id)
+        /* check that both local and remote partids are valid for each side */
+        if (remote_rp->SAL_partid < 0 ||
+            remote_rp->SAL_partid >= xp_max_npartitions ||
+            remote_rp->max_npartitions <= sn_partition_id) {
                 return xpInvalidPartid;
+        }
+
+        if (remote_rp->SAL_partid == sn_partition_id)
+                return xpLocalPartid;
 
         return xpSuccess;
 }
@@ -388,8 +389,8 @@ xpc_partition_disengaged(struct xpc_partition *part)
         disengaged = (xpc_partition_engaged(1UL << partid) == 0);
         if (part->disengage_request_timeout) {
                 if (!disengaged) {
-                        if (time_before(jiffies,
-                            part->disengage_request_timeout)) {
+                        if (time_is_after_jiffies(part->
+                                                  disengage_request_timeout)) {
                                 /* timelimit hasn't been reached yet */
                                 return 0;
                         }
diff --git a/drivers/misc/sgi-xp/xpc_sn2.c b/drivers/misc/sgi-xp/xpc_sn2.c
index 89c0bb9a27f5..7216df36bc73 100644
--- a/drivers/misc/sgi-xp/xpc_sn2.c
+++ b/drivers/misc/sgi-xp/xpc_sn2.c
@@ -597,8 +597,8 @@ xpc_initiate_partition_activation_sn2(struct xpc_rsvd_page *remote_rp,
  */
 static void
 xpc_update_partition_info_sn2(struct xpc_partition *part, u8 remote_rp_version,
-                              struct timespec *remote_rp_stamp,
-                              u64 remote_rp_pa, u64 remote_vars_pa,
+                              unsigned long *remote_rp_stamp, u64 remote_rp_pa,
+                              u64 remote_vars_pa,
                               struct xpc_vars_sn2 *remote_vars)
 {
         part->remote_rp_version = remote_rp_version;
@@ -606,8 +606,8 @@ xpc_update_partition_info_sn2(struct xpc_partition *part, u8 remote_rp_version,
                 part->remote_rp_version);
 
         part->remote_rp_stamp = *remote_rp_stamp;
-        dev_dbg(xpc_part, "  remote_rp_stamp (tv_sec = 0x%lx tv_nsec = 0x%lx\n",
-                part->remote_rp_stamp.tv_sec, part->remote_rp_stamp.tv_nsec);
+        dev_dbg(xpc_part, "  remote_rp_stamp = 0x%016lx\n",
+                part->remote_rp_stamp);
 
         part->remote_rp_pa = remote_rp_pa;
         dev_dbg(xpc_part, "  remote_rp_pa = 0x%016lx\n", part->remote_rp_pa);
@@ -664,8 +664,7 @@ xpc_identify_act_IRQ_req_sn2(int nasid)
         u64 remote_vars_pa;
         int remote_rp_version;
         int reactivate = 0;
-        int stamp_diff;
-        struct timespec remote_rp_stamp = { 0, 0 }; /*>>> ZERO_STAMP */
+        unsigned long remote_rp_stamp = 0;
         short partid;
         struct xpc_partition *part;
         enum xp_retval ret;
@@ -788,10 +787,7 @@ xpc_identify_act_IRQ_req_sn2(int nasid)
         } else {
                 DBUG_ON(!XPC_SUPPORTS_DISENGAGE_REQUEST(remote_vars->version));
 
-                stamp_diff = xpc_compare_stamps(&part->remote_rp_stamp,
-                                                &remote_rp_stamp);
-                if (stamp_diff != 0) {
-                        DBUG_ON(stamp_diff >= 0);
+                if (remote_rp_stamp != part->remote_rp_stamp) {
 
                         /*
                          * Other side rebooted and the previous XPC did support