'struct frame' uses two variables to store the sent timestamp - 'struct
timeval' and jiffies. jiffies is used to avoid discrepancies caused by
updates to system time. 'struct timeval' uses 32-bit representation for
seconds which will overflow in year 2038.
This patch does the following:
- Replace the use of 'struct timeval' and jiffies with ktime_t, which
is a 64-bit timestamp and is year 2038 safe.
- ktime_t provides both long range (like jiffies) and high resolution
(like timeval). Using ktime_get (monotonic time) instead of wall-clock
time prevents any discprepancies caused by updates to system time.
Signed-off-by: Tina Ruchandani <ruchandani.t...@gmail.com>
---
drivers/block/aoe/aoe.h | 3 +--
drivers/block/aoe/aoecmd.c | 36 +++++++-----------------------------
2 files changed, 8 insertions(+), 31 deletions(-)
diff --git a/drivers/block/aoe/aoe.h b/drivers/block/aoe/aoe.h
index 9220f8e..4582b3c 100644
--- a/drivers/block/aoe/aoe.h
+++ b/drivers/block/aoe/aoe.h
@@ -112,8 +112,7 @@ enum frame_flags {
struct frame {
struct list_head head;
u32 tag;
- struct timeval sent; /* high-res time packet was sent */
- u32 sent_jiffs; /* low-res jiffies-based sent time */
+ ktime_t sent;
ulong waited;
ulong waited_total;
struct aoetgt *t; /* parent target I belong to */
diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
index 422b7d8..7f78780 100644
--- a/drivers/block/aoe/aoecmd.c
+++ b/drivers/block/aoe/aoecmd.c
@@ -398,8 +398,7 @@ aoecmd_ata_rw(struct aoedev *d)
skb = skb_clone(f->skb, GFP_ATOMIC);
if (skb) {
- do_gettimeofday(&f->sent);
- f->sent_jiffs = (u32) jiffies;
+ f->sent = ktime_get();
__skb_queue_head_init(&queue);
__skb_queue_tail(&queue, skb);
aoenet_xmit(&queue);
@@ -489,8 +488,7 @@ resend(struct aoedev *d, struct frame *f)
skb = skb_clone(skb, GFP_ATOMIC);
if (skb == NULL)
return;
- do_gettimeofday(&f->sent);
- f->sent_jiffs = (u32) jiffies;
+ f->sent = ktime_get();
__skb_queue_head_init(&queue);
__skb_queue_tail(&queue, skb);
aoenet_xmit(&queue);
@@ -499,32 +497,15 @@ resend(struct aoedev *d, struct frame *f)
static int
tsince_hr(struct frame *f)
{
- struct timeval now;
+ ktime_t now;
int n;
- do_gettimeofday(&now);
- n = now.tv_usec - f->sent.tv_usec;
- n += (now.tv_sec - f->sent.tv_sec) * USEC_PER_SEC;
+ now = ktime_get();
+ n = ktime_to_us(ktime_sub(now, f->sent));
if (n < 0)
n = -n;
- /* For relatively long periods, use jiffies to avoid
- * discrepancies caused by updates to the system time.
- *
- * On system with HZ of 1000, 32-bits is over 49 days
- * worth of jiffies, or over 71 minutes worth of usecs.
- *
- * Jiffies overflow is handled by subtraction of unsigned ints:
- * (gdb) print (unsigned) 2 - (unsigned) 0xfffffffe
- * $3 = 4
- * (gdb)
- */
- if (n > USEC_PER_SEC / 4) {
- n = ((u32) jiffies) - f->sent_jiffs;
- n *= USEC_PER_SEC / HZ;
- }
-
return n;
}
@@ -589,7 +570,6 @@ reassign_frame(struct frame *f)
nf->waited = 0;
nf->waited_total = f->waited_total;
nf->sent = f->sent;
- nf->sent_jiffs = f->sent_jiffs;
f->skb = skb;
return nf;
@@ -633,8 +613,7 @@ probe(struct aoetgt *t)
skb = skb_clone(f->skb, GFP_ATOMIC);
if (skb) {
- do_gettimeofday(&f->sent);
- f->sent_jiffs = (u32) jiffies;
+ f->sent = ktime_get();
__skb_queue_head_init(&queue);
__skb_queue_tail(&queue, skb);
aoenet_xmit(&queue);
@@ -1474,8 +1453,7 @@ aoecmd_ata_id(struct aoedev *d)
skb = skb_clone(skb, GFP_ATOMIC);
if (skb) {
- do_gettimeofday(&f->sent);
- f->sent_jiffs = (u32) jiffies;
+ f->sent = ktime_get();
}
return skb;
--
2.2.0.rc0.207.ga3a616c
--
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