Re: [PATCH v3 06/16] rbd: convert timeouts to secs_to_jiffies()

[Christophe JAILLET]

Le 25/02/2025 à 21:17, Easwar Hariharan a écrit :
Commit b35108a51cf7 ("jiffies: Define secs_to_jiffies()") introduced
secs_to_jiffies().  As the value here is a multiple of 1000, use
secs_to_jiffies() instead of msecs_to_jiffies() to avoid the multiplication
This is converted using scripts/coccinelle/misc/secs_to_jiffies.cocci with
the following Coccinelle rules:

@depends on patch@ expression E; @@

-msecs_to_jiffies(E * 1000)
+secs_to_jiffies(E)

@depends on patch@ expression E; @@

-msecs_to_jiffies(E * MSEC_PER_SEC)
+secs_to_jiffies(E)

While here, remove the no-longer necessary check for range since there's
no multiplication involved.

I'm not sure this is correct.
Now you multiply by HZ and things can still overflow.


Hoping I got casting right:

#define MSEC_PER_SEC    1000L
#define HZ 100


#define secs_to_jiffies(_secs) (unsigned long)((_secs) * HZ)

static inline unsigned long _msecs_to_jiffies(const unsigned int m)
{
        return (m + (MSEC_PER_SEC / HZ) - 1) / (MSEC_PER_SEC / HZ);
}

int main() {

        int n = INT_MAX - 5;

        printf("res  = %ld\n", secs_to_jiffies(n));
        printf("res  = %ld\n", _msecs_to_jiffies(1000 * n));

        return 0;
}


gives :

res  = -600
res  = 429496130

with msec, the previous code would catch the overflow, now it overflows 
silently.

untested, but maybe:
        if (result.uint_32 > INT_MAX / HZ)
                goto out_of_range;

?

CJ



Acked-by: Ilya Dryomov <idryomov-re5jqeeqqe8avxtiumw...@public.gmane.org>
Signed-off-by: Easwar Hariharan 
<eahariha-1pm0nblsjy7jp67uh1nahkeocmrvl...@public.gmane.org>
---
  drivers/block/rbd.c | 8 +++-----
  1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 
faafd7ff43d6ef53110ab3663cc7ac322214cc8c..41207133e21e9203192adf3b92390818e8fa5a58
 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -108,7 +108,7 @@ static int atomic_dec_return_safe(atomic_t *v)
  #define RBD_OBJ_PREFIX_LEN_MAX        64
  
  #define RBD_NOTIFY_TIMEOUT	5	/* seconds */
-#define RBD_RETRY_DELAY                msecs_to_jiffies(1000)
+#define RBD_RETRY_DELAY                secs_to_jiffies(1)
  
  /* Feature bits */
  
@@ -4162,7 +4162,7 @@ static void rbd_acquire_lock(struct work_struct *work)
                dout("%s rbd_dev %p requeuing lock_dwork\n", __func__,
                     rbd_dev);
                mod_delayed_work(rbd_dev->task_wq, &rbd_dev->lock_dwork,
-                   msecs_to_jiffies(2 * RBD_NOTIFY_TIMEOUT * MSEC_PER_SEC));
+                   secs_to_jiffies(2 * RBD_NOTIFY_TIMEOUT));
        }
  }
  
@@ -6283,9 +6283,7 @@ static int rbd_parse_param(struct fs_parameter *param,
                break;
        case Opt_lock_timeout:
                /* 0 is "wait forever" (i.e. infinite timeout) */
-               if (result.uint_32 > INT_MAX / 1000)
-                       goto out_of_range;
-               opt->lock_timeout = msecs_to_jiffies(result.uint_32 * 1000);
+               opt->lock_timeout = secs_to_jiffies(result.uint_32);
                break;
        case Opt_pool_ns:
                kfree(pctx->spec->pool_ns);