swap: don't do discard if no discard option added

When swapon() was not passed the SWAP_FLAG_DISCARD option, sys_swapon()
will still perform a discard operation.  This can cause problems if
discard is slow or buggy.

Reverse the order of the check so that a discard operation is performed
only if the sys_swapon() caller is attempting to enable discard.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Reported-by: Holger Kiehl <Holger.Kiehl@dwd.de>
Tested-by: Holger Kiehl <Holger.Kiehl@dwd.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Shaohua Li 2012-03-21 16:34:17 -07:00 коммит произвёл Linus Torvalds
Родитель 1480de0340
Коммит 052b1987fa
1 изменённых файлов: 1 добавлений и 1 удалений

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@ -2103,7 +2103,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
p->flags |= SWP_SOLIDSTATE;
p->cluster_next = 1 + (random32() % p->highest_bit);
}
if (discard_swap(p) == 0 && (swap_flags & SWAP_FLAG_DISCARD))
if ((swap_flags & SWAP_FLAG_DISCARD) && discard_swap(p) == 0)
p->flags |= SWP_DISCARDABLE;
}