This logic is exactly equivalent to the old logic, but it should be easier to see what it's doing.
The equivalence depends on one fact from outside this function: when 'r->limit' is false, 'reserved' is zero. (Well, two facts; the other is that 'reserved' is never negative.) Cc: "Theodore Ts'o" <[email protected]> Cc: Jiri Kosina <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Signed-off-by: Greg Price <[email protected]> --- drivers/char/random.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index fe7ecdd..5dffca8 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -988,14 +988,10 @@ retry: ibytes = 0; } else { /* If limited, never pull more than available */ - if (r->limit && ibytes + reserved >= have_bytes) - ibytes = have_bytes - reserved; - - if (have_bytes >= ibytes + reserved) - entropy_count -= ibytes << (ENTROPY_SHIFT + 3); - else - entropy_count = reserved << (ENTROPY_SHIFT + 3); - + if (r->limit) + ibytes = min_t(size_t, ibytes, have_bytes - reserved); + entropy_count = max_t(int, 0, + entropy_count - (ibytes << (ENTROPY_SHIFT + 3))); if (cmpxchg(&r->entropy_count, orig, entropy_count) != orig) goto retry; -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
