diff options
author | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-01-17 18:43:02 +0100 |
---|---|---|
committer | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-01-18 13:03:56 +0100 |
commit | a254a0e4093fce8c832414a83940736067eed515 (patch) | |
tree | aa031d332af951e2a787eb8b000f4629a00efcc8 /drivers | |
parent | 248045b8dea5a32ddc0aa44193d6bc70c4b9cd8e (diff) |
random: simplify arithmetic function flow in account()
Now that have_bytes is never modified, we can simplify this function.
First, we move the check for negative entropy_count to be first. That
ensures that subsequent reads of this will be non-negative. Then,
have_bytes and ibytes can be folded into their one use site in the
min_t() function.
Suggested-by: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/char/random.c | 17 |
1 files changed, 6 insertions, 11 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 1f08ce052c54..b411182df6f6 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1293,7 +1293,7 @@ EXPORT_SYMBOL_GPL(add_disk_randomness); */ static size_t account(size_t nbytes, int min) { - int entropy_count, orig, have_bytes; + int entropy_count, orig; size_t ibytes, nfrac; BUG_ON(input_pool.entropy_count > POOL_FRACBITS); @@ -1301,20 +1301,15 @@ static size_t account(size_t nbytes, int min) /* Can we pull enough? */ retry: entropy_count = orig = READ_ONCE(input_pool.entropy_count); - ibytes = nbytes; - /* never pull more than available */ - have_bytes = entropy_count >> (POOL_ENTROPY_SHIFT + 3); - - if (have_bytes < 0) - have_bytes = 0; - ibytes = min_t(size_t, ibytes, have_bytes); - if (ibytes < min) - ibytes = 0; - if (WARN_ON(entropy_count < 0)) { pr_warn("negative entropy count: count %d\n", entropy_count); entropy_count = 0; } + + /* never pull more than available */ + ibytes = min_t(size_t, nbytes, entropy_count >> (POOL_ENTROPY_SHIFT + 3)); + if (ibytes < min) + ibytes = 0; nfrac = ibytes << (POOL_ENTROPY_SHIFT + 3); if ((size_t)entropy_count > nfrac) entropy_count -= nfrac; |