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Optimise OPENSSL_init_crypto

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If everything has already been initialised we can check this with a
single test at the beginning of OPENSSL_init_crypto() and therefore
reduce the amount of time spent in this function. Since this is called
via very many codepaths this should have significant performance benefits.

Partially fixes #13725 and #13578

Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/13733)
This commit is contained in:
Matt Caswell 2020-12-22 17:44:07 +00:00 committed by Dmitry Belyavskiy
parent d5e742de65
commit db6bcc81ab
1 changed files with 38 additions and 0 deletions
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38
crypto/init.c
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@ -34,6 +34,7 @@
#include <openssl/trace.h>
static int stopped = 0;
static uint64_t optsdone = 0;
typedef struct ossl_init_stop_st OPENSSL_INIT_STOP;
struct ossl_init_stop_st {
@ -464,6 +465,28 @@ void OPENSSL_cleanup(void)
*/
int OPENSSL_init_crypto(uint64_t opts, const OPENSSL_INIT_SETTINGS *settings)
{
uint64_t tmp;
int aloaddone = 0;
/*
* We ignore failures from this function. It is probably because we are
* on a platform that doesn't support lockless atomic loads (we may not
* have created init_lock yet so we can't use it). This is just an
* optimisation to skip the full checks in this function if we don't need
* to, so we carry on regardless in the event of failure.
*
* There could be a race here with other threads, so that optsdone has not
* been updated yet, even though the options have in fact been initialised.
* This doesn't matter - it just means we will run the full function
* unnecessarily - but all the critical code is contained in RUN_ONCE
* functions anyway so we are safe.
*/
if (CRYPTO_atomic_load(&optsdone, &tmp, NULL)) {
if ((tmp & opts) == opts)
return 1;
aloaddone = 1;
}
/*
* TODO(3.0): This function needs looking at with a view to moving most/all
* of this into OSSL_LIB_CTX.
@ -492,6 +515,18 @@ int OPENSSL_init_crypto(uint64_t opts, const OPENSSL_INIT_SETTINGS *settings)
if (opts & OPENSSL_INIT_BASE_ONLY)
return 1;
/*
* init_lock should definitely be set up now, so we can now repeat the
* same check from above but be sure that it will work even on platforms
* without lockless CRYPTO_atomic_load
*/
if (!aloaddone) {
if (!CRYPTO_atomic_load(&optsdone, &tmp, init_lock))
return 0;
if ((tmp & opts) == opts)
return 1;
}
/*
* Now we don't always set up exit handlers, the INIT_BASE_ONLY calls
* should not have the side-effect of setting up exit handlers, and
@ -614,6 +649,9 @@ int OPENSSL_init_crypto(uint64_t opts, const OPENSSL_INIT_SETTINGS *settings)
return 0;
#endif
if (!CRYPTO_atomic_or(&optsdone, opts, &tmp, init_lock))
return 0;
return 1;
}