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authorJason A. Donenfeld <Jason@zx2c4.com>2022-03-01 15:14:04 +0100
committerJason A. Donenfeld <Jason@zx2c4.com>2022-03-12 18:00:56 -0700
commita4107d34f960df99ca07fa8eb022425a804f59f3 (patch)
tree2e13e4c5cf1ef5cb52b27a992ac3fb35acf33fd5 /include/linux/random.h
parentaf6b54e2b5baa54c844573b6d49cc91157bcdd7e (diff)
random: do not export add_vmfork_randomness() unless needed
Since add_vmfork_randomness() is only called from vmgenid.o, we can guard it in CONFIG_VMGENID, similarly to how we do with add_disk_randomness() and CONFIG_BLOCK. If we ever have multiple things calling into add_vmfork_randomness(), we can add another shared Kconfig symbol for that, but for now, this is good enough. Even though add_vmfork_randomess() is a pretty small function, removing it means that there are only calls to crng_reseed(false) and none to crng_reseed(true), which means the compiler can constant propagate the false, removing branches from crng_reseed() and its descendants. Additionally, we don't even need the symbol to be exported if CONFIG_VMGENID is not a module, so conditionalize that too. Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'include/linux/random.h')
-rw-r--r--include/linux/random.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/random.h b/include/linux/random.h
index 117468f3a92e..f209f1a78899 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -34,7 +34,9 @@ extern void add_input_randomness(unsigned int type, unsigned int code,
extern void add_interrupt_randomness(int irq) __latent_entropy;
extern void add_hwgenerator_randomness(const void *buffer, size_t count,
size_t entropy);
+#if IS_ENABLED(CONFIG_VMGENID)
extern void add_vmfork_randomness(const void *unique_vm_id, size_t size);
+#endif
extern void get_random_bytes(void *buf, size_t nbytes);
extern int wait_for_random_bytes(void);