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Message-ID: <alpine.LNX.2.00.1011042212460.15856@swampdragon.chaosbits.net>
Date: Thu, 4 Nov 2010 22:27:42 +0100 (CET)
From: Jesper Juhl <jj@...osbits.net>
To: Evgeniy Polyakov <zbr@...emap.net>
cc: linux-kernel@...r.kernel.org, Greg Kroah-Hartman <gregkh@...e.de>,
Ruslan Pisarev <ruslan@...sarev.org.ua>
Subject: [PATCH] pohmelfs: remove unneeded conditionals before calls to
crypto_destroy_tfm wrappers.
Hi,
crypto_free_hash() and crypto_free_ablkcipher() are just wrappers around
crypto_free_tfm() which is itself just a wrapper around
crypto_destroy_tfm().
Passing crypto_destroy_tfm() a NULL pointer is valid, so there's no reason
to check for NULL first.
Removing the unneeded conditionals (which is what the patch does) brings
us the benefit of having to execute a few fewer test/branch instructions
and also reduces object code size slightly:
before:
text data bss dec hex filename
8630 112 3312 12054 2f16 drivers/staging/pohmelfs/crypto.o
0000000000000cbe <pohmelfs_crypto_engine_exit>:
cbe: 55 push %rbp
cbf: 48 89 e5 mov %rsp,%rbp
cc2: 53 push %rbx
cc3: 48 83 ec 08 sub $0x8,%rsp
cc7: e8 00 00 00 00 callq ccc <pohmelfs_crypto_engine_exit+0xe>
ccc: 48 ff 05 00 00 00 00 incq 0x0(%rip) # cd3 <pohmelfs_crypto_engine_exit+0x15>
cd3: 48 89 fb mov %rdi,%rbx
cd6: 48 8b 7f 20 mov 0x20(%rdi),%rdi
cda: 48 85 ff test %rdi,%rdi
cdd: 74 0c je ceb <pohmelfs_crypto_engine_exit+0x2d>
cdf: 48 ff 05 00 00 00 00 incq 0x0(%rip) # ce6 <pohmelfs_crypto_engine_exit+0x28>
ce6: e8 58 fa ff ff callq 743 <crypto_free_hash>
ceb: 48 8b 7b 28 mov 0x28(%rbx),%rdi
cef: 48 85 ff test %rdi,%rdi
cf2: 75 09 jne cfd <pohmelfs_crypto_engine_exit+0x3f>
cf4: 48 ff 05 00 00 00 00 incq 0x0(%rip) # cfb <pohmelfs_crypto_engine_exit+0x3d>
cfb: eb 16 jmp d13 <pohmelfs_crypto_engine_exit+0x55>
cfd: 48 89 fe mov %rdi,%rsi
d00: 48 ff 05 00 00 00 00 incq 0x0(%rip) # d07 <pohmelfs_crypto_engine_exit+0x49>
d07: e8 00 00 00 00 callq d0c <pohmelfs_crypto_engine_exit+0x4e>
d0c: 48 ff 05 00 00 00 00 incq 0x0(%rip) # d13 <pohmelfs_crypto_engine_exit+0x55>
d13: 48 8b 7b 18 mov 0x18(%rbx),%rdi
d17: e8 00 00 00 00 callq d1c <pohmelfs_crypto_engine_exit+0x5e>
d1c: 48 ff 05 00 00 00 00 incq 0x0(%rip) # d23 <pohmelfs_crypto_engine_exit+0x65>
d23: 5e pop %rsi
d24: 5b pop %rbx
d25: c9 leaveq
d26: c3 retq
after:
text data bss dec hex filename
8604 112 3296 12012 2eec drivers/staging/pohmelfs/crypto.o
0000000000000cbe <pohmelfs_crypto_engine_exit>:
cbe: 55 push %rbp
cbf: 48 89 e5 mov %rsp,%rbp
cc2: 53 push %rbx
cc3: 48 83 ec 08 sub $0x8,%rsp
cc7: e8 00 00 00 00 callq ccc <pohmelfs_crypto_engine_exit+0xe>
ccc: 48 ff 05 00 00 00 00 incq 0x0(%rip) # cd3 <pohmelfs_crypto_engine_exit+0x15>
cd3: 48 89 fb mov %rdi,%rbx
cd6: 48 8b 7f 20 mov 0x20(%rdi),%rdi
cda: e8 64 fa ff ff callq 743 <crypto_free_hash>
cdf: 48 8b 7b 28 mov 0x28(%rbx),%rdi
ce3: 48 ff 05 00 00 00 00 incq 0x0(%rip) # cea <pohmelfs_crypto_engine_exit+0x2c>
cea: 48 89 fe mov %rdi,%rsi
ced: e8 00 00 00 00 callq cf2 <pohmelfs_crypto_engine_exit+0x34>
cf2: 48 8b 7b 18 mov 0x18(%rbx),%rdi
cf6: 48 ff 05 00 00 00 00 incq 0x0(%rip) # cfd <pohmelfs_crypto_engine_exit+0x3f>
cfd: e8 00 00 00 00 callq d02 <pohmelfs_crypto_engine_exit+0x44>
d02: 48 ff 05 00 00 00 00 incq 0x0(%rip) # d09 <pohmelfs_crypto_engine_exit+0x4b>
d09: 5e pop %rsi
d0a: 5b pop %rbx
d0b: c9 leaveq
d0c: c3 retq
Signed-off-by: Jesper Juhl <jj@...osbits.net>
---
crypto.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/staging/pohmelfs/crypto.c b/drivers/staging/pohmelfs/crypto.c
index 2fdb3e0..6540864 100644
--- a/drivers/staging/pohmelfs/crypto.c
+++ b/drivers/staging/pohmelfs/crypto.c
@@ -130,10 +130,8 @@ err_out_exit:
void pohmelfs_crypto_engine_exit(struct pohmelfs_crypto_engine *e)
{
- if (e->hash)
- crypto_free_hash(e->hash);
- if (e->cipher)
- crypto_free_ablkcipher(e->cipher);
+ crypto_free_hash(e->hash);
+ crypto_free_ablkcipher(e->cipher);
kfree(e->data);
}
--
Jesper Juhl <jj@...osbits.net> http://www.chaosbits.net/
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