[PATCH] crypto: ccp - avoid uninitialized variable warning

From: Arnd Bergmann
Date: Mon Jul 31 2017 - 16:50:05 EST


The added support for version 5 CCPs introduced a false-positive
warning in the RSA implementation:

drivers/crypto/ccp/ccp-ops.c: In function 'ccp_run_rsa_cmd':
drivers/crypto/ccp/ccp-ops.c:1856:3: error: 'sb_count' may be used uninitialized in this function [-Werror=maybe-uninitialized]

This changes the code in a way that should make it easier for
the compiler to track the state of the sb_count variable, and
avoid the warning.

Fixes: 6ba46c7d4d7e ("crypto: ccp - Fix base RSA function for version 5 CCPs")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/crypto/ccp/ccp-ops.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/crypto/ccp/ccp-ops.c b/drivers/crypto/ccp/ccp-ops.c
index 40c062ad8726..a8bc207b099a 100644
--- a/drivers/crypto/ccp/ccp-ops.c
+++ b/drivers/crypto/ccp/ccp-ops.c
@@ -1758,6 +1758,7 @@ static int ccp_run_rsa_cmd(struct ccp_cmd_queue *cmd_q, struct ccp_cmd *cmd)
o_len = 32 * ((rsa->key_size + 255) / 256);
i_len = o_len * 2;

+ sb_count = 0;
if (cmd_q->ccp->vdata->version < CCP_VERSION(5, 0)) {
/* sb_count is the number of storage block slots required
* for the modulus.
@@ -1852,7 +1853,7 @@ static int ccp_run_rsa_cmd(struct ccp_cmd_queue *cmd_q, struct ccp_cmd *cmd)
ccp_dm_free(&exp);

e_sb:
- if (cmd_q->ccp->vdata->version < CCP_VERSION(5, 0))
+ if (sb_count)
cmd_q->ccp->vdata->perform->sbfree(cmd_q, op.sb_key, sb_count);

return ret;
--
2.9.0