tpm/tpm_ppi: Do not compare strcmp(a,b) == -1

Depending on the implementation strcmp might return the difference between
two strings not only -1,0,1 consequently
 if (strcmp (a,b) == -1)
might lead to taking the wrong branch

-> compare with < 0  instead,
which in any case is more canonical.

Cc: stable@vger.kernel.org
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/char/tpm/tpm_ppi.c b/drivers/char/tpm/tpm_ppi.c
index 8e562dc65601..18c5810b646b 100644
--- a/drivers/char/tpm/tpm_ppi.c
+++ b/drivers/char/tpm/tpm_ppi.c
@@ -169,7 +169,7 @@ static ssize_t tpm_store_ppi_request(struct device *dev,
          * is updated with function index from SUBREQ to SUBREQ2 since PPI
          * version 1.1
          */
-        if (strcmp(version, "1.1") == -1)
+        if (strcmp(version, "1.1") < 0)
                 params[2].integer.value = TPM_PPI_FN_SUBREQ;
         else
                 params[2].integer.value = TPM_PPI_FN_SUBREQ2;
@@ -179,7 +179,7 @@ static ssize_t tpm_store_ppi_request(struct device *dev,
          * string/package type. For PPI version 1.0 and 1.1, use buffer type
          * for compatibility, and use package type since 1.2 according to spec.
          */
-        if (strcmp(version, "1.2") == -1) {
+        if (strcmp(version, "1.2") < 0) {
                 params[3].type = ACPI_TYPE_BUFFER;
                 params[3].buffer.length = sizeof(req);
                 sscanf(buf, "%d", &req);
@@ -245,7 +245,7 @@ static ssize_t tpm_show_ppi_transition_action(struct device *dev,
          * (e.g. Capella with PPI 1.0) need integer/string/buffer type, so for
          * compatibility, define params[3].type as buffer, if PPI version < 1.2
          */
-        if (strcmp(version, "1.2") == -1) {
+        if (strcmp(version, "1.2") < 0) {
                 params[3].type = ACPI_TYPE_BUFFER;
                 params[3].buffer.length =  0;
                 params[3].buffer.pointer = NULL;
@@ -387,7 +387,7 @@ static ssize_t show_ppi_operations(char *buf, u32 start, u32 end)
         kfree(output.pointer);
         output.length = ACPI_ALLOCATE_BUFFER;
         output.pointer = NULL;
-        if (strcmp(version, "1.2") == -1)
+        if (strcmp(version, "1.2") < 0)
                 return -EPERM;
 
         params[2].integer.value = TPM_PPI_FN_GETOPR;