bnx2: Refine VPD logic.

- Replace magic values with constants
- Simplify length calculation and fix a bug

Based on valuable feedback from Ben Hutchings <bhutchings@solarflare.com>

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 21 insertions, 28 deletions

diff --git a/drivers/net/bnx2.c b/drivers/net/bnx2.c
index cf4322d01823..4bfc80812926 100644
--- a/drivers/net/bnx2.c
+++ b/drivers/net/bnx2.c
@@ -7730,24 +7730,27 @@ bnx2_read_vpd_fw_ver(struct bnx2 *bp)
         u8 *v0_str = NULL;
         bool mn_match = false;
 
+#define BNX2_VPD_NVRAM_OFFSET   0x300
+#define BNX2_VPD_LEN            128
 #define BNX2_MAX_VER_SLEN       30
 
         data = kmalloc(256, GFP_KERNEL);
         if (!data)
                 return;
 
-        rc = bnx2_nvram_read(bp, 0x300, data + 128, 128);
+        rc = bnx2_nvram_read(bp, BNX2_VPD_NVRAM_OFFSET, data + BNX2_VPD_LEN,
+                             BNX2_VPD_LEN);
         if (rc)
                 goto vpd_done;
 
-        for (i = 0; i < 128; i += 4) {
-                data[i] = data[i + 131];
-                data[i + 1] = data[i + 130];
-                data[i + 2] = data[i + 129];
-                data[i + 3] = data[i + 128];
+        for (i = 0; i < BNX2_VPD_LEN; i += 4) {
+                data[i] = data[i + BNX2_VPD_LEN + 3];
+                data[i + 1] = data[i + BNX2_VPD_LEN + 2];
+                data[i + 2] = data[i + BNX2_VPD_LEN + 1];
+                data[i + 3] = data[i + BNX2_VPD_LEN];
         }
 
-        for (i = 0; i < 128; ) {
+        for (i = 0; i <= BNX2_VPD_LEN - 3; ) {
                 unsigned char val = data[i];
                 unsigned int block_end;
 
@@ -7762,39 +7765,29 @@ bnx2_read_vpd_fw_ver(struct bnx2 *bp)
                 block_end = (i + 3 + (data[i + 1] + (data[i + 2] << 8)));
                 i += 3;
 
-                if (block_end > 128)
+                if (block_end > BNX2_VPD_LEN)
                         goto vpd_done;
 
                 while (i < (block_end - 2)) {
-                        if (data[i] == 'M' && data[i + 1] == 'N') {
-                                int mn_len = data[i + 2];
+                        int len = data[i + 2];
 
-                                if (mn_len != 4)
-                                        goto vpd_done;
+                        if (i + 3 + len > block_end)
+                                goto vpd_done;
 
-                                i += 3;
-                                if (memcmp(&data[i], "1028", 4))
+                        if (data[i] == 'M' && data[i + 1] == 'N') {
+                                if (len != 4 ||
+                                    memcmp(&data[i + 3], "1028", 4))
                                         goto vpd_done;
                                 mn_match = true;
-                                i += 4;
 
                         } else if (data[i] == 'V' && data[i + 1] == '0') {
-                                v0_len = data[i + 2];
-
-                                i += 3;
-                                if (v0_len > BNX2_MAX_VER_SLEN ||
-                                    (v0_len + i) > 128)
+                                if (len > BNX2_MAX_VER_SLEN)
                                         goto vpd_done;
 
-                                if (v0_len > BNX2_MAX_VER_SLEN)
-                                        v0_len = BNX2_MAX_VER_SLEN;
-
-                                v0_str = &data[i];
-                                i += data[i + 2];
-
-                        } else {
-                                i += 3 + data[i + 2];
+                                v0_len = len;
+                                v0_str = &data[i + 3];
                         }
+                        i += 3 + len;
 
                         if (mn_match && v0_str) {
                                 memcpy(bp->fw_version, v0_str, v0_len);