From: Thorsten Winkler <twinkler@xxxxxxxxxxxxx> This LWN article explains the why scnprintf is preferred over snprintf in general https://lwn.net/Articles/69419/ Ie. snprintf() returns what *would* be the resulting length, while scnprintf() returns the actual length. Note that ctcm_print_statistics() writes the data into the kernel log and is therefore not suitable for sysfs_emit(). Observable behavior is not changed, as there may be dependencies. Reviewed-by: Alexandra Winter <wintera@xxxxxxxxxxxxx> Signed-off-by: Thorsten Winkler <twinkler@xxxxxxxxxxxxx> Signed-off-by: Alexandra Winter <wintera@xxxxxxxxxxxxx> --- drivers/s390/net/ctcm_dbug.c | 2 +- drivers/s390/net/ctcm_main.c | 6 +++--- drivers/s390/net/ctcm_main.h | 1 + drivers/s390/net/ctcm_mpc.c | 18 ++++++++++-------- drivers/s390/net/ctcm_sysfs.c | 36 +++++++++++++++++------------------ 5 files changed, 33 insertions(+), 30 deletions(-) diff --git a/drivers/s390/net/ctcm_dbug.c b/drivers/s390/net/ctcm_dbug.c index f7ec51db3cd6..b6f0e2f114b4 100644 --- a/drivers/s390/net/ctcm_dbug.c +++ b/drivers/s390/net/ctcm_dbug.c @@ -70,7 +70,7 @@ void ctcm_dbf_longtext(enum ctcm_dbf_names dbf_nix, int level, char *fmt, ...) if (!debug_level_enabled(ctcm_dbf[dbf_nix].id, level)) return; va_start(args, fmt); - vsnprintf(dbf_txt_buf, sizeof(dbf_txt_buf), fmt, args); + vscnprintf(dbf_txt_buf, sizeof(dbf_txt_buf), fmt, args); va_end(args); debug_text_event(ctcm_dbf[dbf_nix].id, level, dbf_txt_buf); diff --git a/drivers/s390/net/ctcm_main.c b/drivers/s390/net/ctcm_main.c index e0fdd54bfeb7..79fac5314e67 100644 --- a/drivers/s390/net/ctcm_main.c +++ b/drivers/s390/net/ctcm_main.c @@ -1340,7 +1340,7 @@ static int add_channel(struct ccw_device *cdev, enum ctcm_channel_types type, goto nomem_return; ch->cdev = cdev; - snprintf(ch->id, CTCM_ID_SIZE, "ch-%s", dev_name(&cdev->dev)); + scnprintf(ch->id, CTCM_ID_SIZE, "ch-%s", dev_name(&cdev->dev)); ch->type = type; /* @@ -1505,8 +1505,8 @@ static int ctcm_new_device(struct ccwgroup_device *cgdev) type = get_channel_type(&cdev0->id); - snprintf(read_id, CTCM_ID_SIZE, "ch-%s", dev_name(&cdev0->dev)); - snprintf(write_id, CTCM_ID_SIZE, "ch-%s", dev_name(&cdev1->dev)); + scnprintf(read_id, CTCM_ID_SIZE, "ch-%s", dev_name(&cdev0->dev)); + scnprintf(write_id, CTCM_ID_SIZE, "ch-%s", dev_name(&cdev1->dev)); ret = add_channel(cdev0, type, priv); if (ret) { diff --git a/drivers/s390/net/ctcm_main.h b/drivers/s390/net/ctcm_main.h index 90bd7b3f80c3..25164e8bf13d 100644 --- a/drivers/s390/net/ctcm_main.h +++ b/drivers/s390/net/ctcm_main.h @@ -100,6 +100,7 @@ enum ctcm_channel_types { #define CTCM_PROTO_MPC 4 #define CTCM_PROTO_MAX 4 +#define CTCM_STATSIZE_LIMIT 64 #define CTCM_BUFSIZE_LIMIT 65535 #define CTCM_BUFSIZE_DEFAULT 32768 #define MPC_BUFSIZE_DEFAULT CTCM_BUFSIZE_LIMIT diff --git a/drivers/s390/net/ctcm_mpc.c b/drivers/s390/net/ctcm_mpc.c index 8ac213a55141..64996c86defc 100644 --- a/drivers/s390/net/ctcm_mpc.c +++ b/drivers/s390/net/ctcm_mpc.c @@ -144,9 +144,9 @@ void ctcmpc_dumpit(char *buf, int len) for (ct = 0; ct < len; ct++, ptr++, rptr++) { if (sw == 0) { - sprintf(addr, "%16.16llx", (__u64)rptr); + scnprintf(addr, sizeof(addr), "%16.16llx", (__u64)rptr); - sprintf(boff, "%4.4X", (__u32)ct); + scnprintf(boff, sizeof(boff), "%4.4X", (__u32)ct); bhex[0] = '\0'; basc[0] = '\0'; } @@ -155,7 +155,7 @@ void ctcmpc_dumpit(char *buf, int len) if (sw == 8) strcat(bhex, " "); - sprintf(tbuf, "%2.2llX", (__u64)*ptr); + scnprintf(tbuf, sizeof(tbuf), "%2.2llX", (__u64)*ptr); tbuf[2] = '\0'; strcat(bhex, tbuf); @@ -171,8 +171,8 @@ void ctcmpc_dumpit(char *buf, int len) continue; if ((strcmp(duphex, bhex)) != 0) { if (dup != 0) { - sprintf(tdup, - "Duplicate as above to %s", addr); + scnprintf(tdup, sizeof(tdup), + "Duplicate as above to %s", addr); ctcm_pr_debug(" --- %s ---\n", tdup); } @@ -197,14 +197,16 @@ void ctcmpc_dumpit(char *buf, int len) strcat(basc, " "); } if (dup != 0) { - sprintf(tdup, "Duplicate as above to %s", addr); + scnprintf(tdup, sizeof(tdup), + "Duplicate as above to %s", addr); ctcm_pr_debug(" --- %s ---\n", tdup); } ctcm_pr_debug(" %s (+%s) : %s [%s]\n", addr, boff, bhex, basc); } else { if (dup >= 1) { - sprintf(tdup, "Duplicate as above to %s", addr); + scnprintf(tdup, sizeof(tdup), + "Duplicate as above to %s", addr); ctcm_pr_debug(" --- %s ---\n", tdup); } if (dup != 0) { @@ -291,7 +293,7 @@ static struct net_device *ctcmpc_get_dev(int port_num) struct net_device *dev; struct ctcm_priv *priv; - sprintf(device, "%s%i", MPC_DEVICE_NAME, port_num); + scnprintf(device, sizeof(device), "%s%i", MPC_DEVICE_NAME, port_num); dev = __dev_get_by_name(&init_net, device); diff --git a/drivers/s390/net/ctcm_sysfs.c b/drivers/s390/net/ctcm_sysfs.c index 98680c2cc4e4..0c5d8a3eaa2e 100644 --- a/drivers/s390/net/ctcm_sysfs.c +++ b/drivers/s390/net/ctcm_sysfs.c @@ -86,24 +86,24 @@ static void ctcm_print_statistics(struct ctcm_priv *priv) return; p = sbuf; - p += sprintf(p, " Device FSM state: %s\n", - fsm_getstate_str(priv->fsm)); - p += sprintf(p, " RX channel FSM state: %s\n", - fsm_getstate_str(priv->channel[CTCM_READ]->fsm)); - p += sprintf(p, " TX channel FSM state: %s\n", - fsm_getstate_str(priv->channel[CTCM_WRITE]->fsm)); - p += sprintf(p, " Max. TX buffer used: %ld\n", - priv->channel[WRITE]->prof.maxmulti); - p += sprintf(p, " Max. chained SKBs: %ld\n", - priv->channel[WRITE]->prof.maxcqueue); - p += sprintf(p, " TX single write ops: %ld\n", - priv->channel[WRITE]->prof.doios_single); - p += sprintf(p, " TX multi write ops: %ld\n", - priv->channel[WRITE]->prof.doios_multi); - p += sprintf(p, " Netto bytes written: %ld\n", - priv->channel[WRITE]->prof.txlen); - p += sprintf(p, " Max. TX IO-time: %u\n", - jiffies_to_usecs(priv->channel[WRITE]->prof.tx_time)); + p += scnprintf(p, CTCM_STATSIZE_LIMIT, " Device FSM state: %s\n", + fsm_getstate_str(priv->fsm)); + p += scnprintf(p, CTCM_STATSIZE_LIMIT, " RX channel FSM state: %s\n", + fsm_getstate_str(priv->channel[CTCM_READ]->fsm)); + p += scnprintf(p, CTCM_STATSIZE_LIMIT, " TX channel FSM state: %s\n", + fsm_getstate_str(priv->channel[CTCM_WRITE]->fsm)); + p += scnprintf(p, CTCM_STATSIZE_LIMIT, " Max. TX buffer used: %ld\n", + priv->channel[WRITE]->prof.maxmulti); + p += scnprintf(p, CTCM_STATSIZE_LIMIT, " Max. chained SKBs: %ld\n", + priv->channel[WRITE]->prof.maxcqueue); + p += scnprintf(p, CTCM_STATSIZE_LIMIT, " TX single write ops: %ld\n", + priv->channel[WRITE]->prof.doios_single); + p += scnprintf(p, CTCM_STATSIZE_LIMIT, " TX multi write ops: %ld\n", + priv->channel[WRITE]->prof.doios_multi); + p += scnprintf(p, CTCM_STATSIZE_LIMIT, " Netto bytes written: %ld\n", + priv->channel[WRITE]->prof.txlen); + p += scnprintf(p, CTCM_STATSIZE_LIMIT, " Max. TX IO-time: %u\n", + jiffies_to_usecs(priv->channel[WRITE]->prof.tx_time)); printk(KERN_INFO "Statistics for %s:\n%s", priv->channel[CTCM_WRITE]->netdev->name, sbuf); -- 2.39.2
