[PATCH 04/10] scsi: aacraid: linit: Remove snprintf() from sysfs call-backs and replace with sysfs_emit()

Lee Jones
2024-02-08T08:45:29Z

Since snprintf() has the documented, but still rather strange trait of
returning the length of the data that *would have been* written to the
array if space were available, rather than the arguably more useful
length of data *actually* written, it is usually considered wise to use
something else instead in order to avoid confusion.

In the case of sysfs call-backs, new wrappers exist that do just that.

Link: https://lwn.net/Articles/69419/
Link: https://github.com/KSPP/linux/issues/105
Signed-off-by: Lee Jones <lee@kernel.org>
---
Cc: Adaptec OEM Raid Solutions <aacraid@microsemi.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: "PMC-Sierra, Inc" <aacraid@pmc-sierra.com>
Cc: linux-scsi@vger.kernel.org
---
drivers/scsi/aacraid/linit.c | 34 ++++++++++++++--------------------
1 file changed, 14 insertions(+), 20 deletions(-)

diff --git a/drivers/scsi/aacraid/linit.c b/drivers/scsi/aacraid/linit.c
index 68f4dbcfff492..69526e2bd2e78 100644
--- a/drivers/scsi/aacraid/linit.c
+++ b/drivers/scsi/aacraid/linit.c
@@ -558,11 +558,9 @@ static ssize_t aac_show_raid_level(struct device *dev, struct device_attribute *
struct scsi_device *sdev = to_scsi_device(dev);
struct aac_dev *aac = (struct aac_dev *)(sdev->host->hostdata);
if (sdev_channel(sdev) != CONTAINER_CHANNEL)
- return snprintf(buf, PAGE_SIZE, sdev->no_uld_attach
- ? "Hidden\n" :
+ return sysfs_emit(buf, sdev->no_uld_attach ? "Hidden\n" :
((aac->jbod && (sdev->type == TYPE_DISK)) ? "JBOD\n" : ""));
- return snprintf(buf, PAGE_SIZE, "%s\n",
- get_container_type(aac->fsa_dev[sdev_id(sdev)].type));
+ return sysfs_emit(buf, "%s\n", get_container_type(aac->fsa_dev[sdev_id(sdev)].type));
}

static struct device_attribute aac_raid_level_attr = {
@@ -1195,10 +1193,9 @@ static ssize_t aac_show_model(struct device *device,
++cp;
while (*cp == ' ')
++cp;
- len = snprintf(buf, PAGE_SIZE, "%s\n", cp);
+ len = sysfs_emit(buf, "%s\n", cp);
} else
- len = snprintf(buf, PAGE_SIZE, "%s\n",
- aac_drivers[dev->cardtype].model);
+ len = sysfs_emit(buf, "%s\n", aac_drivers[dev->cardtype].model);
return len;
}

@@ -1214,12 +1211,11 @@ static ssize_t aac_show_vendor(struct device *device,
char *cp = sup_adap_info->adapter_type_text;
while (*cp && *cp != ' ')
++cp;
- len = snprintf(buf, PAGE_SIZE, "%.*s\n",
+ len = sysfs_emit(buf, "%.*s\n",
(int)(cp - (char *)sup_adap_info->adapter_type_text),
sup_adap_info->adapter_type_text);
} else
- len = snprintf(buf, PAGE_SIZE, "%s\n",
- aac_drivers[dev->cardtype].vname);
+ len = sysfs_emit(buf, "%s\n", aac_drivers[dev->cardtype].vname);
return len;
}

@@ -1230,7 +1226,7 @@ static ssize_t aac_show_flags(struct device *cdev,
struct aac_dev *dev = (struct aac_dev*)class_to_shost(cdev)->hostdata;

if (nblank(dprintk(x)))
- len = snprintf(buf, PAGE_SIZE, "dprintk\n");
+ len = sysfs_emit(buf, "dprintk\n");
#ifdef AAC_DETAILED_STATUS_INFO
len += scnprintf(buf + len, PAGE_SIZE - len,
"AAC_DETAILED_STATUS_INFO\n");
@@ -1258,7 +1254,7 @@ static ssize_t aac_show_kernel_version(struct device *device,
int len, tmp;

tmp = le32_to_cpu(dev->adapter_info.kernelrev);
- len = snprintf(buf, PAGE_SIZE, "%d.%d-%d[%d]\n",
+ len = sysfs_emit(buf, "%d.%d-%d[%d]\n",
tmp >> 24, (tmp >> 16) & 0xff, tmp & 0xff,
le32_to_cpu(dev->adapter_info.kernelbuild));
return len;
@@ -1272,7 +1268,7 @@ static ssize_t aac_show_monitor_version(struct device *device,
int len, tmp;

tmp = le32_to_cpu(dev->adapter_info.monitorrev);
- len = snprintf(buf, PAGE_SIZE, "%d.%d-%d[%d]\n",
+ len = sysfs_emit(buf, "%d.%d-%d[%d]\n",
tmp >> 24, (tmp >> 16) & 0xff, tmp & 0xff,
le32_to_cpu(dev->adapter_info.monitorbuild));
return len;
@@ -1286,7 +1282,7 @@ static ssize_t aac_show_bios_version(struct device *device,
int len, tmp;

tmp = le32_to_cpu(dev->adapter_info.biosrev);
- len = snprintf(buf, PAGE_SIZE, "%d.%d-%d[%d]\n",
+ len = sysfs_emit(buf, "%d.%d-%d[%d]\n",
tmp >> 24, (tmp >> 16) & 0xff, tmp & 0xff,
le32_to_cpu(dev->adapter_info.biosbuild));
return len;
@@ -1296,7 +1292,7 @@ static ssize_t aac_show_driver_version(struct device *device,
struct device_attribute *attr,
char *buf)
{
- return snprintf(buf, PAGE_SIZE, "%s\n", aac_driver_version);
+ return sysfs_emit(buf, "%s\n", aac_driver_version);
}

static ssize_t aac_show_serial_number(struct device *device,
@@ -1322,15 +1318,13 @@ static ssize_t aac_show_serial_number(struct device *device,
static ssize_t aac_show_max_channel(struct device *device,
struct device_attribute *attr, char *buf)
{
- return snprintf(buf, PAGE_SIZE, "%d\n",
- class_to_shost(device)->max_channel);
+ return sysfs_emit(buf, "%d\n", class_to_shost(device)->max_channel);
}

static ssize_t aac_show_max_id(struct device *device,
struct device_attribute *attr, char *buf)
{
- return snprintf(buf, PAGE_SIZE, "%d\n",
- class_to_shost(device)->max_id);
+ return sysfs_emit(buf, "%d\n", class_to_shost(device)->max_id);
}

static ssize_t aac_store_reset_adapter(struct device *device,
@@ -1360,7 +1354,7 @@ static ssize_t aac_show_reset_adapter(struct device *device,
tmp = aac_adapter_check_health(dev);
if ((tmp == 0) && dev->in_reset)
tmp = -EBUSY;
- len = snprintf(buf, PAGE_SIZE, "0x%x\n", tmp);
+ len = sysfs_emit(buf, "0x%x\n", tmp);
return len;
}

--
2.43.0.594.gd9cf4e227d-goog