Re: [PATCH 1/3] hpsa: convert show method snprintf usage to scnprintf

[James Bottomley <James.Bottomley@HansenPartnership.com>]

On Wed, 2015-07-01 at 03:45 +0000, Seymour, Shane M wrote:
> Changed all show method snprintf usage to scnprintf per
> Documentation/filesystems/sysfs.txt.
> 
> Signed-off-by: Shane Seymour <shane.seymour@hp.com>

There's been no ack on this one.  However, there's no actual reason to
prefer scnprintf over snprintf: the former will zero terminate, the
latter won't if the write length is over the buffer length, but this is
a file buffer: the routine will return as many bytes to userspace as are
specified in the count (including zeros if they're within the count), so
zero termination of a string in sysfs is unnecessary.

James


> Please let me know if this is not the correct way to submit
> patches by separating them but keeping them logically
> together.
> --- a/drivers/scsi/hpsa.c	2015-06-25 15:52:15.633031319 -0500
> +++ b/drivers/scsi/hpsa.c	2015-06-30 16:12:58.125990687 -0500
> @@ -460,7 +460,7 @@ static ssize_t host_show_firmware_revisi
>  	if (!h->hba_inquiry_data)
>  		return 0;
>  	fwrev = &h->hba_inquiry_data[32];
> -	return snprintf(buf, 20, "%c%c%c%c\n",
> +	return scnprintf(buf, 20, "%c%c%c%c\n",
>  		fwrev[0], fwrev[1], fwrev[2], fwrev[3]);
>  }
>  
> @@ -470,7 +470,7 @@ static ssize_t host_show_commands_outsta
>  	struct Scsi_Host *shost = class_to_shost(dev);
>  	struct ctlr_info *h = shost_to_hba(shost);
>  
> -	return snprintf(buf, 20, "%d\n",
> +	return scnprintf(buf, 20, "%d\n",
>  			atomic_read(&h->commands_outstanding));
>  }
>  
> @@ -481,7 +481,7 @@ static ssize_t host_show_transport_mode(
>  	struct Scsi_Host *shost = class_to_shost(dev);
>  
>  	h = shost_to_hba(shost);
> -	return snprintf(buf, 20, "%s\n",
> +	return scnprintf(buf, 20, "%s\n",
>  		h->transMethod & CFGTBL_Trans_Performant ?
>  			"performant" : "simple");
>  }
> @@ -493,7 +493,7 @@ static ssize_t host_show_hp_ssd_smart_pa
>  	struct Scsi_Host *shost = class_to_shost(dev);
>  
>  	h = shost_to_hba(shost);
> -	return snprintf(buf, 30, "HP SSD Smart Path %s\n",
> +	return scnprintf(buf, 30, "HP SSD Smart Path %s\n",
>  		(h->acciopath_status == 1) ?  "enabled" : "disabled");
>  }
>  
> @@ -589,7 +589,7 @@ static ssize_t host_show_resettable(stru
>  	struct Scsi_Host *shost = class_to_shost(dev);
>  
>  	h = shost_to_hba(shost);
> -	return snprintf(buf, 20, "%d\n", ctlr_is_resettable(h->board_id));
> +	return scnprintf(buf, 20, "%d\n", ctlr_is_resettable(h->board_id));
>  }
>  
>  static inline int is_logical_dev_addr_mode(unsigned char scsi3addr[])
> @@ -631,7 +631,7 @@ static ssize_t raid_level_show(struct de
>  	/* Is this even a logical drive? */
>  	if (!is_logical_dev_addr_mode(hdev->scsi3addr)) {
>  		spin_unlock_irqrestore(&h->lock, flags);
> -		l = snprintf(buf, PAGE_SIZE, "N/A\n");
> +		l = scnprintf(buf, PAGE_SIZE, "N/A\n");
>  		return l;
>  	}
>  
> @@ -639,7 +639,7 @@ static ssize_t raid_level_show(struct de
>  	spin_unlock_irqrestore(&h->lock, flags);
>  	if (rlevel > RAID_UNKNOWN)
>  		rlevel = RAID_UNKNOWN;
> -	l = snprintf(buf, PAGE_SIZE, "RAID %s\n", raid_label[rlevel]);
> +	l = scnprintf(buf, PAGE_SIZE, "RAID %s\n", raid_label[rlevel]);
>  	return l;
>  }
>  
> @@ -662,7 +662,7 @@ static ssize_t lunid_show(struct device
>  	}
>  	memcpy(lunid, hdev->scsi3addr, sizeof(lunid));
>  	spin_unlock_irqrestore(&h->lock, flags);
> -	return snprintf(buf, 20, "0x%02x%02x%02x%02x%02x%02x%02x%02x\n",
> +	return scnprintf(buf, 20, "0x%02x%02x%02x%02x%02x%02x%02x%02x\n",
>  		lunid[0], lunid[1], lunid[2], lunid[3],
>  		lunid[4], lunid[5], lunid[6], lunid[7]);
>  }
> @@ -686,7 +686,7 @@ static ssize_t unique_id_show(struct dev
>  	}
>  	memcpy(sn, hdev->device_id, sizeof(sn));
>  	spin_unlock_irqrestore(&h->lock, flags);
> -	return snprintf(buf, 16 * 2 + 2,
> +	return scnprintf(buf, 16 * 2 + 2,
>  			"%02X%02X%02X%02X%02X%02X%02X%02X"
>  			"%02X%02X%02X%02X%02X%02X%02X%02X\n",
>  			sn[0], sn[1], sn[2], sn[3],
> @@ -714,7 +714,7 @@ static ssize_t host_show_hp_ssd_smart_pa
>  	}
>  	offload_enabled = hdev->offload_enabled;
>  	spin_unlock_irqrestore(&h->lock, flags);
> -	return snprintf(buf, 20, "%d\n", offload_enabled);
> +	return scnprintf(buf, 20, "%d\n", offload_enabled);
>  }
>  
>  static DEVICE_ATTR(raid_level, S_IRUGO, raid_level_show, NULL);
> --
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