Re: [PATCH] FIX: sysfs_disk_to_scsi_id() adapted to current sysfs format

[NeilBrown <neilb@suse.de>]

On Wed, 16 Feb 2011 13:40:21 +0100 Krzysztof Wojcik
<krzysztof.wojcik@intel.com> wrote:

> Problem: sysfs_disk_to_scsi_id() not returns correct scsi_id value.
> Reason: sysfs format has been changed
> 
> This patch adapt sysfs_disk_to_scsi_id() to new sysfs format.

If there has been a change in sysfs format, we want the code to work in both
old and new cases.

Do you know if this new code works in the 'old' case?  Do you know when
(which kernel version) the change happened, or at least can you name a kernel
version when the 'old' style worked.

The patch looks OK, but I want to be sure all bases are covered.

Thanks,
NeilBrown


> 
> Signed-off-by: Krzysztof Wojcik <krzysztof.wojcik@intel.com>
> ---
>  sysfs.c |   14 ++++++--------
>  1 files changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/sysfs.c b/sysfs.c
> index f0773d4..883a834 100644
> --- a/sysfs.c
> +++ b/sysfs.c
> @@ -705,7 +705,7 @@ int sysfs_disk_to_scsi_id(int fd, __u32 *id)
>  	if (fstat(fd, &st))
>  		return 1;
>  
> -	snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device",
> +	snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device/scsi_device",
>  		 major(st.st_rdev), minor(st.st_rdev));
>  
>  	dir = opendir(path);
> @@ -714,8 +714,7 @@ int sysfs_disk_to_scsi_id(int fd, __u32 *id)
>  
>  	de = readdir(dir);
>  	while (de) {
> -		if (strncmp("scsi_disk:", de->d_name,
> -			    strlen("scsi_disk:")) == 0)
> +		if (strchr(de->d_name, ':'))
>  			break;
>  		de = readdir(dir);
>  	}
> @@ -724,21 +723,20 @@ int sysfs_disk_to_scsi_id(int fd, __u32 *id)
>  	if (!de)
>  		return 1;
>  
> -	c1 = strchr(de->d_name, ':');
> -	c1++;
> +	c1 = de->d_name;
>  	c2 = strchr(c1, ':');
>  	*c2 = '\0';
>  	*id = strtol(c1, NULL, 10) << 24; /* host */
>  	c1 = c2 + 1;
>  	c2 = strchr(c1, ':');
>  	*c2 = '\0';
> -	*id |= strtol(c1, NULL, 10) << 16; /* channel */
> +	*id |= strtol(c1, NULL, 10) << 16; /* bus */
>  	c1 = c2 + 1;
>  	c2 = strchr(c1, ':');
>  	*c2 = '\0';
> -	*id |= strtol(c1, NULL, 10) << 8; /* lun */
> +	*id |= strtol(c1, NULL, 10) << 8; /* target */
>  	c1 = c2 + 1;
> -	*id |= strtol(c1, NULL, 10); /* id */
> +	*id |= strtol(c1, NULL, 10); /* lun */
>  
>  	return 0;
>  }