ACK: [SRU][Zesty][PATCH 1/1] scsi: cxlflash: Fix vlun resize failure in the shrink path

[Stefan Bader]

On 20.09.2017 11:47, Joseph Salisbury wrote:
> From: Uma Krishnan <ukrishn at linux.vnet.ibm.com>
> 
> BugLink: http://bugs.launchpad.net/bugs/1713575
> 
> The ioctl DK_CAPI_VLUN_RESIZE can fail if the allocated vlun size is
> reduced from almost maximum capacity and then increased again.
> 
> The shrink_lxt() routine is currently using the SISL_ASTATUS_MASK to
> mask the higher 48 bits of the lxt entry. This is unnecessary and
> incorrect as it uses a mask designed for the asynchronous interrupt
> status register.  When the 4 port support was added to cxlflash, the
> SISL_ASTATUS_MASK was updated to reflect the status bits for all 4
> ports. This change indirectly affected the shrink_lxt() code path.
> 
> To extract the base, simply shift the bits without masking.
> 
> Fixes: 565180723294 ("scsi: cxlflash: SISlite updates to support 4 ports")
> Signed-off-by: Uma Krishnan <ukrishn at linux.vnet.ibm.com>
> Signed-off-by: Martin K. Petersen <martin.petersen at oracle.com>
> (cherry picked from commit 07a191f762a7b8d0db13c38036380927116e29bb)
> Signed-off-by: Joseph Salisbury <joseph.salisbury at canonical.com>
Acked-by: Stefan Bader <stefan.bader at canonical.com>

> ---
>  drivers/scsi/cxlflash/vlun.c | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/drivers/scsi/cxlflash/vlun.c b/drivers/scsi/cxlflash/vlun.c
> index 6c4cd3f..8de6a80 100644
> --- a/drivers/scsi/cxlflash/vlun.c
> +++ b/drivers/scsi/cxlflash/vlun.c
> @@ -694,11 +694,7 @@ static int shrink_lxt(struct afu *afu,
>  	/* Free LBAs allocated to freed chunks */
>  	mutex_lock(&blka->mutex);
>  	for (i = delta - 1; i >= 0; i--) {
> -		/* Mask the higher 48 bits before shifting, even though
> -		 * it is a noop
> -		 */
> -		aun = (lxt_old[my_new_size + i].rlba_base & SISL_ASTATUS_MASK);
> -		aun = (aun >> MC_CHUNK_SHIFT);
> +		aun = lxt_old[my_new_size + i].rlba_base >> MC_CHUNK_SHIFT;
>  		if (needs_ws)
>  			write_same16(sdev, aun, MC_CHUNK_SIZE);
>  		ba_free(&blka->ba_lun, aun);
> 


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