On 7/14/20 2:03 PM, Stefan Haberland wrote:
> During initialization of the DASD DIAG driver a request is issued
> that has a bio structure that resides on the stack. With virtually
> mapped kernel stacks this bio address might be in virtual storage
> which is unsuitable for usage with the diag250 call.
> In this case the device can not be set online using the DIAG
> discipline and fails with -EOPNOTSUP.
> In the system journal the following error message is presented:
>
> dasd: X.X.XXXX Setting the DASD online with discipline DIAG failed
> with rc=-95
>
> Fix by allocating the bio structure instead of having it on the stack.
>
> Fixes: ce3dc447493f ("s390: add support for virtually mapped kernel stacks")
> Cc: stable@xxxxxxxxxxxxxxx #4.20
> Signed-off-by: Stefan Haberland <sth@xxxxxxxxxxxxx>
> Reviewed-by: Peter Oberparleiter <oberpar@xxxxxxxxxxxxx>
> ---
> drivers/s390/block/dasd_diag.c | 25 +++++++++++++++++--------
> 1 file changed, 17 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/s390/block/dasd_diag.c b/drivers/s390/block/dasd_diag.c
> index facb588d09e4..069d6b39cacf 100644
> --- a/drivers/s390/block/dasd_diag.c
> +++ b/drivers/s390/block/dasd_diag.c
> @@ -319,7 +319,7 @@ dasd_diag_check_device(struct dasd_device *device)
> struct dasd_diag_characteristics *rdc_data;
> struct vtoc_cms_label *label;
> struct dasd_block *block;
> - struct dasd_diag_bio bio;
> + struct dasd_diag_bio *bio;
> unsigned int sb, bsize;
> blocknum_t end_block;
> int rc;
> @@ -395,29 +395,36 @@ dasd_diag_check_device(struct dasd_device *device)
> rc = -ENOMEM;
> goto out;
> }
> + bio = kzalloc(sizeof(*bio), GFP_KERNEL);
> + if (bio == NULL) {
> + DBF_DEV_EVENT(DBF_WARNING, device, "%s",
> + "No memory to allocate initialization bio");
> + rc = -ENOMEM;
> + goto out_label;
> + }
Just curious, any reason this isn't just using bio_alloc()?
--
Jens Axboe
