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| Started by | Johannes Thumshirn <jthumshirn@suse.de> |
|---|---|
| First post | 2017-07-05 15:50 +0200 |
| Last post | 2017-07-07 10:00 +0200 |
| Articles | 4 — 3 participants |
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[PATCH] scsi: sg: fix SG_DXFER_FROM_DEV transfers Johannes Thumshirn <jthumshirn@suse.de> - 2017-07-05 15:50 +0200
Re: [PATCH] scsi: sg: fix SG_DXFER_FROM_DEV transfers Hannes Reinecke <hare@suse.de> - 2017-07-06 13:50 +0200
Re: [PATCH] scsi: sg: fix SG_DXFER_FROM_DEV transfers Douglas Gilbert <dgilbert@interlog.com> - 2017-07-06 21:00 +0200
Re: [PATCH] scsi: sg: fix SG_DXFER_FROM_DEV transfers Johannes Thumshirn <jthumshirn@suse.de> - 2017-07-07 10:00 +0200
| From | Johannes Thumshirn <jthumshirn@suse.de> |
|---|---|
| Date | 2017-07-05 15:50 +0200 |
| Subject | [PATCH] scsi: sg: fix SG_DXFER_FROM_DEV transfers |
| Message-ID | <tZSQO-6PZ-15@gated-at.bofh.it> |
SG_DXFER_FROM_DEV transfers do not have a dxferp as we set it to NULL,
but must have a length bigger than 0. This fixes a regression introduced
by commit 28676d869bbb ("scsi: sg: check for valid direction before
starting the request")
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Fixes: 28676d869bbb ("scsi: sg: check for valid direction before starting the request")
Reported-by: Chris Clayton <chris2553@googlemail.com>
Tested-by: Chris Clayton <chris2553@googlemail.com>
Cc: Doug Gilbert <dgilbert@interlog.com>
---
drivers/scsi/sg.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 21225d62b0c1..3c91593260aa 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -758,8 +758,11 @@ static bool sg_is_valid_dxfer(sg_io_hdr_t *hp)
if (hp->dxferp || hp->dxfer_len > 0)
return false;
return true;
- case SG_DXFER_TO_DEV:
case SG_DXFER_FROM_DEV:
+ if (hp->dxferp || hp->dxfer_len < 0)
+ return false;
+ return true;
+ case SG_DXFER_TO_DEV:
case SG_DXFER_TO_FROM_DEV:
if (!hp->dxferp || hp->dxfer_len == 0)
return false;
--
2.12.3
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| From | Hannes Reinecke <hare@suse.de> |
|---|---|
| Date | 2017-07-06 13:50 +0200 |
| Message-ID | <u0dse-3Lz-27@gated-at.bofh.it> |
| In reply to | #1681543 |
On 07/05/2017 03:49 PM, Johannes Thumshirn wrote:
> SG_DXFER_FROM_DEV transfers do not have a dxferp as we set it to NULL,
> but must have a length bigger than 0. This fixes a regression introduced
> by commit 28676d869bbb ("scsi: sg: check for valid direction before
> starting the request")
>
> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
> Fixes: 28676d869bbb ("scsi: sg: check for valid direction before starting the request")
> Reported-by: Chris Clayton <chris2553@googlemail.com>
> Tested-by: Chris Clayton <chris2553@googlemail.com>
> Cc: Doug Gilbert <dgilbert@interlog.com>
> ---
> drivers/scsi/sg.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
> index 21225d62b0c1..3c91593260aa 100644
> --- a/drivers/scsi/sg.c
> +++ b/drivers/scsi/sg.c
> @@ -758,8 +758,11 @@ static bool sg_is_valid_dxfer(sg_io_hdr_t *hp)
> if (hp->dxferp || hp->dxfer_len > 0)
> return false;
> return true;
> - case SG_DXFER_TO_DEV:
> case SG_DXFER_FROM_DEV:
> + if (hp->dxferp || hp->dxfer_len < 0)
> + return false;
> + return true;
> + case SG_DXFER_TO_DEV:
> case SG_DXFER_TO_FROM_DEV:
> if (!hp->dxferp || hp->dxfer_len == 0)
> return false;
>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
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| From | Douglas Gilbert <dgilbert@interlog.com> |
|---|---|
| Date | 2017-07-06 21:00 +0200 |
| Message-ID | <u0kam-RF-23@gated-at.bofh.it> |
| In reply to | #1681543 |
On 2017-07-05 09:49 AM, Johannes Thumshirn wrote:
> SG_DXFER_FROM_DEV transfers do not have a dxferp as we set it to NULL,
> but must have a length bigger than 0. This fixes a regression introduced
> by commit 28676d869bbb ("scsi: sg: check for valid direction before
> starting the request")
It is not clear to me that dxferp is set to NULL for the newer sg_v3
interface. In the sg.c source of lk 4.12.0 around line 654 (in the
sg_write(...) function) only the older interface passes through; the
newer interface bypasses that section with a 'return sg_new_write(...)'
on line 606.
Can you check your patch with one of the utilities from sg3_utils
such as sg_inq which will use SG_DXFER_FROM_DEV with the newer
interface?
BTW I'm not sure why dxferp is set to NULL for SG_DXFER_FROM_DEV
transfers; perhaps some magic done by the block layer. Maybe a
comment in the code (e.g. on line 654) would help.
Also sg_is_valid_dxfer() is only called once and is more complex
than it looks; so perhaps it could be inlined back in
sg_common_write().
Doug Gilbert
> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
> Fixes: 28676d869bbb ("scsi: sg: check for valid direction before starting the request")
> Reported-by: Chris Clayton <chris2553@googlemail.com>
> Tested-by: Chris Clayton <chris2553@googlemail.com>
> Cc: Doug Gilbert <dgilbert@interlog.com>
> ---
> drivers/scsi/sg.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
> index 21225d62b0c1..3c91593260aa 100644
> --- a/drivers/scsi/sg.c
> +++ b/drivers/scsi/sg.c
> @@ -758,8 +758,11 @@ static bool sg_is_valid_dxfer(sg_io_hdr_t *hp)
> if (hp->dxferp || hp->dxfer_len > 0)
> return false;
> return true;
> - case SG_DXFER_TO_DEV:
> case SG_DXFER_FROM_DEV:
> + if (hp->dxferp || hp->dxfer_len < 0)
> + return false;
> + return true;
> + case SG_DXFER_TO_DEV:
> case SG_DXFER_TO_FROM_DEV:
> if (!hp->dxferp || hp->dxfer_len == 0)
> return false;
>
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| From | Johannes Thumshirn <jthumshirn@suse.de> |
|---|---|
| Date | 2017-07-07 10:00 +0200 |
| Message-ID | <u0wlc-P2-9@gated-at.bofh.it> |
| In reply to | #1682658 |
On Thu, Jul 06, 2017 at 02:47:22PM -0400, Douglas Gilbert wrote:
> Can you check your patch with one of the utilities from sg3_utils
> such as sg_inq which will use SG_DXFER_FROM_DEV with the newer
> interface?
Correct, this patch broke sg_inq. I'll send a corrected v2.
> BTW I'm not sure why dxferp is set to NULL for SG_DXFER_FROM_DEV
> transfers; perhaps some magic done by the block layer. Maybe a
> comment in the code (e.g. on line 654) would help.
This is due to:
commit fad7f01e61bf737fe8a3740d803f000db57ecac6
Author: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Date: Tue Sep 2 16:20:20 2008 +0900
sg: set dxferp to NULL for READ with the older SG interface
With the older SG interface, we don't know a user-space address to
trasfer data when executing a SCSI command. So we can't pass a
user-space address to blk_rq_map_user.
This patch fixes sg to pass a NULL user-space address to
blk_rq_map_user so that it just sets up a request and bios with page
frames propely without data transfer.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
>
> Also sg_is_valid_dxfer() is only called once and is more complex
> than it looks; so perhaps it could be inlined back in
> sg_common_write().
The compiler will inline it anyways (at least the one I checked with) and
inlining it into sg_common_write() won't make the code more readable IMHO. But
ultimately it's your driver so if you insist I'll do.
--
Johannes Thumshirn Storage
jthumshirn@suse.de +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
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