Re: [PATCHv2 1/1] IB/srp: fix invalid indirect_sg_entries parameter value

Max Gurtovoy
2017-01-24T16:50:32Z

On 1/24/2017 6:32 PM, Doug Ledford wrote:
> On Wed, 2017-01-04 at 15:09 +0000, Bart Van Assche wrote:
>> On Wed, 2017-01-04 at 15:59 +0200, Max Gurtovoy wrote:
>>>
>>> From: Israel Rukshin <israelr-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
>>>
>>> After setting indirect_sg_entries module_param to huge value (e.g
>>> 500,000),
>>> srp_alloc_req_data() fails to allocate indirect descriptors for the
>>> request
>>> ring (kmalloc fails). This commit enforces the maximum value of
>>> indirect_sg_entries
>>> to be SG_MAX_SEGMENTS as signified in module param description.
>>>
>>> Signed-off-by: Israel Rukshin <israelr-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
>>> Signed-off-by: Max Gurtovoy <maxg-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
>>> ---
>>> drivers/infiniband/ulp/srp/ib_srp.c | 6 ++++++
>>> 1 file changed, 6 insertions(+)
>>>
>>> diff --git a/drivers/infiniband/ulp/srp/ib_srp.c
>>> b/drivers/infiniband/ulp/srp/ib_srp.c
>>> index 0f67cf9..79bf484 100644
>>> --- a/drivers/infiniband/ulp/srp/ib_srp.c
>>> +++ b/drivers/infiniband/ulp/srp/ib_srp.c
>>> @@ -3699,6 +3699,12 @@ static int __init srp_init_module(void)
>>> indirect_sg_entries = cmd_sg_entries;
>>> }
>>>
>>> + if (indirect_sg_entries > SG_MAX_SEGMENTS) {
>>> + pr_warn("Clamping indirect_sg_entries to %u\n",
>>> + SG_MAX_SEGMENTS);
>>> + indirect_sg_entries = SG_MAX_SEGMENTS;
>>> + }
>>> +
>>> srp_remove_wq = create_workqueue("srp_remove");
>>> if (!srp_remove_wq) {
>>> ret = -ENOMEM;
>>
>> Thanks!
>>
>> Reviewed-by: Bart Van Assche <bart.vanassche-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
>
> This patch is a fix patch and should have been tagged as such.
> However, the proper tagging is complicated by the fact that the
> SG_MAX_SEGMENTS was originally named SCSI_MAX_SG_CHAIN_SEGMENTS. The
> fix applies all the way back to the first patch to enable SG segments
> in the srp driver, but you will need a different patch for the kernels
> prior to the rename. For this patch, I've added the following tags and
> applied the patch:
>
> Fixes: 65e8617fba17 (scsi: rename SCSI_MAX_{SG, SG_CHAIN}_SEGMENTS)
> Fixes: c07d424d6118 (IB/srp: add support for indirect tables that don't
> fit in SRP_CMD)
> Cc: stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org # 4.7+
>
> Someone should write a patch for the earlier kernels and submit it
> directly to stable@ with the patch flagged for application on kernels
> from 2.6.39 to 4.6. The upstream hash for the fix to mainline is:
>
> commit 0a475ef4226e305bdcffe12b401ca1eab06c4913
> Author: Israel Rukshin <israelr-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> Date: Wed Jan 4 15:59:37 2017 +0200
>
> IB/srp: fix invalid indirect_sg_entries parameter value
>

Israel,
please take it for earlier kernels as well.

Max.