* [PATCH] RDMA/hns: Work around broken constant propogation in gcc 8
@ 2021-09-16 15:05 Jason Gunthorpe
2021-09-24 8:39 ` Wenpeng Liang
2021-09-24 12:28 ` Jason Gunthorpe
0 siblings, 2 replies; 3+ messages in thread
From: Jason Gunthorpe @ 2021-09-16 15:05 UTC (permalink / raw)
To: Wenpeng Liang, linux-rdma; +Cc: Lang Cheng, Geert Uytterhoeven, Weihang Li
gcc 8.3 and 5.4 throw this:
In function 'modify_qp_init_to_rtr',
././include/linux/compiler_types.h:322:38: error: call to '__compiletime_assert_1859' declared with attribute error: FIELD_PREP: value too large for the field
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
[..]
drivers/infiniband/hw/hns/hns_roce_common.h:91:52: note: in expansion of macro 'FIELD_PREP'
*((__le32 *)ptr + (field_h) / 32) |= cpu_to_le32(FIELD_PREP( \
^~~~~~~~~~
drivers/infiniband/hw/hns/hns_roce_common.h:95:39: note: in expansion of macro '_hr_reg_write'
#define hr_reg_write(ptr, field, val) _hr_reg_write(ptr, field, val)
^~~~~~~~~~~~~
drivers/infiniband/hw/hns/hns_roce_hw_v2.c:4412:2: note: in expansion of macro 'hr_reg_write'
hr_reg_write(context, QPC_LP_PKTN_INI, lp_pktn_ini);
Because gcc has miscalculated the constantness of lp_pktn_ini:
mtu = ib_mtu_enum_to_int(ib_mtu);
if (WARN_ON(mtu < 0)) [..]
lp_pktn_ini = ilog2(MAX_LP_MSG_LEN / mtu);
Since mtu is limited to {256,512,1024,2048,4096} lp_pktn_ini is between 4
and 8 which is compatible with the 4 bit field in the FIELD_PREP.
Work around this broken compiler by adding a 'can never be true'
constraint on lp_pktn_ini's value which clears out the problem.
Fixes: f0cb411aad23 ("RDMA/hns: Use new interface to modify QP context")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
drivers/infiniband/hw/hns/hns_roce_hw_v2.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
index 5b9953105752c3..a9c00a2e8ebdbb 100644
--- a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
+++ b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
@@ -4397,7 +4397,12 @@ static int modify_qp_init_to_rtr(struct ib_qp *ibqp,
hr_qp->path_mtu = ib_mtu;
mtu = ib_mtu_enum_to_int(ib_mtu);
- if (WARN_ON(mtu < 0))
+ if (WARN_ON(mtu <= 0))
+ return -EINVAL;
+#define MAX_LP_MSG_LEN 65536
+ /* MTU * (2 ^ LP_PKTN_INI) shouldn't be bigger than 64KB */
+ lp_pktn_ini = ilog2(MAX_LP_MSG_LEN / mtu);
+ if (WARN_ON(lp_pktn_ini >= 0xF))
return -EINVAL;
if (attr_mask & IB_QP_PATH_MTU) {
@@ -4405,10 +4410,6 @@ static int modify_qp_init_to_rtr(struct ib_qp *ibqp,
hr_reg_clear(qpc_mask, QPC_MTU);
}
-#define MAX_LP_MSG_LEN 65536
- /* MTU * (2 ^ LP_PKTN_INI) shouldn't be bigger than 64KB */
- lp_pktn_ini = ilog2(MAX_LP_MSG_LEN / mtu);
-
hr_reg_write(context, QPC_LP_PKTN_INI, lp_pktn_ini);
hr_reg_clear(qpc_mask, QPC_LP_PKTN_INI);
base-commit: ad17bbef3dd573da937816edc0ab84fed6a17fa6
--
2.33.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] RDMA/hns: Work around broken constant propogation in gcc 8
2021-09-16 15:05 [PATCH] RDMA/hns: Work around broken constant propogation in gcc 8 Jason Gunthorpe
@ 2021-09-24 8:39 ` Wenpeng Liang
2021-09-24 12:28 ` Jason Gunthorpe
1 sibling, 0 replies; 3+ messages in thread
From: Wenpeng Liang @ 2021-09-24 8:39 UTC (permalink / raw)
To: Jason Gunthorpe, linux-rdma; +Cc: Lang Cheng, Geert Uytterhoeven, Weihang Li
On 2021/9/16 23:05, Jason Gunthorpe wrote:
> gcc 8.3 and 5.4 throw this:
>
> In function 'modify_qp_init_to_rtr',
> ././include/linux/compiler_types.h:322:38: error: call to '__compiletime_assert_1859' declared with attribute error: FIELD_PREP: value too large for the field
> _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> [..]
> drivers/infiniband/hw/hns/hns_roce_common.h:91:52: note: in expansion of macro 'FIELD_PREP'
> *((__le32 *)ptr + (field_h) / 32) |= cpu_to_le32(FIELD_PREP( \
> ^~~~~~~~~~
> drivers/infiniband/hw/hns/hns_roce_common.h:95:39: note: in expansion of macro '_hr_reg_write'
> #define hr_reg_write(ptr, field, val) _hr_reg_write(ptr, field, val)
> ^~~~~~~~~~~~~
> drivers/infiniband/hw/hns/hns_roce_hw_v2.c:4412:2: note: in expansion of macro 'hr_reg_write'
> hr_reg_write(context, QPC_LP_PKTN_INI, lp_pktn_ini);
>
> Because gcc has miscalculated the constantness of lp_pktn_ini:
>
> mtu = ib_mtu_enum_to_int(ib_mtu);
> if (WARN_ON(mtu < 0)) [..]
> lp_pktn_ini = ilog2(MAX_LP_MSG_LEN / mtu);
>
> Since mtu is limited to {256,512,1024,2048,4096} lp_pktn_ini is between 4
> and 8 which is compatible with the 4 bit field in the FIELD_PREP.
>
> Work around this broken compiler by adding a 'can never be true'
> constraint on lp_pktn_ini's value which clears out the problem.
>
> Fixes: f0cb411aad23 ("RDMA/hns: Use new interface to modify QP context")
> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
> drivers/infiniband/hw/hns/hns_roce_hw_v2.c | 11 ++++++-----
> 1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
> index 5b9953105752c3..a9c00a2e8ebdbb 100644
> --- a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
> +++ b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
> @@ -4397,7 +4397,12 @@ static int modify_qp_init_to_rtr(struct ib_qp *ibqp,
> hr_qp->path_mtu = ib_mtu;
>
> mtu = ib_mtu_enum_to_int(ib_mtu);
> - if (WARN_ON(mtu < 0))
> + if (WARN_ON(mtu <= 0))
> + return -EINVAL;
> +#define MAX_LP_MSG_LEN 65536
> + /* MTU * (2 ^ LP_PKTN_INI) shouldn't be bigger than 64KB */
> + lp_pktn_ini = ilog2(MAX_LP_MSG_LEN / mtu);
> + if (WARN_ON(lp_pktn_ini >= 0xF))
> return -EINVAL;
>
> if (attr_mask & IB_QP_PATH_MTU) {
> @@ -4405,10 +4410,6 @@ static int modify_qp_init_to_rtr(struct ib_qp *ibqp,
> hr_reg_clear(qpc_mask, QPC_MTU);
> }
>
> -#define MAX_LP_MSG_LEN 65536
> - /* MTU * (2 ^ LP_PKTN_INI) shouldn't be bigger than 64KB */
> - lp_pktn_ini = ilog2(MAX_LP_MSG_LEN / mtu);
> -
> hr_reg_write(context, QPC_LP_PKTN_INI, lp_pktn_ini);
> hr_reg_clear(qpc_mask, QPC_LP_PKTN_INI);
>
>
> base-commit: ad17bbef3dd573da937816edc0ab84fed6a17fa6
>
Hi, Jason,
Sorry for the late reply,
It seems okay to me, thanks!
Wengpeng
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] RDMA/hns: Work around broken constant propogation in gcc 8
2021-09-16 15:05 [PATCH] RDMA/hns: Work around broken constant propogation in gcc 8 Jason Gunthorpe
2021-09-24 8:39 ` Wenpeng Liang
@ 2021-09-24 12:28 ` Jason Gunthorpe
1 sibling, 0 replies; 3+ messages in thread
From: Jason Gunthorpe @ 2021-09-24 12:28 UTC (permalink / raw)
To: Wenpeng Liang, linux-rdma; +Cc: Lang Cheng, Geert Uytterhoeven, Weihang Li
On Thu, Sep 16, 2021 at 12:05:28PM -0300, Jason Gunthorpe wrote:
> gcc 8.3 and 5.4 throw this:
>
> In function 'modify_qp_init_to_rtr',
> ././include/linux/compiler_types.h:322:38: error: call to '__compiletime_assert_1859' declared with attribute error: FIELD_PREP: value too large for the field
> _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> [..]
> drivers/infiniband/hw/hns/hns_roce_common.h:91:52: note: in expansion of macro 'FIELD_PREP'
> *((__le32 *)ptr + (field_h) / 32) |= cpu_to_le32(FIELD_PREP( \
> ^~~~~~~~~~
> drivers/infiniband/hw/hns/hns_roce_common.h:95:39: note: in expansion of macro '_hr_reg_write'
> #define hr_reg_write(ptr, field, val) _hr_reg_write(ptr, field, val)
> ^~~~~~~~~~~~~
> drivers/infiniband/hw/hns/hns_roce_hw_v2.c:4412:2: note: in expansion of macro 'hr_reg_write'
> hr_reg_write(context, QPC_LP_PKTN_INI, lp_pktn_ini);
>
> Because gcc has miscalculated the constantness of lp_pktn_ini:
>
> mtu = ib_mtu_enum_to_int(ib_mtu);
> if (WARN_ON(mtu < 0)) [..]
> lp_pktn_ini = ilog2(MAX_LP_MSG_LEN / mtu);
>
> Since mtu is limited to {256,512,1024,2048,4096} lp_pktn_ini is between 4
> and 8 which is compatible with the 4 bit field in the FIELD_PREP.
>
> Work around this broken compiler by adding a 'can never be true'
> constraint on lp_pktn_ini's value which clears out the problem.
>
> Fixes: f0cb411aad23 ("RDMA/hns: Use new interface to modify QP context")
> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
> drivers/infiniband/hw/hns/hns_roce_hw_v2.c | 11 ++++++-----
> 1 file changed, 6 insertions(+), 5 deletions(-)
Applied to for-rc
Jason
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-09-16 15:05 [PATCH] RDMA/hns: Work around broken constant propogation in gcc 8 Jason Gunthorpe
2021-09-24 8:39 ` Wenpeng Liang
2021-09-24 12:28 ` Jason Gunthorpe
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