Hi,
Le mercredi 29 janvier 2014 à 16:27 +0200, Eli Cohen a écrit :
> Commit c1be523 "Fix micro UAR allocator" broke binary compatibility between
^^^^^^^
12 digits identifier are the norm for kernel. Please update your git
configuration:
git config --global core.abbrev 12
See http://lwn.net/Articles/571980/
http://blog.cuviper.com/2013/11/10/how-short-can-git-abbreviate/
> libmlx5 and mlx5_ib since it defines a different value to the number of micro
> UARs per page, leading to wrong calculation in libmlx5. This patch defines
> struct mlx5_ib_alloc_ucontext_req_v2 as an extension to struct
> mlx5_ib_alloc_ucontext_req. The extended size is determined in
> mlx5_ib_alloc_ucontext() and in case of old library we use uuarn 0 which works
> fine. For new libraries we use the more sophisticated allocation algorithm.
>
> Fixes: c1be523 ('Fix micro UAR allocator')
^^^^^^^
Likewise
> Signed-off-by: Eli Cohen <eli@xxxxxxxxxxxx>
> ---
>
> Hi Roland,
>
> This fixes a regression introduced during the 3.14 merge window, and must
> be applied for 3.14, thanks
>
> Eli
>
> drivers/infiniband/hw/mlx5/main.c | 19 +++++++++++++++++--
> drivers/infiniband/hw/mlx5/qp.c | 11 +++++++++--
> drivers/infiniband/hw/mlx5/user.h | 7 +++++++
> include/linux/mlx5/driver.h | 1 +
> 4 files changed, 34 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
> index 9660d09..e24d912 100644
> --- a/drivers/infiniband/hw/mlx5/main.c
> +++ b/drivers/infiniband/hw/mlx5/main.c
> @@ -536,24 +536,38 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev,
> struct ib_udata *udata)
> {
> struct mlx5_ib_dev *dev = to_mdev(ibdev);
> - struct mlx5_ib_alloc_ucontext_req req;
> + struct mlx5_ib_alloc_ucontext_req_v2 req;
> struct mlx5_ib_alloc_ucontext_resp resp;
> struct mlx5_ib_ucontext *context;
> struct mlx5_uuar_info *uuari;
> struct mlx5_uar *uars;
> int gross_uuars;
> int num_uars;
> + int ver;
> int uuarn;
> int err;
> int i;
> + int reqlen;
>
> if (!dev->ib_active)
> return ERR_PTR(-EAGAIN);
>
> - err = ib_copy_from_udata(&req, udata, sizeof(req));
> + memset(&req, 0, sizeof(req));
> + reqlen = udata->inlen - sizeof(struct ib_uverbs_get_context);
I'm not sure how this could work without subtracting sizeof(struct
ib_uverbs_cmd_hdr).
As I explained in "Re: [PATCHv4 for-3.13 00/10] create_flow/destroy_flow
fixes for v3.13" [1] ib_uverbs_write() does not decrement input length:
it gives hdr.in_words * 4 to the uverbs function, here
ib_uverbs_get_context(). Then, the function built struct ib_udata
without taking care of the extra bytes count in in_len:
struct ib_uverbs_get_context cmd;
...
INIT_UDATA(&udata, buf + sizeof cmd,
(unsigned long) cmd.response + sizeof resp,
in_len - sizeof cmd, out_len - sizeof resp);
Driver mthca does some handling which look like to what's proposed in
your patch, but takes care of subtracting the header size from the input
length, see mthca_reg_user_mr()[2].
[1]
<http://marc.info/?i=1387493822.11925.217.camel@localhost.localdomain>
[2]
<http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/infiniband/hw/mthca/mthca_provider.c?id=0e47c969c65e213421450c31043353ebe3c67e0c#n988>
> + if (reqlen == sizeof(struct mlx5_ib_alloc_ucontext_req))
> + ver = 0;
> + else if (reqlen == sizeof(struct mlx5_ib_alloc_ucontext_req_v2))
> + ver = 2;
> + else
> + return ERR_PTR(-EINVAL);
> +
Doing so introduce a subtle regression: there was no check on the length
before, so it was legal to pass a input buffer far larger than needed,
aka. trailing garbage.
With such new test in place, it's no more allowed, and this is a
regression. It's not a big issue, but a little departure from current
behavor.
BTW, this is the correct way to handle the request, every other uverbs
functions should behave like this, eg. being strict on its accepted
input.
> + err = ib_copy_from_udata(&req, udata, reqlen);
> if (err)
> return ERR_PTR(err);
>
> + if (req.flags || req.reserved)
> + return ERR_PTR(-EINVAL);
> +
Just like this :)
> if (req.total_num_uuars > MLX5_MAX_UUARS)
> return ERR_PTR(-ENOMEM);
>
> @@ -626,6 +640,7 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev,
> if (err)
> goto out_uars;
>
> + uuari->ver = ver;
> uuari->num_low_latency_uuars = req.num_low_latency_uuars;
> uuari->uars = uars;
> uuari->num_uars = num_uars;
> diff --git a/drivers/infiniband/hw/mlx5/qp.c b/drivers/infiniband/hw/mlx5/qp.c
> index 492dc33..300475c 100644
> --- a/drivers/infiniband/hw/mlx5/qp.c
> +++ b/drivers/infiniband/hw/mlx5/qp.c
> @@ -430,11 +430,17 @@ static int alloc_uuar(struct mlx5_uuar_info *uuari,
> break;
>
> case MLX5_IB_LATENCY_CLASS_MEDIUM:
> - uuarn = alloc_med_class_uuar(uuari);
> + if (uuari->ver < 2)
> + uuarn = -ENOMEM;
In the commit message, you specified that uuarn is set to 0 when v1 is
used. But here it's set to -ENOMEM.
> + else
> + uuarn = alloc_med_class_uuar(uuari);
> break;
>
> case MLX5_IB_LATENCY_CLASS_HIGH:
> - uuarn = alloc_high_class_uuar(uuari);
> + if (uuari->ver < 2)
> + uuarn = -ENOMEM;
Likewise.
> + else
> + uuarn = alloc_high_class_uuar(uuari);
> break;
>
> case MLX5_IB_LATENCY_CLASS_FAST_PATH:
> @@ -559,6 +565,7 @@ static int create_user_qp(struct mlx5_ib_dev *dev, struct ib_pd *pd,
> }
> }
>
> +
Remove this white space.
> uar_index = uuarn_to_uar_index(&context->uuari, uuarn);
> mlx5_ib_dbg(dev, "uuarn 0x%x, uar_index 0x%x\n", uuarn, uar_index);
>
> diff --git a/drivers/infiniband/hw/mlx5/user.h b/drivers/infiniband/hw/mlx5/user.h
> index 32a2a5d..0f4f8e4 100644
> --- a/drivers/infiniband/hw/mlx5/user.h
> +++ b/drivers/infiniband/hw/mlx5/user.h
> @@ -62,6 +62,13 @@ struct mlx5_ib_alloc_ucontext_req {
> __u32 num_low_latency_uuars;
> };
>
> +struct mlx5_ib_alloc_ucontext_req_v2 {
> + __u32 total_num_uuars;
> + __u32 num_low_latency_uuars;
> + __u32 flags;
> + __u32 reserved;
> +};
> +
> struct mlx5_ib_alloc_ucontext_resp {
> __u32 qp_tab_size;
> __u32 bf_reg_size;
> diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h
> index 554548c..32cb18c 100644
> --- a/include/linux/mlx5/driver.h
> +++ b/include/linux/mlx5/driver.h
> @@ -227,6 +227,7 @@ struct mlx5_uuar_info {
> * protect uuar allocation data structs
> */
> struct mutex lock;
> + u32 ver;
> };
>
> struct mlx5_bf {
Regards.
--
Yann Droneaud
OPTEYA
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