From baaad380c0aa955f7d62e846467316c94067f1a5 Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Tue, 29 Apr 2008 13:46:53 -0700 Subject: [PATCH] IB/mthca: Avoid changing userspace ABI to handle DMA write barrier attribute Commit cb9fbc5c ("IB: expand ib_umem_get() prototype") changed the mthca userspace ABI to provide a way for userspace to indicate which memory regions need the DMA write barrier attribute. However, it is possible to handle this without breaking existing userspace, by having the mthca kernel driver recognize whether it is talking to old or new userspace, depending on the size of the register MR structure passed in. The only potential drawback of this is that is allows old userspace (which has a bug with DMA ordering on large SGI Altix systems) to continue to run on new kernels, but the advantage of allowing old userspace to continue to work on unaffected systems seems to outweigh this, and we can print a warning to push people to upgrade their userspace. Signed-off-by: Roland Dreier --- drivers/infiniband/hw/mthca/mthca_provider.c | 14 +++++++++++++- drivers/infiniband/hw/mthca/mthca_provider.h | 1 + drivers/infiniband/hw/mthca/mthca_user.h | 10 ++++++---- 3 files changed, 20 insertions(+), 5 deletions(-) diff --git a/drivers/infiniband/hw/mthca/mthca_provider.c b/drivers/infiniband/hw/mthca/mthca_provider.c index 2a9f460cf06..be34f99ca62 100644 --- a/drivers/infiniband/hw/mthca/mthca_provider.c +++ b/drivers/infiniband/hw/mthca/mthca_provider.c @@ -39,6 +39,8 @@ #include #include #include + +#include #include #include "mthca_dev.h" @@ -367,6 +369,8 @@ static struct ib_ucontext *mthca_alloc_ucontext(struct ib_device *ibdev, return ERR_PTR(-EFAULT); } + context->reg_mr_warned = 0; + return &context->ibucontext; } @@ -1013,7 +1017,15 @@ static struct ib_mr *mthca_reg_user_mr(struct ib_pd *pd, u64 start, u64 length, int err = 0; int write_mtt_size; - if (ib_copy_from_udata(&ucmd, udata, sizeof ucmd)) + if (udata->inlen - sizeof (struct ib_uverbs_cmd_hdr) < sizeof ucmd) { + if (!to_mucontext(pd->uobject->context)->reg_mr_warned) { + mthca_warn(dev, "Process '%s' did not pass in MR attrs.\n", + current->comm); + mthca_warn(dev, " Update libmthca to fix this.\n"); + } + ++to_mucontext(pd->uobject->context)->reg_mr_warned; + ucmd.mr_attrs = 0; + } else if (ib_copy_from_udata(&ucmd, udata, sizeof ucmd)) return ERR_PTR(-EFAULT); mr = kmalloc(sizeof *mr, GFP_KERNEL); diff --git a/drivers/infiniband/hw/mthca/mthca_provider.h b/drivers/infiniband/hw/mthca/mthca_provider.h index 262616c8ebb..934bf954403 100644 --- a/drivers/infiniband/hw/mthca/mthca_provider.h +++ b/drivers/infiniband/hw/mthca/mthca_provider.h @@ -67,6 +67,7 @@ struct mthca_ucontext { struct ib_ucontext ibucontext; struct mthca_uar uar; struct mthca_user_db_table *db_tab; + int reg_mr_warned; }; struct mthca_mtt; diff --git a/drivers/infiniband/hw/mthca/mthca_user.h b/drivers/infiniband/hw/mthca/mthca_user.h index f8cb3b664d3..e1262c942db 100644 --- a/drivers/infiniband/hw/mthca/mthca_user.h +++ b/drivers/infiniband/hw/mthca/mthca_user.h @@ -41,7 +41,7 @@ * Increment this value if any changes that break userspace ABI * compatibility are made. */ -#define MTHCA_UVERBS_ABI_VERSION 2 +#define MTHCA_UVERBS_ABI_VERSION 1 /* * Make sure that all structs defined in this file remain laid out so @@ -62,10 +62,12 @@ struct mthca_alloc_pd_resp { }; struct mthca_reg_mr { +/* + * Mark the memory region with a DMA attribute that causes + * in-flight DMA to be flushed when the region is written to: + */ +#define MTHCA_MR_DMASYNC 0x1 __u32 mr_attrs; -#define MTHCA_MR_DMASYNC 0x1 -/* mark the memory region with a DMA attribute that causes - * in-flight DMA to be flushed when the region is written to */ __u32 reserved; }; -- 2.41.0