From f4fd0b224d60044d2da5ca02f8f2b5150c1d8731 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Thu, 3 May 2007 13:48:47 +0300 Subject: IB: Add CQ comp_vector support Add a num_comp_vectors member to struct ib_device and extend ib_create_cq() to pass in a comp_vector parameter -- this parallels the userspace libibverbs API. Update all hardware drivers to set num_comp_vectors to 1 and have all ULPs pass 0 for the comp_vector value. Pass the value of num_comp_vectors to userspace rather than hard-coding a value of 1. We want multiple CQ event vector support (via MSI-X or similar for adapters that can generate multiple interrupts), but it's not clear how many vectors we want, or how we want to deal with policy issues such as how to decide which vector to use or how to set up interrupt affinity. This patch is useful for experimenting, since no core changes will be necessary when updating a driver to support multiple vectors, and we know that we want to make at least these changes anyway. Signed-off-by: Michael S. Tsirkin Signed-off-by: Roland Dreier --- drivers/infiniband/hw/ehca/ehca_iverbs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/infiniband/hw/ehca/ehca_iverbs.h') diff --git a/drivers/infiniband/hw/ehca/ehca_iverbs.h b/drivers/infiniband/hw/ehca/ehca_iverbs.h index 95fd59fb452..aff96ac4fd1 100644 --- a/drivers/infiniband/hw/ehca/ehca_iverbs.h +++ b/drivers/infiniband/hw/ehca/ehca_iverbs.h @@ -123,7 +123,7 @@ int ehca_destroy_eq(struct ehca_shca *shca, struct ehca_eq *eq); void *ehca_poll_eq(struct ehca_shca *shca, struct ehca_eq *eq); -struct ib_cq *ehca_create_cq(struct ib_device *device, int cqe, +struct ib_cq *ehca_create_cq(struct ib_device *device, int cqe, int comp_vector, struct ib_ucontext *context, struct ib_udata *udata); -- cgit v1.2.3 From ed23a72778f3dbd465e55b06fe31629e7e1dd2f3 Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Sun, 6 May 2007 21:02:48 -0700 Subject: IB: Return "maybe missed event" hint from ib_req_notify_cq() The semantics defined by the InfiniBand specification say that completion events are only generated when a completions is added to a completion queue (CQ) after completion notification is requested. In other words, this means that the following race is possible: while (CQ is not empty) ib_poll_cq(CQ); // new completion is added after while loop is exited ib_req_notify_cq(CQ); // no event is generated for the existing completion To close this race, the IB spec recommends doing another poll of the CQ after requesting notification. However, it is not always possible to arrange code this way (for example, we have found that NAPI for IPoIB cannot poll after requesting notification). Also, some hardware (eg Mellanox HCAs) actually will generate an event for completions added before the call to ib_req_notify_cq() -- which is allowed by the spec, since there's no way for any upper-layer consumer to know exactly when a completion was really added -- so the extra poll of the CQ is just a waste. Motivated by this, we add a new flag "IB_CQ_REPORT_MISSED_EVENTS" for ib_req_notify_cq() so that it can return a hint about whether the a completion may have been added before the request for notification. The return value of ib_req_notify_cq() is extended so: < 0 means an error occurred while requesting notification == 0 means notification was requested successfully, and if IB_CQ_REPORT_MISSED_EVENTS was passed in, then no events were missed and it is safe to wait for another event. > 0 is only returned if IB_CQ_REPORT_MISSED_EVENTS was passed in. It means that the consumer must poll the CQ again to make sure it is empty to avoid the race described above. We add a flag to enable this behavior rather than turning it on unconditionally, because checking for missed events may incur significant overhead for some low-level drivers, and consumers that don't care about the results of this test shouldn't be forced to pay for the test. Signed-off-by: Roland Dreier --- drivers/infiniband/hw/ehca/ehca_iverbs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/infiniband/hw/ehca/ehca_iverbs.h') diff --git a/drivers/infiniband/hw/ehca/ehca_iverbs.h b/drivers/infiniband/hw/ehca/ehca_iverbs.h index aff96ac4fd1..e14b029332c 100644 --- a/drivers/infiniband/hw/ehca/ehca_iverbs.h +++ b/drivers/infiniband/hw/ehca/ehca_iverbs.h @@ -135,7 +135,7 @@ int ehca_poll_cq(struct ib_cq *cq, int num_entries, struct ib_wc *wc); int ehca_peek_cq(struct ib_cq *cq, int wc_cnt); -int ehca_req_notify_cq(struct ib_cq *cq, enum ib_cq_notify cq_notify); +int ehca_req_notify_cq(struct ib_cq *cq, enum ib_cq_notify_flags notify_flags); struct ib_qp *ehca_create_qp(struct ib_pd *pd, struct ib_qp_init_attr *init_attr, -- cgit v1.2.3 From f7c6a7b5d59980b076abbf2ceeb8735591290285 Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Sun, 4 Mar 2007 16:15:11 -0800 Subject: IB/uverbs: Export ib_umem_get()/ib_umem_release() to modules Export ib_umem_get()/ib_umem_release() and put low-level drivers in control of when to call ib_umem_get() to pin and DMA map userspace, rather than always calling it in ib_uverbs_reg_mr() before calling the low-level driver's reg_user_mr method. Also move these functions to be in the ib_core module instead of ib_uverbs, so that driver modules using them do not depend on ib_uverbs. This has a number of advantages: - It is better design from the standpoint of making generic code a library that can be used or overridden by device-specific code as the details of specific devices dictate. - Drivers that do not need to pin userspace memory regions do not need to take the performance hit of calling ib_mem_get(). For example, although I have not tried to implement it in this patch, the ipath driver should be able to avoid pinning memory and just use copy_{to,from}_user() to access userspace memory regions. - Buffers that need special mapping treatment can be identified by the low-level driver. For example, it may be possible to solve some Altix-specific memory ordering issues with mthca CQs in userspace by mapping CQ buffers with extra flags. - Drivers that need to pin and DMA map userspace memory for things other than memory regions can use ib_umem_get() directly, instead of hacks using extra parameters to their reg_phys_mr method. For example, the mlx4 driver that is pending being merged needs to pin and DMA map QP and CQ buffers, but it does not need to create a memory key for these buffers. So the cleanest solution is for mlx4 to call ib_umem_get() in the create_qp and create_cq methods. Signed-off-by: Roland Dreier --- drivers/infiniband/hw/ehca/ehca_iverbs.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'drivers/infiniband/hw/ehca/ehca_iverbs.h') diff --git a/drivers/infiniband/hw/ehca/ehca_iverbs.h b/drivers/infiniband/hw/ehca/ehca_iverbs.h index e14b029332c..37e7fe0908c 100644 --- a/drivers/infiniband/hw/ehca/ehca_iverbs.h +++ b/drivers/infiniband/hw/ehca/ehca_iverbs.h @@ -78,8 +78,7 @@ struct ib_mr *ehca_reg_phys_mr(struct ib_pd *pd, int num_phys_buf, int mr_access_flags, u64 *iova_start); -struct ib_mr *ehca_reg_user_mr(struct ib_pd *pd, - struct ib_umem *region, +struct ib_mr *ehca_reg_user_mr(struct ib_pd *pd, u64 start, u64 length, u64 virt, int mr_access_flags, struct ib_udata *udata); int ehca_rereg_phys_mr(struct ib_mr *mr, -- cgit v1.2.3