[PATCH rdma-next 0/3] Add support for dynamic UAR usage

[PATCH rdma-next 0/3] Add support for dynamic UAR usage

[Leon Romanovsky]

>From Yishai:

This series enables the user space driver to ask for a dynamic UAR
allocation and uses its internal BF (i.e. blue-flame) registers as part
of QP creation.

The motivation behind this functionality is to let the user space driver
share BF register between few QPs or to set a dedicated BF for a given QP.

The above gives an option to user space applications to utilize its
resources and performance according to its needs.

For example:
An application can improve its performance by having a dedicated BF for
collection of QPs that are running from the same thread and drop the
need to take a lock as part of its post send flow. This is not enabled
today as the kernel driver assigned BF registers in some FIFO logic and
as such QPs from different threads may share same BF and as such a lock
when accessing this BF will be needed.

The series consists from 3 patches:
The first patch extends the alloc context flow to be prepared for
working with dynamic UAR allocations.
The second patch exposes the option to dynamic allocates a UAR.
The third patch uses the given BF register from the user area as
part of QP creation instead of using some arbitrary BF register.

The patches are available in the git repository at:
  git.kernel.org/pub/scm/linux/kernel/git/leon/linux-rdma.git tags/rdma-next-2017-12-24-5

	Thanks
---------------------------------------

Yishai Hadas (3):
  IB/mlx5: Extend UAR stuff to support dynamic allocation
  IB/mlx5: Expose dynamic mmap allocation
  IB/mlx5: Enable QP creation with a given blue flame index

 drivers/infiniband/hw/mlx5/main.c    | 141 ++++++++++++++++++++++++++++-------
 drivers/infiniband/hw/mlx5/mlx5_ib.h |  13 +++-
 drivers/infiniband/hw/mlx5/qp.c      |  55 ++++++++++----
 include/linux/mlx5/device.h          |   2 +
 include/linux/mlx5/driver.h          |   3 +
 include/uapi/rdma/mlx5-abi.h         |   5 +-
 6 files changed, 177 insertions(+), 42 deletions(-)

--
2.15.1

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[PATCH rdma-next 1/3] IB/mlx5: Extend UAR stuff to support dynamic allocation

[Leon Romanovsky]

From: Yishai Hadas <yishaih-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>

This patch extends the alloc context flow to be prepared for working
with dynamic UAR allocations.

Currently upon alloc context there is some fix size of UARs that are
allocated (named 'static allocation') and there is no option to user
application to ask for more or control which UAR will be used by which
QP.

In this patch the driver prepares its data structures to manage both the
static and the dynamic allocations and let the user driver knows about
the max value of dynamic blue-flame registers that are allowed.

Downstream patches from this series will enable the dynamic allocation
and the association as part of QP creation.

Signed-off-by: Yishai Hadas <yishaih-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Signed-off-by: Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 drivers/infiniband/hw/mlx5/main.c    | 37 +++++++++++++++++++++++++++---------
 drivers/infiniband/hw/mlx5/mlx5_ib.h |  6 +++---
 drivers/infiniband/hw/mlx5/qp.c      |  2 +-
 include/linux/mlx5/device.h          |  2 ++
 include/linux/mlx5/driver.h          |  3 +++
 include/uapi/rdma/mlx5-abi.h         |  2 ++
 6 files changed, 39 insertions(+), 13 deletions(-)

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index 9e2d6a872e5a..4f2d71298937 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -1417,9 +1417,18 @@ static void print_lib_caps(struct mlx5_ib_dev *dev, u64 caps)
 		    caps & MLX5_LIB_CAP_4K_UAR ? "y" : "n");
 }
 
+static u16 calc_dynamic_bfregs(int uars_per_sys_page)
+{
+	/* Large page with non 4k uar support might limit the dynamic size */
+	if (uars_per_sys_page == 1  && PAGE_SIZE > 4096)
+		return MLX5_MIN_DYN_BFREGS;
+
+	return MLX5_MAX_DYN_BFREGS;
+}
+
 static int calc_total_bfregs(struct mlx5_ib_dev *dev, bool lib_uar_4k,
 			     struct mlx5_ib_alloc_ucontext_req_v2 *req,
-			     u32 *num_sys_pages)
+			     struct mlx5_bfreg_info *bfregi)
 {
 	int uars_per_sys_page;
 	int bfregs_per_sys_page;
@@ -1436,16 +1445,21 @@ static int calc_total_bfregs(struct mlx5_ib_dev *dev, bool lib_uar_4k,
 
 	uars_per_sys_page = get_uars_per_sys_page(dev, lib_uar_4k);
 	bfregs_per_sys_page = uars_per_sys_page * MLX5_NON_FP_BFREGS_PER_UAR;
+	/* This holds the required static allocation asked by the user */
 	req->total_num_bfregs = ALIGN(req->total_num_bfregs, bfregs_per_sys_page);
-	*num_sys_pages = req->total_num_bfregs / bfregs_per_sys_page;
-
 	if (req->num_low_latency_bfregs > req->total_num_bfregs - 1)
 		return -EINVAL;
 
-	mlx5_ib_dbg(dev, "uar_4k: fw support %s, lib support %s, user requested %d bfregs, allocated %d, using %d sys pages\n",
+	bfregi->num_static_sys_pages = req->total_num_bfregs / bfregs_per_sys_page;
+	bfregi->num_dyn_bfregs = ALIGN(calc_dynamic_bfregs(uars_per_sys_page), bfregs_per_sys_page);
+	bfregi->total_num_bfregs = req->total_num_bfregs + bfregi->num_dyn_bfregs;
+	bfregi->num_sys_pages = bfregi->total_num_bfregs / bfregs_per_sys_page;
+
+	mlx5_ib_dbg(dev, "uar_4k: fw support %s, lib support %s, user requested %d bfregs, allocated %d, total bfregs %d, using %d sys pages\n",
 		    MLX5_CAP_GEN(dev->mdev, uar_4k) ? "yes" : "no",
 		    lib_uar_4k ? "yes" : "no", ref_bfregs,
-		    req->total_num_bfregs, *num_sys_pages);
+		    req->total_num_bfregs, bfregi->total_num_bfregs,
+		    bfregi->num_sys_pages);
 
 	return 0;
 }
@@ -1457,7 +1471,7 @@ static int allocate_uars(struct mlx5_ib_dev *dev, struct mlx5_ib_ucontext *conte
 	int i;
 
 	bfregi = &context->bfregi;
-	for (i = 0; i < bfregi->num_sys_pages; i++) {
+	for (i = 0; i < bfregi->num_static_sys_pages; i++) {
 		err = mlx5_cmd_alloc_uar(dev->mdev, &bfregi->sys_pages[i]);
 		if (err)
 			goto error;
@@ -1481,7 +1495,7 @@ static int deallocate_uars(struct mlx5_ib_dev *dev, struct mlx5_ib_ucontext *con
 	int i;
 
 	bfregi = &context->bfregi;
-	for (i = 0; i < bfregi->num_sys_pages; i++) {
+	for (i = 0; i < bfregi->num_static_sys_pages; i++) {
 		err = mlx5_cmd_free_uar(dev->mdev, bfregi->sys_pages[i]);
 		if (err) {
 			mlx5_ib_warn(dev, "failed to free uar %d\n", i);
@@ -1596,13 +1610,13 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev,
 	bfregi = &context->bfregi;
 
 	/* updates req->total_num_bfregs */
-	err = calc_total_bfregs(dev, lib_uar_4k, &req, &bfregi->num_sys_pages);
+	err = calc_total_bfregs(dev, lib_uar_4k, &req, bfregi);
 	if (err)
 		goto out_ctx;
 
 	mutex_init(&bfregi->lock);
 	bfregi->lib_uar_4k = lib_uar_4k;
-	bfregi->count = kcalloc(req.total_num_bfregs, sizeof(*bfregi->count),
+	bfregi->count = kcalloc(bfregi->total_num_bfregs, sizeof(*bfregi->count),
 				GFP_KERNEL);
 	if (!bfregi->count) {
 		err = -ENOMEM;
@@ -1685,6 +1699,11 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev,
 	if (field_avail(typeof(resp), num_uars_per_page, udata->outlen))
 		resp.response_length += sizeof(resp.num_uars_per_page);
 
+	if (field_avail(typeof(resp), num_dyn_bfregs, udata->outlen)) {
+		resp.num_dyn_bfregs = bfregi->num_dyn_bfregs;
+		resp.response_length += sizeof(resp.num_dyn_bfregs);
+	}
+
 	err = ib_copy_to_udata(udata, &resp, resp.response_length);
 	if (err)
 		goto out_td;
diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index 196b55b90c60..32b317d16280 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -1177,10 +1177,10 @@ static inline int get_uars_per_sys_page(struct mlx5_ib_dev *dev, bool lib_suppor
 				MLX5_UARS_IN_PAGE : 1;
 }
 
-static inline int get_num_uars(struct mlx5_ib_dev *dev,
-			       struct mlx5_bfreg_info *bfregi)
+static inline int get_num_static_uars(struct mlx5_ib_dev *dev,
+				      struct mlx5_bfreg_info *bfregi)
 {
-	return get_uars_per_sys_page(dev, bfregi->lib_uar_4k) * bfregi->num_sys_pages;
+	return get_uars_per_sys_page(dev, bfregi->lib_uar_4k) * bfregi->num_static_sys_pages;
 }
 
 #endif /* MLX5_IB_H */
diff --git a/drivers/infiniband/hw/mlx5/qp.c b/drivers/infiniband/hw/mlx5/qp.c
index 33b132a9a0fc..166b37daa794 100644
--- a/drivers/infiniband/hw/mlx5/qp.c
+++ b/drivers/infiniband/hw/mlx5/qp.c
@@ -493,7 +493,7 @@ enum {
 
 static int max_bfregs(struct mlx5_ib_dev *dev, struct mlx5_bfreg_info *bfregi)
 {
-	return get_num_uars(dev, bfregi) * MLX5_NON_FP_BFREGS_PER_UAR;
+	return get_num_static_uars(dev, bfregi) * MLX5_NON_FP_BFREGS_PER_UAR;
 }
 
 static int num_med_bfreg(struct mlx5_ib_dev *dev,
diff --git a/include/linux/mlx5/device.h b/include/linux/mlx5/device.h
index 18c041966ab8..2ff9f48ebec3 100644
--- a/include/linux/mlx5/device.h
+++ b/include/linux/mlx5/device.h
@@ -249,6 +249,8 @@ enum {
 					  MLX5_NON_FP_BFREGS_PER_UAR,
 	MLX5_UARS_IN_PAGE		= PAGE_SIZE / MLX5_ADAPTER_PAGE_SIZE,
 	MLX5_NON_FP_BFREGS_IN_PAGE	= MLX5_NON_FP_BFREGS_PER_UAR * MLX5_UARS_IN_PAGE,
+	MLX5_MIN_DYN_BFREGS		= 512,
+	MLX5_MAX_DYN_BFREGS		= 1024,
 };
 
 enum {
diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h
index bc494ddefcf8..4d1ed35fdbb4 100644
--- a/include/linux/mlx5/driver.h
+++ b/include/linux/mlx5/driver.h
@@ -230,6 +230,9 @@ struct mlx5_bfreg_info {
 	u32			ver;
 	bool			lib_uar_4k;
 	u32			num_sys_pages;
+	u32			num_static_sys_pages;
+	u32			total_num_bfregs;
+	u32			num_dyn_bfregs;
 };
 
 struct mlx5_cmd_first {
diff --git a/include/uapi/rdma/mlx5-abi.h b/include/uapi/rdma/mlx5-abi.h
index 062d14f07b61..12c523a1dd18 100644
--- a/include/uapi/rdma/mlx5-abi.h
+++ b/include/uapi/rdma/mlx5-abi.h
@@ -125,6 +125,8 @@ struct mlx5_ib_alloc_ucontext_resp {
 	__u64	hca_core_clock_offset;
 	__u32	log_uar_size;
 	__u32	num_uars_per_page;
+	__u32	num_dyn_bfregs;
+	__u32	reserved3;
 };
 
 struct mlx5_ib_alloc_pd_resp {
-- 
2.15.1

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[PATCH rdma-next 2/3] IB/mlx5: Expose dynamic mmap allocation

[Leon Romanovsky]

From: Yishai Hadas <yishaih-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>

This patch exposes the option to dynamic allocates a UAR, this
functionality will be used in downstream patch in this series as
part of QP creation.

Specifically, the user space driver asks for a UAR allocation in a given
page index, upon success this UAR and its bfregs can be used as part of
QP creation by the user space driver.

To enable allocating more than 256 UARs the page index is encoded in an
extra one byte just after the command byte.

Signed-off-by: Yishai Hadas <yishaih-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Signed-off-by: Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 drivers/infiniband/hw/mlx5/main.c    | 108 +++++++++++++++++++++++++++++------
 drivers/infiniband/hw/mlx5/mlx5_ib.h |   6 ++
 drivers/infiniband/hw/mlx5/qp.c      |   6 +-
 3 files changed, 99 insertions(+), 21 deletions(-)

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index 4f2d71298937..9c737cc65503 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -1478,6 +1478,10 @@ static int allocate_uars(struct mlx5_ib_dev *dev, struct mlx5_ib_ucontext *conte
 
 		mlx5_ib_dbg(dev, "allocated uar %d\n", bfregi->sys_pages[i]);
 	}
+
+	for (i = bfregi->num_static_sys_pages; i < bfregi->num_sys_pages; i++)
+		bfregi->sys_pages[i] = MLX5_IB_INVALID_UAR_INDEX;
+
 	return 0;
 
 error:
@@ -1495,13 +1499,17 @@ static int deallocate_uars(struct mlx5_ib_dev *dev, struct mlx5_ib_ucontext *con
 	int i;
 
 	bfregi = &context->bfregi;
-	for (i = 0; i < bfregi->num_static_sys_pages; i++) {
-		err = mlx5_cmd_free_uar(dev->mdev, bfregi->sys_pages[i]);
-		if (err) {
-			mlx5_ib_warn(dev, "failed to free uar %d\n", i);
-			return err;
+	for (i = 0; i < bfregi->num_sys_pages; i++) {
+		if (i < bfregi->num_static_sys_pages ||
+		    bfregi->sys_pages[i] != MLX5_IB_INVALID_UAR_INDEX) {
+			err = mlx5_cmd_free_uar(dev->mdev, bfregi->sys_pages[i]);
+			if (err) {
+				mlx5_ib_warn(dev, "failed to free uar %d, err=%d\n", i, err);
+				return err;
+			}
 		}
 	}
+
 	return 0;
 }
 
@@ -1758,15 +1766,13 @@ static int mlx5_ib_dealloc_ucontext(struct ib_ucontext *ibcontext)
 }
 
 static phys_addr_t uar_index2pfn(struct mlx5_ib_dev *dev,
-				 struct mlx5_bfreg_info *bfregi,
-				 int idx)
+				 int uar_idx)
 {
 	int fw_uars_per_page;
 
 	fw_uars_per_page = MLX5_CAP_GEN(dev->mdev, uar_4k) ? MLX5_UARS_IN_PAGE : 1;
 
-	return (pci_resource_start(dev->mdev->pdev, 0) >> PAGE_SHIFT) +
-			bfregi->sys_pages[idx] / fw_uars_per_page;
+	return (pci_resource_start(dev->mdev->pdev, 0) >> PAGE_SHIFT) + uar_idx / fw_uars_per_page;
 }
 
 static int get_command(unsigned long offset)
@@ -1784,6 +1790,12 @@ static int get_index(unsigned long offset)
 	return get_arg(offset);
 }
 
+/* Index resides in an extra byte to enable larger values than 255 */
+static int get_extended_index(unsigned long offset)
+{
+	return get_arg(offset) | ((offset >> 16) & 0xff) << 8;
+}
+
 static void  mlx5_ib_vma_open(struct vm_area_struct *area)
 {
 	/* vma_open is called when a new VMA is created on top of our VMA.  This
@@ -1927,21 +1939,29 @@ static int uar_mmap(struct mlx5_ib_dev *dev, enum mlx5_ib_mmap_cmd cmd,
 	unsigned long idx;
 	phys_addr_t pfn, pa;
 	pgprot_t prot;
-	int uars_per_page;
+	u32 bfreg_dyn_idx = 0;
+	u32 uar_index;
+	int dyn_uar = (cmd == MLX5_IB_MMAP_ALLOC_WC);
+	int max_valid_idx = dyn_uar ? bfregi->num_sys_pages :
+				bfregi->num_static_sys_pages;
 
 	if (vma->vm_end - vma->vm_start != PAGE_SIZE)
 		return -EINVAL;
 
-	uars_per_page = get_uars_per_sys_page(dev, bfregi->lib_uar_4k);
-	idx = get_index(vma->vm_pgoff);
-	if (idx % uars_per_page ||
-	    idx * uars_per_page >= bfregi->num_sys_pages) {
-		mlx5_ib_warn(dev, "invalid uar index %lu\n", idx);
+	if (dyn_uar)
+		idx = get_extended_index(vma->vm_pgoff) + bfregi->num_static_sys_pages;
+	else
+		idx = get_index(vma->vm_pgoff);
+
+	if (idx >= max_valid_idx) {
+		mlx5_ib_warn(dev, "invalid uar index %lu, max=%d\n",
+			     idx, max_valid_idx);
 		return -EINVAL;
 	}
 
 	switch (cmd) {
 	case MLX5_IB_MMAP_WC_PAGE:
+	case MLX5_IB_MMAP_ALLOC_WC:
 /* Some architectures don't support WC memory */
 #if defined(CONFIG_X86)
 		if (!pat_enabled())
@@ -1961,7 +1981,40 @@ static int uar_mmap(struct mlx5_ib_dev *dev, enum mlx5_ib_mmap_cmd cmd,
 		return -EINVAL;
 	}
 
-	pfn = uar_index2pfn(dev, bfregi, idx);
+	if (dyn_uar) {
+		int uars_per_page;
+
+		uars_per_page = get_uars_per_sys_page(dev, bfregi->lib_uar_4k);
+		bfreg_dyn_idx = idx * (uars_per_page * MLX5_NON_FP_BFREGS_PER_UAR);
+		if (bfreg_dyn_idx >= bfregi->total_num_bfregs) {
+			mlx5_ib_warn(dev, "invalid bfreg_dyn_idx %u, max=%u\n",
+				     bfreg_dyn_idx, bfregi->total_num_bfregs);
+			return -EINVAL;
+		}
+
+		mutex_lock(&bfregi->lock);
+		/* Fail if uar already allocated, first bfreg index of each
+		 * page holds its count.
+		 */
+		if (bfregi->count[bfreg_dyn_idx]) {
+			mlx5_ib_warn(dev, "wrong offset, idx %lu is busy, bfregn=%u\n", idx, bfreg_dyn_idx);
+			mutex_unlock(&bfregi->lock);
+			return -EINVAL;
+		}
+
+		bfregi->count[bfreg_dyn_idx]++;
+		mutex_unlock(&bfregi->lock);
+
+		err = mlx5_cmd_alloc_uar(dev->mdev, &uar_index);
+		if (err) {
+			mlx5_ib_warn(dev, "UAR alloc failed\n");
+			goto free_bfreg;
+		}
+	} else {
+		uar_index = bfregi->sys_pages[idx];
+	}
+
+	pfn = uar_index2pfn(dev, uar_index);
 	mlx5_ib_dbg(dev, "uar idx 0x%lx, pfn %pa\n", idx, &pfn);
 
 	vma->vm_page_prot = prot;
@@ -1970,14 +2023,32 @@ static int uar_mmap(struct mlx5_ib_dev *dev, enum mlx5_ib_mmap_cmd cmd,
 	if (err) {
 		mlx5_ib_err(dev, "io_remap_pfn_range failed with error=%d, vm_start=0x%lx, pfn=%pa, mmap_cmd=%s\n",
 			    err, vma->vm_start, &pfn, mmap_cmd2str(cmd));
-		return -EAGAIN;
+		err = -EAGAIN;
+		goto err;
 	}
 
 	pa = pfn << PAGE_SHIFT;
 	mlx5_ib_dbg(dev, "mapped %s at 0x%lx, PA %pa\n", mmap_cmd2str(cmd),
 		    vma->vm_start, &pa);
 
-	return mlx5_ib_set_vma_data(vma, context);
+	err = mlx5_ib_set_vma_data(vma, context);
+	if (err)
+		goto err;
+
+	if (dyn_uar)
+		bfregi->sys_pages[idx] = uar_index;
+	return 0;
+
+err:
+	if (!dyn_uar)
+		return err;
+
+	mlx5_cmd_free_uar(dev->mdev, idx);
+
+free_bfreg:
+	mlx5_ib_free_bfreg(dev, bfregi, bfreg_dyn_idx);
+
+	return err;
 }
 
 static int mlx5_ib_mmap(struct ib_ucontext *ibcontext, struct vm_area_struct *vma)
@@ -1992,6 +2063,7 @@ static int mlx5_ib_mmap(struct ib_ucontext *ibcontext, struct vm_area_struct *vm
 	case MLX5_IB_MMAP_WC_PAGE:
 	case MLX5_IB_MMAP_NC_PAGE:
 	case MLX5_IB_MMAP_REGULAR_PAGE:
+	case MLX5_IB_MMAP_ALLOC_WC:
 		return uar_mmap(dev, command, vma, context);
 
 	case MLX5_IB_MMAP_GET_CONTIGUOUS_PAGES:
diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index 32b317d16280..c471e11b720c 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -77,6 +77,7 @@ enum mlx5_ib_mmap_cmd {
 	MLX5_IB_MMAP_NC_PAGE			= 3,
 	/* 5 is chosen in order to be compatible with old versions of libmlx5 */
 	MLX5_IB_MMAP_CORE_CLOCK			= 5,
+	MLX5_IB_MMAP_ALLOC_WC			= 6,
 };
 
 enum {
@@ -112,6 +113,10 @@ enum {
 	MLX5_TM_MAX_SGE			= 1,
 };
 
+enum {
+	MLX5_IB_INVALID_UAR_INDEX	= BIT(31),
+};
+
 struct mlx5_ib_vma_private_data {
 	struct list_head list;
 	struct vm_area_struct *vma;
@@ -1085,6 +1090,7 @@ struct mlx5_core_dev *mlx5_ib_get_native_port_mdev(struct mlx5_ib_dev *dev,
 void mlx5_ib_put_native_port_mdev(struct mlx5_ib_dev *dev,
 				  u8 port_num);
 
+void mlx5_ib_free_bfreg(struct mlx5_ib_dev *dev, struct mlx5_bfreg_info *bfregi, int bfregn);
 static inline void init_query_mad(struct ib_smp *mad)
 {
 	mad->base_version  = 1;
diff --git a/drivers/infiniband/hw/mlx5/qp.c b/drivers/infiniband/hw/mlx5/qp.c
index 166b37daa794..0f299dfd8ae0 100644
--- a/drivers/infiniband/hw/mlx5/qp.c
+++ b/drivers/infiniband/hw/mlx5/qp.c
@@ -581,7 +581,7 @@ static int alloc_bfreg(struct mlx5_ib_dev *dev,
 	return bfregn;
 }
 
-static void free_bfreg(struct mlx5_ib_dev *dev, struct mlx5_bfreg_info *bfregi, int bfregn)
+void mlx5_ib_free_bfreg(struct mlx5_ib_dev *dev, struct mlx5_bfreg_info *bfregi, int bfregn)
 {
 	mutex_lock(&bfregi->lock);
 	bfregi->count[bfregn]--;
@@ -874,7 +874,7 @@ static int create_user_qp(struct mlx5_ib_dev *dev, struct ib_pd *pd,
 		ib_umem_release(ubuffer->umem);
 
 err_bfreg:
-	free_bfreg(dev, &context->bfregi, bfregn);
+	mlx5_ib_free_bfreg(dev, &context->bfregi, bfregn);
 	return err;
 }
 
@@ -887,7 +887,7 @@ static void destroy_qp_user(struct mlx5_ib_dev *dev, struct ib_pd *pd,
 	mlx5_ib_db_unmap_user(context, &qp->db);
 	if (base->ubuffer.umem)
 		ib_umem_release(base->ubuffer.umem);
-	free_bfreg(dev, &context->bfregi, qp->bfregn);
+	mlx5_ib_free_bfreg(dev, &context->bfregi, qp->bfregn);
 }
 
 static int create_kernel_qp(struct mlx5_ib_dev *dev,
-- 
2.15.1

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[PATCH rdma-next 3/3] IB/mlx5: Enable QP creation with a given blue flame index

[Leon Romanovsky]

From: Yishai Hadas <yishaih-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>

This patch enables QP creation with a given BF index, this allows the
user space driver to share same BF between few QPs or alternatively have
a dedicated BF per QP.

Signed-off-by: Yishai Hadas <yishaih-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Signed-off-by: Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 drivers/infiniband/hw/mlx5/mlx5_ib.h |  1 +
 drivers/infiniband/hw/mlx5/qp.c      | 51 ++++++++++++++++++++++++++++--------
 include/uapi/rdma/mlx5-abi.h         |  3 ++-
 3 files changed, 43 insertions(+), 12 deletions(-)

diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index c471e11b720c..88b89ed15d1c 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -115,6 +115,7 @@ enum {
 
 enum {
 	MLX5_IB_INVALID_UAR_INDEX	= BIT(31),
+	MLX5_IB_INVALID_BFREG		= BIT(31),
 };
 
 struct mlx5_ib_vma_private_data {
diff --git a/drivers/infiniband/hw/mlx5/qp.c b/drivers/infiniband/hw/mlx5/qp.c
index 0f299dfd8ae0..4b0420e67870 100644
--- a/drivers/infiniband/hw/mlx5/qp.c
+++ b/drivers/infiniband/hw/mlx5/qp.c
@@ -627,7 +627,8 @@ static void mlx5_ib_unlock_cqs(struct mlx5_ib_cq *send_cq,
 			       struct mlx5_ib_cq *recv_cq);
 
 static int bfregn_to_uar_index(struct mlx5_ib_dev *dev,
-			       struct mlx5_bfreg_info *bfregi, int bfregn)
+			       struct mlx5_bfreg_info *bfregi, int bfregn,
+			       bool dyn_bfreg)
 {
 	int bfregs_per_sys_page;
 	int index_of_sys_page;
@@ -637,8 +638,16 @@ static int bfregn_to_uar_index(struct mlx5_ib_dev *dev,
 				MLX5_NON_FP_BFREGS_PER_UAR;
 	index_of_sys_page = bfregn / bfregs_per_sys_page;
 
-	offset = bfregn % bfregs_per_sys_page / MLX5_NON_FP_BFREGS_PER_UAR;
+	if (dyn_bfreg) {
+		index_of_sys_page += bfregi->num_static_sys_pages;
+		if (bfregn > bfregi->num_dyn_bfregs ||
+		    bfregi->sys_pages[index_of_sys_page] == MLX5_IB_INVALID_UAR_INDEX) {
+			mlx5_ib_dbg(dev, "Invalid dynamic uar index\n");
+			return -EINVAL;
+		}
+	}
 
+	offset = bfregn % bfregs_per_sys_page / MLX5_NON_FP_BFREGS_PER_UAR;
 	return bfregi->sys_pages[index_of_sys_page] + offset;
 }
 
@@ -764,7 +773,7 @@ static int create_user_qp(struct mlx5_ib_dev *dev, struct ib_pd *pd,
 	struct mlx5_ib_create_qp ucmd;
 	struct mlx5_ib_ubuffer *ubuffer = &base->ubuffer;
 	int page_shift = 0;
-	int uar_index;
+	int uar_index = 0;
 	int npages;
 	u32 offset = 0;
 	int bfregn;
@@ -780,12 +789,20 @@ static int create_user_qp(struct mlx5_ib_dev *dev, struct ib_pd *pd,
 	}
 
 	context = to_mucontext(pd->uobject->context);
-	/*
-	 * TBD: should come from the verbs when we have the API
-	 */
-	if (qp->flags & MLX5_IB_QP_CROSS_CHANNEL)
+	if (ucmd.flags & MLX5_QP_FLAG_BFREG_INDEX) {
+		uar_index = bfregn_to_uar_index(dev, &context->bfregi,
+						ucmd.bfreg_index, true);
+		if (uar_index < 0)
+			return uar_index;
+
+		bfregn = MLX5_IB_INVALID_BFREG;
+	} else if (qp->flags & MLX5_IB_QP_CROSS_CHANNEL) {
+		/*
+		 * TBD: should come from the verbs when we have the API
+		 */
 		/* In CROSS_CHANNEL CQ and QP must use the same UAR */
 		bfregn = MLX5_CROSS_CHANNEL_BFREG;
+	}
 	else {
 		bfregn = alloc_bfreg(dev, &context->bfregi, MLX5_IB_LATENCY_CLASS_HIGH);
 		if (bfregn < 0) {
@@ -804,8 +821,10 @@ static int create_user_qp(struct mlx5_ib_dev *dev, struct ib_pd *pd,
 		}
 	}
 
-	uar_index = bfregn_to_uar_index(dev, &context->bfregi, bfregn);
 	mlx5_ib_dbg(dev, "bfregn 0x%x, uar_index 0x%x\n", bfregn, uar_index);
+	if (bfregn != MLX5_IB_INVALID_BFREG)
+		uar_index = bfregn_to_uar_index(dev, &context->bfregi, bfregn,
+						false);
 
 	qp->rq.offset = 0;
 	qp->sq.wqe_shift = ilog2(MLX5_SEND_WQE_BB);
@@ -845,7 +864,10 @@ static int create_user_qp(struct mlx5_ib_dev *dev, struct ib_pd *pd,
 	MLX5_SET(qpc, qpc, page_offset, offset);
 
 	MLX5_SET(qpc, qpc, uar_page, uar_index);
-	resp->bfreg_index = adjust_bfregn(dev, &context->bfregi, bfregn);
+	if (bfregn != MLX5_IB_INVALID_BFREG)
+		resp->bfreg_index = adjust_bfregn(dev, &context->bfregi, bfregn);
+	else
+		resp->bfreg_index = MLX5_IB_INVALID_BFREG;
 	qp->bfregn = bfregn;
 
 	err = mlx5_ib_db_map_user(context, ucmd.db_addr, &qp->db);
@@ -874,7 +896,8 @@ static int create_user_qp(struct mlx5_ib_dev *dev, struct ib_pd *pd,
 		ib_umem_release(ubuffer->umem);
 
 err_bfreg:
-	mlx5_ib_free_bfreg(dev, &context->bfregi, bfregn);
+	if (bfregn != MLX5_IB_INVALID_BFREG)
+		mlx5_ib_free_bfreg(dev, &context->bfregi, bfregn);
 	return err;
 }
 
@@ -887,7 +910,13 @@ static void destroy_qp_user(struct mlx5_ib_dev *dev, struct ib_pd *pd,
 	mlx5_ib_db_unmap_user(context, &qp->db);
 	if (base->ubuffer.umem)
 		ib_umem_release(base->ubuffer.umem);
-	mlx5_ib_free_bfreg(dev, &context->bfregi, qp->bfregn);
+
+	/*
+	 * Free only the BFREGs which are handled by the kernel.
+	 * BFREGs of UARs allocated dynamically are handled by user.
+	 */
+	if (qp->bfregn != MLX5_IB_INVALID_BFREG)
+		mlx5_ib_free_bfreg(dev, &context->bfregi, qp->bfregn);
 }
 
 static int create_kernel_qp(struct mlx5_ib_dev *dev,
diff --git a/include/uapi/rdma/mlx5-abi.h b/include/uapi/rdma/mlx5-abi.h
index 12c523a1dd18..0f7e45680ce5 100644
--- a/include/uapi/rdma/mlx5-abi.h
+++ b/include/uapi/rdma/mlx5-abi.h
@@ -41,6 +41,7 @@ enum {
 	MLX5_QP_FLAG_SIGNATURE		= 1 << 0,
 	MLX5_QP_FLAG_SCATTER_CQE	= 1 << 1,
 	MLX5_QP_FLAG_TUNNEL_OFFLOADS	= 1 << 2,
+	MLX5_QP_FLAG_BFREG_INDEX	= 1 << 3,
 };
 
 enum {
@@ -282,7 +283,7 @@ struct mlx5_ib_create_qp {
 	__u32	rq_wqe_shift;
 	__u32	flags;
 	__u32	uidx;
-	__u32	reserved0;
+	__u32	bfreg_index;
 	__u64	sq_buf_addr;
 };
 
-- 
2.15.1

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Re: [PATCH rdma-next 0/3] Add support for dynamic UAR usage

[Jason Gunthorpe]

On Sun, Dec 24, 2017 at 04:31:33PM +0200, Leon Romanovsky wrote:
> >From Yishai:
> 
> This series enables the user space driver to ask for a dynamic UAR
> allocation and uses its internal BF (i.e. blue-flame) registers as part
> of QP creation.
> 
> The motivation behind this functionality is to let the user space driver
> share BF register between few QPs or to set a dedicated BF for a given QP.
> 
> The above gives an option to user space applications to utilize its
> resources and performance according to its needs.
> 
> For example:
> An application can improve its performance by having a dedicated BF for
> collection of QPs that are running from the same thread and drop the
> need to take a lock as part of its post send flow. This is not enabled
> today as the kernel driver assigned BF registers in some FIFO logic and
> as such QPs from different threads may share same BF and as such a lock
> when accessing this BF will be needed.
> 
> The series consists from 3 patches:
> The first patch extends the alloc context flow to be prepared for
> working with dynamic UAR allocations.
> The second patch exposes the option to dynamic allocates a UAR.
> The third patch uses the given BF register from the user area as
> part of QP creation instead of using some arbitrary BF register.
> 
> The patches are available in the git repository at:
>   git.kernel.org/pub/scm/linux/kernel/git/leon/linux-rdma.git tags/rdma-next-2017-12-24-5

Applied to for-next

Thanks
Jason
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