[openib-general] [PATCH 5/6] iSER handling of memory for RDMA
Or Gerlitz
ogerlitz at voltaire.com
Thu May 11 00:03:08 PDT 2006
This file contains the processing carried over an SG list associated with
a SCSI command such that it can be registered with the IB verbs. The
registration produces a network virtual address (VA) and a remote access
key (RKEY or STAG in iSER spec notation) which are used by the target for
its RDMA operation.
Signed-off-by: Or Gerlitz <ogerlitz at voltaire.com>
--- /usr/src/linux-2.6.17-rc3/drivers/infiniband/ulp/iser-x/iser_memory.c 1970-01-01 02:00:00.000000000 +0200
+++ /usr/src/linux-2.6.17-rc3/drivers/infiniband/ulp/iser/iser_memory.c 2006-05-10 15:32:01.000000000 +0300
@@ -0,0 +1,401 @@
+/*
+ * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses. You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials
+ * provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * $Id: iser_memory.c 6964 2006-05-07 11:11:43Z ogerlitz $
+ */
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <asm/io.h>
+#include <asm/scatterlist.h>
+#include <linux/scatterlist.h>
+
+#include "iscsi_iser.h"
+
+#define ISER_KMALLOC_THRESHOLD 0x20000 /* 128K - kmalloc limit */
+/**
+ * Decrements the reference count for the
+ * registered buffer & releases it
+ *
+ * returns 0 if released, 1 if deferred
+ */
+int iser_regd_buff_release(struct iser_regd_buf *regd_buf)
+{
+ struct device *dma_device;
+
+ if ((atomic_read(®d_buf->ref_count) == 0) ||
+ atomic_dec_and_test(®d_buf->ref_count)) {
+ /* if we used the dma mr, unreg is just NOP */
+ if (regd_buf->reg.rkey != 0)
+ iser_unreg_mem(®d_buf->reg);
+
+ if (regd_buf->dma_addr) {
+ dma_device = regd_buf->device->ib_device->dma_device;
+ dma_unmap_single(dma_device,
+ regd_buf->dma_addr,
+ regd_buf->data_size,
+ regd_buf->direction);
+ }
+ /* else this regd buf is associated with task which we */
+ /* dma_unmap_single/sg later */
+ return 0;
+ } else {
+ iser_dbg("Release deferred, regd.buff: 0x%p\n", regd_buf);
+ return 1;
+ }
+}
+
+/**
+ * iser_reg_single - fills registered buffer descriptor with
+ * registration information
+ */
+void iser_reg_single(struct iser_device *device,
+ struct iser_regd_buf *regd_buf,
+ enum dma_data_direction direction)
+{
+ dma_addr_t dma_addr;
+
+ dma_addr = dma_map_single(device->ib_device->dma_device,
+ regd_buf->virt_addr,
+ regd_buf->data_size, direction);
+ BUG_ON(dma_mapping_error(dma_addr));
+
+ regd_buf->reg.lkey = device->mr->lkey;
+ regd_buf->reg.rkey = 0; /* indicate there's no need to unreg */
+ regd_buf->reg.len = regd_buf->data_size;
+ regd_buf->reg.va = dma_addr;
+
+ regd_buf->dma_addr = dma_addr;
+ regd_buf->direction = direction;
+}
+
+/**
+ * iser_start_rdma_unaligned_sg
+ */
+int iser_start_rdma_unaligned_sg(struct iscsi_iser_cmd_task *iser_ctask,
+ enum iser_data_dir cmd_dir)
+{
+ int dma_nents;
+ struct device *dma_device;
+ char *mem = NULL;
+ struct iser_data_buf *data = &iser_ctask->data[cmd_dir];
+ unsigned long cmd_data_len = data->data_len;
+
+ if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
+ mem = (void *)__get_free_pages(GFP_KERNEL,
+ long_log2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
+ else
+ mem = kmalloc(cmd_data_len, GFP_KERNEL);
+
+ if (mem == NULL) {
+ iser_err("Failed to allocate mem size %d %d for copying sglist\n",
+ data->size,(int)cmd_data_len);
+ return -ENOMEM;
+ }
+
+ if (cmd_dir == ISER_DIR_OUT) {
+ /* copy the unaligned sg the buffer which is used for RDMA */
+ struct scatterlist *sg = (struct scatterlist *)data->buf;
+ int i;
+ char *p, *from;
+
+ for (p = mem, i = 0; i < data->size; i++) {
+ from = kmap_atomic(sg[i].page, KM_USER0);
+ memcpy(p,
+ from + sg[i].offset,
+ sg[i].length);
+ kunmap_atomic(from, KM_USER0);
+ p += sg[i].length;
+ }
+ }
+
+ sg_init_one(&iser_ctask->data_copy[cmd_dir].sg_single, mem, cmd_data_len);
+ iser_ctask->data_copy[cmd_dir].buf =
+ &iser_ctask->data_copy[cmd_dir].sg_single;
+ iser_ctask->data_copy[cmd_dir].size = 1;
+
+ iser_ctask->data_copy[cmd_dir].copy_buf = mem;
+
+ dma_device = iser_ctask->iser_conn->ib_conn->device->ib_device->dma_device;
+
+ if (cmd_dir == ISER_DIR_OUT)
+ dma_nents = dma_map_sg(dma_device,
+ &iser_ctask->data_copy[cmd_dir].sg_single,
+ 1, DMA_TO_DEVICE);
+ else
+ dma_nents = dma_map_sg(dma_device,
+ &iser_ctask->data_copy[cmd_dir].sg_single,
+ 1, DMA_FROM_DEVICE);
+
+ BUG_ON(dma_nents == 0);
+
+ iser_ctask->data_copy[cmd_dir].dma_nents = dma_nents;
+ return 0;
+}
+
+/**
+ * iser_finalize_rdma_unaligned_sg
+ */
+void iser_finalize_rdma_unaligned_sg(struct iscsi_iser_cmd_task *iser_ctask,
+ enum iser_data_dir cmd_dir)
+{
+ struct device *dma_device;
+ struct iser_data_buf *mem_copy;
+ unsigned long cmd_data_len;
+
+ dma_device = iser_ctask->iser_conn->ib_conn->device->ib_device->dma_device;
+ mem_copy = &iser_ctask->data_copy[cmd_dir];
+
+ if (cmd_dir == ISER_DIR_OUT)
+ dma_unmap_sg(dma_device, &mem_copy->sg_single, 1,
+ DMA_TO_DEVICE);
+ else
+ dma_unmap_sg(dma_device, &mem_copy->sg_single, 1,
+ DMA_FROM_DEVICE);
+
+ if (cmd_dir == ISER_DIR_IN) {
+ char *mem;
+ struct scatterlist *sg;
+ unsigned char *p, *to;
+ unsigned int sg_size;
+ int i;
+
+ /* copy back read RDMA to unaligned sg */
+ mem = mem_copy->copy_buf;
+
+ sg = (struct scatterlist *)iser_ctask->data[ISER_DIR_IN].buf;
+ sg_size = iser_ctask->data[ISER_DIR_IN].size;
+
+ for (p = mem, i = 0; i < sg_size; i++){
+ to = kmap_atomic(sg[i].page, KM_SOFTIRQ0);
+ memcpy(to + sg[i].offset,
+ p,
+ sg[i].length);
+ kunmap_atomic(to, KM_SOFTIRQ0);
+ p += sg[i].length;
+ }
+ }
+
+ cmd_data_len = iser_ctask->data[cmd_dir].data_len;
+
+ if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
+ free_pages((unsigned long)mem_copy->copy_buf,
+ long_log2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
+ else
+ kfree(mem_copy->copy_buf);
+
+ mem_copy->copy_buf = NULL;
+}
+
+/**
+ * iser_sg_to_page_vec - Translates scatterlist entries to physical addresses
+ * and returns the length of resulting physical address array (may be less than
+ * the original due to possible compaction).
+ *
+ * we build a "page vec" under the assumption that the SG meets the RDMA
+ * alignment requirements. Other then the first and last SG elements, all
+ * the "internal" elements can be compacted into a list whose elements are
+ * dma addresses of physical pages. The code supports also the weird case
+ * where --few fragments of the same page-- are present in the SG as
+ * consecutive elements. Also, it handles one entry SG.
+ */
+static int iser_sg_to_page_vec(struct iser_data_buf *data,
+ struct iser_page_vec *page_vec)
+{
+ struct scatterlist *sg = (struct scatterlist *)data->buf;
+ dma_addr_t first_addr, last_addr, page;
+ int start_aligned, end_aligned;
+ unsigned int cur_page = 0;
+ unsigned long total_sz = 0;
+ int i;
+
+ /* compute the offset of first element */
+ page_vec->offset = (u64) sg[0].offset;
+
+ for (i = 0; i < data->dma_nents; i++) {
+ total_sz += sg_dma_len(&sg[i]);
+
+ first_addr = sg_dma_address(&sg[i]);
+ last_addr = first_addr + sg_dma_len(&sg[i]);
+
+ start_aligned = !(first_addr & ~PAGE_MASK);
+ end_aligned = !(last_addr & ~PAGE_MASK);
+
+ /* continue to collect page fragments till aligned or SG ends */
+ while (!end_aligned && (i + 1 < data->dma_nents)) {
+ i++;
+ total_sz += sg_dma_len(&sg[i]);
+ last_addr = sg_dma_address(&sg[i]) + sg_dma_len(&sg[i]);
+ end_aligned = !(last_addr & ~PAGE_MASK);
+ }
+
+ first_addr = first_addr & PAGE_MASK;
+
+ for (page = first_addr; page < last_addr; page += PAGE_SIZE)
+ page_vec->pages[cur_page++] = page;
+
+ }
+ page_vec->data_size = total_sz;
+ iser_dbg("page_vec->data_size:%d cur_page %d\n", page_vec->data_size,cur_page);
+ return cur_page;
+}
+
+#define MASK_4K ((1UL << 12) - 1) /* 0xFFF */
+#define IS_4K_ALIGNED(addr) ((((unsigned long)addr) & MASK_4K) == 0)
+
+/**
+ * iser_data_buf_aligned_len - Tries to determine the maximal correctly aligned
+ * for RDMA sub-list of a scatter-gather list of memory buffers, and returns
+ * the number of entries which are aligned correctly. Supports the case where
+ * consecutive SG elements are actually fragments of the same physcial page.
+ */
+static unsigned int iser_data_buf_aligned_len(struct iser_data_buf *data)
+{
+ struct scatterlist *sg;
+ dma_addr_t end_addr, next_addr;
+ int i, cnt;
+ unsigned int ret_len = 0;
+
+ sg = (struct scatterlist *)data->buf;
+
+ for (cnt = 0, i = 0; i < data->dma_nents; i++, cnt++) {
+ /* iser_dbg("Checking sg iobuf [%d]: phys=0x%08lX "
+ "offset: %ld sz: %ld\n", i,
+ (unsigned long)page_to_phys(sg[i].page),
+ (unsigned long)sg[i].offset,
+ (unsigned long)sg[i].length); */
+ end_addr = sg_dma_address(&sg[i]) +
+ sg_dma_len(&sg[i]);
+ /* iser_dbg("Checking sg iobuf end address "
+ "0x%08lX\n", end_addr); */
+ if (i + 1 < data->dma_nents) {
+ next_addr = sg_dma_address(&sg[i+1]);
+ /* are i, i+1 fragments of the same page? */
+ if (end_addr == next_addr)
+ continue;
+ else if (!IS_4K_ALIGNED(end_addr)) {
+ ret_len = cnt + 1;
+ break;
+ }
+ }
+ }
+ if (i == data->dma_nents)
+ ret_len = cnt; /* loop ended */
+ iser_dbg("Found %d aligned entries out of %d in sg:0x%p\n",
+ ret_len, data->dma_nents, data);
+ return ret_len;
+}
+
+static void iser_data_buf_dump(struct iser_data_buf *data)
+{
+ struct scatterlist *sg = (struct scatterlist *)data->buf;
+ int i;
+
+ for (i = 0; i < data->size; i++)
+ iser_err("sg[%d] dma_addr:0x%lX page:0x%p "
+ "off:%d sz:%d dma_len:%d\n",
+ i, (unsigned long)sg_dma_address(&sg[i]),
+ sg[i].page, sg[i].offset,
+ sg[i].length,sg_dma_len(&sg[i]));
+}
+
+static void iser_dump_page_vec(struct iser_page_vec *page_vec)
+{
+ int i;
+
+ iser_err("page vec length %d data size %d\n",
+ page_vec->length, page_vec->data_size);
+ for (i = 0; i < page_vec->length; i++)
+ iser_err("%d %lx\n",i,(unsigned long)page_vec->pages[i]);
+}
+
+static void iser_page_vec_build(struct iser_data_buf *data,
+ struct iser_page_vec *page_vec)
+{
+ int page_vec_len = 0;
+
+ page_vec->length = 0;
+ page_vec->offset = 0;
+
+ iser_dbg("Translating sg sz: %d\n", data->dma_nents);
+ page_vec_len = iser_sg_to_page_vec(data,page_vec);
+ iser_dbg("sg len %d page_vec_len %d\n", data->dma_nents,page_vec_len);
+
+ page_vec->length = page_vec_len;
+
+ if (page_vec_len * PAGE_SIZE < page_vec->data_size) {
+ iser_err("page_vec too short to hold this SG\n");
+ iser_data_buf_dump(data);
+ iser_dump_page_vec(page_vec);
+ BUG();
+ }
+}
+
+/**
+ * iser_reg_rdma_mem - Registers memory intended for RDMA,
+ * obtaining rkey and va
+ *
+ * returns 0 on success, errno code on failure
+ */
+int iser_reg_rdma_mem(struct iscsi_iser_cmd_task *iser_ctask,
+ enum iser_data_dir cmd_dir)
+{
+ struct iser_conn *ib_conn = iser_ctask->iser_conn->ib_conn;
+ struct iser_data_buf *mem = &iser_ctask->data[cmd_dir];
+ struct iser_regd_buf *regd_buf;
+ int aligned_len;
+ int err;
+
+ regd_buf = &iser_ctask->rdma_regd[cmd_dir];
+
+ aligned_len = iser_data_buf_aligned_len(mem);
+ if (aligned_len != mem->size) {
+ iser_err("rdma alignment violation %d/%d aligned\n",
+ aligned_len, mem->size);
+ iser_data_buf_dump(mem);
+ /* allocate copy buf, if we are writing, copy the */
+ /* unaligned scatterlist, dma map the copy */
+ if (iser_start_rdma_unaligned_sg(iser_ctask, cmd_dir) != 0)
+ return -ENOMEM;
+ mem = &iser_ctask->data_copy[cmd_dir];
+ }
+
+ iser_page_vec_build(mem, ib_conn->page_vec);
+ err = iser_reg_page_vec(ib_conn, ib_conn->page_vec, ®d_buf->reg);
+ if (err)
+ return err;
+
+ /* take a reference on this regd buf such that it will not be released *
+ * (eg in send dto completion) before we get the scsi response */
+ atomic_inc(®d_buf->ref_count);
+ return 0;
+}
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