RDMA/hns: Get rid of page operation after dma_alloc_coherent

In general, dma_alloc_coherent() returns a CPU virtual address and
a DMA address, and we have no guarantee that the underlying memory
even has an associated struct page at all.

This patch gets rid of the page operation after dma_alloc_coherent,
and records the VA returned form dma_alloc_coherent in the struct
of hem in hns RoCE driver.

Fixes: 9a44353("IB/hns: Add driver files for hns RoCE driver")
Signed-off-by: Wei Hu (Xavier) <xavier.huwei@huawei.com>
Signed-off-by: Shaobo Xu <xushaobo2@huawei.com>
Signed-off-by: Lijun Ou <oulijun@huawei.com>
Signed-off-by: Yixian Liu <liuyixian@huawei.com>
Signed-off-by: Xiping Zhang (Francis) <zhangxiping3@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

2 files changed, 14 insertions, 12 deletions

diff --git a/drivers/infiniband/hw/hns/hns_roce_hem.c b/drivers/infiniband/hw/hns/hns_roce_hem.c
index 8b733a66fae5..0eeabfbee192 100644
--- a/drivers/infiniband/hw/hns/hns_roce_hem.c
+++ b/drivers/infiniband/hw/hns/hns_roce_hem.c
@@ -224,6 +224,7 @@ static struct hns_roce_hem *hns_roce_alloc_hem(struct hns_roce_dev *hr_dev,
                         sg_init_table(chunk->mem, HNS_ROCE_HEM_CHUNK_LEN);
                         chunk->npages = 0;
                         chunk->nsg = 0;
+                        memset(chunk->buf, 0, sizeof(chunk->buf));
                         list_add_tail(&chunk->list, &hem->chunk_list);
                 }
 
@@ -240,8 +241,7 @@ static struct hns_roce_hem *hns_roce_alloc_hem(struct hns_roce_dev *hr_dev,
                 if (!buf)
                         goto fail;
 
-                sg_set_buf(mem, buf, PAGE_SIZE << order);
-                WARN_ON(mem->offset);
+                chunk->buf[chunk->npages] = buf;
                 sg_dma_len(mem) = PAGE_SIZE << order;
 
                 ++chunk->npages;
@@ -267,8 +267,8 @@ void hns_roce_free_hem(struct hns_roce_dev *hr_dev, struct hns_roce_hem *hem)
         list_for_each_entry_safe(chunk, tmp, &hem->chunk_list, list) {
                 for (i = 0; i < chunk->npages; ++i)
                         dma_free_coherent(hr_dev->dev,
-                                   chunk->mem[i].length,
-                                   lowmem_page_address(sg_page(&chunk->mem[i])),
+                                   sg_dma_len(&chunk->mem[i]),
+                                   chunk->buf[i],
                                    sg_dma_address(&chunk->mem[i]));
                 kfree(chunk);
         }
@@ -722,11 +722,12 @@ void *hns_roce_table_find(struct hns_roce_dev *hr_dev,
         struct hns_roce_hem_chunk *chunk;
         struct hns_roce_hem_mhop mhop;
         struct hns_roce_hem *hem;
-        struct page *page = NULL;
+        void *addr = NULL;
         unsigned long mhop_obj = obj;
         unsigned long obj_per_chunk;
         unsigned long idx_offset;
         int offset, dma_offset;
+        int length;
         int i, j;
         u32 hem_idx = 0;
 
@@ -763,25 +764,25 @@ void *hns_roce_table_find(struct hns_roce_dev *hr_dev,
 
         list_for_each_entry(chunk, &hem->chunk_list, list) {
                 for (i = 0; i < chunk->npages; ++i) {
+                        length = sg_dma_len(&chunk->mem[i]);
                         if (dma_handle && dma_offset >= 0) {
-                                if (sg_dma_len(&chunk->mem[i]) >
-                                    (u32)dma_offset)
+                                if (length > (u32)dma_offset)
                                         *dma_handle = sg_dma_address(
                                                 &chunk->mem[i]) + dma_offset;
-                                dma_offset -= sg_dma_len(&chunk->mem[i]);
+                                dma_offset -= length;
                         }
 
-                        if (chunk->mem[i].length > (u32)offset) {
-                                page = sg_page(&chunk->mem[i]);
+                        if (length > (u32)offset) {
+                                addr = chunk->buf[i] + offset;
                                 goto out;
                         }
-                        offset -= chunk->mem[i].length;
+                        offset -= length;
                 }
         }
 
 out:
         mutex_unlock(&table->mutex);
-        return page ? lowmem_page_address(page) + offset : NULL;
+        return addr;
 }
 EXPORT_SYMBOL_GPL(hns_roce_table_find);
 
diff --git a/drivers/infiniband/hw/hns/hns_roce_hem.h b/drivers/infiniband/hw/hns/hns_roce_hem.h
index db66db12075e..e8850d59e780 100644
--- a/drivers/infiniband/hw/hns/hns_roce_hem.h
+++ b/drivers/infiniband/hw/hns/hns_roce_hem.h
@@ -78,6 +78,7 @@ struct hns_roce_hem_chunk {
         int                      npages;
         int                      nsg;
         struct scatterlist       mem[HNS_ROCE_HEM_CHUNK_LEN];
+        void                     *buf[HNS_ROCE_HEM_CHUNK_LEN];
 };
 
 struct hns_roce_hem {