Okay, I haven't really figured out this copy works in detail and
something here is wring since I lose my data and iblock working.
However it is possible to implement the same functionality with less
code. This patch is proof of it :)
So the advantages of this version is less code, no BUG() statements and
it works on highmem. RD's pages are allocated via GFP_KERNEL so
sg_virt() is fine.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
drivers/target/target_core_rd.c | 247 +++++++--------------------------------
1 files changed, 40 insertions(+), 207 deletions(-)
diff --git a/drivers/target/target_core_rd.c b/drivers/target/target_core_rd.c
index d42cbec..1d2c4b6 100644
--- a/drivers/target/target_core_rd.c
+++ b/drivers/target/target_core_rd.c
@@ -341,237 +341,74 @@ static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
return NULL;
}
-/* rd_MEMCPY_read():
- *
- *
- */
-static int rd_MEMCPY_read(struct rd_request *req)
+static int rd_MEMCPY(struct rd_request *req, u32 read_rd)
{
struct se_task *task = &req->rd_task;
struct rd_dev *dev = req->rd_task.task_se_cmd->se_dev->dev_ptr;
struct rd_dev_sg_table *table;
- struct scatterlist *sg_d, *sg_s;
- void *dst, *src;
- u32 dst_offset = 0, src_offset = 0;
- u32 length, page_end = 0, table_sg_end;
+ struct scatterlist *rd_sg;
+ struct sg_mapping_iter m;
u32 rd_offset = req->rd_offset;
+ u32 src_len;
table = rd_get_sg_table(dev, req->rd_page);
if (!table)
return -EINVAL;
- table_sg_end = (table->page_end_offset - req->rd_page);
- sg_d = task->task_sg;
- sg_s = &table->sg_table[req->rd_page - table->page_start_offset];
+ rd_sg = &table->sg_table[req->rd_page - table->page_start_offset];
- pr_debug("RD[%u]: Read LBA: %llu, Size: %u Page: %u, Offset:"
- " %u\n", dev->rd_dev_id, task->task_lba, req->rd_size,
- req->rd_page, req->rd_offset);
+ pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
+ dev->rd_dev_id, read_rd ? "Read" : "Write",
+ task->task_lba, req->rd_size, req->rd_page,
+ rd_offset);
- src_offset = rd_offset;
+ src_len = PAGE_SIZE - rd_offset;
+ sg_miter_start(&m, task->task_sg, task->task_sg_nents,
+ read_rd ? SG_MITER_TO_SG : SG_MITER_FROM_SG);
while (req->rd_size) {
- if ((sg_d->length - dst_offset) <
- (sg_s->length - src_offset)) {
- length = (sg_d->length - dst_offset);
-
- pr_debug("Step 1 - sg_d: %p length: %d"
- " offset: %u sg_s[%p].length: %u\n",
- sg_d, sg_d->length, sg_d->offset, sg_s,
- sg_s->length);
- pr_debug("Step 1 - length: %u dst_offset: %u"
- " src_offset: %u\n", length, dst_offset,
- src_offset);
-
- if (length > req->rd_size)
- length = req->rd_size;
-
- dst = sg_virt(sg_d) + dst_offset;
- BUG_ON(!dst);
- sg_d = sg_next(sg_d);
-
- src = sg_virt(sg_s) + src_offset;
- BUG_ON(!src);
-
- dst_offset = 0;
- src_offset = length;
- page_end = 0;
- } else {
- length = (sg_s->length - src_offset);
-
- pr_debug("Step 2 - sg_d: %p length: %d"
- " offset: %u sg_s[%p].length: %u\n",
- sg_d, sg_d->length, sg_d->offset,
- sg_s, sg_s->length);
- pr_debug("Step 2 - length: %u dst_offset: %u"
- " src_offset: %u\n", length, dst_offset,
- src_offset);
-
- if (length > req->rd_size)
- length = req->rd_size;
-
- dst = sg_virt(sg_d) + dst_offset;
- BUG_ON(!dst);
-
- if (sg_d->length == length) {
- sg_d = sg_next(sg_d);
- dst_offset = 0;
- } else
- dst_offset = length;
-
- src = sg_virt(sg_s) + src_offset;
- sg_s = sg_next(sg_s);
- BUG_ON(!src);
-
- src_offset = 0;
- page_end = 1;
- }
+ u32 len;
+ void *rd_addr;
- memcpy(dst, src, length);
+ sg_miter_next(&m);
+ len = min(m.length, src_len);
+ m.consumed = len;
- pr_debug("page: %u, remaining size: %u, length: %u,"
- "\n", req->rd_page,
- (req->rd_size - length), length);
+ rd_addr = sg_virt(rd_sg) + rd_offset;
- req->rd_size -= length;
- if (!req->rd_size)
- return 0;
+ if (read_rd)
+ memcpy(m.addr, rd_addr, len);
+ else
+ memcpy(rd_addr, m.addr, len);
- if (!page_end)
+ req->rd_size -= len;
+ if (!req->rd_size)
continue;
- if (++req->rd_page <= table->page_end_offset) {
- pr_debug("page: %u in same page table\n",
- req->rd_page);
+ src_len -= len;
+ if (src_len) {
+ rd_offset += len;
continue;
}
- pr_debug("getting new page table for page: %u\n",
- req->rd_page);
-
- table = rd_get_sg_table(dev, req->rd_page);
- if (!table)
- return -EINVAL;
-
- sg_s = table->sg_table;
- }
-
- return 0;
-}
-
-/* rd_MEMCPY_write():
- *
- *
- */
-static int rd_MEMCPY_write(struct rd_request *req)
-{
- struct se_task *task = &req->rd_task;
- struct rd_dev *dev = req->rd_task.task_se_cmd->se_dev->dev_ptr;
- struct rd_dev_sg_table *table;
- struct scatterlist *sg_d, *sg_s;
- void *dst, *src;
- u32 dst_offset = 0, src_offset = 0;
- u32 length, page_end = 0, table_sg_end;
- u32 rd_offset = req->rd_offset;
-
- table = rd_get_sg_table(dev, req->rd_page);
- if (!table)
- return -EINVAL;
-
- table_sg_end = (table->page_end_offset - req->rd_page);
- sg_d = &table->sg_table[req->rd_page - table->page_start_offset];
- sg_s = task->task_sg;
-
- pr_debug("RD[%d] Write LBA: %llu, Size: %u, Page: %u,"
- " Offset: %u\n", dev->rd_dev_id, task->task_lba, req->rd_size,
- req->rd_page, req->rd_offset);
-
- dst_offset = rd_offset;
-
- while (req->rd_size) {
- if ((sg_s->length - src_offset) <
- (sg_d->length - dst_offset)) {
- length = (sg_s->length - src_offset);
-
- pr_debug("Step 1 - sg_s: %p length: %d"
- " offset: %d sg_d.length: %u\n",
- sg_s, sg_s->length, sg_s->offset,
- sg_d->length);
- pr_debug("Step 1 - length: %u src_offset: %u"
- " dst_offset: %u\n", length, src_offset,
- dst_offset);
-
- if (length > req->rd_size)
- length = req->rd_size;
-
- src = sg_virt(sg_s) + src_offset;
- BUG_ON(!src);
- sg_s = sg_next(sg_s);
-
- dst = sg_virt(sg_d) + dst_offset;
- BUG_ON(!dst);
-
- src_offset = 0;
- dst_offset = length;
- page_end = 0;
- } else {
- length = (sg_d->length - dst_offset);
-
- pr_debug("Step 2 - sg_s: %p length: %d"
- " offset: %d sg_d.length: %u\n",
- sg_s, sg_s->length, sg_s->offset,
- sg_d->length);
- pr_debug("Step 2 - length: %u src_offset: %u"
- " dst_offset: %u\n", length, src_offset,
- dst_offset);
-
- if (length > req->rd_size)
- length = req->rd_size;
-
- src = sg_virt(sg_s) + src_offset;
- BUG_ON(!src);
-
- if (sg_s->length == length) {
- sg_s = sg_next(sg_s);
- src_offset = 0;
- } else
- src_offset = length;
-
- dst = sg_virt(sg_d) + dst_offset;
- BUG_ON(!dst);
- sg_d = sg_next(sg_d);
-
- dst_offset = 0;
- page_end = 1;
- }
-
- memcpy(dst, src, length);
-
- pr_debug("page: %u, remaining size: %u, length: %u\n",
- req->rd_page, (req->rd_size - length), length);
-
- req->rd_size -= length;
- if (!req->rd_size)
- return 0;
-
- if (!page_end)
- continue;
-
- if (++req->rd_page <= table->page_end_offset) {
- pr_debug("page: %u in same page table\n",
- req->rd_page);
+ /* rd page completed, next one please */
+ req->rd_page++;
+ rd_offset = 0;
+ src_len = PAGE_SIZE;
+ if (req->rd_page <= table->page_end_offset) {
+ rd_sg++;
continue;
}
- pr_debug("getting new page table for page: %u\n",
- req->rd_page);
-
table = rd_get_sg_table(dev, req->rd_page);
- if (!table)
+ if (!table) {
+ sg_miter_stop(&m);
return -EINVAL;
+ }
- sg_d = table->sg_table;
+ /* since we increment, the first sg entry is correct */
+ rd_sg = table->sg_table;
}
-
+ sg_miter_stop(&m);
return 0;
}
@@ -591,11 +428,7 @@ static int rd_MEMCPY_do_task(struct se_task *task)
req->rd_page = tmp;
req->rd_size = task->task_size;
- if (task->task_data_direction == DMA_FROM_DEVICE)
- ret = rd_MEMCPY_read(req);
- else
- ret = rd_MEMCPY_write(req);
-
+ ret = rd_MEMCPY(req, task->task_data_direction == DMA_FROM_DEVICE);
if (ret != 0)
return ret;
--
1.7.7.1
--
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