forked from Minki/linux
target/rd: fix or rewrite the copy routine
So the code assumes that the sg list is only a array while in reality loopback SGL memory via scsi_cmnd into target-core may be already chained. This patch converts ramdisk code to use sg_miter logic from scatterlist.h in order to properly support passthrough SGL usage with transport_generic_map_mem_to_cmd() via loopback. With this patch the bug goes away. However after umount/mount of the device my files are gone. So something is still not right. After looking at it for a while I decided to rewrite the that part of the code and now things do work for me. For reference: - http://article.gmane.org/gmane.linux.scsi.target.devel/595 the sg_next() conversion - http://article.gmane.org/gmane.linux.scsi.target.devel/602 the rewrite of the copy code (nab: Fix compile warning in rd_MEMCPY) Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: stable@kernel.org Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Sebastian Andrzej Siewior
Nicholas Bellinger
parent
5bff9e8584
commit
65b0c78d5a
@ -343,235 +343,74 @@ static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
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return NULL;
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}
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/* rd_MEMCPY_read():
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*
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*
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*/
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static int rd_MEMCPY_read(struct rd_request *req)
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static int rd_MEMCPY(struct rd_request *req, u32 read_rd)
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{
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struct se_task *task = &req->rd_task;
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struct rd_dev *dev = req->rd_task.task_se_cmd->se_dev->dev_ptr;
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struct rd_dev_sg_table *table;
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struct scatterlist *sg_d, *sg_s;
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void *dst, *src;
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u32 i = 0, j = 0, dst_offset = 0, src_offset = 0;
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u32 length, page_end = 0, table_sg_end;
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struct scatterlist *rd_sg;
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struct sg_mapping_iter m;
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u32 rd_offset = req->rd_offset;
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u32 src_len;
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table = rd_get_sg_table(dev, req->rd_page);
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if (!table)
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return -EINVAL;
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table_sg_end = (table->page_end_offset - req->rd_page);
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sg_d = task->task_sg;
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sg_s = &table->sg_table[req->rd_page - table->page_start_offset];
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rd_sg = &table->sg_table[req->rd_page - table->page_start_offset];
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pr_debug("RD[%u]: Read LBA: %llu, Size: %u Page: %u, Offset:"
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" %u\n", dev->rd_dev_id, task->task_lba, req->rd_size,
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req->rd_page, req->rd_offset);
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src_offset = rd_offset;
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pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
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dev->rd_dev_id, read_rd ? "Read" : "Write",
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task->task_lba, req->rd_size, req->rd_page,
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rd_offset);
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src_len = PAGE_SIZE - rd_offset;
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sg_miter_start(&m, task->task_sg, task->task_sg_nents,
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read_rd ? SG_MITER_TO_SG : SG_MITER_FROM_SG);
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while (req->rd_size) {
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if ((sg_d[i].length - dst_offset) <
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(sg_s[j].length - src_offset)) {
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length = (sg_d[i].length - dst_offset);
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u32 len;
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void *rd_addr;
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pr_debug("Step 1 - sg_d[%d]: %p length: %d"
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" offset: %u sg_s[%d].length: %u\n", i,
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&sg_d[i], sg_d[i].length, sg_d[i].offset, j,
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sg_s[j].length);
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pr_debug("Step 1 - length: %u dst_offset: %u"
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" src_offset: %u\n", length, dst_offset,
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src_offset);
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sg_miter_next(&m);
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len = min((u32)m.length, src_len);
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m.consumed = len;
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if (length > req->rd_size)
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length = req->rd_size;
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rd_addr = sg_virt(rd_sg) + rd_offset;
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dst = sg_virt(&sg_d[i++]) + dst_offset;
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BUG_ON(!dst);
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if (read_rd)
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memcpy(m.addr, rd_addr, len);
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else
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memcpy(rd_addr, m.addr, len);
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src = sg_virt(&sg_s[j]) + src_offset;
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BUG_ON(!src);
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dst_offset = 0;
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src_offset = length;
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page_end = 0;
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} else {
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length = (sg_s[j].length - src_offset);
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pr_debug("Step 2 - sg_d[%d]: %p length: %d"
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" offset: %u sg_s[%d].length: %u\n", i,
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&sg_d[i], sg_d[i].length, sg_d[i].offset,
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j, sg_s[j].length);
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pr_debug("Step 2 - length: %u dst_offset: %u"
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" src_offset: %u\n", length, dst_offset,
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src_offset);
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if (length > req->rd_size)
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length = req->rd_size;
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dst = sg_virt(&sg_d[i]) + dst_offset;
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BUG_ON(!dst);
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if (sg_d[i].length == length) {
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i++;
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dst_offset = 0;
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} else
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dst_offset = length;
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src = sg_virt(&sg_s[j++]) + src_offset;
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BUG_ON(!src);
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src_offset = 0;
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page_end = 1;
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}
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memcpy(dst, src, length);
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pr_debug("page: %u, remaining size: %u, length: %u,"
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" i: %u, j: %u\n", req->rd_page,
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(req->rd_size - length), length, i, j);
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req->rd_size -= length;
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req->rd_size -= len;
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if (!req->rd_size)
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return 0;
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if (!page_end)
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continue;
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if (++req->rd_page <= table->page_end_offset) {
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pr_debug("page: %u in same page table\n",
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req->rd_page);
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src_len -= len;
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if (src_len) {
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rd_offset += len;
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continue;
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}
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pr_debug("getting new page table for page: %u\n",
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req->rd_page);
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/* rd page completed, next one please */
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req->rd_page++;
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rd_offset = 0;
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src_len = PAGE_SIZE;
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if (req->rd_page <= table->page_end_offset) {
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rd_sg++;
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continue;
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}
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table = rd_get_sg_table(dev, req->rd_page);
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if (!table)
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if (!table) {
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sg_miter_stop(&m);
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return -EINVAL;
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sg_s = &table->sg_table[j = 0];
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}
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return 0;
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}
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/* rd_MEMCPY_write():
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*
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*
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*/
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static int rd_MEMCPY_write(struct rd_request *req)
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{
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struct se_task *task = &req->rd_task;
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struct rd_dev *dev = req->rd_task.task_se_cmd->se_dev->dev_ptr;
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struct rd_dev_sg_table *table;
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struct scatterlist *sg_d, *sg_s;
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void *dst, *src;
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u32 i = 0, j = 0, dst_offset = 0, src_offset = 0;
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u32 length, page_end = 0, table_sg_end;
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u32 rd_offset = req->rd_offset;
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table = rd_get_sg_table(dev, req->rd_page);
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if (!table)
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return -EINVAL;
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table_sg_end = (table->page_end_offset - req->rd_page);
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sg_d = &table->sg_table[req->rd_page - table->page_start_offset];
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sg_s = task->task_sg;
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pr_debug("RD[%d] Write LBA: %llu, Size: %u, Page: %u,"
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" Offset: %u\n", dev->rd_dev_id, task->task_lba, req->rd_size,
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req->rd_page, req->rd_offset);
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dst_offset = rd_offset;
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while (req->rd_size) {
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if ((sg_s[i].length - src_offset) <
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(sg_d[j].length - dst_offset)) {
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length = (sg_s[i].length - src_offset);
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pr_debug("Step 1 - sg_s[%d]: %p length: %d"
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" offset: %d sg_d[%d].length: %u\n", i,
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&sg_s[i], sg_s[i].length, sg_s[i].offset,
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j, sg_d[j].length);
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pr_debug("Step 1 - length: %u src_offset: %u"
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" dst_offset: %u\n", length, src_offset,
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dst_offset);
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if (length > req->rd_size)
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length = req->rd_size;
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src = sg_virt(&sg_s[i++]) + src_offset;
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BUG_ON(!src);
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dst = sg_virt(&sg_d[j]) + dst_offset;
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BUG_ON(!dst);
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src_offset = 0;
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dst_offset = length;
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page_end = 0;
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} else {
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length = (sg_d[j].length - dst_offset);
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pr_debug("Step 2 - sg_s[%d]: %p length: %d"
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" offset: %d sg_d[%d].length: %u\n", i,
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&sg_s[i], sg_s[i].length, sg_s[i].offset,
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j, sg_d[j].length);
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pr_debug("Step 2 - length: %u src_offset: %u"
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" dst_offset: %u\n", length, src_offset,
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dst_offset);
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if (length > req->rd_size)
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length = req->rd_size;
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src = sg_virt(&sg_s[i]) + src_offset;
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BUG_ON(!src);
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if (sg_s[i].length == length) {
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i++;
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src_offset = 0;
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} else
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src_offset = length;
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dst = sg_virt(&sg_d[j++]) + dst_offset;
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BUG_ON(!dst);
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dst_offset = 0;
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page_end = 1;
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}
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memcpy(dst, src, length);
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pr_debug("page: %u, remaining size: %u, length: %u,"
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" i: %u, j: %u\n", req->rd_page,
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(req->rd_size - length), length, i, j);
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req->rd_size -= length;
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if (!req->rd_size)
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return 0;
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if (!page_end)
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continue;
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if (++req->rd_page <= table->page_end_offset) {
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pr_debug("page: %u in same page table\n",
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req->rd_page);
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continue;
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}
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pr_debug("getting new page table for page: %u\n",
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req->rd_page);
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table = rd_get_sg_table(dev, req->rd_page);
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if (!table)
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return -EINVAL;
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sg_d = &table->sg_table[j = 0];
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/* since we increment, the first sg entry is correct */
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rd_sg = table->sg_table;
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}
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sg_miter_stop(&m);
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return 0;
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}
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@ -591,11 +430,7 @@ static int rd_MEMCPY_do_task(struct se_task *task)
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req->rd_page = tmp;
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req->rd_size = task->task_size;
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if (task->task_data_direction == DMA_FROM_DEVICE)
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ret = rd_MEMCPY_read(req);
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else
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ret = rd_MEMCPY_write(req);
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ret = rd_MEMCPY(req, task->task_data_direction == DMA_FROM_DEVICE);
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if (ret != 0)
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return ret;
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