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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2011-11-30 10:48:30 +0100
committerNicholas Bellinger <nab@linux-iscsi.org>2011-12-06 06:00:58 +0000
commit65b0c78d5a0ca2cb82b7b9f54f855896e0d7fc10 (patch)
tree64a27fa0aa08795154674909ccbf2106f56783eb
parent5bff9e8584fbcdb361dada5a0425724b9e31e608 (diff)
downloadlinux-stericsson-65b0c78d5a0ca2cb82b7b9f54f855896e0d7fc10.tar.gz
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>
-rw-r--r--drivers/target/target_core_rd.c245
1 files changed, 40 insertions, 205 deletions
diff --git a/drivers/target/target_core_rd.c b/drivers/target/target_core_rd.c
index 6119ed5a3311..02e51faa2f4e 100644
--- a/drivers/target/target_core_rd.c
+++ b/drivers/target/target_core_rd.c
@@ -343,235 +343,74 @@ 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 i = 0, j = 0, 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);
-
- src_offset = 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_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[i].length - dst_offset) <
- (sg_s[j].length - src_offset)) {
- length = (sg_d[i].length - dst_offset);
-
- pr_debug("Step 1 - sg_d[%d]: %p length: %d"
- " offset: %u sg_s[%d].length: %u\n", i,
- &sg_d[i], sg_d[i].length, sg_d[i].offset, j,
- sg_s[j].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[i++]) + dst_offset;
- BUG_ON(!dst);
-
- src = sg_virt(&sg_s[j]) + src_offset;
- BUG_ON(!src);
-
- dst_offset = 0;
- src_offset = length;
- page_end = 0;
- } else {
- length = (sg_s[j].length - src_offset);
-
- pr_debug("Step 2 - sg_d[%d]: %p length: %d"
- " offset: %u sg_s[%d].length: %u\n", i,
- &sg_d[i], sg_d[i].length, sg_d[i].offset,
- j, sg_s[j].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[i]) + dst_offset;
- BUG_ON(!dst);
-
- if (sg_d[i].length == length) {
- i++;
- dst_offset = 0;
- } else
- dst_offset = length;
-
- src = sg_virt(&sg_s[j++]) + src_offset;
- BUG_ON(!src);
-
- src_offset = 0;
- page_end = 1;
- }
+ u32 len;
+ void *rd_addr;
- memcpy(dst, src, length);
+ sg_miter_next(&m);
+ len = min((u32)m.length, src_len);
+ m.consumed = len;
- pr_debug("page: %u, remaining size: %u, length: %u,"
- " i: %u, j: %u\n", req->rd_page,
- (req->rd_size - length), length, i, j);
+ 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[j = 0];
- }
-
- 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 i = 0, j = 0, 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[i].length - src_offset) <
- (sg_d[j].length - dst_offset)) {
- length = (sg_s[i].length - src_offset);
-
- pr_debug("Step 1 - sg_s[%d]: %p length: %d"
- " offset: %d sg_d[%d].length: %u\n", i,
- &sg_s[i], sg_s[i].length, sg_s[i].offset,
- j, sg_d[j].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[i++]) + src_offset;
- BUG_ON(!src);
-
- dst = sg_virt(&sg_d[j]) + dst_offset;
- BUG_ON(!dst);
-
- src_offset = 0;
- dst_offset = length;
- page_end = 0;
- } else {
- length = (sg_d[j].length - dst_offset);
-
- pr_debug("Step 2 - sg_s[%d]: %p length: %d"
- " offset: %d sg_d[%d].length: %u\n", i,
- &sg_s[i], sg_s[i].length, sg_s[i].offset,
- j, sg_d[j].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[i]) + src_offset;
- BUG_ON(!src);
-
- if (sg_s[i].length == length) {
- i++;
- src_offset = 0;
- } else
- src_offset = length;
-
- dst = sg_virt(&sg_d[j++]) + dst_offset;
- BUG_ON(!dst);
-
- dst_offset = 0;
- page_end = 1;
- }
-
- memcpy(dst, src, length);
-
- pr_debug("page: %u, remaining size: %u, length: %u,"
- " i: %u, j: %u\n", req->rd_page,
- (req->rd_size - length), length, i, j);
-
- 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[j = 0];
+ /* since we increment, the first sg entry is correct */
+ rd_sg = table->sg_table;
}
-
+ sg_miter_stop(&m);
return 0;
}
@@ -591,11 +430,7 @@ 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;