From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
transport_map_mem_to_sg() is used by dev_obj_do_se_mem_map() to map
the passed struct se_mem *in_se_mem pointer into newly allocated contigious
array of struct scatterlist at struct task->task_sg[].
This patch follows commit ffde9cbccdbf and updates transport_map_mem_to_sg()
to fix an issue that was originally reported by an IBLOCK HBA reporting
255 max_sectors, number of scatterlists to be determined when a task_offset
was carried between struct se_task allocations in transport_generic_get_cdb_count()
This patch also adds the usage of !list_is_last() before calling
list_entry() when picking off the next struct se_mem list_head member.
The current struct se_mem pointer will be set to *out_se_mem before returning from
transport_map_mem_to_sg(). This is done so the next struct se_task allocation
happening in transport_generic_get_cdb_count() will, together with the passed
u32 *task_offset, know where to start it's struct task->task_sg[] physical memory
mapping from.
Finally, this patch converts transport_map_mem_to_sg() to use the
include/linux/scatterlist.h:sg_next() macros to follow mainline SG convention.
Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/target_core_transport.c | 95 ++++++++++++++++----------------
1 files changed, 47 insertions(+), 48 deletions(-)
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 43eeb14..8aa4785 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -6847,10 +6847,10 @@ int transport_map_mem_to_sg(
u32 *se_mem_cnt,
u32 *task_offset)
{
+ struct se_cmd *se_cmd = task->task_se_cmd;
struct se_mem *se_mem = in_se_mem;
struct scatterlist *sg = (struct scatterlist *)in_mem;
- u32 saved_task_offset = 0, sg_no = 0;
- u32 task_size = task->task_size;
+ u32 task_size = task->task_size, sg_no = 0;
if (!sg) {
printk(KERN_ERR "Unable to locate valid struct"
@@ -6858,85 +6858,84 @@ int transport_map_mem_to_sg(
return -1;
}
- while (task_size) {
+ while (task_size != 0) {
+ /*
+ * Setup the contigious array of scatterlists for
+ * this struct se_task.
+ */
+ sg_assign_page(sg, se_mem->se_page);
+
if (*task_offset == 0) {
- sg_assign_page(&sg[sg_no], se_mem->se_page);
- sg[sg_no].offset = se_mem->se_off;
+ sg->offset = se_mem->se_off;
if (task_size >= se_mem->se_len) {
- sg[sg_no].length = se_mem->se_len;
+ sg->length = se_mem->se_len;
- se_mem = list_entry(se_mem->se_list.next,
+ if (!(list_is_last(&se_mem->se_list,
+ T_TASK(se_cmd)->t_mem_list))) {
+ se_mem = list_entry(se_mem->se_list.next,
struct se_mem, se_list);
- if (!(se_mem)) {
- printk(KERN_ERR "Unable to locate"
- " next struct se_mem\n");
- return -1;
+ (*se_mem_cnt)++;
}
- (*se_mem_cnt)++;
} else {
- sg[sg_no].length = task_size;
+ sg->length = task_size;
/*
* Determine if we need to calculate an offset
* into the struct se_mem on the next go around..
*/
- task_size -= sg[sg_no].length;
- if (!(task_size)) {
- *task_offset = (sg[sg_no].length +
- saved_task_offset);
- goto next;
- }
+ task_size -= sg->length;
+ if (!(task_size))
+ *task_offset = sg->length;
+
+ goto next;
}
- if (saved_task_offset)
- *task_offset = saved_task_offset;
} else {
- sg_assign_page(&sg[sg_no], se_mem->se_page);
- sg[sg_no].offset = (*task_offset + se_mem->se_off);
+ sg->offset = (*task_offset + se_mem->se_off);
if ((se_mem->se_len - *task_offset) > task_size) {
- sg[sg_no].length = task_size;
+ sg->length = task_size;
/*
* Determine if we need to calculate an offset
* into the struct se_mem on the next go around..
*/
- task_size -= sg[sg_no].length;
- if (!(task_size)) {
- *task_offset += sg[sg_no].length;
- goto next;
- }
+ task_size -= sg->length;
+ if (!(task_size))
+ *task_offset += sg->length;
+
+ goto next;
} else {
- sg[sg_no].length = (se_mem->se_len -
- *task_offset);
+ sg->length = (se_mem->se_len - *task_offset);
- se_mem = list_entry(se_mem->se_list.next,
- struct se_mem, se_list);
- if (!(se_mem)) {
- printk(KERN_ERR "Unable to locate"
- " next struct se_mem\n");
- return -1;
+ if (!(list_is_last(&se_mem->se_list,
+ T_TASK(se_cmd)->t_mem_list))) {
+ se_mem = list_entry(se_mem->se_list.next,
+ struct se_mem, se_list);
+ (*se_mem_cnt)++;
}
- (*se_mem_cnt)++;
}
- saved_task_offset = *task_offset;
*task_offset = 0;
}
- task_size -= sg[sg_no].length;
+ task_size -= sg->length;
next:
- DEBUG_MEM("task[%u] - sg[%u](%p)(%u)(%u) - Reducing task_size"
- " to(%u)\n", task->task_no, sg_no,
- sg_page(&sg[sg_no]), sg[sg_no].length,
- sg[sg_no].offset, task_size);
+ DEBUG_MEM("task[%u] mem_to_sg - sg[%u](%p)(%u)(%u) - Reducing"
+ " task_size to(%u), task_offset: %u\n", task->task_no, sg_no,
+ sg_page(sg), sg->length, sg->offset, task_size, *task_offset);
sg_no++;
+ if (!(task_size))
+ break;
+
+ sg = sg_next(sg);
+
+ if (task_size > se_cmd->data_length)
+ BUG();
}
*out_se_mem = se_mem;
- task->task_sg_num = sg_no;
- DEBUG_MEM("task[%u] - Mapped(%u) struct se_mem segments to total(%u) SGs"
- " saved task_offset(%u)\n", task->task_no, *se_mem_cnt,
- sg_no, *task_offset);
+ DEBUG_MEM("task[%u] - Mapped(%u) struct se_mem segments to total(%u)"
+ " SGs\n", task->task_no, *se_mem_cnt, sg_no);
return 0;
}
--
1.5.6.5
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