Re: [PATCH] tcmu: Skip Data-Out blocks before gathering Data-In buffer for BIDI case

[Nicholas A. Bellinger]

On Fri, 2017-03-31 at 10:35 +0800, lixi...@cmss.chinamobile.com wrote:
> From: Xiubo Li 
> 
> For the bidirectional case, the Data-Out buffer blocks will always at
> the head of the tcmu_cmd's bitmap, and before gathering the Data-In
> buffer, first of all it should skip the Data-Out ones, or the device
> supporting BIDI commands won't work.
> 
> Fixed: 26418649eead ("target/user: Introduce data_bitmap, replace
>   data_length/data_head/data_tail")
> Reported-by: Ilias Tsitsimpis 
> Signed-off-by: Xiubo Li 
> ---
>  drivers/target/target_core_user.c | 48 
> +++
>  1 file changed, 33 insertions(+), 15 deletions(-)

Applied to target-pending/master, with a CC' to linux-4.6.y stable.

Thanks Xiubo + Ilias.

Re: [PATCH] tcmu: Skip Data-Out blocks before gathering Data-In buffer for BIDI case

[Ilias Tsitsimpis]

Hi Xiubo,

On Fri, Mar 31, 2017 at 10:35AM, lixi...@cmss.chinamobile.com wrote:
> From: Xiubo Li 
> 
> For the bidirectional case, the Data-Out buffer blocks will always at
> the head of the tcmu_cmd's bitmap, and before gathering the Data-In
> buffer, first of all it should skip the Data-Out ones, or the device
> supporting BIDI commands won't work.
> 
> Fixed: 26418649eead ("target/user: Introduce data_bitmap, replace
>   data_length/data_head/data_tail")
> Reported-by: Ilias Tsitsimpis 
> Signed-off-by: Xiubo Li 

Thanks for taking care of this.

Tested-by: Ilias Tsitsimpis 

Best,

-- 
Ilias

[PATCH] tcmu: Skip Data-Out blocks before gathering Data-In buffer for BIDI case

[lixiubo]

From: Xiubo Li 

For the bidirectional case, the Data-Out buffer blocks will always at
the head of the tcmu_cmd's bitmap, and before gathering the Data-In
buffer, first of all it should skip the Data-Out ones, or the device
supporting BIDI commands won't work.

Fixed: 26418649eead ("target/user: Introduce data_bitmap, replace
data_length/data_head/data_tail")
Reported-by: Ilias Tsitsimpis 
Signed-off-by: Xiubo Li 
---
 drivers/target/target_core_user.c | 48 +++
 1 file changed, 33 insertions(+), 15 deletions(-)

diff --git a/drivers/target/target_core_user.c 
b/drivers/target/target_core_user.c
index ede815c..63e3a1b 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -311,24 +311,50 @@ static void free_data_area(struct tcmu_dev *udev, struct 
tcmu_cmd *cmd)
   DATA_BLOCK_BITS);
 }
 
-static void gather_data_area(struct tcmu_dev *udev, unsigned long *cmd_bitmap,
-   struct scatterlist *data_sg, unsigned int data_nents)
+static void gather_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
+bool bidi)
 {
+   struct se_cmd *se_cmd = cmd->se_cmd;
int i, block;
int block_remaining = 0;
void *from, *to;
size_t copy_bytes, from_offset;
-   struct scatterlist *sg;
+   struct scatterlist *sg, *data_sg;
+   unsigned int data_nents;
+   DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);
+
+   bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
+
+   if (!bidi) {
+   data_sg = se_cmd->t_data_sg;
+   data_nents = se_cmd->t_data_nents;
+   } else {
+   uint32_t count;
+
+   /*
+* For bidi case, the first count blocks are for Data-Out
+* buffer blocks, and before gathering the Data-In buffer
+* the Data-Out buffer blocks should be discarded.
+*/
+   count = DIV_ROUND_UP(se_cmd->data_length, DATA_BLOCK_SIZE);
+   while (count--) {
+   block = find_first_bit(bitmap, DATA_BLOCK_BITS);
+   clear_bit(block, bitmap);
+   }
+
+   data_sg = se_cmd->t_bidi_data_sg;
+   data_nents = se_cmd->t_bidi_data_nents;
+   }
 
for_each_sg(data_sg, sg, data_nents, i) {
int sg_remaining = sg->length;
to = kmap_atomic(sg_page(sg)) + sg->offset;
while (sg_remaining > 0) {
if (block_remaining == 0) {
-   block = find_first_bit(cmd_bitmap,
+   block = find_first_bit(bitmap,
DATA_BLOCK_BITS);
block_remaining = DATA_BLOCK_SIZE;
-   clear_bit(block, cmd_bitmap);
+   clear_bit(block, bitmap);
}
copy_bytes = min_t(size_t, sg_remaining,
block_remaining);
@@ -610,19 +636,11 @@ static void tcmu_handle_completion(struct tcmu_cmd *cmd, 
struct tcmu_cmd_entry *
   se_cmd->scsi_sense_length);
free_data_area(udev, cmd);
} else if (se_cmd->se_cmd_flags & SCF_BIDI) {
-   DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);
-
/* Get Data-In buffer before clean up */
-   bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
-   gather_data_area(udev, bitmap,
-   se_cmd->t_bidi_data_sg, se_cmd->t_bidi_data_nents);
+   gather_data_area(udev, cmd, true);
free_data_area(udev, cmd);
} else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
-   DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);
-
-   bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
-   gather_data_area(udev, bitmap,
-   se_cmd->t_data_sg, se_cmd->t_data_nents);
+   gather_data_area(udev, cmd, false);
free_data_area(udev, cmd);
} else if (se_cmd->data_direction == DMA_TO_DEVICE) {
free_data_area(udev, cmd);
-- 
1.8.3.1