From 491620267ec3fa947b29114613f113b2914bf0e4 Mon Sep 17 00:00:00 2001 From: Xiubo Li Date: Fri, 31 Mar 2017 10:35:25 +0800 Subject: [PATCH] tcmu: Skip Data-Out blocks before gathering Data-In buffer for BIDI case 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: cd82decc6332 ("target/user: Introduce data_bitmap, replace data_length/data_head/data_tail") Reported-by: Ilias Tsitsimpis Tested-by: Ilias Tsitsimpis Signed-off-by: Xiubo Li Cc: stable@vger.kernel.org # 4.6+ Signed-off-by: Nicholas Bellinger --- 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 9885d1b521fe8..f615c3bbb73e8 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); -- 2.39.5