From: Xiubo Li <lixi...@cmss.chinamobile.com> Add two helpers to simplify the code, and move some code out of the cmdr spin lock to reduce the size of critical region.
Signed-off-by: Xiubo Li <lixi...@cmss.chinamobile.com> --- drivers/target/target_core_user.c | 54 ++++++++++++++++++++++----------------- 1 file changed, 30 insertions(+), 24 deletions(-) diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index 117be07..5205d2f 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -366,18 +366,22 @@ static inline void tcmu_free_cmd(struct tcmu_cmd *tcmu_cmd) kmem_cache_free(tcmu_cmd_cache, tcmu_cmd); } -static inline uint32_t tcmu_cmd_get_dbi_len(struct se_cmd *se_cmd) +static inline uint32_t tcmu_cmd_get_data_length(struct se_cmd *se_cmd) { size_t data_length = round_up(se_cmd->data_length, DATA_BLOCK_SIZE); - uint32_t dbi_len; if (se_cmd->se_cmd_flags & SCF_BIDI) data_length += round_up(se_cmd->t_bidi_data_sg->length, DATA_BLOCK_SIZE); - dbi_len = data_length / DATA_BLOCK_SIZE; + return data_length; +} + +static inline uint32_t tcmu_cmd_get_dbi_len(struct se_cmd *se_cmd) +{ + size_t data_length = tcmu_cmd_get_data_length(se_cmd); - return dbi_len; + return data_length / DATA_BLOCK_SIZE; } static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd) @@ -624,13 +628,27 @@ static bool is_ring_space_avail(struct tcmu_dev *udev, struct tcmu_cmd *cmd, return true; } +static inline void tcmu_cmd_get_cmd_size(struct se_cmd *se_cmd, + size_t *base_size, size_t *cmd_size) +{ + struct se_cmd *se_cmd = tcmu_cmd->se_cmd; + + *base_size = max(offsetof(struct tcmu_cmd_entry, + req.iov[tcmu_cmd->dbi_len]), + sizeof(struct tcmu_cmd_entry)); + + *cmd_size = round_up(scsi_command_size(se_cmd->t_task_cdb), + TCMU_OP_ALIGN_SIZE) + *base_size; + WARN_ON(*cmd_size & (TCMU_OP_ALIGN_SIZE-1)); +} + static sense_reason_t tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd) { struct tcmu_dev *udev = tcmu_cmd->tcmu_dev; struct se_cmd *se_cmd = tcmu_cmd->se_cmd; size_t base_command_size, command_size; - struct tcmu_mailbox *mb; + struct tcmu_mailbox *mb = udev->mb_addr; struct tcmu_cmd_entry *entry; struct iovec *iov; int iov_cnt, ret; @@ -642,6 +660,8 @@ static bool is_ring_space_avail(struct tcmu_dev *udev, struct tcmu_cmd *cmd, if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; + if (se_cmd->se_cmd_flags & SCF_BIDI) + BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents)); /* * Must be a certain minimum size for response sense info, but * also may be larger if the iov array is large. @@ -649,33 +669,19 @@ static bool is_ring_space_avail(struct tcmu_dev *udev, struct tcmu_cmd *cmd, * We prepare way too many iovs for potential uses here, because it's * expensive to tell how many regions are freed in the bitmap */ - base_command_size = max(offsetof(struct tcmu_cmd_entry, - req.iov[tcmu_cmd->dbi_len]), - sizeof(struct tcmu_cmd_entry)); - command_size = base_command_size - + round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE); - - WARN_ON(command_size & (TCMU_OP_ALIGN_SIZE-1)); - - spin_lock_irq(&udev->cmdr_lock); - - mb = udev->mb_addr; - cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ - data_length = round_up(se_cmd->data_length, DATA_BLOCK_SIZE); - if (se_cmd->se_cmd_flags & SCF_BIDI) { - BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents)); - data_length += round_up(se_cmd->t_bidi_data_sg->length, - DATA_BLOCK_SIZE); - } + tcmu_cmd_get_cmd_size(tcmu_cmd, &base_command_size, &command_size); + data_length = tcmu_cmd_get_data_length(se_cmd); if ((command_size > (udev->cmdr_size / 2)) || data_length > udev->data_size) { pr_warn("TCMU: Request of size %zu/%zu is too big for %u/%zu " "cmd ring/data area\n", command_size, data_length, udev->cmdr_size, udev->data_size); - spin_unlock_irq(&udev->cmdr_lock); return TCM_INVALID_CDB_FIELD; } + spin_lock_irq(&udev->cmdr_lock); + + cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */ while (!is_ring_space_avail(udev, tcmu_cmd, command_size, data_length)) { int ret; DEFINE_WAIT(__wait); -- 1.8.3.1