From 750a1d93f90583a270eb62f36e6d32ebbb6af779 Mon Sep 17 00:00:00 2001 From: Mike Christie Date: Sat, 27 Feb 2021 10:59:45 -0600 Subject: scsi: target: core: Break up target_submit_cmd_map_sgls() This breaks up target_submit_cmd_map_sgls() into 3 helpers: - target_init_cmd(): Do the basic general setup and get a refcount to the session to make sure the caller can execute the cmd. - target_submit_prep(): Do the mapping, cdb processing and get a ref to the LUN. - target_submit(): Pass the cmd to LIO core for execution. The above functions must be used by drivers that either: 1. Rely on LIO for session shutdown synchronization by calling target_stop_session(). 2. Need to map sgls. When the next patches are applied then simple drivers that do not need the extra functionality above can use target_submit_cmd() and not worry about failures being returned and how to handle them, since many drivers were getting this wrong and would have hit refcount bugs. Also, by breaking target_submit_cmd_map_sgls() up into these 3 helper functions, we can allow the later patches to do the init/prep from interrupt context and then do the submission from a workqueue. Link: https://lore.kernel.org/r/20210227170006.5077-5-michael.christie@oracle.com Cc: Bart Van Assche Cc: Juergen Gross Cc: Hannes Reinecke Cc: Nilesh Javali Cc: Michael Cyr Cc: Chris Boot Cc: Felipe Balbi Cc: "Michael S. Tsirkin" Cc: Stefan Hajnoczi Tested-by: Laurence Oberman Reviewed-by: Christoph Hellwig Reviewed-by: Himanshu Madhani Signed-off-by: Mike Christie Signed-off-by: Martin K. Petersen --- drivers/target/target_core_transport.c | 201 +++++++++++++++++++++++---------- include/target/target_core_fabric.h | 8 ++ 2 files changed, 148 insertions(+), 61 deletions(-) diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 44ebabad3b99..000819112bc7 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1573,46 +1573,31 @@ transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *sgl, } /** - * target_submit_cmd_map_sgls - lookup unpacked lun and submit uninitialized - * se_cmd + use pre-allocated SGL memory. - * - * @se_cmd: command descriptor to submit + * target_init_cmd - initialize se_cmd + * @se_cmd: command descriptor to init * @se_sess: associated se_sess for endpoint - * @cdb: pointer to SCSI CDB * @sense: pointer to SCSI sense buffer * @unpacked_lun: unpacked LUN to reference for struct se_lun * @data_length: fabric expected data transfer length * @task_attr: SAM task attribute * @data_dir: DMA data direction * @flags: flags for command submission from target_sc_flags_tables - * @sgl: struct scatterlist memory for unidirectional mapping - * @sgl_count: scatterlist count for unidirectional mapping - * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping - * @sgl_bidi_count: scatterlist count for bidirectional READ mapping - * @sgl_prot: struct scatterlist memory protection information - * @sgl_prot_count: scatterlist count for protection information * * Task tags are supported if the caller has set @se_cmd->tag. * - * Returns non zero to signal active I/O shutdown failure. All other - * setup exceptions will be returned as a SCSI CHECK_CONDITION response, - * but still return zero here. + * Returns: + * - less than zero to signal active I/O shutdown failure. + * - zero on success. * - * This may only be called from process context, and also currently - * assumes internal allocation of fabric payload buffer by target-core. + * If the fabric driver calls target_stop_session, then it must check the + * return code and handle failures. This will never fail for other drivers, + * and the return code can be ignored. */ -int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess, - unsigned char *cdb, unsigned char *sense, u64 unpacked_lun, - u32 data_length, int task_attr, int data_dir, int flags, - struct scatterlist *sgl, u32 sgl_count, - struct scatterlist *sgl_bidi, u32 sgl_bidi_count, - struct scatterlist *sgl_prot, u32 sgl_prot_count) +int target_init_cmd(struct se_cmd *se_cmd, struct se_session *se_sess, + unsigned char *sense, u64 unpacked_lun, + u32 data_length, int task_attr, int data_dir, int flags) { struct se_portal_group *se_tpg; - sense_reason_t rc; - int ret; - - might_sleep(); se_tpg = se_sess->se_tpg; BUG_ON(!se_tpg); @@ -1620,53 +1605,69 @@ int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess if (flags & TARGET_SCF_USE_CPUID) se_cmd->se_cmd_flags |= SCF_USE_CPUID; + /* + * Signal bidirectional data payloads to target-core + */ + if (flags & TARGET_SCF_BIDI_OP) + se_cmd->se_cmd_flags |= SCF_BIDI; + + if (flags & TARGET_SCF_UNKNOWN_SIZE) + se_cmd->unknown_data_length = 1; /* * Initialize se_cmd for target operation. From this point * exceptions are handled by sending exception status via * target_core_fabric_ops->queue_status() callback */ - __target_init_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess, - data_length, data_dir, task_attr, sense, - unpacked_lun); + __target_init_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess, data_length, + data_dir, task_attr, sense, unpacked_lun); - if (flags & TARGET_SCF_UNKNOWN_SIZE) - se_cmd->unknown_data_length = 1; /* * Obtain struct se_cmd->cmd_kref reference. A second kref_get here is * necessary for fabrics using TARGET_SCF_ACK_KREF that expect a second * kref_put() to happen during fabric packet acknowledgement. */ - ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF); - if (ret) - return ret; - /* - * Signal bidirectional data payloads to target-core - */ - if (flags & TARGET_SCF_BIDI_OP) - se_cmd->se_cmd_flags |= SCF_BIDI; + return target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF); +} +EXPORT_SYMBOL_GPL(target_init_cmd); + +/** + * target_submit_prep - prepare cmd for submission + * @se_cmd: command descriptor to prep + * @cdb: pointer to SCSI CDB + * @sgl: struct scatterlist memory for unidirectional mapping + * @sgl_count: scatterlist count for unidirectional mapping + * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping + * @sgl_bidi_count: scatterlist count for bidirectional READ mapping + * @sgl_prot: struct scatterlist memory protection information + * @sgl_prot_count: scatterlist count for protection information + * + * Returns: + * - less than zero to signal failure. + * - zero on success. + * If failure is returned, lio will the callers queue_status to complete + * the cmd. + */ +int target_submit_prep(struct se_cmd *se_cmd, unsigned char *cdb, + struct scatterlist *sgl, u32 sgl_count, + struct scatterlist *sgl_bidi, u32 sgl_bidi_count, + struct scatterlist *sgl_prot, u32 sgl_prot_count) +{ + sense_reason_t rc; rc = target_cmd_init_cdb(se_cmd, cdb); - if (rc) { - transport_send_check_condition_and_sense(se_cmd, rc, 0); - target_put_sess_cmd(se_cmd); - return 0; - } + if (rc) + goto send_cc_direct; /* * Locate se_lun pointer and attach it to struct se_cmd */ rc = transport_lookup_cmd_lun(se_cmd); - if (rc) { - transport_send_check_condition_and_sense(se_cmd, rc, 0); - target_put_sess_cmd(se_cmd); - return 0; - } + if (rc) + goto send_cc_direct; rc = target_cmd_parse_cdb(se_cmd); - if (rc != 0) { - transport_generic_request_failure(se_cmd, rc); - return 0; - } + if (rc != 0) + goto generic_fail; /* * Save pointers for SGLs containing protection information, @@ -1686,6 +1687,41 @@ int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess if (sgl_count != 0) { BUG_ON(!sgl); + rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count, + sgl_bidi, sgl_bidi_count); + if (rc != 0) + goto generic_fail; + } + + return 0; + +send_cc_direct: + transport_send_check_condition_and_sense(se_cmd, rc, 0); + target_put_sess_cmd(se_cmd); + return -EIO; + +generic_fail: + transport_generic_request_failure(se_cmd, rc); + return -EIO; +} +EXPORT_SYMBOL_GPL(target_submit_prep); + +/** + * target_submit - perform final initialization and submit cmd to LIO core + * @se_cmd: command descriptor to submit + * + * target_submit_prep must have been called on the cmd, and this must be + * called from process context. + */ +void target_submit(struct se_cmd *se_cmd) +{ + struct scatterlist *sgl = se_cmd->t_data_sg; + unsigned char *buf = NULL; + + might_sleep(); + + if (se_cmd->t_data_nents != 0) { + BUG_ON(!sgl); /* * A work-around for tcm_loop as some userspace code via * scsi-generic do not memset their associated read buffers, @@ -1696,8 +1732,6 @@ int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess */ if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) && se_cmd->data_direction == DMA_FROM_DEVICE) { - unsigned char *buf = NULL; - if (sgl) buf = kmap(sg_page(sgl)) + sgl->offset; @@ -1707,12 +1741,6 @@ int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess } } - rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count, - sgl_bidi, sgl_bidi_count); - if (rc != 0) { - transport_generic_request_failure(se_cmd, rc); - return 0; - } } /* @@ -1722,6 +1750,57 @@ int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess core_alua_check_nonop_delay(se_cmd); transport_handle_cdb_direct(se_cmd); +} +EXPORT_SYMBOL_GPL(target_submit); + +/** + * target_submit_cmd_map_sgls - lookup unpacked lun and submit uninitialized + * se_cmd + use pre-allocated SGL memory. + * + * @se_cmd: command descriptor to submit + * @se_sess: associated se_sess for endpoint + * @cdb: pointer to SCSI CDB + * @sense: pointer to SCSI sense buffer + * @unpacked_lun: unpacked LUN to reference for struct se_lun + * @data_length: fabric expected data transfer length + * @task_attr: SAM task attribute + * @data_dir: DMA data direction + * @flags: flags for command submission from target_sc_flags_tables + * @sgl: struct scatterlist memory for unidirectional mapping + * @sgl_count: scatterlist count for unidirectional mapping + * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping + * @sgl_bidi_count: scatterlist count for bidirectional READ mapping + * @sgl_prot: struct scatterlist memory protection information + * @sgl_prot_count: scatterlist count for protection information + * + * Task tags are supported if the caller has set @se_cmd->tag. + * + * Returns non zero to signal active I/O shutdown failure. All other + * setup exceptions will be returned as a SCSI CHECK_CONDITION response, + * but still return zero here. + * + * This may only be called from process context, and also currently + * assumes internal allocation of fabric payload buffer by target-core. + */ +int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess, + unsigned char *cdb, unsigned char *sense, u64 unpacked_lun, + u32 data_length, int task_attr, int data_dir, int flags, + struct scatterlist *sgl, u32 sgl_count, + struct scatterlist *sgl_bidi, u32 sgl_bidi_count, + struct scatterlist *sgl_prot, u32 sgl_prot_count) +{ + int rc; + + rc = target_init_cmd(se_cmd, se_sess, sense, unpacked_lun, + data_length, task_attr, data_dir, flags); + if (rc < 0) + return rc; + + if (target_submit_prep(se_cmd, cdb, sgl, sgl_count, sgl_bidi, + sgl_bidi_count, sgl_prot, sgl_prot_count)) + return 0; + + target_submit(se_cmd); return 0; } EXPORT_SYMBOL(target_submit_cmd_map_sgls); diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h index 4975c4d2a933..4b5f6687393a 100644 --- a/include/target/target_core_fabric.h +++ b/include/target/target_core_fabric.h @@ -151,6 +151,14 @@ void transport_deregister_session(struct se_session *); void __target_init_cmd(struct se_cmd *, const struct target_core_fabric_ops *, struct se_session *, u32, int, int, unsigned char *, u64); +int target_init_cmd(struct se_cmd *se_cmd, struct se_session *se_sess, + unsigned char *sense, u64 unpacked_lun, u32 data_length, + int task_attr, int data_dir, int flags); +int target_submit_prep(struct se_cmd *se_cmd, unsigned char *cdb, + struct scatterlist *sgl, u32 sgl_count, + struct scatterlist *sgl_bidi, u32 sgl_bidi_count, + struct scatterlist *sgl_prot, u32 sgl_prot_count); +void target_submit(struct se_cmd *se_cmd); sense_reason_t transport_lookup_cmd_lun(struct se_cmd *); sense_reason_t target_cmd_init_cdb(struct se_cmd *, unsigned char *); sense_reason_t target_cmd_parse_cdb(struct se_cmd *); -- cgit v1.2.3