From a026757ff56365b4aa3875c14f1bd5733e0e8bb2 Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Mon, 1 Oct 2012 17:23:22 -0700 Subject: target: Add target_submit_cmd_map_sgls for SGL fabric memory passthrough This patch adds a new target_submit_cmd_map_sgls() to pass pre-allocated SGL memory using transport_generic_map_mem_to_cmd() logic into the generic target submit I/O codepath. It also adds a target_submit_cmd() wrapper around target_submit_cmd_map_sgls() for existing fabric code that already assumes internal target-core SGL memory allocation. (v2: Rename to target_submit_cmd_map_sgls + drop TARGET_SCF_MAP_MEM flag in favor of non zero sgl_count check) Reported-by: Christoph Hellwig Cc: Christoph Hellwig Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_transport.c | 65 ++++++++++++++++++++++++++++++---- 1 file changed, 59 insertions(+), 6 deletions(-) (limited to 'drivers/target') diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 221f67f3427..d96d9aa3a49 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1455,8 +1455,9 @@ int transport_handle_cdb_direct( } EXPORT_SYMBOL(transport_handle_cdb_direct); -/** - * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd +/* + * 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 @@ -1467,6 +1468,10 @@ EXPORT_SYMBOL(transport_handle_cdb_direct); * @task_addr: 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 * * Returns non zero to signal active I/O shutdown failure. All other * setup exceptions will be returned as a SCSI CHECK_CONDITION response, @@ -1474,10 +1479,12 @@ EXPORT_SYMBOL(transport_handle_cdb_direct); * * 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(struct se_cmd *se_cmd, struct se_session *se_sess, + */ +int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess, unsigned char *cdb, unsigned char *sense, u32 unpacked_lun, - u32 data_length, int task_attr, int data_dir, int flags) + 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 se_portal_group *se_tpg; int rc; @@ -1524,7 +1531,21 @@ int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess, transport_generic_request_failure(se_cmd); return 0; } - + /* + * When a non zero sgl_count has been passed perform SGL passthrough + * mapping for pre-allocated fabric memory instead of having target + * core perform an internal SGL allocation.. + */ + 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) { + transport_generic_request_failure(se_cmd); + return 0; + } + } /* * Check if we need to delay processing because of ALUA * Active/NonOptimized primary access state.. @@ -1534,6 +1555,38 @@ int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess, transport_handle_cdb_direct(se_cmd); return 0; } +EXPORT_SYMBOL(target_submit_cmd_map_sgls); + +/* + * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd + * + * @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_addr: SAM task attribute + * @data_dir: DMA data direction + * @flags: flags for command submission from target_sc_flags_tables + * + * 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. + * + * It also assumes interal target core SGL memory allocation. + */ +int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess, + unsigned char *cdb, unsigned char *sense, u32 unpacked_lun, + u32 data_length, int task_attr, int data_dir, int flags) +{ + return target_submit_cmd_map_sgls(se_cmd, se_sess, cdb, sense, + unpacked_lun, data_length, task_attr, data_dir, + flags, NULL, 0, NULL, 0); +} EXPORT_SYMBOL(target_submit_cmd); static void target_complete_tmr_failure(struct work_struct *work) -- cgit v1.2.3