From ae13b9c8b4d38cef997274929a72f619bbadbd37 Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Thu, 19 May 2011 20:19:09 -0700 Subject: [PATCH] target: Fix multi task->task_sg[] chaining logic bug BugLink: http://bugs.launchpad.net/bugs/793702 commit 97868c8905a1537153d406c4a3aa39a503a5c299 upstream. This patch fixes a bug in transport_do_task_sg_chain() used by HW target mode modules with sg_chain() to provide a single sg_next() walkable memory layout for use with pci_map_sg() and friends. This patch addresses an issue with mapping multiple small block max_sector tasks across multiple struct se_task->task_sg[] mappings for HW target mode operation. This was causing OOPs with (cmd->t_task->t_tasks_no > 1) I/O traffic for HW target drivers using transport_do_task_sg_chain(), and has been tested so far with tcm_fc(openfcoe), tcm_qla2xxx, and ib_srpt fabrics with t_tasks_no > 1 IBLOCK backends using a smaller max_sectors to trigger the original issue. Signed-off-by: Nicholas Bellinger Acked-by: Kiran Patil Signed-off-by: James Bottomley Signed-off-by: Greg Kroah-Hartman Signed-off-by: Tim Gardner --- drivers/target/target_core_transport.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 4bbf6c1..a0ad2f4 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -4777,18 +4777,20 @@ void transport_do_task_sg_chain(struct se_cmd *cmd) sg_end_cur->page_link &= ~0x02; sg_chain(sg_head, task_sg_num, sg_head_cur); - sg_count += (task->task_sg_num + 1); - } else sg_count += task->task_sg_num; + task_sg_num = (task->task_sg_num + 1); + } else { + sg_chain(sg_head, task_sg_num, sg_head_cur); + sg_count += task->task_sg_num; + task_sg_num = task->task_sg_num; + } sg_head = sg_head_cur; sg_link = sg_link_cur; - task_sg_num = task->task_sg_num; continue; } sg_head = sg_first = &task->task_sg[0]; sg_link = &task->task_sg[task->task_sg_num]; - task_sg_num = task->task_sg_num; /* * Check for single task.. */ @@ -4799,9 +4801,12 @@ void transport_do_task_sg_chain(struct se_cmd *cmd) */ sg_end = &task->task_sg[task->task_sg_num - 1]; sg_end->page_link &= ~0x02; - sg_count += (task->task_sg_num + 1); - } else sg_count += task->task_sg_num; + task_sg_num = (task->task_sg_num + 1); + } else { + sg_count += task->task_sg_num; + task_sg_num = task->task_sg_num; + } } /* * Setup the starting pointer and total t_tasks_sg_linked_no including @@ -4810,21 +4815,20 @@ void transport_do_task_sg_chain(struct se_cmd *cmd) T_TASK(cmd)->t_tasks_sg_chained = sg_first; T_TASK(cmd)->t_tasks_sg_chained_no = sg_count; - DEBUG_CMD_M("Setup T_TASK(cmd)->t_tasks_sg_chained: %p and" - " t_tasks_sg_chained_no: %u\n", T_TASK(cmd)->t_tasks_sg_chained, + DEBUG_CMD_M("Setup cmd: %p T_TASK(cmd)->t_tasks_sg_chained: %p and" + " t_tasks_sg_chained_no: %u\n", cmd, T_TASK(cmd)->t_tasks_sg_chained, T_TASK(cmd)->t_tasks_sg_chained_no); for_each_sg(T_TASK(cmd)->t_tasks_sg_chained, sg, T_TASK(cmd)->t_tasks_sg_chained_no, i) { - DEBUG_CMD_M("SG: %p page: %p length: %d offset: %d\n", - sg, sg_page(sg), sg->length, sg->offset); + DEBUG_CMD_M("SG[%d]: %p page: %p length: %d offset: %d, magic: 0x%08x\n", + i, sg, sg_page(sg), sg->length, sg->offset, sg->sg_magic); if (sg_is_chain(sg)) DEBUG_CMD_M("SG: %p sg_is_chain=1\n", sg); if (sg_is_last(sg)) DEBUG_CMD_M("SG: %p sg_is_last=1\n", sg); } - } EXPORT_SYMBOL(transport_do_task_sg_chain); -- 1.7.10.4