Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2993601AbbEPITK (ORCPT ); Sat, 16 May 2015 04:19:10 -0400 Received: from bband-dyn183.178-41-215.t-com.sk ([178.41.215.183]:22931 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2993105AbbEPITA (ORCPT ); Sat, 16 May 2015 04:19:00 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Nicholas Bellinger , Christoph Hellwig , Jiri Slaby Subject: [PATCH 3.12 055/142] target: Fix COMPARE_AND_WRITE with SG_TO_MEM_NOALLOC handling Date: Sat, 16 May 2015 09:36:55 +0200 Message-Id: <15a557ae69ea1e86aa8db5c9a48f7406d9235b72.1431761807.git.jslaby@suse.cz> X-Mailer: git-send-email 2.3.7 In-Reply-To: <70c3d4ae1322b9e9bd7443ef574af5635234a0fa.1431761807.git.jslaby@suse.cz> References: <70c3d4ae1322b9e9bd7443ef574af5635234a0fa.1431761807.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7313 Lines: 198 From: Nicholas Bellinger 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit c8e639852ad720499912acedfd6b072325fd2807 upstream. This patch fixes a bug for COMPARE_AND_WRITE handling with fabrics using SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC. It adds the missing allocation for cmd->t_bidi_data_sg within transport_generic_new_cmd() that is used by COMPARE_AND_WRITE for the initial READ payload, even if the fabric is already providing a pre-allocated buffer for cmd->t_data_sg. Also, fix zero-length COMPARE_AND_WRITE handling within the compare_and_write_callback() and target_complete_ok_work() to queue the response, skipping the initial READ. This fixes COMPARE_AND_WRITE emulation with loopback, vhost, and xen-backend fabric drivers using SG_TO_MEM_NOALLOC. Reported-by: Christoph Hellwig Cc: Christoph Hellwig Signed-off-by: Nicholas Bellinger Signed-off-by: Jiri Slaby --- drivers/target/target_core_sbc.c | 15 +++++++++----- drivers/target/target_core_transport.c | 37 ++++++++++++++++++++++++++++++---- include/target/target_core_base.h | 2 +- 3 files changed, 44 insertions(+), 10 deletions(-) diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c index 63d56cda2b96..75f126538a72 100644 --- a/drivers/target/target_core_sbc.c +++ b/drivers/target/target_core_sbc.c @@ -298,7 +298,7 @@ sbc_setup_write_same(struct se_cmd *cmd, unsigned char *flags, struct sbc_ops *o return 0; } -static sense_reason_t xdreadwrite_callback(struct se_cmd *cmd) +static sense_reason_t xdreadwrite_callback(struct se_cmd *cmd, bool success) { unsigned char *buf, *addr; struct scatterlist *sg; @@ -362,7 +362,7 @@ sbc_execute_rw(struct se_cmd *cmd) cmd->data_direction); } -static sense_reason_t compare_and_write_post(struct se_cmd *cmd) +static sense_reason_t compare_and_write_post(struct se_cmd *cmd, bool success) { struct se_device *dev = cmd->se_dev; @@ -385,7 +385,7 @@ static sense_reason_t compare_and_write_post(struct se_cmd *cmd) return TCM_NO_SENSE; } -static sense_reason_t compare_and_write_callback(struct se_cmd *cmd) +static sense_reason_t compare_and_write_callback(struct se_cmd *cmd, bool success) { struct se_device *dev = cmd->se_dev; struct scatterlist *write_sg = NULL, *sg; @@ -400,11 +400,16 @@ static sense_reason_t compare_and_write_callback(struct se_cmd *cmd) /* * Handle early failure in transport_generic_request_failure(), - * which will not have taken ->caw_mutex yet.. + * which will not have taken ->caw_sem yet.. */ - if (!cmd->t_data_sg || !cmd->t_bidi_data_sg) + if (!success && (!cmd->t_data_sg || !cmd->t_bidi_data_sg)) return TCM_NO_SENSE; /* + * Handle special case for zero-length COMPARE_AND_WRITE + */ + if (!cmd->data_length) + goto out; + /* * Immediately exit + release dev->caw_sem if command has already * been failed with a non-zero SCSI status. */ diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 65ecaa1c59a7..b52bf3cad494 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1589,11 +1589,11 @@ void transport_generic_request_failure(struct se_cmd *cmd, transport_complete_task_attr(cmd); /* * Handle special case for COMPARE_AND_WRITE failure, where the - * callback is expected to drop the per device ->caw_mutex. + * callback is expected to drop the per device ->caw_sem. */ if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) && cmd->transport_complete_callback) - cmd->transport_complete_callback(cmd); + cmd->transport_complete_callback(cmd, false); switch (sense_reason) { case TCM_NON_EXISTENT_LUN: @@ -1942,8 +1942,12 @@ static void target_complete_ok_work(struct work_struct *work) if (cmd->transport_complete_callback) { sense_reason_t rc; - rc = cmd->transport_complete_callback(cmd); + rc = cmd->transport_complete_callback(cmd, true); if (!rc && !(cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE_POST)) { + if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) && + !cmd->data_length) + goto queue_rsp; + return; } else if (rc) { ret = transport_send_check_condition_and_sense(cmd, @@ -1957,6 +1961,7 @@ static void target_complete_ok_work(struct work_struct *work) } } +queue_rsp: switch (cmd->data_direction) { case DMA_FROM_DEVICE: spin_lock(&cmd->se_lun->lun_sep_lock); @@ -2045,6 +2050,16 @@ static inline void transport_reset_sgl_orig(struct se_cmd *cmd) static inline void transport_free_pages(struct se_cmd *cmd) { if (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) { + /* + * Release special case READ buffer payload required for + * SG_TO_MEM_NOALLOC to function with COMPARE_AND_WRITE + */ + if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) { + transport_free_sgl(cmd->t_bidi_data_sg, + cmd->t_bidi_data_nents); + cmd->t_bidi_data_sg = NULL; + cmd->t_bidi_data_nents = 0; + } transport_reset_sgl_orig(cmd); return; } @@ -2193,6 +2208,7 @@ sense_reason_t transport_generic_new_cmd(struct se_cmd *cmd) { int ret = 0; + bool zero_flag = !(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB); /* * Determine is the TCM fabric module has already allocated physical @@ -2201,7 +2217,6 @@ transport_generic_new_cmd(struct se_cmd *cmd) */ if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) && cmd->data_length) { - bool zero_flag = !(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB); if ((cmd->se_cmd_flags & SCF_BIDI) || (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)) { @@ -2224,6 +2239,20 @@ transport_generic_new_cmd(struct se_cmd *cmd) cmd->data_length, zero_flag); if (ret < 0) return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; + } else if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) && + cmd->data_length) { + /* + * Special case for COMPARE_AND_WRITE with fabrics + * using SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC. + */ + u32 caw_length = cmd->t_task_nolb * + cmd->se_dev->dev_attrib.block_size; + + ret = target_alloc_sgl(&cmd->t_bidi_data_sg, + &cmd->t_bidi_data_nents, + caw_length, zero_flag); + if (ret < 0) + return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; } /* * If this command is not a write we can execute it right here, diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h index 38647a3441c9..085e6bedf393 100644 --- a/include/target/target_core_base.h +++ b/include/target/target_core_base.h @@ -457,7 +457,7 @@ struct se_cmd { sense_reason_t (*execute_cmd)(struct se_cmd *); sense_reason_t (*execute_rw)(struct se_cmd *, struct scatterlist *, u32, enum dma_data_direction); - sense_reason_t (*transport_complete_callback)(struct se_cmd *); + sense_reason_t (*transport_complete_callback)(struct se_cmd *, bool); unsigned char *t_task_cdb; unsigned char __t_task_cdb[TCM_MAX_COMMAND_SIZE]; -- 2.3.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/