Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1947027AbbEBTeY (ORCPT ); Sat, 2 May 2015 15:34:24 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:45800 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030177AbbEBTeS (ORCPT ); Sat, 2 May 2015 15:34:18 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Christoph Hellwig , Nicholas Bellinger Subject: [PATCH 3.19 106/177] target: Fix COMPARE_AND_WRITE with SG_TO_MEM_NOALLOC handling Date: Sat, 2 May 2015 21:02:08 +0200 Message-Id: <20150502190124.714427681@linuxfoundation.org> X-Mailer: git-send-email 2.3.7 In-Reply-To: <20150502190119.666291882@linuxfoundation.org> References: <20150502190119.666291882@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6767 Lines: 192 3.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nicholas Bellinger 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: Greg Kroah-Hartman --- 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(-) --- a/drivers/target/target_core_sbc.c +++ b/drivers/target/target_core_sbc.c @@ -299,7 +299,7 @@ sbc_setup_write_same(struct se_cmd *cmd, 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; @@ -363,7 +363,7 @@ 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; @@ -386,7 +386,7 @@ static sense_reason_t compare_and_write_ 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; @@ -401,11 +401,16 @@ static sense_reason_t compare_and_write_ /* * 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. */ --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1615,11 +1615,11 @@ void transport_generic_request_failure(s 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: @@ -1975,8 +1975,12 @@ static void target_complete_ok_work(stru 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, @@ -1990,6 +1994,7 @@ static void target_complete_ok_work(stru } } +queue_rsp: switch (cmd->data_direction) { case DMA_FROM_DEVICE: spin_lock(&cmd->se_lun->lun_sep_lock); @@ -2094,6 +2099,16 @@ static inline void transport_reset_sgl_o 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; } @@ -2246,6 +2261,7 @@ 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 @@ -2254,7 +2270,6 @@ transport_generic_new_cmd(struct se_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)) { @@ -2285,6 +2300,20 @@ transport_generic_new_cmd(struct se_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, --- a/include/target/target_core_base.h +++ b/include/target/target_core_base.h @@ -524,7 +524,7 @@ 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]; 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