Messages in this thread Patch in this message | | | From | "Nicholas A. Bellinger" <> | Subject | [PATCH-v3 13/13] target: Release COMPARE_AND_WRITE mutex in generic failure path | Date | Mon, 26 Aug 2013 21:13:46 +0000 |
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From: Nicholas Bellinger <nab@daterainc.com>
This patch adds a extra check for SCF_COMPARE_AND_WRITE within transport_generic_request_failure() to invoke the callback for compare_and_write_callback() or compare_and_write_done(), in order to release se_dev->caw_mutex from the generic failure path.
It also adds to checks within compare_and_write_callback() to avoid processing when transport_generic_request_failure() occurs early enough that cmd->t_data_sg or cmd->t_bidi_data_sg have not been setup yet, nor se_dev->caw_mutex obtained from within sbc_compare_and_write().
Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Martin Petersen <martin.petersen@oracle.com> Cc: Chris Mason <chris.mason@fusionio.com> Cc: James Bottomley <JBottomley@Parallels.com> Cc: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> --- drivers/target/target_core_sbc.c | 7 +++++++ drivers/target/target_core_transport.c | 6 ++++++ 2 files changed, 13 insertions(+), 0 deletions(-)
diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c index bb1b42b..287e960 100644 --- a/drivers/target/target_core_sbc.c +++ b/drivers/target/target_core_sbc.c @@ -372,6 +372,13 @@ static sense_reason_t compare_and_write_callback(struct se_cmd *cmd) sense_reason_t ret = TCM_NO_SENSE; int rc, i; + /* + * Handle early failure in transport_generic_request_failure(), + * which will not have taken ->caw_mutex yet.. + */ + if (!cmd->t_data_sg || !cmd->t_bidi_data_sg) + return TCM_NO_SENSE; + buf = kzalloc(cmd->data_length, GFP_KERNEL); if (!buf) { pr_err("Unable to allocate compare_and_write buf\n"); diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index e53c59b..526e5ba 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1559,6 +1559,12 @@ void transport_generic_request_failure(struct se_cmd *cmd, * For SAM Task Attribute emulation for failed struct se_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. + */ + if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) + cmd->transport_complete_callback(cmd); switch (sense_reason) { case TCM_NON_EXISTENT_LUN: -- 1.7.2.5
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