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| author |   Nicholas Bellinger <nab@linux-iscsi.org> | 2015-04-07 21:53:27 +0000 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2015-04-14 12:37:38 -0700 |
| commit | c8e639852ad720499912acedfd6b072325fd2807 (patch) | |
| tree | 9a36ded92c2e3dab7c7e8a0bd5a5f0aa0d7dd884 /drivers/target/target_core_sbc.c | |
| parent | target: simplify the target template registration API (diff) | |
| download | linux-dev-c8e639852ad720499912acedfd6b072325fd2807.tar.xz linux-dev-c8e639852ad720499912acedfd6b072325fd2807.zip | |
target: Fix COMPARE_AND_WRITE with SG_TO_MEM_NOALLOC handling
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 <hch@lst.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: <stable@vger.kernel.org> # v3.12+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target/target_core_sbc.c')
| -rw-r--r-- | drivers/target/target_core_sbc.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c index 315ff641408b..0064ffe9a219 100644 --- a/drivers/target/target_core_sbc.c +++ b/drivers/target/target_core_sbc.c @@ -321,7 +321,7 @@ 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; @@ -385,7 +385,7 @@ 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; @@ -408,7 +408,7 @@ 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; @@ -423,11 +423,16 @@ 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. */ |