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authorNicholas Bellinger <nab@linux-iscsi.org>2015-04-07 21:53:27 +0000
committerNicholas Bellinger <nab@linux-iscsi.org>2015-04-14 12:37:38 -0700
commitc8e639852ad720499912acedfd6b072325fd2807 (patch)
tree9a36ded92c2e3dab7c7e8a0bd5a5f0aa0d7dd884 /drivers/target/target_core_sbc.c
parent9ac8928e6a3e1ed02e632e45aa766129fe6b1802 (diff)
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.c15
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.
*/