In preparation for finding and returning the miscompare offset.
Signed-off-by: David Disseldorp <ddiss@xxxxxxx>
---
drivers/target/target_core_sbc.c | 121 +++++++++++++++++--------------
1 file changed, 68 insertions(+), 53 deletions(-)
diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index 5f77dd95f1b9..22d0cbba6ff3 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -434,20 +434,75 @@ static sense_reason_t compare_and_write_post(struct se_cmd *cmd, bool success,
return ret;
}
+/*
+ * compare @cmp_len bytes of @read_sgl with @cmp_sgl. On miscompare return
+ * TCM_MISCOMPARE_VERIFY.
+ */
+static sense_reason_t
+compare_and_write_do_cmp(struct scatterlist *read_sgl, unsigned int read_nents,
+ struct scatterlist *cmp_sgl, unsigned int cmp_nents,
+ unsigned int cmp_len)
+{
+ unsigned char *buf = NULL;
+ struct scatterlist *sg;
+ sense_reason_t ret;
+ unsigned int offset;
+ size_t rc;
+ int i;
+
+ buf = kzalloc(cmp_len, GFP_KERNEL);
+ if (!buf) {
+ ret = TCM_OUT_OF_RESOURCES;
+ goto out;
+ }
+
+ rc = sg_copy_to_buffer(cmp_sgl, cmp_nents, buf, cmp_len);
+ if (!rc) {
+ pr_err("sg_copy_to_buffer() failed for compare_and_write\n");
+ ret = TCM_OUT_OF_RESOURCES;
+ goto out;
+ }
+ /*
+ * Compare SCSI READ payload against verify payload
+ */
+ offset = 0;
+ for_each_sg(read_sgl, sg, read_nents, i) {
+ unsigned int len = min(sg->length, cmp_len);
+ unsigned char *addr = kmap_atomic(sg_page(sg));
+
+ if (memcmp(addr, buf + offset, len)) {
+ pr_warn("Detected MISCOMPARE for addr: %p buf: %p\n",
+ addr, buf + offset);
+ kunmap_atomic(addr);
+ ret = TCM_MISCOMPARE_VERIFY;
+ goto out;
+ }
+ kunmap_atomic(addr);
+
+ offset += len;
+ cmp_len -= len;
+ if (!cmp_len)
+ break;
+ }
+ pr_debug("COMPARE AND WRITE read data matches compare data\n");
+ ret = TCM_NO_SENSE;
+out:
+ kfree(buf);
+ return ret;
+}
+
static sense_reason_t compare_and_write_callback(struct se_cmd *cmd, bool success,
int *post_ret)
{
struct se_device *dev = cmd->se_dev;
struct sg_table write_tbl = { };
- struct scatterlist *write_sg, *sg;
- unsigned char *buf = NULL, *addr;
+ struct scatterlist *write_sg;
struct sg_mapping_iter m;
- unsigned int offset = 0, len;
- unsigned int nlbas = cmd->t_task_nolb;
+ unsigned int len;
unsigned int block_size = dev->dev_attrib.block_size;
- unsigned int compare_len = (nlbas * block_size);
+ unsigned int compare_len = (cmd->t_task_nolb * block_size);
sense_reason_t ret = TCM_NO_SENSE;
- int rc, i;
+ int i;
/*
* Handle early failure in transport_generic_request_failure(),
@@ -473,12 +528,13 @@ static sense_reason_t compare_and_write_callback(struct se_cmd *cmd, bool succes
goto out;
}
- buf = kzalloc(cmd->data_length, GFP_KERNEL);
- if (!buf) {
- pr_err("Unable to allocate compare_and_write buf\n");
- ret = TCM_OUT_OF_RESOURCES;
+ ret = compare_and_write_do_cmp(cmd->t_bidi_data_sg,
+ cmd->t_bidi_data_nents,
+ cmd->t_data_sg,
+ cmd->t_data_nents,
+ compare_len);
+ if (ret)
goto out;
- }
if (sg_alloc_table(&write_tbl, cmd->t_data_nents, GFP_KERNEL) < 0) {
pr_err("Unable to allocate compare_and_write sg\n");
@@ -486,44 +542,9 @@ static sense_reason_t compare_and_write_callback(struct se_cmd *cmd, bool succes
goto out;
}
write_sg = write_tbl.sgl;
- /*
- * Setup verify and write data payloads from total NumberLBAs.
- */
- rc = sg_copy_to_buffer(cmd->t_data_sg, cmd->t_data_nents, buf,
- cmd->data_length);
- if (!rc) {
- pr_err("sg_copy_to_buffer() failed for compare_and_write\n");
- ret = TCM_OUT_OF_RESOURCES;
- goto out;
- }
- /*
- * Compare against SCSI READ payload against verify payload
- */
- for_each_sg(cmd->t_bidi_data_sg, sg, cmd->t_bidi_data_nents, i) {
- addr = (unsigned char *)kmap_atomic(sg_page(sg));
- if (!addr) {
- ret = TCM_OUT_OF_RESOURCES;
- goto out;
- }
-
- len = min(sg->length, compare_len);
-
- if (memcmp(addr, buf + offset, len)) {
- pr_warn("Detected MISCOMPARE for addr: %p buf: %p\n",
- addr, buf + offset);
- kunmap_atomic(addr);
- goto miscompare;
- }
- kunmap_atomic(addr);
-
- offset += len;
- compare_len -= len;
- if (!compare_len)
- break;
- }
i = 0;
- len = cmd->t_task_nolb * block_size;
+ len = compare_len;
sg_miter_start(&m, cmd->t_data_sg, cmd->t_data_nents, SG_MITER_TO_SG);
/*
* Currently assumes NoLB=1 and SGLs are PAGE_SIZE..
@@ -568,13 +589,8 @@ static sense_reason_t compare_and_write_callback(struct se_cmd *cmd, bool succes
__target_execute_cmd(cmd, false);
- kfree(buf);
return ret;
-miscompare:
- pr_warn("Target/%s: Send MISCOMPARE check condition and sense\n",
- dev->transport->name);
- ret = TCM_MISCOMPARE_VERIFY;
out:
/*
* In the MISCOMPARE or failure case, unlock ->caw_sem obtained in
@@ -582,7 +598,6 @@ static sense_reason_t compare_and_write_callback(struct se_cmd *cmd, bool succes
*/
up(&dev->caw_sem);
sg_free_table(&write_tbl);
- kfree(buf);
return ret;
}
--
2.26.2
