| Message ID | 20201023205723.17880-6-ddiss@suse.de |
|---|---|
| State | New |
| Headers | show |
| Series | scsi: target: COMPARE AND WRITE miscompare sense | expand |
On 10/23/20 3:57 PM, David Disseldorp wrote: > SBC-4 r15 5.3 COMPARE AND WRITE command states: > if the compare operation does not indicate a match, then terminate the > command with CHECK CONDITION status with the sense key set to > MISCOMPARE and the additional sense code set to MISCOMPARE DURING > VERIFY OPERATION. In the sense data (see 4.18 and SPC-5) the offset > from the start of the Data-Out Buffer to the first byte of data that > was not equal shall be reported in the INFORMATION field. > > This change implements the missing logic to report the miscompare offset > in the sense data INFORMATION field. > > Signed-off-by: David Disseldorp <ddiss@suse.de> > --- > drivers/target/target_core_sbc.c | 35 ++++++++++++++++++-------- > drivers/target/target_core_transport.c | 1 + > 2 files changed, 26 insertions(+), 10 deletions(-) > > diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c > index 79216d0355e7..e40359e45726 100644 > --- a/drivers/target/target_core_sbc.c > +++ b/drivers/target/target_core_sbc.c > @@ -435,13 +435,13 @@ static sense_reason_t compare_and_write_post(struct se_cmd *cmd, bool success, > } > > /* > - * compare @cmp_len bytes of @read_sgl with @cmp_sgl. On miscompare return > - * TCM_MISCOMPARE_VERIFY. > + * compare @cmp_len bytes of @read_sgl with @cmp_sgl. On miscompare, fill > + * @miscmp_off and 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 int cmp_len, unsigned int *miscmp_off) > { > unsigned char *buf = NULL; > struct scatterlist *sg; > @@ -468,17 +468,20 @@ compare_and_write_do_cmp(struct scatterlist *read_sgl, unsigned int read_nents, > */ > offset = 0; > for_each_sg(read_sgl, sg, read_nents, i) { > + unsigned int 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); > + for (i = 0; i < len && addr[i] == buf[offset + i]; i++); I think it's a little nicer to put the ";" on the next line. It's just not a common line of code so your eyes miss it. It should also make the checkpatch script happy. > + > + kunmap_atomic(addr); > + if (i < len) { > + *miscmp_off = offset + i; > + pr_warn("Detected MISCOMPARE at offset %u\n", > + *miscmp_off); > ret = TCM_MISCOMPARE_VERIFY; > goto out; > } > - kunmap_atomic(addr); > > offset += len; > cmp_len -= len; > @@ -503,6 +506,7 @@ static sense_reason_t compare_and_write_callback(struct se_cmd *cmd, bool succes > unsigned int nlbas = cmd->t_task_nolb; > unsigned int block_size = dev->dev_attrib.block_size; > unsigned int compare_len = (nlbas * block_size); > + unsigned int miscmp_off = 0; > sense_reason_t ret = TCM_NO_SENSE; > int i; > > @@ -534,8 +538,19 @@ static sense_reason_t compare_and_write_callback(struct se_cmd *cmd, bool succes > cmd->t_bidi_data_nents, > cmd->t_data_sg, > cmd->t_data_nents, > - compare_len); > - if (ret) > + compare_len, > + &miscmp_off); > + if (ret == TCM_MISCOMPARE_VERIFY) { > + /* > + * SBC-4 r15: 5.3 COMPARE AND WRITE command > + * In the sense data (see 4.18 and SPC-5) the offset from the > + * start of the Data-Out Buffer to the first byte of data that > + * was not equal shall be reported in the INFORMATION field. > + */ > + WARN_ON(miscmp_off >= compare_len); I'm not sure how useful this is. If we hit this then we went wild in compare_and_write_do_cmp since we only allocate the cmp buffer to be compare_len bytes. If we think it's possible to hit this due to a incorrectly setup cmd or buffer/sgl or something, I would be more defensive in compare_and_write_do_cmp. > + cmd->sense_info = miscmp_off; > + goto out; > + } else if (ret) > goto out; > > if (sg_alloc_table(&write_tbl, cmd->t_data_nents, GFP_KERNEL) < 0) { > diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c > index c6f45c12d564..693ed3fe4388 100644 > --- a/drivers/target/target_core_transport.c > +++ b/drivers/target/target_core_transport.c > @@ -3196,6 +3196,7 @@ static const struct sense_detail sense_detail_table[] = { > .key = MISCOMPARE, > .asc = 0x1d, /* MISCOMPARE DURING VERIFY OPERATION */ > .ascq = 0x00, > + .add_sense_info = true, > }, > [TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED] = { > .key = ABORTED_COMMAND, >
Thanks for the feedback Mike... On Sun, 25 Oct 2020 20:14:42 -0500, Mike Christie wrote: > On 10/23/20 3:57 PM, David Disseldorp wrote: > > SBC-4 r15 5.3 COMPARE AND WRITE command states: > > if the compare operation does not indicate a match, then terminate the > > command with CHECK CONDITION status with the sense key set to > > MISCOMPARE and the additional sense code set to MISCOMPARE DURING > > VERIFY OPERATION. In the sense data (see 4.18 and SPC-5) the offset > > from the start of the Data-Out Buffer to the first byte of data that > > was not equal shall be reported in the INFORMATION field. > > > > This change implements the missing logic to report the miscompare offset > > in the sense data INFORMATION field. > > > > Signed-off-by: David Disseldorp <ddiss@suse.de> > > --- > > drivers/target/target_core_sbc.c | 35 ++++++++++++++++++-------- > > drivers/target/target_core_transport.c | 1 + > > 2 files changed, 26 insertions(+), 10 deletions(-) > > > > diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c > > index 79216d0355e7..e40359e45726 100644 > > --- a/drivers/target/target_core_sbc.c > > +++ b/drivers/target/target_core_sbc.c > > @@ -435,13 +435,13 @@ static sense_reason_t compare_and_write_post(struct se_cmd *cmd, bool success, > > } > > > > /* > > - * compare @cmp_len bytes of @read_sgl with @cmp_sgl. On miscompare return > > - * TCM_MISCOMPARE_VERIFY. > > + * compare @cmp_len bytes of @read_sgl with @cmp_sgl. On miscompare, fill > > + * @miscmp_off and 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 int cmp_len, unsigned int *miscmp_off) > > { > > unsigned char *buf = NULL; > > struct scatterlist *sg; > > @@ -468,17 +468,20 @@ compare_and_write_do_cmp(struct scatterlist *read_sgl, unsigned int read_nents, > > */ > > offset = 0; > > for_each_sg(read_sgl, sg, read_nents, i) { > > + unsigned int 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); > > + for (i = 0; i < len && addr[i] == buf[offset + i]; i++); > > I think it's a little nicer to put the ";" on the next line. It's just > not a common line of code so your eyes miss it. It should also make the > checkpatch script happy. Sure, will change this. > > + > > + kunmap_atomic(addr); > > + if (i < len) { > > + *miscmp_off = offset + i; > > + pr_warn("Detected MISCOMPARE at offset %u\n", > > + *miscmp_off); > > ret = TCM_MISCOMPARE_VERIFY; > > goto out; > > } > > - kunmap_atomic(addr); > > > > offset += len; > > cmp_len -= len; > > @@ -503,6 +506,7 @@ static sense_reason_t compare_and_write_callback(struct se_cmd *cmd, bool succes > > unsigned int nlbas = cmd->t_task_nolb; > > unsigned int block_size = dev->dev_attrib.block_size; > > unsigned int compare_len = (nlbas * block_size); > > + unsigned int miscmp_off = 0; > > sense_reason_t ret = TCM_NO_SENSE; > > int i; > > > > @@ -534,8 +538,19 @@ static sense_reason_t compare_and_write_callback(struct se_cmd *cmd, bool succes > > cmd->t_bidi_data_nents, > > cmd->t_data_sg, > > cmd->t_data_nents, > > - compare_len); > > - if (ret) > > + compare_len, > > + &miscmp_off); > > + if (ret == TCM_MISCOMPARE_VERIFY) { > > + /* > > + * SBC-4 r15: 5.3 COMPARE AND WRITE command > > + * In the sense data (see 4.18 and SPC-5) the offset from the > > + * start of the Data-Out Buffer to the first byte of data that > > + * was not equal shall be reported in the INFORMATION field. > > + */ > > + WARN_ON(miscmp_off >= compare_len); > > I'm not sure how useful this is. If we hit this then we went wild in > compare_and_write_do_cmp since we only allocate the cmp buffer to be > compare_len bytes. If we think it's possible to hit this due to a > incorrectly setup cmd or buffer/sgl or something, I would be more > defensive in compare_and_write_do_cmp. I don't think it's possible to hit, but figured it didn't harm readability. I'll drop it in the next round. Cheers, David
diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c index 79216d0355e7..e40359e45726 100644 --- a/drivers/target/target_core_sbc.c +++ b/drivers/target/target_core_sbc.c @@ -435,13 +435,13 @@ static sense_reason_t compare_and_write_post(struct se_cmd *cmd, bool success, } /* - * compare @cmp_len bytes of @read_sgl with @cmp_sgl. On miscompare return - * TCM_MISCOMPARE_VERIFY. + * compare @cmp_len bytes of @read_sgl with @cmp_sgl. On miscompare, fill + * @miscmp_off and 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 int cmp_len, unsigned int *miscmp_off) { unsigned char *buf = NULL; struct scatterlist *sg; @@ -468,17 +468,20 @@ compare_and_write_do_cmp(struct scatterlist *read_sgl, unsigned int read_nents, */ offset = 0; for_each_sg(read_sgl, sg, read_nents, i) { + unsigned int 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); + for (i = 0; i < len && addr[i] == buf[offset + i]; i++); + + kunmap_atomic(addr); + if (i < len) { + *miscmp_off = offset + i; + pr_warn("Detected MISCOMPARE at offset %u\n", + *miscmp_off); ret = TCM_MISCOMPARE_VERIFY; goto out; } - kunmap_atomic(addr); offset += len; cmp_len -= len; @@ -503,6 +506,7 @@ static sense_reason_t compare_and_write_callback(struct se_cmd *cmd, bool succes unsigned int nlbas = cmd->t_task_nolb; unsigned int block_size = dev->dev_attrib.block_size; unsigned int compare_len = (nlbas * block_size); + unsigned int miscmp_off = 0; sense_reason_t ret = TCM_NO_SENSE; int i; @@ -534,8 +538,19 @@ static sense_reason_t compare_and_write_callback(struct se_cmd *cmd, bool succes cmd->t_bidi_data_nents, cmd->t_data_sg, cmd->t_data_nents, - compare_len); - if (ret) + compare_len, + &miscmp_off); + if (ret == TCM_MISCOMPARE_VERIFY) { + /* + * SBC-4 r15: 5.3 COMPARE AND WRITE command + * In the sense data (see 4.18 and SPC-5) the offset from the + * start of the Data-Out Buffer to the first byte of data that + * was not equal shall be reported in the INFORMATION field. + */ + WARN_ON(miscmp_off >= compare_len); + cmd->sense_info = miscmp_off; + goto out; + } else if (ret) goto out; if (sg_alloc_table(&write_tbl, cmd->t_data_nents, GFP_KERNEL) < 0) { diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index c6f45c12d564..693ed3fe4388 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -3196,6 +3196,7 @@ static const struct sense_detail sense_detail_table[] = { .key = MISCOMPARE, .asc = 0x1d, /* MISCOMPARE DURING VERIFY OPERATION */ .ascq = 0x00, + .add_sense_info = true, }, [TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED] = { .key = ABORTED_COMMAND,
SBC-4 r15 5.3 COMPARE AND WRITE command states: if the compare operation does not indicate a match, then terminate the command with CHECK CONDITION status with the sense key set to MISCOMPARE and the additional sense code set to MISCOMPARE DURING VERIFY OPERATION. In the sense data (see 4.18 and SPC-5) the offset from the start of the Data-Out Buffer to the first byte of data that was not equal shall be reported in the INFORMATION field. This change implements the missing logic to report the miscompare offset in the sense data INFORMATION field. Signed-off-by: David Disseldorp <ddiss@suse.de> --- drivers/target/target_core_sbc.c | 35 ++++++++++++++++++-------- drivers/target/target_core_transport.c | 1 + 2 files changed, 26 insertions(+), 10 deletions(-)