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SubjectRe: [PATCH 05/11] target: support zero allocation length in REQUEST SENSE
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On Fri, 2012-09-07 at 17:30 +0200, Paolo Bonzini wrote:
> Similar to INQUIRY and MODE SENSE, construct the sense data in a
> buffer and later copy it to the scatterlist. Do not do anything,
> but still clear a pending unit attention condition, if the allocation
> length is zero.
>
> However, SPC tells us that "If a REQUEST SENSE command is terminated with
> CHECK CONDITION status [and] the REQUEST SENSE command was received on
> an I_T nexus with a pending unit attention condition (i.e., before the
> device server reports CHECK CONDITION status), then the device server
> shall not clear the pending unit attention condition." Do the
> transport_kmap_data_sg early to detect this case.
>
> It also tells us "Device servers shall not adjust the additional sense
> length to reflect truncation if the allocation length is less than the
> sense data available", so do not do that! Note that the err variable
> is write-only.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---

Ditto on this one as well. Applied to target-pending/master.

Thanks Paolo!

> drivers/target/target_core_spc.c | 35 ++++++++++++++++++-----------------
> include/target/target_core_base.h | 1 +
> 2 files changed, 19 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c
> index 4c861de..b905fb2 100644
> --- a/drivers/target/target_core_spc.c
> +++ b/drivers/target/target_core_spc.c
> @@ -877,9 +877,11 @@ static int spc_emulate_modesense(struct se_cmd *cmd)
> static int spc_emulate_request_sense(struct se_cmd *cmd)
> {
> unsigned char *cdb = cmd->t_task_cdb;
> - unsigned char *buf;
> + unsigned char *rbuf;
> u8 ua_asc = 0, ua_ascq = 0;
> - int err = 0;
> + unsigned char buf[SE_SENSE_BUF];
> +
> + memset(buf, 0, SE_SENSE_BUF);
>
> if (cdb[1] & 0x01) {
> pr_err("REQUEST_SENSE description emulation not"
> @@ -888,20 +890,21 @@ static int spc_emulate_request_sense(struct se_cmd *cmd)
> return -ENOSYS;
> }
>
> - buf = transport_kmap_data_sg(cmd);
> -
> - if (!core_scsi3_ua_clear_for_request_sense(cmd, &ua_asc, &ua_ascq)) {
> + rbuf = transport_kmap_data_sg(cmd);
> + if (cmd->scsi_sense_reason != 0) {
> + /*
> + * Out of memory. We will fail with CHECK CONDITION, so
> + * we must not clear the unit attention condition.
> + */
> + target_complete_cmd(cmd, CHECK_CONDITION);
> + return 0;
> + } else if (!core_scsi3_ua_clear_for_request_sense(cmd, &ua_asc, &ua_ascq)) {
> /*
> * CURRENT ERROR, UNIT ATTENTION
> */
> buf[0] = 0x70;
> buf[SPC_SENSE_KEY_OFFSET] = UNIT_ATTENTION;
>
> - if (cmd->data_length < 18) {
> - buf[7] = 0x00;
> - err = -EINVAL;
> - goto end;
> - }
> /*
> * The Additional Sense Code (ASC) from the UNIT ATTENTION
> */
> @@ -915,11 +916,6 @@ static int spc_emulate_request_sense(struct se_cmd *cmd)
> buf[0] = 0x70;
> buf[SPC_SENSE_KEY_OFFSET] = NO_SENSE;
>
> - if (cmd->data_length < 18) {
> - buf[7] = 0x00;
> - err = -EINVAL;
> - goto end;
> - }
> /*
> * NO ADDITIONAL SENSE INFORMATION
> */
> @@ -927,8 +923,11 @@ static int spc_emulate_request_sense(struct se_cmd *cmd)
> buf[7] = 0x0A;
> }
>
> -end:
> - transport_kunmap_data_sg(cmd);
> + if (rbuf) {
> + memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length));
> + transport_kunmap_data_sg(cmd);
> + }
> +
> target_complete_cmd(cmd, GOOD);
> return 0;
> }
> diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
> index 015cea0..5be8937 100644
> --- a/include/target/target_core_base.h
> +++ b/include/target/target_core_base.h
> @@ -121,6 +121,7 @@
>
> #define SE_INQUIRY_BUF 512
> #define SE_MODE_PAGE_BUF 512
> +#define SE_SENSE_BUF 96
>
> /* struct se_hba->hba_flags */
> enum hba_flags_table {




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