Re: [PATCH 01/11] target: go through normal processing forzero-length PSCSI commands

From: Nicholas A. Bellinger
Date: Fri Sep 07 2012 - 14:06:42 EST


On Fri, 2012-09-07 at 17:30 +0200, Paolo Bonzini wrote:
> Right now, commands with a zero-size payload are skipped completely.
> This is wrong; such commands should be passed down to the device and
> processed normally.
>
> For physical backends, this ignores completely things such as START
> STOP UNIT. For virtual backends, we have a hack in place to clear a
> unit attention state on a zero-size REQUEST SENSE, but we still do
> not report errors properly on zero-length commands---out-of-bounds
> 0-block reads and writes, too small parameter list lengths, etc.
>
> This patch fixes this for PSCSI. Uses of transport_kmap_data_sg are
> guarded with a check for non-zero cmd->data_length; for all other
> commands a zero length is handled properly in pscsi_execute_cmd.
> The sole exception will be for now REPORT LUNS, which is handled
> through the normal SPC emulation.
>
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>

Applied to target-pending/master for-3.6.

Thanks Paolo!

> ---
> drivers/target/target_core_pscsi.c | 8 ++++----
> drivers/target/target_core_transport.c | 4 +++-
> 2 files changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
> index c026ee3..682a581 100644
> --- a/drivers/target/target_core_pscsi.c
> +++ b/drivers/target/target_core_pscsi.c
> @@ -688,11 +688,11 @@ static void pscsi_transport_complete(struct se_cmd *cmd, struct scatterlist *sg,
> * Hack to make sure that Write-Protect modepage is set if R/O mode is
> * forced.
> */
> + if (!cmd->se_deve || !cmd->data_length)
> + goto after_mode_sense;
> +
> if (((cdb[0] == MODE_SENSE) || (cdb[0] == MODE_SENSE_10)) &&
> (status_byte(result) << 1) == SAM_STAT_GOOD) {
> - if (!cmd->se_deve)
> - goto after_mode_sense;
> -
> if (cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_READ_ONLY) {
> unsigned char *buf = transport_kmap_data_sg(cmd);
>
> @@ -709,7 +709,7 @@ static void pscsi_transport_complete(struct se_cmd *cmd, struct scatterlist *sg,
> }
> after_mode_sense:
>
> - if (sd->type != TYPE_TAPE)
> + if (sd->type != TYPE_TAPE || !cmd->data_length)
> goto after_mode_select;
>
> /*
> diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
> index 09028af..2e55aa9 100644
> --- a/drivers/target/target_core_transport.c
> +++ b/drivers/target/target_core_transport.c
> @@ -2295,7 +2295,9 @@ int transport_generic_new_cmd(struct se_cmd *cmd)
> * into the fabric for data transfers, go ahead and complete it right
> * away.
> */
> - if (!cmd->data_length) {
> + if (!cmd->data_length &&
> + (cmd->se_dev->transport->transport_type != TRANSPORT_PLUGIN_PHBA_PDEV ||
> + cmd->t_task_cdb[0] == REPORT_LUNS) {
> spin_lock_irq(&cmd->t_state_lock);
> cmd->t_state = TRANSPORT_COMPLETE;
> cmd->transport_state |= CMD_T_ACTIVE;


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