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target: Fix zero-length MODE_SENSE regression 

This patch fixes a regression introduced in v3.8-rc1 code where
a zero-length MODE_SENSE was no longer returning GOOD status, but
instead returning TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE to generate
a CHECK_CONDITION status.

This regression was introduced with the following commit:

  commit de103c93af
  Author: Christoph Hellwig <hch@lst.de>
  Date:   Tue Nov 6 12:24:09 2012 -0800

      target: pass sense_reason as a return value

and this patch has been tested with the following zero-length CDB:

  sg_raw /dev/sdd 5a 00 0a 00 00 00 00 00 00 00
  SCSI Status: Good

  Sense Information:
  sense buffer empty

Cc: Christoph Hellwig <hch@lst.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Nicholas Bellinger 2013-01-29 14:10:01 -08:00
parent 49df9fc9b9
commit cab9609b44
1 changed files with 7 additions and 28 deletions
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35
drivers/target/target_core_spc.c
View File

@ -850,7 +850,7 @@ static sense_reason_t spc_emulate_modesense(struct se_cmd *cmd)
{
struct se_device *dev = cmd->se_dev;
char *cdb = cmd->t_task_cdb;
unsigned char *buf, *map_buf;
unsigned char buf[SE_MODE_PAGE_BUF], *rbuf;
int type = dev->transport->get_device_type(dev);
int ten = (cmd->t_task_cdb[0] == MODE_SENSE_10);
bool dbd = !!(cdb[1] & 0x08);
@ -862,26 +862,8 @@ static sense_reason_t spc_emulate_modesense(struct se_cmd *cmd)
int ret;
int i;
map_buf = transport_kmap_data_sg(cmd);
if (!map_buf)
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
/*
* If SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC is not set, then we
* know we actually allocated a full page. Otherwise, if the
* data buffer is too small, allocate a temporary buffer so we
* don't have to worry about overruns in all our INQUIRY
* emulation handling.
*/
if (cmd->data_length < SE_MODE_PAGE_BUF &&
(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC)) {
buf = kzalloc(SE_MODE_PAGE_BUF, GFP_KERNEL);
if (!buf) {
transport_kunmap_data_sg(cmd);
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
}
} else {
buf = map_buf;
}
memset(buf, 0, SE_MODE_PAGE_BUF);
/*
* Skip over MODE DATA LENGTH + MEDIUM TYPE fields to byte 3 for
* MODE_SENSE_10 and byte 2 for MODE_SENSE (6).
@ -933,8 +915,6 @@ static sense_reason_t spc_emulate_modesense(struct se_cmd *cmd)
if (page == 0x3f) {
if (subpage != 0x00 && subpage != 0xff) {
pr_warn("MODE_SENSE: Invalid subpage code: 0x%02x\n", subpage);
kfree(buf);
transport_kunmap_data_sg(cmd);
return TCM_INVALID_CDB_FIELD;
}
@ -971,7 +951,6 @@ static sense_reason_t spc_emulate_modesense(struct se_cmd *cmd)
pr_err("MODE SENSE: unimplemented page/subpage: 0x%02x/0x%02x\n",
page, subpage);
transport_kunmap_data_sg(cmd);
return TCM_UNKNOWN_MODE_PAGE;
set_length:
@ -980,12 +959,12 @@ set_length:
else
buf[0] = length - 1;
if (buf != map_buf) {
memcpy(map_buf, buf, cmd->data_length);
kfree(buf);
rbuf = transport_kmap_data_sg(cmd);
if (rbuf) {
memcpy(rbuf, buf, min_t(u32, SE_MODE_PAGE_BUF, cmd->data_length));
transport_kunmap_data_sg(cmd);
}
transport_kunmap_data_sg(cmd);
target_complete_cmd(cmd, GOOD);
return 0;
}