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target: fix truncation of mode data, support zero allocation length

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The offset was not bumped back to the full size after writing the
header of the MODE SENSE response, so the last 1 or 2 bytes were
not copied.

On top of this, support zero-length requests by checking for the
return value of transport_kmap_data_sg.

Testcase: sg_raw -r20 /dev/sdb 5a 00 0a 00 00 00 00 00 14 00
    last byte should be 0x1e
    it is 0x00 without the patch
    it is correct with the patch

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Paolo Bonzini 2012-09-07 17:30:39 +02:00 committed by Nicholas Bellinger
parent ffe7b0e932
commit 7a3f369ce3
1 changed files with 7 additions and 10 deletions
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17
drivers/target/target_core_spc.c
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@ -784,7 +784,7 @@ static int spc_emulate_modesense(struct se_cmd *cmd)
unsigned char *rbuf;
int type = dev->transport->get_device_type(dev);
int ten = (cmd->t_task_cdb[0] == MODE_SENSE_10);
int offset = ten ? 8 : 4;
u32 offset = ten ? 8 : 4;
int length = 0;
unsigned char buf[SE_MODE_PAGE_BUF];
@ -817,6 +817,7 @@ static int spc_emulate_modesense(struct se_cmd *cmd)
offset -= 2;
buf[0] = (offset >> 8) & 0xff;
buf[1] = offset & 0xff;
offset += 2;
if ((cmd->se_lun->lun_access & TRANSPORT_LUNFLAGS_READ_ONLY) ||
(cmd->se_deve &&
@ -826,13 +827,10 @@ static int spc_emulate_modesense(struct se_cmd *cmd)
if ((dev->se_sub_dev->se_dev_attrib.emulate_write_cache > 0) &&
(dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0))
spc_modesense_dpofua(&buf[3], type);
if ((offset + 2) > cmd->data_length)
offset = cmd->data_length;
} else {
offset -= 1;
buf[0] = offset & 0xff;
offset += 1;
if ((cmd->se_lun->lun_access & TRANSPORT_LUNFLAGS_READ_ONLY) ||
(cmd->se_deve &&
@ -842,14 +840,13 @@ static int spc_emulate_modesense(struct se_cmd *cmd)
if ((dev->se_sub_dev->se_dev_attrib.emulate_write_cache > 0) &&
(dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0))
spc_modesense_dpofua(&buf[2], type);
if ((offset + 1) > cmd->data_length)
offset = cmd->data_length;
}
rbuf = transport_kmap_data_sg(cmd);
memcpy(rbuf, buf, offset);
transport_kunmap_data_sg(cmd);
if (rbuf) {
memcpy(rbuf, buf, min(offset, cmd->data_length));
transport_kunmap_data_sg(cmd);
}
target_complete_cmd(cmd, GOOD);
return 0;