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 de103c93aff0bed0ae984274e5dc8b95899badab
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>
diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c
index f8857d4..2d88f08 100644
--- a/drivers/target/target_core_spc.c
+++ b/drivers/target/target_core_spc.c
@@ -850,7 +850,7 @@
{
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 @@
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 @@
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 @@
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 @@
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;
}