target: Report correct response length for some commands

commit 2426bd456a61407388b6e61fc5f98dbcbebc50e2 upstream.

When an initiator sends an allocation length bigger than what its
command consumes, the target should only return the actual response data
and set the residual length to the unused part of the allocation length.

Add a helper function that command handlers (INQUIRY, READ CAPACITY,
etc) can use to do this correctly, and use this code to get the correct
residual for commands that don't use the full initiator allocation in the
handlers for READ CAPACITY, READ CAPACITY(16), INQUIRY, MODE SENSE and
REPORT LUNS.

This addresses a handful of failures as reported by Christophe with
the Windows Certification Kit:

  http://permalink.gmane.org/gmane.linux.scsi.target.devel/6515

Signed-off-by: Roland Dreier <roland@purestorage.com>
Tested-by: Christophe Vu-Brugier <cvubrugier@yahoo.fr>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index bbc5b0ee2bdc5bb1d2c7d45ea370d8834cbfbed2..0ef75fb0ecbae3cafb85180bd86efbe0c0b75c35 100644 (file)
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -63,7 +63,7 @@ sbc_emulate_readcapacity(struct se_cmd *cmd)
                transport_kunmap_data_sg(cmd);
        }
 
-       target_complete_cmd(cmd, GOOD);
+       target_complete_cmd_with_length(cmd, GOOD, 8);
        return 0;
 }
 
@@ -101,7 +101,7 @@ sbc_emulate_readcapacity_16(struct se_cmd *cmd)
                transport_kunmap_data_sg(cmd);
        }
 
-       target_complete_cmd(cmd, GOOD);
+       target_complete_cmd_with_length(cmd, GOOD, 32);
        return 0;
 }
 

diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c
index 9fabbf7214cd70cc3d4ad3e1bfa74f7ac516cdd0..34254b2ec4668fd0e285f5bb2d5770e4ee274b46 100644 (file)
--- a/drivers/target/target_core_spc.c
+++ b/drivers/target/target_core_spc.c
@@ -628,6 +628,7 @@ spc_emulate_inquiry(struct se_cmd *cmd)
        unsigned char buf[SE_INQUIRY_BUF];
        sense_reason_t ret;
        int p;
+       int len = 0;
 
        memset(buf, 0, SE_INQUIRY_BUF);
 
@@ -645,6 +646,7 @@ spc_emulate_inquiry(struct se_cmd *cmd)
                }
 
                ret = spc_emulate_inquiry_std(cmd, buf);
+               len = buf[4] + 5;
                goto out;
        }
 
@@ -652,6 +654,7 @@ spc_emulate_inquiry(struct se_cmd *cmd)
                if (cdb[2] == evpd_handlers[p].page) {
                        buf[1] = cdb[2];
                        ret = evpd_handlers[p].emulate(cmd, buf);
+                       len = get_unaligned_be16(&buf[2]) + 4;
                        goto out;
                }
        }
@@ -667,7 +670,7 @@ out:
        }
 
        if (!ret)
-               target_complete_cmd(cmd, GOOD);
+               target_complete_cmd_with_length(cmd, GOOD, len);
        return ret;
 }
 
@@ -985,7 +988,7 @@ set_length:
                transport_kunmap_data_sg(cmd);
        }
 
-       target_complete_cmd(cmd, GOOD);
+       target_complete_cmd_with_length(cmd, GOOD, length);
        return 0;
 }
 
@@ -1162,7 +1165,7 @@ done:
        buf[3] = (lun_count & 0xff);
        transport_kunmap_data_sg(cmd);
 
-       target_complete_cmd(cmd, GOOD);
+       target_complete_cmd_with_length(cmd, GOOD, 8 + lun_count * 8);
        return 0;
 }
 EXPORT_SYMBOL(spc_emulate_report_luns);

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index f2c5ed90d3569783f828b9665db0020ab948d6d8..6866d86e86630bfa8cd15e6c7269af1370f23073 100644 (file)
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -633,6 +633,23 @@ void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
 }
 EXPORT_SYMBOL(target_complete_cmd);
 
+void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length)
+{
+       if (scsi_status == SAM_STAT_GOOD && length < cmd->data_length) {
+               if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
+                       cmd->residual_count += cmd->data_length - length;
+               } else {
+                       cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
+                       cmd->residual_count = cmd->data_length - length;
+               }
+
+               cmd->data_length = length;
+       }
+
+       target_complete_cmd(cmd, scsi_status);
+}
+EXPORT_SYMBOL(target_complete_cmd_with_length);
+
 static void target_add_to_state_list(struct se_cmd *cmd)
 {
        struct se_device *dev = cmd->se_dev;

diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
index ffa2696d64dcfe9794ec87a83be887b0e2aab453..a63529ab9fd7365cbd292a78247286f49ff8174e 100644 (file)
--- a/include/target/target_core_backend.h
+++ b/include/target/target_core_backend.h
@@ -50,6 +50,7 @@ int   transport_subsystem_register(struct se_subsystem_api *);
 void   transport_subsystem_release(struct se_subsystem_api *);
 
 void   target_complete_cmd(struct se_cmd *, u8);
+void   target_complete_cmd_with_length(struct se_cmd *, u8, int);
 
 sense_reason_t spc_parse_cdb(struct se_cmd *cmd, unsigned int *size);
 sense_reason_t spc_emulate_report_luns(struct se_cmd *cmd);