USB: g_file_storage: Set sense info Valid bit only when needed

Strictly speaking, the Valid bit in SCSI sense data is supposed to
be set only when the Information field contains a valid number.  This
patch (as793) turns off the Valid bit when the Information field
hasn't been set.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 15 insertions, 1 deletions

diff --git a/drivers/usb/gadget/file_storage.c b/drivers/usb/gadget/file_storage.c
index d472c9c29904..c83d3b6c68f2 100644
--- a/drivers/usb/gadget/file_storage.c
+++ b/drivers/usb/gadget/file_storage.c
@@ -567,6 +567,7 @@ struct lun {
         unsigned int    ro : 1;
         unsigned int    prevent_medium_removal : 1;
         unsigned int    registered : 1;
+        unsigned int    info_valid : 1;
 
         u32             sense_data;
         u32             sense_data_info;
@@ -1656,6 +1657,7 @@ static int do_read(struct fsg_dev *fsg)
                         curlun->sense_data =
                                         SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
                         curlun->sense_data_info = file_offset >> 9;
+                        curlun->info_valid = 1;
                         bh->inreq->length = 0;
                         bh->state = BUF_STATE_FULL;
                         break;
@@ -1691,6 +1693,7 @@ static int do_read(struct fsg_dev *fsg)
                 if (nread < amount) {
                         curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
                         curlun->sense_data_info = file_offset >> 9;
+                        curlun->info_valid = 1;
                         break;
                 }
 
@@ -1785,6 +1788,7 @@ static int do_write(struct fsg_dev *fsg)
                                 curlun->sense_data =
                                         SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
                                 curlun->sense_data_info = usb_offset >> 9;
+                                curlun->info_valid = 1;
                                 continue;
                         }
                         amount -= (amount & 511);
@@ -1827,6 +1831,7 @@ static int do_write(struct fsg_dev *fsg)
                         if (bh->outreq->status != 0) {
                                 curlun->sense_data = SS_COMMUNICATION_FAILURE;
                                 curlun->sense_data_info = file_offset >> 9;
+                                curlun->info_valid = 1;
                                 break;
                         }
 
@@ -1868,6 +1873,7 @@ static int do_write(struct fsg_dev *fsg)
                         if (nwritten < amount) {
                                 curlun->sense_data = SS_WRITE_ERROR;
                                 curlun->sense_data_info = file_offset >> 9;
+                                curlun->info_valid = 1;
                                 break;
                         }
 
@@ -2010,6 +2016,7 @@ static int do_verify(struct fsg_dev *fsg)
                         curlun->sense_data =
                                         SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
                         curlun->sense_data_info = file_offset >> 9;
+                        curlun->info_valid = 1;
                         break;
                 }
 
@@ -2036,6 +2043,7 @@ static int do_verify(struct fsg_dev *fsg)
                 if (nread == 0) {
                         curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
                         curlun->sense_data_info = file_offset >> 9;
+                        curlun->info_valid = 1;
                         break;
                 }
                 file_offset += nread;
@@ -2079,6 +2087,7 @@ static int do_request_sense(struct fsg_dev *fsg, struct fsg_buffhd *bh)
         struct lun      *curlun = fsg->curlun;
         u8              *buf = (u8 *) bh->buf;
         u32             sd, sdinfo;
+        int             valid;
 
         /*
          * From the SCSI-2 spec., section 7.9 (Unit attention condition):
@@ -2106,15 +2115,18 @@ static int do_request_sense(struct fsg_dev *fsg, struct fsg_buffhd *bh)
                 fsg->bad_lun_okay = 1;
                 sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
                 sdinfo = 0;
+                valid = 0;
         } else {
                 sd = curlun->sense_data;
                 sdinfo = curlun->sense_data_info;
+                valid = curlun->info_valid << 7;
                 curlun->sense_data = SS_NO_SENSE;
                 curlun->sense_data_info = 0;
+                curlun->info_valid = 0;
         }
 
         memset(buf, 0, 18);
-        buf[0] = 0x80 | 0x70;                   // Valid, current error
+        buf[0] = valid | 0x70;                  // Valid, current error
         buf[2] = SK(sd);
         put_be32(&buf[3], sdinfo);              // Sense information
         buf[7] = 18 - 8;                        // Additional sense length
@@ -2703,6 +2715,7 @@ static int check_command(struct fsg_dev *fsg, int cmnd_size,
                 if (fsg->cmnd[0] != SC_REQUEST_SENSE) {
                         curlun->sense_data = SS_NO_SENSE;
                         curlun->sense_data_info = 0;
+                        curlun->info_valid = 0;
                 }
         } else {
                 fsg->curlun = curlun = NULL;
@@ -3332,6 +3345,7 @@ static void handle_exception(struct fsg_dev *fsg)
                         curlun->sense_data = curlun->unit_attention_data =
                                         SS_NO_SENSE;
                         curlun->sense_data_info = 0;
+                        curlun->info_valid = 0;
                 }
                 fsg->state = FSG_STATE_IDLE;
         }