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authorAlan Stern <stern@rowland.harvard.edu>2011-10-25 10:50:58 -0400
committerPaul Gortmaker <paul.gortmaker@windriver.com>2012-08-17 15:35:59 -0400
commit432bc4aa49105127524ad91672803924e4848f6e (patch)
treed8f2bcf05a11879e98092704701e1cf747fded7e
parent87ece72cc91a8fb96013070ca12cb1a02c2d4605 (diff)
usb-storage: Accept 8020i-protocol commands longer than 12 bytes
commit 2f640bf4c94324aeaa1b6385c10aab8c5ad1e1cf upstream. The 8020i protocol (also 8070i and QIC-157) uses 12-byte commands; shorter commands must be padded. Simon Detheridge reports that his 3-TB USB disk drive claims to use the 8020i protocol (which is normally meant for ATAPI devices like CD drives), and because of its large size, the disk drive requires the use of 16-byte commands. However the usb_stor_pad12_command() routine in usb-storage always sets the command length to 12, making the drive impossible to use. Since the SFF-8020i specification allows for 16-byte commands in future extensions, we may as well accept them. This patch (as1490) changes usb_stor_pad12_command() to leave commands larger than 12 bytes alone rather than truncating them. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Tested-by: Simon Detheridge <simon@widgit.com> CC: Matthew Dharm <mdharm-usb@one-eyed-alien.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
-rw-r--r--drivers/usb/storage/protocol.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/usb/storage/protocol.c b/drivers/usb/storage/protocol.c
index fc310f75eada..0fded39e3b3e 100644
--- a/drivers/usb/storage/protocol.c
+++ b/drivers/usb/storage/protocol.c
@@ -58,7 +58,9 @@
void usb_stor_pad12_command(struct scsi_cmnd *srb, struct us_data *us)
{
- /* Pad the SCSI command with zeros out to 12 bytes
+ /*
+ * Pad the SCSI command with zeros out to 12 bytes. If the
+ * command already is 12 bytes or longer, leave it alone.
*
* NOTE: This only works because a scsi_cmnd struct field contains
* a unsigned char cmnd[16], so we know we have storage available
@@ -66,9 +68,6 @@ void usb_stor_pad12_command(struct scsi_cmnd *srb, struct us_data *us)
for (; srb->cmd_len<12; srb->cmd_len++)
srb->cmnd[srb->cmd_len] = 0;
- /* set command length to 12 bytes */
- srb->cmd_len = 12;
-
/* send the command to the transport layer */
usb_stor_invoke_transport(srb, us);
}