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authorAlan Stern <stern@rowland.harvard.edu>2011-10-25 10:50:58 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2011-11-26 09:10:37 -0800
commita7c5393627f3bbb97d22f98823b660e6b62b67db (patch)
treec3df4cfa6b64879e3f9d4bbc0794934da0c32169
parent552f6bf1bb0eda0011c0525dd587aa9e7ba5b846 (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>
-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);
}