[PATCH] PATCH: usb-storage: allocate separate sense buffer

This patch is from Alan Stern (as560).  It has been rediffed against a
current tree.

This patch allocates a separate buffer for usb-storage to use when
auto-sensing.  Up to now we have been using the sense buffer embedded in a
scsi_cmnd struct, which is dangerous on hosts that (a) don't do
cache-coherent DMA or (b) have DMA alignment restrictions.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index 92ee079d9172..eb901817b7d2 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -467,6 +467,12 @@ static int associate_dev(struct us_data *us, struct usb_interface *intf)
                 US_DEBUGP("I/O buffer allocation failed\n");
                 return -ENOMEM;
         }
+
+        us->sensebuf = kmalloc(US_SENSE_SIZE, GFP_KERNEL);
+        if (!us->sensebuf) {
+                US_DEBUGP("Sense buffer allocation failed\n");
+                return -ENOMEM;
+        }
         return 0;
 }
 
@@ -800,6 +806,8 @@ static void dissociate_dev(struct us_data *us)
 {
         US_DEBUGP("-- %s\n", __FUNCTION__);
 
+        kfree(us->sensebuf);
+
         /* Free the device-related DMA-mapped buffers */
         if (us->cr)
                 usb_buffer_free(us->pusb_dev, sizeof(*us->cr), us->cr,