USB: make the usbfs memory limit configurable

The 16-MB global limit on memory used by usbfs isn't suitable for all
people.  It's a reasonable default, but there are applications
(especially for SuperSpeed devices) that need a lot more.

This patch (as1498) creates a writable module parameter for usbcore to
control the global limit.  The default is still 16 MB, but users can
change it at runtime, even after usbcore has been loaded.  As a
special case, setting the value to 0 is treated the same as the hard
limit of 2047 MB.

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

1 files changed, 4 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a0c5c5f4fce6..72c68bbec5d4 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2632,6 +2632,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         [USB] Start with the old device initialization
                         scheme (default 0 = off).
 
+        usbcore.usbfs_memory_mb=
+                        [USB] Memory limit (in MB) for buffers allocated by
+                        usbfs (default = 16, 0 = max = 2047).
+
         usbcore.use_both_schemes=
                         [USB] Try the other device initialization scheme
                         if the first one fails (default 1 = enabled).