On 10/16/23 20:49, Alan Stern wrote:
On Mon, Oct 16, 2023 at 09:26:01AM +0200, Milan Broz wrote:
The USB mass storage quirks flags can be stored in driver_info in
a 32-bit integer (unsigned long on 32-bit platforms).
As this attribute cannot be enlarged, we need to use some form
of translation of 64-bit quirk bits.
This problem was discussed on the USB list
https://lore.kernel.org/linux-usb/f9e8acb5-32d5-4a30-859f-d4336a86b31a@xxxxxxxxx/
The initial solution to use a static array extensively increased the size
of the kernel module, so I decided to try the second suggested solution:
generate a table by host-compiled program and use bit 31 to indicate
that the value is an index, not the actual value.
This patch adds a host-compiled program that processes unusual_devs.h
(and unusual_uas.h) and generates files usb-ids.c and usb-ids-uas.c
(for pre-processed USB device table with 32-bit device info).
These files also contain a generated translation table for device_info
to 64-bit values.
The translation function is used only in usb-storage and uas modules; all
other USB storage modules store flags directly, using only 32-bit integers.
This translation is unnecessary for a 64-bit system, but I keep it
in place for simplicity in this patch.
Signed-off-by: Milan Broz <gmazyland@xxxxxxxxx>
---
drivers/usb/storage/Makefile | 25 ++++
drivers/usb/storage/mkflags.c | 226 +++++++++++++++++++++++++++++
drivers/usb/storage/uas-detect.h | 4 +-
drivers/usb/storage/uas.c | 20 +--
drivers/usb/storage/usb-ids.h | 33 +++++
drivers/usb/storage/usb.c | 10 +-
drivers/usb/storage/usual-tables.c | 23 +--
7 files changed, 301 insertions(+), 40 deletions(-)
create mode 100644 drivers/usb/storage/mkflags.c
create mode 100644 drivers/usb/storage/usb-ids.h
diff --git a/drivers/usb/storage/Makefile b/drivers/usb/storage/Makefile
index 46635fa4a340..612678f108d0 100644
--- a/drivers/usb/storage/Makefile
+++ b/drivers/usb/storage/Makefile
@@ -45,3 +45,28 @@ ums-realtek-y := realtek_cr.o
ums-sddr09-y := sddr09.o
ums-sddr55-y := sddr55.o
ums-usbat-y := shuttle_usbat.o
+
+# The mkflags host-compiled generator produces usb-ids.c (usb-storage)
+# and usb-ids-uas.c (uas) with USB device tables.
+# These tables include pre-computed 32-bit flags as USB driver device_info
s/flags as/flags, as/
Otherwise this seems to say that the 32-bit flags are converted to USB
driver device_info values -- an incorrect parsing that makes no sense
and will confuse readers. (It confused me at first.)
Also, don't you really mean "driver_info" rather than "driver
device_info"? That's the name of the field in struct usb_device_id.
Yes, not sure why I mixed these. Fixed in v3 patch (and now only one
patch is needed as 2 previous are merged in usb-next).
I hope I fixed all other comments too, thanks!
Milan
