[PATCH v2] usbip: add USBIP_URB_* URB transfer flags

From: Shuah Khan
Date: Tue Aug 23 2022 - 20:25:06 EST

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USBIP driver packs URB transfer flags in network packets that are
exchanged between Server (usbip_host) and Client (vhci_hcd).

URB_* flags are internal to kernel and could change. Where as USBIP
URB flags exchanged in network packets are USBIP user API must not
change.

Add USBIP_URB* flags to make this an explicit API and change the
client and server to map them. Details as follows:

Client tx path (USBIP_CMD_SUBMIT):
- Maps URB_* to USBIP_URB_* when it sends USBIP_CMD_SUBMIT packet.

Server rx path (USBIP_CMD_SUBMIT):
- Maps USBIP_URB_* to URB_* when it receives USBIP_CMD_SUBMIT packet.

Flags aren't included in USBIP_CMD_UNLINK and USBIP_RET_SUBMIT packets
and no special handling is needed for them in the following cases:

- Server rx path (USBIP_CMD_UNLINK)
- Client rx path & Server tx path (USBIP_RET_SUBMIT)

Update protocol documentation to reflect the change.

Suggested-by: Hongren Zenithal Zheng <i@xxxxxxxxxxx>
Suggested-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
---

Changes since v1: addressed review comments

Documentation/usb/usbip_protocol.rst | 13 ++--
drivers/usb/usbip/stub_rx.c | 4 +-
drivers/usb/usbip/usbip_common.c | 91 +++++++++++++++++++++++++++-
include/uapi/linux/usbip.h | 26 ++++++++
4 files changed, 122 insertions(+), 12 deletions(-)

diff --git a/Documentation/usb/usbip_protocol.rst b/Documentation/usb/usbip_protocol.rst
index 0b8541fda4d8..adc158967cc6 100644
--- a/Documentation/usb/usbip_protocol.rst
+++ b/Documentation/usb/usbip_protocol.rst
@@ -340,13 +340,12 @@ USBIP_CMD_SUBMIT:
| 0 | 20 | usbip_header_basic, 'command' shall be 0x00000001 |
+-----------+--------+---------------------------------------------------+
| 0x14 | 4 | transfer_flags: possible values depend on the |
-| | | URB transfer_flags (refer to URB doc in |
-| | | Documentation/driver-api/usb/URB.rst) |
-| | | but with URB_NO_TRANSFER_DMA_MAP masked. Refer to |
-| | | function usbip_pack_cmd_submit and function |
-| | | tweak_transfer_flags in drivers/usb/usbip/ |
-| | | usbip_common.c. The following fields may also ref |
-| | | to function usbip_pack_cmd_submit and URB doc |
+| | | USBIP_URB transfer_flags. |
+| | | Refer to include/uapi/linux/usbip.h and |
+| | | Documentation/driver-api/usb/URB.rst. |
+| | | Refer to usbip_pack_cmd_submit() and |
+| | | tweak_transfer_flags() in drivers/usb/usbip/ |
+| | | usbip_common.c. |
+-----------+--------+---------------------------------------------------+
| 0x18 | 4 | transfer_buffer_length: |
| | | use URB transfer_buffer_length |
diff --git a/drivers/usb/usbip/stub_rx.c b/drivers/usb/usbip/stub_rx.c
index 5dd41e8215e0..fc01b31bbb87 100644
--- a/drivers/usb/usbip/stub_rx.c
+++ b/drivers/usb/usbip/stub_rx.c
@@ -464,7 +464,7 @@ static void stub_recv_cmd_submit(struct stub_device *sdev,
int nents;
int num_urbs = 1;
int pipe = get_pipe(sdev, pdu);
- int use_sg = pdu->u.cmd_submit.transfer_flags & URB_DMA_MAP_SG;
+ int use_sg = pdu->u.cmd_submit.transfer_flags & USBIP_URB_DMA_MAP_SG;
int support_sg = 1;
int np = 0;
int ret, i;
@@ -514,7 +514,7 @@ static void stub_recv_cmd_submit(struct stub_device *sdev,
num_urbs = nents;
priv->completed_urbs = 0;
pdu->u.cmd_submit.transfer_flags &=
- ~URB_DMA_MAP_SG;
+ ~USBIP_URB_DMA_MAP_SG;
}
} else {
buffer = kzalloc(buf_len, GFP_KERNEL);
diff --git a/drivers/usb/usbip/usbip_common.c b/drivers/usb/usbip/usbip_common.c
index 2ab99244bc31..053a2bca4c47 100644
--- a/drivers/usb/usbip/usbip_common.c
+++ b/drivers/usb/usbip/usbip_common.c
@@ -344,6 +344,91 @@ static unsigned int tweak_transfer_flags(unsigned int flags)
return flags;
}

+/*
+ * USBIP driver packs URB transfer flags in PDUs that are exchanged
+ * between Server (usbip_host) and Client (vhci_hcd). URB_* flags
+ * are internal to kernel and could change. Where as USBIP URB flags
+ * exchanged in PDUs are USBIP user API must not change.
+ *
+ * USBIP_URB* flags are exported as explicit API and client and server
+ * do mapping from kernel flags to USBIP_URB*. Details as follows:
+ *
+ * Client tx path (USBIP_CMD_SUBMIT):
+ * - Maps URB_* to USBIP_URB_* when it sends USBIP_CMD_SUBMIT packet.
+ *
+ * Server rx path (USBIP_CMD_SUBMIT):
+ * - Maps USBIP_URB_* to URB_* when it receives USBIP_CMD_SUBMIT packet.
+ *
+ * Flags aren't included in USBIP_CMD_UNLINK and USBIP_RET_SUBMIT packets
+ * and no special handling is needed for them in the following cases:
+ * - Server rx path (USBIP_CMD_UNLINK)
+ * - Client rx path & Server tx path (USBIP_RET_SUBMIT)
+ *
+ * Code paths:
+ * usbip_pack_pdu() is the common routine that handles packing pdu from
+ * urb and unpack pdu to an urb.
+ *
+ * usbip_pack_cmd_submit() and usbip_pack_ret_submit() handle
+ * USBIP_CMD_SUBMIT and USBIP_RET_SUBMIT respectively.
+ *
+ * usbip_map_urb_to_usbip() and usbip_map_usbip_to_urb() are used
+ * by usbip_pack_cmd_submit() and usbip_pack_ret_submit() to map
+ * flags.
+ */
+
+struct urb_to_usbip_flags {
+ u32 urb_flag;
+ u32 usbip_flag;
+};
+
+#define NUM_USBIP_FLAGS 17
+
+static const struct urb_to_usbip_flags flag_map[NUM_USBIP_FLAGS] = {
+ {URB_SHORT_NOT_OK, USBIP_URB_SHORT_NOT_OK},
+ {URB_ISO_ASAP, USBIP_URB_ISO_ASAP},
+ {URB_NO_TRANSFER_DMA_MAP, USBIP_URB_NO_TRANSFER_DMA_MAP},
+ {URB_ZERO_PACKET, USBIP_URB_ZERO_PACKET},
+ {URB_NO_INTERRUPT, USBIP_URB_NO_INTERRUPT},
+ {URB_FREE_BUFFER, USBIP_URB_FREE_BUFFER},
+ {URB_DIR_IN, USBIP_URB_DIR_IN},
+ {URB_DIR_OUT, USBIP_URB_DIR_OUT},
+ {URB_DIR_MASK, USBIP_URB_DIR_MASK},
+ {URB_DMA_MAP_SINGLE, USBIP_URB_DMA_MAP_SINGLE},
+ {URB_DMA_MAP_PAGE, USBIP_URB_DMA_MAP_PAGE},
+ {URB_DMA_MAP_SG, USBIP_URB_DMA_MAP_SG},
+ {URB_MAP_LOCAL, USBIP_URB_MAP_LOCAL},
+ {URB_SETUP_MAP_SINGLE, USBIP_URB_SETUP_MAP_SINGLE},
+ {URB_SETUP_MAP_LOCAL, USBIP_URB_SETUP_MAP_LOCAL},
+ {URB_DMA_SG_COMBINED, USBIP_URB_DMA_SG_COMBINED},
+ {URB_ALIGNED_TEMP_BUFFER, USBIP_URB_ALIGNED_TEMP_BUFFER},
+};
+
+static unsigned int urb_to_usbip(unsigned int flags)
+{
+ unsigned int map_flags = 0;
+ int loop;
+
+ for (loop = 0; loop < NUM_USBIP_FLAGS; loop++) {
+ if (flags & flag_map[loop].urb_flag)
+ map_flags |= flag_map[loop].usbip_flag;
+ }
+
+ return map_flags;
+}
+
+static unsigned int usbip_to_urb(unsigned int flags)
+{
+ unsigned int map_flags = 0;
+ int loop;
+
+ for (loop = 0; loop < NUM_USBIP_FLAGS; loop++) {
+ if (flags & flag_map[loop].usbip_flag)
+ map_flags |= flag_map[loop].urb_flag;
+ }
+
+ return map_flags;
+}
+
static void usbip_pack_cmd_submit(struct usbip_header *pdu, struct urb *urb,
int pack)
{
@@ -354,14 +439,14 @@ static void usbip_pack_cmd_submit(struct usbip_header *pdu, struct urb *urb,
* will be discussed when usbip is ported to other operating systems.
*/
if (pack) {
- spdu->transfer_flags =
- tweak_transfer_flags(urb->transfer_flags);
+ /* map after tweaking the urb flags */
+ spdu->transfer_flags = urb_to_usbip(tweak_transfer_flags(urb->transfer_flags));
spdu->transfer_buffer_length = urb->transfer_buffer_length;
spdu->start_frame = urb->start_frame;
spdu->number_of_packets = urb->number_of_packets;
spdu->interval = urb->interval;
} else {
- urb->transfer_flags = spdu->transfer_flags;
+ urb->transfer_flags = usbip_to_urb(spdu->transfer_flags);
urb->transfer_buffer_length = spdu->transfer_buffer_length;
urb->start_frame = spdu->start_frame;
urb->number_of_packets = spdu->number_of_packets;
diff --git a/include/uapi/linux/usbip.h b/include/uapi/linux/usbip.h
index fd393d908d8a..e4421ad55b2e 100644
--- a/include/uapi/linux/usbip.h
+++ b/include/uapi/linux/usbip.h
@@ -24,4 +24,30 @@ enum usbip_device_status {
VDEV_ST_USED,
VDEV_ST_ERROR
};
+
+/* USB URB Transfer flags:
+ *
+ * USBIP server and client (vchi) pack URBs in TCP packets. The following
+ * are the transfer type defines used in USBIP protocol.
+ */
+
+#define USBIP_URB_SHORT_NOT_OK 0x0001
+#define USBIP_URB_ISO_ASAP 0x0002
+#define USBIP_URB_NO_TRANSFER_DMA_MAP 0x0004
+#define USBIP_URB_ZERO_PACKET 0x0040
+#define USBIP_URB_NO_INTERRUPT 0x0080
+#define USBIP_URB_FREE_BUFFER 0x0100
+#define USBIP_URB_DIR_IN 0x0200
+#define USBIP_URB_DIR_OUT 0
+#define USBIP_URB_DIR_MASK USBIP_URB_DIR_IN
+
+#define USBIP_URB_DMA_MAP_SINGLE 0x00010000
+#define USBIP_URB_DMA_MAP_PAGE 0x00020000
+#define USBIP_URB_DMA_MAP_SG 0x00040000
+#define USBIP_URB_MAP_LOCAL 0x00080000
+#define USBIP_URB_SETUP_MAP_SINGLE 0x00100000
+#define USBIP_URB_SETUP_MAP_LOCAL 0x00200000
+#define USBIP_URB_DMA_SG_COMBINED 0x00400000
+#define USBIP_URB_ALIGNED_TEMP_BUFFER 0x00800000
+
#endif /* _UAPI_LINUX_USBIP_H */
--
2.34.1

Next message: HORIGUCHI NAOYA(堀口　直也): "Re: [PATCH v2 4/6] mm, hwpoison: fix possible use-after-free in mf_dax_kill_procs()"
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