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greybus: explicitly mark cookies as opaque

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Use simple macros to mark the conversion of an URB pointer into an
opaque cookie value (and vice-versa).  We scramble some bits, but
the main point is to make it explicit where we're returning and
using opaque values.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
This commit is contained in:
Alex Elder
2014-11-19 12:27:13 -06:00
committed by Greg Kroah-Hartman
parent c002b0ec60
commit 2292bac5e7
1 changed files with 9 additions and 2 deletions
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11
drivers/staging/greybus/es1-ap-usb.c
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@@ -16,6 +16,13 @@
#include "svc_msg.h"
#include "kernel_ver.h"
/*
* Macros for making pointers explicitly opaque, such that the result
* isn't valid but also can't be mistaken for an ERR_PTR() value.
*/
#define conceal_urb(urb) ((void *)((uintptr_t)(urb) ^ 0xbad))
#define reveal_urb(cookie) ((void *)((uintptr_t)(cookie) ^ 0xbad))
/* Memory sizes for the buffers sent to/from the ES1 controller */
#define ES1_SVC_MSG_SIZE (sizeof(struct svc_msg) + SZ_64K)
#define ES1_GBUF_MSG_SIZE PAGE_SIZE
@@ -241,12 +248,12 @@ static void *buffer_send(struct greybus_host_device *hd, u16 dest_cport_id,
return ERR_PTR(retval);
}
return urb;
return conceal_urb(urb);
}
static void buffer_cancel(void *cookie)
{
struct urb *urb = cookie;
struct urb *urb = reveal_urb(cookie);
/*
* We really should be defensive and track all outstanding