Today RING_HAS_UNCONSUMED_*() macros are returning the number of
unconsumed requests or responses instead of a boolean as the name of
the macros would imply.
As this "feature" is already being used, rename the macros to
XEN_RING_NR_UNCONSUMED_*() and define the RING_HAS_UNCONSUMED_*() macros
by using the new XEN_RING_NR_UNCONSUMED_*() macros. In order to avoid
future misuse let RING_HAS_UNCONSUMED_*() optionally really return a
boolean (can be activated by defining XEN_RING_HAS_UNCONSUMED_IS_BOOL).
Note that the known misuses need to be switched to the new
XEN_RING_NR_UNCONSUMED_*() macros when using the RING_HAS_UNCONSUMED_*()
variants returning a boolean value.
Cc: Roger Pau Monne <roger.pau@citrix.com>
Cc: Manuel Bouyer <bouyer@antioche.eu.org>
Cc: Simon Kuenzer <simon.kuenzer@neclab.eu>
Cc: Paul Durrant <paul@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V3:
- add XEN_ prefix to new macros (Jan Beulich)
---
xen/include/public/io/ring.h | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/xen/include/public/io/ring.h b/xen/include/public/io/ring.h
index c486c457e0..277af36e61 100644
--- a/xen/include/public/io/ring.h
+++ b/xen/include/public/io/ring.h
@@ -208,11 +208,11 @@ typedef struct __name##_back_ring __name##_back_ring_t
(RING_FREE_REQUESTS(_r) == 0)
/* Test if there are outstanding messages to be processed on a ring. */
-#define RING_HAS_UNCONSUMED_RESPONSES(_r) \
+#define XEN_RING_NR_UNCONSUMED_RESPONSES(_r) \
((_r)->sring->rsp_prod - (_r)->rsp_cons)
#ifdef __GNUC__
-#define RING_HAS_UNCONSUMED_REQUESTS(_r) ({ \
+#define XEN_RING_NR_UNCONSUMED_REQUESTS(_r) ({ \
unsigned int req = (_r)->sring->req_prod - (_r)->req_cons; \
unsigned int rsp = RING_SIZE(_r) - \
((_r)->req_cons - (_r)->rsp_prod_pvt); \
@@ -220,13 +220,27 @@ typedef struct __name##_back_ring __name##_back_ring_t
})
#else
/* Same as above, but without the nice GCC ({ ... }) syntax. */
-#define RING_HAS_UNCONSUMED_REQUESTS(_r) \
+#define XEN_RING_NR_UNCONSUMED_REQUESTS(_r) \
((((_r)->sring->req_prod - (_r)->req_cons) < \
(RING_SIZE(_r) - ((_r)->req_cons - (_r)->rsp_prod_pvt))) ? \
((_r)->sring->req_prod - (_r)->req_cons) : \
(RING_SIZE(_r) - ((_r)->req_cons - (_r)->rsp_prod_pvt)))
#endif
+#ifdef XEN_RING_HAS_UNCONSUMED_IS_BOOL
+/*
+ * These variants should only be used in case no caller is abusing them for
+ * obtaining the number of unconsumed responses/requests.
+ */
+#define RING_HAS_UNCONSUMED_RESPONSES(_r) \
+ (!!XEN_RING_NR_UNCONSUMED_RESPONSES(_r))
+#define RING_HAS_UNCONSUMED_REQUESTS(_r) \
+ (!!XEN_RING_NR_UNCONSUMED_REQUESTS(_r))
+#else
+#define RING_HAS_UNCONSUMED_RESPONSES(_r) XEN_RING_NR_UNCONSUMED_RESPONSES(_r)
+#define RING_HAS_UNCONSUMED_REQUESTS(_r) XEN_RING_NR_UNCONSUMED_REQUESTS(_r)
+#endif
+
/* Direct access to individual ring elements, by index. */
#define RING_GET_REQUEST(_r, _idx) \
(&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].req))
--
2.31.1
On 27.01.2022 07:30, Juergen Gross wrote: > Today RING_HAS_UNCONSUMED_*() macros are returning the number of > unconsumed requests or responses instead of a boolean as the name of > the macros would imply. > > As this "feature" is already being used, rename the macros to > XEN_RING_NR_UNCONSUMED_*() and define the RING_HAS_UNCONSUMED_*() macros > by using the new XEN_RING_NR_UNCONSUMED_*() macros. In order to avoid > future misuse let RING_HAS_UNCONSUMED_*() optionally really return a > boolean (can be activated by defining XEN_RING_HAS_UNCONSUMED_IS_BOOL). > > Note that the known misuses need to be switched to the new > XEN_RING_NR_UNCONSUMED_*() macros when using the RING_HAS_UNCONSUMED_*() > variants returning a boolean value. > > Cc: Roger Pau Monne <roger.pau@citrix.com> > Cc: Manuel Bouyer <bouyer@antioche.eu.org> > Cc: Simon Kuenzer <simon.kuenzer@neclab.eu> > Cc: Paul Durrant <paul@xen.org> > Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
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