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flow: Introduce 'sidx' type to represent one side of one flow

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In a number of places, we use indices into the flow table to identify a
specific flow.  We also have cases where we need to identify a particular
side of a particular flow, and we expect those to become more common as
we generalise the flow table to cover more things.

To assist with that, introduces flow_sidx_t, an index type which identifies
a specific side of a specific flow in the table.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[sbrivio: Suppress false cppcheck positive in flow_sidx()]
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
David Gibson 2023-11-30 13:02:14 +11:00 committed by Stefano Brivio
parent eb8b1a233b
commit df96a4cb5d
2 changed files with 52 additions and 0 deletions
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14
flow.h
View file

@ -39,6 +39,20 @@ struct flow_common {
#define FLOW_TABLE_PRESSURE 30 /* % of FLOW_MAX */ #define FLOW_TABLE_PRESSURE 30 /* % of FLOW_MAX */
#define FLOW_FILE_PRESSURE 30 /* % of c->nofile */ #define FLOW_FILE_PRESSURE 30 /* % of c->nofile */
/**
* struct flow_sidx - ID for one side of a specific flow
* @side: Side referenced (0 or 1)
* @flow: Index of flow referenced
*/
typedef struct flow_sidx {
int side :1;
unsigned flow :FLOW_INDEX_BITS;
} flow_sidx_t;
static_assert(sizeof(flow_sidx_t) <= sizeof(uint32_t),
"flow_sidx_t must fit within 32 bits");
#define FLOW_SIDX_NONE ((flow_sidx_t){ .flow = FLOW_MAX })
union flow; union flow;
void flow_table_compact(struct ctx *c, union flow *hole); void flow_table_compact(struct ctx *c, union flow *hole);

38
flow_table.h
View file

@ -47,4 +47,42 @@ static inline unsigned flow_idx(const struct flow_common *f)
*/ */
#define FLOW(idx) (&flowtab[(idx)]) #define FLOW(idx) (&flowtab[(idx)])
/** flow_at_sidx - Flow entry for a given sidx
* @sidx: Flow & side index
*
* Return: pointer to the corresponding flow entry, or NULL
*/
static inline union flow *flow_at_sidx(flow_sidx_t sidx)
{
if (sidx.flow >= FLOW_MAX)
return NULL;
return FLOW(sidx.flow);
}
/** flow_sidx_t - Index of one side of a flow from common structure
* @f: Common flow fields pointer
* @side: Which side to refer to (0 or 1)
*
* Return: index of @f and @side in the flow table
*/
static inline flow_sidx_t flow_sidx(const struct flow_common *f,
int side)
{
/* cppcheck-suppress [knownConditionTrueFalse, unmatchedSuppression] */
ASSERT(side == !!side);
return (flow_sidx_t){
.side = side,
.flow = flow_idx(f),
};
}
/** FLOW_SIDX - Find the index of one side of a flow
* @f_: Flow pointer, either union flow * or protocol specific
* @side: Which side to index (0 or 1)
*
* Return: index of @f and @side in the flow table
*/
#define FLOW_SIDX(f_, side) (flow_sidx(&(f_)->f, (side)))
#endif /* FLOW_TABLE_H */ #endif /* FLOW_TABLE_H */