pie: improve comments and commenting style

Improve the comments along with the commenting style used to
describe the members of the structures and their initial values
in the init functions.

Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>
Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
Signed-off-by: Gautam Ramakrishnan <gautamramk@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/pie.h b/include/net/pie.h
index ec0fbe98ec2fe8034ebaef4ae45ee1ccfc5b19a3..51a1984c2dce1b41be6f06921b3fe466d8107fbc 100644 (file)
--- a/include/net/pie.h
+++ b/include/net/pie.h
@@ -14,42 +14,74 @@
 #define DQCOUNT_INVALID        -1
 #define PIE_SCALE      8
 
-/* parameters used */
+/**
+ * struct pie_params - contains pie parameters
+ * @target:            target delay in pschedtime
+ * @tudpate:           interval at which drop probability is calculated
+ * @limit:             total number of packets that can be in the queue
+ * @alpha:             parameter to control drop probability
+ * @beta:              parameter to control drop probability
+ * @ecn:               is ECN marking of packets enabled
+ * @bytemode:          is drop probability scaled based on pkt size
+ * @dq_rate_estimator: is Little's law used for qdelay calculation
+ */
 struct pie_params {
-       psched_time_t target;   /* user specified target delay in pschedtime */
-       u32 tupdate;            /* timer frequency (in jiffies) */
-       u32 limit;              /* number of packets that can be enqueued */
-       u32 alpha;              /* alpha and beta are between 0 and 32 */
-       u32 beta;               /* and are used for shift relative to 1 */
-       u8 ecn;                 /* true if ecn is enabled */
-       u8 bytemode;            /* to scale drop early prob based on pkt size */
-       u8 dq_rate_estimator;   /* to calculate delay using Little's law */
+       psched_time_t target;
+       u32 tupdate;
+       u32 limit;
+       u32 alpha;
+       u32 beta;
+       u8 ecn;
+       u8 bytemode;
+       u8 dq_rate_estimator;
 };
 
-/* variables used */
+/**
+ * struct pie_vars - contains pie variables
+ * @qdelay:                    current queue delay
+ * @qdelay_old:                        queue delay in previous qdelay calculation
+ * @burst_time:                        burst time allowance
+ * @dq_tstamp:                 timestamp at which dq rate was last calculated
+ * @prob:                      drop probability
+ * @accu_prob:                 accumulated drop probability
+ * @dq_count:                  number of bytes dequeued in a measurement cycle
+ * @avg_dq_rate:               calculated average dq rate
+ * @qlen_old:                  queue length during previous qdelay calculation
+ * @accu_prob_overflows:       number of times accu_prob overflows
+ */
 struct pie_vars {
        psched_time_t qdelay;
        psched_time_t qdelay_old;
        psched_time_t burst_time;
-       psched_time_t dq_tstamp;        /* drain rate */
-       u64 prob;               /* probability but scaled by u64 limit. */
-       u64 accu_prob;          /* accumulated drop probability */
-       u64 dq_count;           /* measured in bytes */
-       u32 avg_dq_rate;        /* bytes per pschedtime tick,scaled */
-       u32 qlen_old;           /* in bytes */
-       u8 accu_prob_overflows; /* overflows of accu_prob */
+       psched_time_t dq_tstamp;
+       u64 prob;
+       u64 accu_prob;
+       u64 dq_count;
+       u32 avg_dq_rate;
+       u32 qlen_old;
+       u8 accu_prob_overflows;
 };
 
-/* statistics gathering */
+/**
+ * struct pie_stats - contains pie stats
+ * @packets_in:        total number of packets enqueued
+ * @dropped:   packets dropped due to pie action
+ * @overlimit: packets dropped due to lack of space in queue
+ * @ecn_mark:  packets marked with ECN
+ * @maxq:      maximum queue size
+ */
 struct pie_stats {
-       u32 packets_in;         /* total number of packets enqueued */
-       u32 dropped;            /* packets dropped due to pie_action */
-       u32 overlimit;          /* dropped due to lack of space in queue */
-       u32 ecn_mark;           /* packets marked with ECN */
-       u32 maxq;               /* maximum queue size */
+       u32 packets_in;
+       u32 dropped;
+       u32 overlimit;
+       u32 ecn_mark;
+       u32 maxq;
 };
 
-/* private skb vars */
+/**
+ * struct pie_skb_cb - contains private skb vars
+ * @enqueue_time:      timestamp when the packet is enqueued
+ */
 struct pie_skb_cb {
        psched_time_t enqueue_time;
 };
@@ -58,7 +90,7 @@ static inline void pie_params_init(struct pie_params *params)
 {
        params->target = PSCHED_NS2TICKS(15 * NSEC_PER_MSEC);   /* 15 ms */
        params->tupdate = usecs_to_jiffies(15 * USEC_PER_MSEC); /* 15 ms */
-       params->limit = 1000;   /* default of 1000 packets */
+       params->limit = 1000;
        params->alpha = 2;
        params->beta = 20;
        params->ecn = false;
@@ -68,8 +100,7 @@ static inline void pie_params_init(struct pie_params *params)
 
 static inline void pie_vars_init(struct pie_vars *vars)
 {
-       /* default of 150 ms in pschedtime */
-       vars->burst_time = PSCHED_NS2TICKS(150 * NSEC_PER_MSEC);
+       vars->burst_time = PSCHED_NS2TICKS(150 * NSEC_PER_MSEC); /* 150 ms */
        vars->dq_tstamp = DTIME_INVALID;
        vars->accu_prob = 0;
        vars->dq_count = DQCOUNT_INVALID;