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Commit d1a3fe26 authored by David Laight's avatar David Laight Committed by David S. Miller
Browse files

net: sctp: Use pointers (not array indexes) to access sctp_cmd_seq_t.cmds[]. 



Using pointers into sctp_cmd_seq_t.cmds[] lets the compiler generate much
better code.
Use the last entry first to optimise the overflow check.

Signed-off-by: default avatarDavid Laight <david.laight@aculab.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b9420e1c

include/net/sctp/command.h

+14 −12
Original line number Diff line number Diff line
@@ -203,8 +203,8 @@ typedef struct { 


typedef struct {

	sctp_cmd_t cmds[SCTP_MAX_NUM_COMMANDS];

	__u8 next_free_slot;

	__u8 next_cmd;

	sctp_cmd_t *last_used_slot;

	sctp_cmd_t *next_cmd;

} sctp_cmd_seq_t;
@@ -213,8 +213,9 @@ typedef struct { 
 */

static inline int sctp_init_cmd_seq(sctp_cmd_seq_t *seq)

{

	seq->next_free_slot = 0;

	seq->next_cmd = 0;

	/* cmds[] is filled backwards to simplify the overflow BUG() check */

	seq->last_used_slot = seq->cmds + SCTP_MAX_NUM_COMMANDS;

	seq->next_cmd = seq->last_used_slot;

	return 1;		/* We always succeed.  */

}
@@ -227,10 +228,13 @@ static inline int sctp_init_cmd_seq(sctp_cmd_seq_t *seq) 
static inline void sctp_add_cmd_sf(sctp_cmd_seq_t *seq, sctp_verb_t verb,

				   sctp_arg_t obj)

{

	BUG_ON(seq->next_free_slot >= SCTP_MAX_NUM_COMMANDS);

	sctp_cmd_t *cmd = seq->last_used_slot - 1;



	seq->cmds[seq->next_free_slot].verb = verb;

	seq->cmds[seq->next_free_slot++].obj = obj;

	BUG_ON(cmd < seq->cmds);



	cmd->verb = verb;

	cmd->obj = obj;

	seq->last_used_slot = cmd;

}



/* Return the next command structure in an sctp_cmd_seq.
@@ -238,12 +242,10 @@ static inline void sctp_add_cmd_sf(sctp_cmd_seq_t *seq, sctp_verb_t verb, 
 */

static inline sctp_cmd_t *sctp_next_cmd(sctp_cmd_seq_t *seq)

{

	sctp_cmd_t *retval = NULL;



	if (seq->next_cmd < seq->next_free_slot)

		retval = &seq->cmds[seq->next_cmd++];

	if (seq->next_cmd <= seq->last_used_slot)

		return NULL;



	return retval;

	return --seq->next_cmd;

}



#endif /* __net_sctp_command_h__ */