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Commit b030a4dd authored by Pekka Enberg's avatar Pekka Enberg Committed by Linus Torvalds
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[PATCH] Remove eventpoll macro obfuscation 



This patch gets rid of some macro obfuscation from fs/eventpoll.c by
removing slab allocator wrappers and converting macros to static inline
functions.

Signed-off-by: default avatarPekka Enberg <penberg@cs.helsinki.fi>
Acked-by: default avatarDavide Libenzi <davidel@xmailserver.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 46c271be

fs/eventpoll.c

+110 −85
Original line number Diff line number Diff line
@@ -101,57 +101,6 @@ 
/* Maximum number of poll wake up nests we are allowing */

#define EP_MAX_POLLWAKE_NESTS 4



/* Macro to allocate a "struct epitem" from the slab cache */

#define EPI_MEM_ALLOC()	(struct epitem *) kmem_cache_alloc(epi_cache, SLAB_KERNEL)



/* Macro to free a "struct epitem" to the slab cache */

#define EPI_MEM_FREE(p) kmem_cache_free(epi_cache, p)



/* Macro to allocate a "struct eppoll_entry" from the slab cache */

#define PWQ_MEM_ALLOC()	(struct eppoll_entry *) kmem_cache_alloc(pwq_cache, SLAB_KERNEL)



/* Macro to free a "struct eppoll_entry" to the slab cache */

#define PWQ_MEM_FREE(p) kmem_cache_free(pwq_cache, p)



/* Fast test to see if the file is an evenpoll file */

#define IS_FILE_EPOLL(f) ((f)->f_op == &eventpoll_fops)



/* Setup the structure that is used as key for the rb-tree */

#define EP_SET_FFD(p, f, d) do { (p)->file = (f); (p)->fd = (d); } while (0)



/* Compare rb-tree keys */

#define EP_CMP_FFD(p1, p2) ((p1)->file > (p2)->file ? +1: \

			    ((p1)->file < (p2)->file ? -1: (p1)->fd - (p2)->fd))



/* Special initialization for the rb-tree node to detect linkage */

#define EP_RB_INITNODE(n) (n)->rb_parent = (n)



/* Removes a node from the rb-tree and marks it for a fast is-linked check */

#define EP_RB_ERASE(n, r) do { rb_erase(n, r); (n)->rb_parent = (n); } while (0)



/* Fast check to verify that the item is linked to the main rb-tree */

#define EP_RB_LINKED(n) ((n)->rb_parent != (n))



/*

 * Remove the item from the list and perform its initialization.

 * This is useful for us because we can test if the item is linked

 * using "EP_IS_LINKED(p)".

 */

#define EP_LIST_DEL(p) do { list_del(p); INIT_LIST_HEAD(p); } while (0)



/* Tells us if the item is currently linked */

#define EP_IS_LINKED(p) (!list_empty(p))



/* Get the "struct epitem" from a wait queue pointer */

#define EP_ITEM_FROM_WAIT(p) ((struct epitem *) container_of(p, struct eppoll_entry, wait)->base)



/* Get the "struct epitem" from an epoll queue wrapper */

#define EP_ITEM_FROM_EPQUEUE(p) (container_of(p, struct ep_pqueue, pt)->epi)



/* Tells if the epoll_ctl(2) operation needs an event copy from userspace */

#define EP_OP_HASH_EVENT(op) ((op) != EPOLL_CTL_DEL)





struct epoll_filefd {

	struct file *file;

	int fd;
@@ -357,6 +306,82 @@ static struct dentry_operations eventpollfs_dentry_operations = { 






/* Fast test to see if the file is an evenpoll file */

static inline int is_file_epoll(struct file *f)

{

	return f->f_op == &eventpoll_fops;

}



/* Setup the structure that is used as key for the rb-tree */

static inline void ep_set_ffd(struct epoll_filefd *ffd,

			      struct file *file, int fd)

{

	ffd->file = file;

	ffd->fd = fd;

}



/* Compare rb-tree keys */

static inline int ep_cmp_ffd(struct epoll_filefd *p1,

			     struct epoll_filefd *p2)

{

	return (p1->file > p2->file ? +1:

	        (p1->file < p2->file ? -1 : p1->fd - p2->fd));

}



/* Special initialization for the rb-tree node to detect linkage */

static inline void ep_rb_initnode(struct rb_node *n)

{

	n->rb_parent = n;

}



/* Removes a node from the rb-tree and marks it for a fast is-linked check */

static inline void ep_rb_erase(struct rb_node *n, struct rb_root *r)

{

	rb_erase(n, r);

	n->rb_parent = n;

}



/* Fast check to verify that the item is linked to the main rb-tree */

static inline int ep_rb_linked(struct rb_node *n)

{

	return n->rb_parent != n;

}



/*

 * Remove the item from the list and perform its initialization.

 * This is useful for us because we can test if the item is linked

 * using "ep_is_linked(p)".

 */

static inline void ep_list_del(struct list_head *p)

{

	list_del(p);

	INIT_LIST_HEAD(p);

}



/* Tells us if the item is currently linked */

static inline int ep_is_linked(struct list_head *p)

{

	return !list_empty(p);

}



/* Get the "struct epitem" from a wait queue pointer */

static inline struct epitem * ep_item_from_wait(wait_queue_t *p)

{

	return container_of(p, struct eppoll_entry, wait)->base;

}



/* Get the "struct epitem" from an epoll queue wrapper */

static inline struct epitem * ep_item_from_epqueue(poll_table *p)

{

	return container_of(p, struct ep_pqueue, pt)->epi;

}



/* Tells if the epoll_ctl(2) operation needs an event copy from userspace */

static inline int ep_op_hash_event(int op)

{

	return op != EPOLL_CTL_DEL;

}



/* Initialize the poll safe wake up structure */

static void ep_poll_safewake_init(struct poll_safewake *psw)

{
@@ -456,7 +481,7 @@ void eventpoll_release_file(struct file *file) 
		epi = list_entry(lsthead->next, struct epitem, fllink);



		ep = epi->ep;

		EP_LIST_DEL(&epi->fllink);

		ep_list_del(&epi->fllink);

		down_write(&ep->sem);

		ep_remove(ep, epi);

		up_write(&ep->sem);
@@ -534,7 +559,7 @@ sys_epoll_ctl(int epfd, int op, int fd, struct epoll_event __user *event) 
		     current, epfd, op, fd, event));



	error = -EFAULT;

	if (EP_OP_HASH_EVENT(op) &&

	if (ep_op_hash_event(op) &&

	    copy_from_user(&epds, event, sizeof(struct epoll_event)))

		goto eexit_1;
@@ -560,7 +585,7 @@ sys_epoll_ctl(int epfd, int op, int fd, struct epoll_event __user *event) 
	 * adding an epoll file descriptor inside itself.

	 */

	error = -EINVAL;

	if (file == tfile || !IS_FILE_EPOLL(file))

	if (file == tfile || !is_file_epoll(file))

		goto eexit_3;



	/*
@@ -656,7 +681,7 @@ asmlinkage long sys_epoll_wait(int epfd, struct epoll_event __user *events, 
	 * the user passed to us _is_ an eventpoll file.

	 */

	error = -EINVAL;

	if (!IS_FILE_EPOLL(file))

	if (!is_file_epoll(file))

		goto eexit_2;



	/*
@@ -831,11 +856,11 @@ static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd) 
	struct epitem *epi, *epir = NULL;

	struct epoll_filefd ffd;



	EP_SET_FFD(&ffd, file, fd);

	ep_set_ffd(&ffd, file, fd);

	read_lock_irqsave(&ep->lock, flags);

	for (rbp = ep->rbr.rb_node; rbp; ) {

		epi = rb_entry(rbp, struct epitem, rbn);

		kcmp = EP_CMP_FFD(&ffd, &epi->ffd);

		kcmp = ep_cmp_ffd(&ffd, &epi->ffd);

		if (kcmp > 0)

			rbp = rbp->rb_right;

		else if (kcmp < 0)
@@ -875,7 +900,7 @@ static void ep_release_epitem(struct epitem *epi) 
{



	if (atomic_dec_and_test(&epi->usecnt))

		EPI_MEM_FREE(epi);

		kmem_cache_free(epi_cache, epi);

}
@@ -886,10 +911,10 @@ static void ep_release_epitem(struct epitem *epi) 
static void ep_ptable_queue_proc(struct file *file, wait_queue_head_t *whead,

				 poll_table *pt)

{

	struct epitem *epi = EP_ITEM_FROM_EPQUEUE(pt);

	struct epitem *epi = ep_item_from_epqueue(pt);

	struct eppoll_entry *pwq;



	if (epi->nwait >= 0 && (pwq = PWQ_MEM_ALLOC())) {

	if (epi->nwait >= 0 && (pwq = kmem_cache_alloc(pwq_cache, SLAB_KERNEL))) {

		init_waitqueue_func_entry(&pwq->wait, ep_poll_callback);

		pwq->whead = whead;

		pwq->base = epi;
@@ -912,7 +937,7 @@ static void ep_rbtree_insert(struct eventpoll *ep, struct epitem *epi) 
	while (*p) {

		parent = *p;

		epic = rb_entry(parent, struct epitem, rbn);

		kcmp = EP_CMP_FFD(&epi->ffd, &epic->ffd);

		kcmp = ep_cmp_ffd(&epi->ffd, &epic->ffd);

		if (kcmp > 0)

			p = &parent->rb_right;

		else
@@ -932,17 +957,17 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event, 
	struct ep_pqueue epq;



	error = -ENOMEM;

	if (!(epi = EPI_MEM_ALLOC()))

	if (!(epi = kmem_cache_alloc(epi_cache, SLAB_KERNEL)))

		goto eexit_1;



	/* Item initialization follow here ... */

	EP_RB_INITNODE(&epi->rbn);

	ep_rb_initnode(&epi->rbn);

	INIT_LIST_HEAD(&epi->rdllink);

	INIT_LIST_HEAD(&epi->fllink);

	INIT_LIST_HEAD(&epi->txlink);

	INIT_LIST_HEAD(&epi->pwqlist);

	epi->ep = ep;

	EP_SET_FFD(&epi->ffd, tfile, fd);

	ep_set_ffd(&epi->ffd, tfile, fd);

	epi->event = *event;

	atomic_set(&epi->usecnt, 1);

	epi->nwait = 0;
@@ -978,7 +1003,7 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event, 
	ep_rbtree_insert(ep, epi);



	/* If the file is already "ready" we drop it inside the ready list */

	if ((revents & event->events) && !EP_IS_LINKED(&epi->rdllink)) {

	if ((revents & event->events) && !ep_is_linked(&epi->rdllink)) {

		list_add_tail(&epi->rdllink, &ep->rdllist);



		/* Notify waiting tasks that events are available */
@@ -1007,11 +1032,11 @@ eexit_2: 
	 * allocated wait queue.

	 */

	write_lock_irqsave(&ep->lock, flags);

	if (EP_IS_LINKED(&epi->rdllink))

		EP_LIST_DEL(&epi->rdllink);

	if (ep_is_linked(&epi->rdllink))

		ep_list_del(&epi->rdllink);

	write_unlock_irqrestore(&ep->lock, flags);



	EPI_MEM_FREE(epi);

	kmem_cache_free(epi_cache, epi);

eexit_1:

	return error;

}
@@ -1050,14 +1075,14 @@ static int ep_modify(struct eventpoll *ep, struct epitem *epi, struct epoll_even 
	 * If the item is not linked to the hash it means that it's on its

	 * way toward the removal. Do nothing in this case.

	 */

	if (EP_RB_LINKED(&epi->rbn)) {

	if (ep_rb_linked(&epi->rbn)) {

		/*

		 * If the item is "hot" and it is not registered inside the ready

		 * list, push it inside. If the item is not "hot" and it is currently

		 * registered inside the ready list, unlink it.

		 */

		if (revents & event->events) {

			if (!EP_IS_LINKED(&epi->rdllink)) {

			if (!ep_is_linked(&epi->rdllink)) {

				list_add_tail(&epi->rdllink, &ep->rdllist);



				/* Notify waiting tasks that events are available */
@@ -1097,9 +1122,9 @@ static void ep_unregister_pollwait(struct eventpoll *ep, struct epitem *epi) 
		while (!list_empty(lsthead)) {

			pwq = list_entry(lsthead->next, struct eppoll_entry, llink);



			EP_LIST_DEL(&pwq->llink);

			ep_list_del(&pwq->llink);

			remove_wait_queue(pwq->whead, &pwq->wait);

			PWQ_MEM_FREE(pwq);

			kmem_cache_free(pwq_cache, pwq);

		}

	}

}
@@ -1118,7 +1143,7 @@ static int ep_unlink(struct eventpoll *ep, struct epitem *epi) 
	 * The check protect us from doing a double unlink ( crash ).

	 */

	error = -ENOENT;

	if (!EP_RB_LINKED(&epi->rbn))

	if (!ep_rb_linked(&epi->rbn))

		goto eexit_1;



	/*
@@ -1133,14 +1158,14 @@ static int ep_unlink(struct eventpoll *ep, struct epitem *epi) 
	 * This operation togheter with the above check closes the door to

	 * double unlinks.

	 */

	EP_RB_ERASE(&epi->rbn, &ep->rbr);

	ep_rb_erase(&epi->rbn, &ep->rbr);



	/*

	 * If the item we are going to remove is inside the ready file descriptors

	 * we want to remove it from this list to avoid stale events.

	 */

	if (EP_IS_LINKED(&epi->rdllink))

		EP_LIST_DEL(&epi->rdllink);

	if (ep_is_linked(&epi->rdllink))

		ep_list_del(&epi->rdllink);



	error = 0;

eexit_1:
@@ -1174,8 +1199,8 @@ static int ep_remove(struct eventpoll *ep, struct epitem *epi) 


	/* Remove the current item from the list of epoll hooks */

	spin_lock(&file->f_ep_lock);

	if (EP_IS_LINKED(&epi->fllink))

		EP_LIST_DEL(&epi->fllink);

	if (ep_is_linked(&epi->fllink))

		ep_list_del(&epi->fllink);

	spin_unlock(&file->f_ep_lock);



	/* We need to acquire the write IRQ lock before calling ep_unlink() */
@@ -1210,7 +1235,7 @@ static int ep_poll_callback(wait_queue_t *wait, unsigned mode, int sync, void *k 
{

	int pwake = 0;

	unsigned long flags;

	struct epitem *epi = EP_ITEM_FROM_WAIT(wait);

	struct epitem *epi = ep_item_from_wait(wait);

	struct eventpoll *ep = epi->ep;



	DNPRINTK(3, (KERN_INFO "[%p] eventpoll: poll_callback(%p) epi=%p ep=%p\n",
@@ -1228,7 +1253,7 @@ static int ep_poll_callback(wait_queue_t *wait, unsigned mode, int sync, void *k 
		goto is_disabled;



	/* If this file is already in the ready list we exit soon */

	if (EP_IS_LINKED(&epi->rdllink))

	if (ep_is_linked(&epi->rdllink))

		goto is_linked;



	list_add_tail(&epi->rdllink, &ep->rdllist);
@@ -1307,7 +1332,7 @@ static int ep_collect_ready_items(struct eventpoll *ep, struct list_head *txlist 
		lnk = lnk->next;



		/* If this file is already in the ready list we exit soon */

		if (!EP_IS_LINKED(&epi->txlink)) {

		if (!ep_is_linked(&epi->txlink)) {

			/*

			 * This is initialized in this way so that the default

			 * behaviour of the reinjecting code will be to push back
@@ -1322,7 +1347,7 @@ static int ep_collect_ready_items(struct eventpoll *ep, struct list_head *txlist 
			/*

			 * Unlink the item from the ready list.

			 */

			EP_LIST_DEL(&epi->rdllink);

			ep_list_del(&epi->rdllink);

		}

	}
@@ -1401,7 +1426,7 @@ static void ep_reinject_items(struct eventpoll *ep, struct list_head *txlist) 
		epi = list_entry(txlist->next, struct epitem, txlink);



		/* Unlink the current item from the transfer list */

		EP_LIST_DEL(&epi->txlink);

		ep_list_del(&epi->txlink);



		/*

		 * If the item is no more linked to the interest set, we don't
@@ -1410,8 +1435,8 @@ static void ep_reinject_items(struct eventpoll *ep, struct list_head *txlist) 
		 * item is set to have an Edge Triggered behaviour, we don't have

		 * to push it back either.

		 */

		if (EP_RB_LINKED(&epi->rbn) && !(epi->event.events & EPOLLET) &&

		    (epi->revents & epi->event.events) && !EP_IS_LINKED(&epi->rdllink)) {

		if (ep_rb_linked(&epi->rbn) && !(epi->event.events & EPOLLET) &&

		    (epi->revents & epi->event.events) && !ep_is_linked(&epi->rdllink)) {

			list_add_tail(&epi->rdllink, &ep->rdllist);

			ricnt++;

		}