X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=fs%2Ffile.c;h=c5575de01113eb24aa182c77b35d46d0f0fced48;hb=97bf2856c6014879bd04983a3e9dfcdac1e7fe85;hp=44ab07a080ec0791b1f334370092f772fc106018;hpb=76828883507a47dae78837ab5dec5a5b4513c667;p=linux-2.6.git

diff --git a/fs/file.c b/fs/file.c
index 44ab07a08..c5575de01 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -21,7 +21,6 @@
 struct fdtable_defer {
 	spinlock_t lock;
 	struct work_struct wq;
-	struct timer_list timer;
 	struct fdtable *next;
 };
 
@@ -33,66 +32,34 @@ struct fdtable_defer {
  */
 static DEFINE_PER_CPU(struct fdtable_defer, fdtable_defer_list);
 
-
-/*
- * Allocate an fd array, using kmalloc or vmalloc.
- * Note: the array isn't cleared at allocation time.
- */
-struct file ** alloc_fd_array(int num)
+static inline void * alloc_fdmem(unsigned int size)
 {
-	struct file **new_fds;
-	int size = num * sizeof(struct file *);
-
 	if (size <= PAGE_SIZE)
-		new_fds = (struct file **) kmalloc(size, GFP_KERNEL);
-	else 
-		new_fds = (struct file **) vmalloc(size);
-	return new_fds;
-}
-
-void free_fd_array(struct file **array, int num)
-{
-	int size = num * sizeof(struct file *);
-
-	if (!array) {
-		printk (KERN_ERR "free_fd_array: array = 0 (num = %d)\n", num);
-		return;
-	}
-
-	if (num <= NR_OPEN_DEFAULT) /* Don't free the embedded fd array! */
-		return;
-	else if (size <= PAGE_SIZE)
-		kfree(array);
+		return kmalloc(size, GFP_KERNEL);
 	else
-		vfree(array);
+		return vmalloc(size);
 }
 
-static void __free_fdtable(struct fdtable *fdt)
+static inline void free_fdarr(struct fdtable *fdt)
 {
-	free_fdset(fdt->open_fds, fdt->max_fdset);
-	free_fdset(fdt->close_on_exec, fdt->max_fdset);
-	free_fd_array(fdt->fd, fdt->max_fds);
-	kfree(fdt);
+	if (fdt->max_fds <= (PAGE_SIZE / sizeof(struct file *)))
+		kfree(fdt->fd);
+	else
+		vfree(fdt->fd);
 }
 
-static void fdtable_timer(unsigned long data)
+static inline void free_fdset(struct fdtable *fdt)
 {
-	struct fdtable_defer *fddef = (struct fdtable_defer *)data;
-
-	spin_lock(&fddef->lock);
-	/*
-	 * If someone already emptied the queue return.
-	 */
-	if (!fddef->next)
-		goto out;
-	if (!schedule_work(&fddef->wq))
-		mod_timer(&fddef->timer, 5);
-out:
-	spin_unlock(&fddef->lock);
+	if (fdt->max_fds <= (PAGE_SIZE * BITS_PER_BYTE / 2))
+		kfree(fdt->open_fds);
+	else
+		vfree(fdt->open_fds);
 }
 
-static void free_fdtable_work(struct fdtable_defer *f)
+static void free_fdtable_work(struct work_struct *work)
 {
+	struct fdtable_defer *f =
+		container_of(work, struct fdtable_defer, wq);
 	struct fdtable *fdt;
 
 	spin_lock_bh(&f->lock);
@@ -101,286 +68,189 @@ static void free_fdtable_work(struct fdtable_defer *f)
 	spin_unlock_bh(&f->lock);
 	while(fdt) {
 		struct fdtable *next = fdt->next;
-		__free_fdtable(fdt);
+		vfree(fdt->fd);
+		free_fdset(fdt);
+		kfree(fdt);
 		fdt = next;
 	}
 }
 
-static void free_fdtable_rcu(struct rcu_head *rcu)
+void free_fdtable_rcu(struct rcu_head *rcu)
 {
 	struct fdtable *fdt = container_of(rcu, struct fdtable, rcu);
-	int fdset_size, fdarray_size;
 	struct fdtable_defer *fddef;
 
 	BUG_ON(!fdt);
-	fdset_size = fdt->max_fdset / 8;
-	fdarray_size = fdt->max_fds * sizeof(struct file *);
 
-	if (fdt->free_files) {
-		/*
-		 * The this fdtable was embedded in the files structure
-		 * and the files structure itself was getting destroyed.
-		 * It is now safe to free the files structure.
-		 */
-		kmem_cache_free(files_cachep, fdt->free_files);
-		return;
-	}
-	if (fdt->max_fdset <= __FD_SETSIZE && fdt->max_fds <= NR_OPEN_DEFAULT) {
+	if (fdt->max_fds <= NR_OPEN_DEFAULT) {
 		/*
-		 * The fdtable was embedded
+		 * This fdtable is embedded in the files structure and that
+		 * structure itself is getting destroyed.
 		 */
+		kmem_cache_free(files_cachep,
+				container_of(fdt, struct files_struct, fdtab));
 		return;
 	}
-	if (fdset_size <= PAGE_SIZE && fdarray_size <= PAGE_SIZE) {
-		kfree(fdt->open_fds);
-		kfree(fdt->close_on_exec);
+	if (fdt->max_fds <= (PAGE_SIZE / sizeof(struct file *))) {
 		kfree(fdt->fd);
+		kfree(fdt->open_fds);
 		kfree(fdt);
 	} else {
 		fddef = &get_cpu_var(fdtable_defer_list);
 		spin_lock(&fddef->lock);
 		fdt->next = fddef->next;
 		fddef->next = fdt;
-		/*
-		 * vmallocs are handled from the workqueue context.
-		 * If the per-cpu workqueue is running, then we
-		 * defer work scheduling through a timer.
-		 */
-		if (!schedule_work(&fddef->wq))
-			mod_timer(&fddef->timer, 5);
+		/* vmallocs are handled from the workqueue context */
+		schedule_work(&fddef->wq);
 		spin_unlock(&fddef->lock);
 		put_cpu_var(fdtable_defer_list);
 	}
 }
 
-void free_fdtable(struct fdtable *fdt)
-{
-	if (fdt->free_files || fdt->max_fdset > __FD_SETSIZE ||
-					fdt->max_fds > NR_OPEN_DEFAULT)
-		call_rcu(&fdt->rcu, free_fdtable_rcu);
-}
-
 /*
  * Expand the fdset in the files_struct.  Called with the files spinlock
  * held for write.
  */
-static void copy_fdtable(struct fdtable *nfdt, struct fdtable *fdt)
+static void copy_fdtable(struct fdtable *nfdt, struct fdtable *ofdt)
 {
-	int i;
-	int count;
-
-	BUG_ON(nfdt->max_fdset < fdt->max_fdset);
-	BUG_ON(nfdt->max_fds < fdt->max_fds);
-	/* Copy the existing tables and install the new pointers */
+	unsigned int cpy, set;
 
-	i = fdt->max_fdset / (sizeof(unsigned long) * 8);
-	count = (nfdt->max_fdset - fdt->max_fdset) / 8;
-
-	/*
-	 * Don't copy the entire array if the current fdset is
-	 * not yet initialised.
-	 */
-	if (i) {
-		memcpy (nfdt->open_fds, fdt->open_fds,
-						fdt->max_fdset/8);
-		memcpy (nfdt->close_on_exec, fdt->close_on_exec,
-						fdt->max_fdset/8);
-		memset (&nfdt->open_fds->fds_bits[i], 0, count);
-		memset (&nfdt->close_on_exec->fds_bits[i], 0, count);
-	}
+	BUG_ON(nfdt->max_fds < ofdt->max_fds);
+	if (ofdt->max_fds == 0)
+		return;
 
-	/* Don't copy/clear the array if we are creating a new
-	   fd array for fork() */
-	if (fdt->max_fds) {
-		memcpy(nfdt->fd, fdt->fd,
-			fdt->max_fds * sizeof(struct file *));
-		/* clear the remainder of the array */
-		memset(&nfdt->fd[fdt->max_fds], 0,
-		       (nfdt->max_fds - fdt->max_fds) *
-					sizeof(struct file *));
-	}
-	nfdt->next_fd = fdt->next_fd;
+	cpy = ofdt->max_fds * sizeof(struct file *);
+	set = (nfdt->max_fds - ofdt->max_fds) * sizeof(struct file *);
+	memcpy(nfdt->fd, ofdt->fd, cpy);
+	memset((char *)(nfdt->fd) + cpy, 0, set);
+
+	cpy = ofdt->max_fds / BITS_PER_BYTE;
+	set = (nfdt->max_fds - ofdt->max_fds) / BITS_PER_BYTE;
+	memcpy(nfdt->open_fds, ofdt->open_fds, cpy);
+	memset((char *)(nfdt->open_fds) + cpy, 0, set);
+	memcpy(nfdt->close_on_exec, ofdt->close_on_exec, cpy);
+	memset((char *)(nfdt->close_on_exec) + cpy, 0, set);
 }
 
-/*
- * Allocate an fdset array, using kmalloc or vmalloc.
- * Note: the array isn't cleared at allocation time.
- */
-fd_set * alloc_fdset(int num)
+static struct fdtable * alloc_fdtable(unsigned int nr)
 {
-	fd_set *new_fdset;
-	int size = num / 8;
-
-	if (size <= PAGE_SIZE)
-		new_fdset = (fd_set *) kmalloc(size, GFP_KERNEL);
-	else
-		new_fdset = (fd_set *) vmalloc(size);
-	return new_fdset;
-}
-
-void free_fdset(fd_set *array, int num)
-{
-	int size = num / 8;
-
-	if (num <= __FD_SETSIZE) /* Don't free an embedded fdset */
-		return;
-	else if (size <= PAGE_SIZE)
-		kfree(array);
-	else
-		vfree(array);
-}
+	struct fdtable *fdt;
+	char *data;
 
-static struct fdtable *alloc_fdtable(int nr)
-{
-	struct fdtable *fdt = NULL;
-	int nfds = 0;
-  	fd_set *new_openset = NULL, *new_execset = NULL;
-	struct file **new_fds;
+	/*
+	 * Figure out how many fds we actually want to support in this fdtable.
+	 * Allocation steps are keyed to the size of the fdarray, since it
+	 * grows far faster than any of the other dynamic data. We try to fit
+	 * the fdarray into comfortable page-tuned chunks: starting at 1024B
+	 * and growing in powers of two from there on.
+	 */
+	nr /= (1024 / sizeof(struct file *));
+	nr = roundup_pow_of_two(nr + 1);
+	nr *= (1024 / sizeof(struct file *));
+	if (nr > NR_OPEN)
+		nr = NR_OPEN;
 
-	fdt = kmalloc(sizeof(*fdt), GFP_KERNEL);
+	fdt = kmalloc(sizeof(struct fdtable), GFP_KERNEL);
 	if (!fdt)
-  		goto out;
-	memset(fdt, 0, sizeof(*fdt));
-
-	nfds = __FD_SETSIZE;
-  	/* Expand to the max in easy steps */
-  	do {
-		if (nfds < (PAGE_SIZE * 8))
-			nfds = PAGE_SIZE * 8;
-		else {
-			nfds = nfds * 2;
-			if (nfds > NR_OPEN)
-				nfds = NR_OPEN;
-		}
-	} while (nfds <= nr);
-
-  	new_openset = alloc_fdset(nfds);
-  	new_execset = alloc_fdset(nfds);
-  	if (!new_openset || !new_execset)
-  		goto out;
-	fdt->open_fds = new_openset;
-	fdt->close_on_exec = new_execset;
-	fdt->max_fdset = nfds;
+		goto out;
+	fdt->max_fds = nr;
+	data = alloc_fdmem(nr * sizeof(struct file *));
+	if (!data)
+		goto out_fdt;
+	fdt->fd = (struct file **)data;
+	data = alloc_fdmem(max_t(unsigned int,
+				 2 * nr / BITS_PER_BYTE, L1_CACHE_BYTES));
+	if (!data)
+		goto out_arr;
+	fdt->open_fds = (fd_set *)data;
+	data += nr / BITS_PER_BYTE;
+	fdt->close_on_exec = (fd_set *)data;
+	INIT_RCU_HEAD(&fdt->rcu);
+	fdt->next = NULL;
 
-	nfds = NR_OPEN_DEFAULT;
-	/*
-	 * Expand to the max in easy steps, and keep expanding it until
-	 * we have enough for the requested fd array size.
-	 */
-	do {
-#if NR_OPEN_DEFAULT < 256
-		if (nfds < 256)
-			nfds = 256;
-		else
-#endif
-		if (nfds < (PAGE_SIZE / sizeof(struct file *)))
-			nfds = PAGE_SIZE / sizeof(struct file *);
-		else {
-			nfds = nfds * 2;
-			if (nfds > NR_OPEN)
-				nfds = NR_OPEN;
-  		}
-	} while (nfds <= nr);
-	new_fds = alloc_fd_array(nfds);
-	if (!new_fds)
-		goto out2;
-	fdt->fd = new_fds;
-	fdt->max_fds = nfds;
-	fdt->free_files = NULL;
 	return fdt;
-out2:
-	nfds = fdt->max_fdset;
-out:
-  	if (new_openset)
-  		free_fdset(new_openset, nfds);
-  	if (new_execset)
-  		free_fdset(new_execset, nfds);
+
+out_arr:
+	free_fdarr(fdt);
+out_fdt:
 	kfree(fdt);
+out:
 	return NULL;
 }
 
 /*
- * Expands the file descriptor table - it will allocate a new fdtable and
- * both fd array and fdset. It is expected to be called with the
- * files_lock held.
+ * Expand the file descriptor table.
+ * This function will allocate a new fdtable and both fd array and fdset, of
+ * the given size.
+ * Return <0 error code on error; 1 on successful completion.
+ * The files->file_lock should be held on entry, and will be held on exit.
  */
 static int expand_fdtable(struct files_struct *files, int nr)
 	__releases(files->file_lock)
 	__acquires(files->file_lock)
 {
-	int error = 0;
-	struct fdtable *fdt;
-	struct fdtable *nfdt = NULL;
+	struct fdtable *new_fdt, *cur_fdt;
 
 	spin_unlock(&files->file_lock);
-	nfdt = alloc_fdtable(nr);
-	if (!nfdt) {
-		error = -ENOMEM;
-		spin_lock(&files->file_lock);
-		goto out;
-	}
-
+	new_fdt = alloc_fdtable(nr);
 	spin_lock(&files->file_lock);
-	fdt = files_fdtable(files);
+	if (!new_fdt)
+		return -ENOMEM;
 	/*
-	 * Check again since another task may have expanded the
-	 * fd table while we dropped the lock
+	 * Check again since another task may have expanded the fd table while
+	 * we dropped the lock
 	 */
-	if (nr >= fdt->max_fds || nr >= fdt->max_fdset) {
-		copy_fdtable(nfdt, fdt);
+	cur_fdt = files_fdtable(files);
+	if (nr >= cur_fdt->max_fds) {
+		/* Continue as planned */
+		copy_fdtable(new_fdt, cur_fdt);
+		rcu_assign_pointer(files->fdt, new_fdt);
+		if (cur_fdt->max_fds > NR_OPEN_DEFAULT)
+			free_fdtable(cur_fdt);
 	} else {
-		/* Somebody expanded while we dropped file_lock */
-		spin_unlock(&files->file_lock);
-		__free_fdtable(nfdt);
-		spin_lock(&files->file_lock);
-		goto out;
+		/* Somebody else expanded, so undo our attempt */
+		free_fdarr(new_fdt);
+		free_fdset(new_fdt);
+		kfree(new_fdt);
 	}
-	rcu_assign_pointer(files->fdt, nfdt);
-	free_fdtable(fdt);
-out:
-	return error;
+	return 1;
 }
 
 /*
  * Expand files.
- * Return <0 on error; 0 nothing done; 1 files expanded, we may have blocked.
- * Should be called with the files->file_lock spinlock held for write.
+ * This function will expand the file structures, if the requested size exceeds
+ * the current capacity and there is room for expansion.
+ * Return <0 error code on error; 0 when nothing done; 1 when files were
+ * expanded and execution may have blocked.
+ * The files->file_lock should be held on entry, and will be held on exit.
  */
 int expand_files(struct files_struct *files, int nr)
 {
-	int err, expand = 0;
 	struct fdtable *fdt;
 
 	fdt = files_fdtable(files);
-	if (nr >= fdt->max_fdset || nr >= fdt->max_fds) {
-		if (fdt->max_fdset >= NR_OPEN ||
-			fdt->max_fds >= NR_OPEN || nr >= NR_OPEN) {
-			err = -EMFILE;
-			goto out;
-		}
-		expand = 1;
-		if ((err = expand_fdtable(files, nr)))
-			goto out;
-	}
-	err = expand;
-out:
-	return err;
+	/* Do we need to expand? */
+	if (nr < fdt->max_fds)
+		return 0;
+	/* Can we expand? */
+	if (nr >= NR_OPEN)
+		return -EMFILE;
+
+	/* All good, so we try */
+	return expand_fdtable(files, nr);
 }
 
 static void __devinit fdtable_defer_list_init(int cpu)
 {
 	struct fdtable_defer *fddef = &per_cpu(fdtable_defer_list, cpu);
 	spin_lock_init(&fddef->lock);
-	INIT_WORK(&fddef->wq, (void (*)(void *))free_fdtable_work, fddef);
-	init_timer(&fddef->timer);
-	fddef->timer.data = (unsigned long)fddef;
-	fddef->timer.function = fdtable_timer;
+	INIT_WORK(&fddef->wq, free_fdtable_work);
 	fddef->next = NULL;
 }
 
 void __init files_defer_init(void)
 {
 	int i;
-	for_each_cpu(i)
+	for_each_possible_cpu(i)
 		fdtable_defer_list_init(i);
 }