1 files changed, 84 insertions, 171 deletions

diff --git a/fs/file.c b/fs/file.c
index 51aef675470f..857fa49e984c 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -32,46 +32,28 @@ 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;
+                return kmalloc(size, GFP_KERNEL);
+        else
+                return vmalloc(size);
 }
 
-void free_fd_array(struct file **array, int num)
+static inline void free_fdarr(struct fdtable *fdt)
 {
-        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);
+        if (fdt->max_fds <= (PAGE_SIZE / sizeof(struct file *)))
+                kfree(fdt->fd);
         else
-                vfree(array);
+                vfree(fdt->fd);
 }
 
-static void __free_fdtable(struct fdtable *fdt)
+static inline void free_fdset(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 * BITS_PER_BYTE / 2))
+                kfree(fdt->open_fds);
+        else
+                vfree(fdt->open_fds);
 }
 
 static void free_fdtable_work(struct work_struct *work)
@@ -86,41 +68,32 @@ static void free_fdtable_work(struct work_struct *work)
         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) {
+        if (fdt->max_fds <= NR_OPEN_DEFAULT) {
                 /*
-                 * 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.
+                 * This fdtable is embedded in the files structure and that
+                 * structure itself is getting destroyed.
                  */
-                kmem_cache_free(files_cachep, fdt->free_files);
+                kmem_cache_free(files_cachep,
+                                container_of(fdt, struct files_struct, fdtab));
                 return;
         }
-        if (fdt->max_fdset <= EMBEDDED_FD_SET_SIZE &&
-                fdt->max_fds <= NR_OPEN_DEFAULT) {
-                /*
-                 * The fdtable was embedded
-                 */
-                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);
@@ -134,136 +107,74 @@ static void free_fdtable_rcu(struct rcu_head *rcu)
         }
 }
 
-void free_fdtable(struct fdtable *fdt)
-{
-        if (fdt->free_files ||
-                fdt->max_fdset > EMBEDDED_FD_SET_SIZE ||
-                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 */
-
-        i = fdt->max_fdset / (sizeof(unsigned long) * 8);
-        count = (nfdt->max_fdset - fdt->max_fdset) / 8;
+        unsigned int cpy, set;
 
-        /*
-         * 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);
-        }
-
-        /* 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 *));
-        }
-}
-
-/*
- * Allocate an fdset array, using kmalloc or vmalloc.
- * Note: the array isn't cleared at allocation time.
- */
-fd_set * alloc_fdset(int num)
-{
-        fd_set *new_fdset;
-        int size = num / 8;
+        BUG_ON(nfdt->max_fds < ofdt->max_fds);
+        if (ofdt->max_fds == 0)
+                return;
 
-        if (size <= PAGE_SIZE)
-                new_fdset = (fd_set *) kmalloc(size, GFP_KERNEL);
-        else
-                new_fdset = (fd_set *) vmalloc(size);
-        return new_fdset;
+        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);
 }
 
-void free_fdset(fd_set *array, int num)
+static struct fdtable * alloc_fdtable(unsigned int nr)
 {
-        if (num <= EMBEDDED_FD_SET_SIZE) /* Don't free an embedded fdset */
-                return;
-        else if (num <= 8 * 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 = kzalloc(sizeof(*fdt), GFP_KERNEL);
+        fdt = kmalloc(sizeof(struct fdtable), GFP_KERNEL);
         if (!fdt)
-                goto out;
-
-        nfds = max_t(int, 8 * L1_CACHE_BYTES, roundup_pow_of_two(nr + 1));
-        if (nfds > NR_OPEN)
-                nfds = NR_OPEN;
+                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;
 
-        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;
-
-        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:
-        free_fdset(new_openset, nfds);
-        free_fdset(new_execset, nfds);
+
+out_arr:
+        free_fdarr(fdt);
+out_fdt:
         kfree(fdt);
+out:
         return NULL;
 }
 
@@ -290,14 +201,17 @@ static int expand_fdtable(struct files_struct *files, int nr)
          * we dropped the lock
          */
         cur_fdt = files_fdtable(files);
-        if (nr >= cur_fdt->max_fds || nr >= cur_fdt->max_fdset) {
+        if (nr >= cur_fdt->max_fds) {
                 /* Continue as planned */
                 copy_fdtable(new_fdt, cur_fdt);
                 rcu_assign_pointer(files->fdt, new_fdt);
-                free_fdtable(cur_fdt);
+                if (cur_fdt->max_fds > NR_OPEN_DEFAULT)
+                        call_rcu(&cur_fdt->rcu, free_fdtable_rcu);
         } else {
                 /* Somebody else expanded, so undo our attempt */
-                __free_fdtable(new_fdt);
+                free_fdarr(new_fdt);
+                free_fdset(new_fdt);
+                kfree(new_fdt);
         }
         return 1;
 }
@@ -316,11 +230,10 @@ int expand_files(struct files_struct *files, int nr)
 
         fdt = files_fdtable(files);
         /* Do we need to expand? */
-        if (nr < fdt->max_fdset && nr < fdt->max_fds)
+        if (nr < fdt->max_fds)
                 return 0;
         /* Can we expand? */
-        if (fdt->max_fdset >= NR_OPEN || fdt->max_fds >= NR_OPEN ||
-            nr >= NR_OPEN)
+        if (nr >= NR_OPEN)
                 return -EMFILE;
 
         /* All good, so we try */