[PATCH] files: files struct with RCU
Patch to eliminate struct files_struct.file_lock spinlock on the reader side and use rcu refcounting rcuref_xxx api for the f_count refcounter. The updates to the fdtable are done by allocating a new fdtable structure and setting files->fdt to point to the new structure. The fdtable structure is protected by RCU thereby allowing lock-free lookup. For fd arrays/sets that are vmalloced, we use keventd to free them since RCU callbacks can't sleep. A global list of fdtable to be freed is not scalable, so we use a per-cpu list. If keventd is already handling the current cpu's work, we use a timer to defer queueing of that work. Since the last publication, this patch has been re-written to avoid using explicit memory barriers and use rcu_assign_pointer(), rcu_dereference() premitives instead. This required that the fd information is kept in a separate structure (fdtable) and updated atomically. Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
parent
6e72ad2c58
commit
ab2af1f500
10 changed files with 354 additions and 175 deletions
3
fs/aio.c
3
fs/aio.c
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@ -29,6 +29,7 @@
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#include <linux/highmem.h>
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#include <linux/highmem.h>
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#include <linux/workqueue.h>
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#include <linux/workqueue.h>
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#include <linux/security.h>
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#include <linux/security.h>
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#include <linux/rcuref.h>
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#include <asm/kmap_types.h>
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#include <asm/kmap_types.h>
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#include <asm/uaccess.h>
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#include <asm/uaccess.h>
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@ -499,7 +500,7 @@ static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
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/* Must be done under the lock to serialise against cancellation.
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/* Must be done under the lock to serialise against cancellation.
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* Call this aio_fput as it duplicates fput via the fput_work.
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* Call this aio_fput as it duplicates fput via the fput_work.
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*/
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*/
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if (unlikely(atomic_dec_and_test(&req->ki_filp->f_count))) {
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if (unlikely(rcuref_dec_and_test(&req->ki_filp->f_count))) {
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get_ioctx(ctx);
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get_ioctx(ctx);
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spin_lock(&fput_lock);
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spin_lock(&fput_lock);
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list_add(&req->ki_list, &fput_head);
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list_add(&req->ki_list, &fput_head);
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13
fs/fcntl.c
13
fs/fcntl.c
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@ -16,6 +16,7 @@
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#include <linux/security.h>
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#include <linux/security.h>
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#include <linux/ptrace.h>
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#include <linux/ptrace.h>
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#include <linux/signal.h>
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#include <linux/signal.h>
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#include <linux/rcupdate.h>
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#include <asm/poll.h>
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#include <asm/poll.h>
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#include <asm/siginfo.h>
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#include <asm/siginfo.h>
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@ -64,8 +65,8 @@ static int locate_fd(struct files_struct *files,
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if (orig_start >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
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if (orig_start >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
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goto out;
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goto out;
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fdt = files_fdtable(files);
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repeat:
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repeat:
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fdt = files_fdtable(files);
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/*
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/*
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* Someone might have closed fd's in the range
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* Someone might have closed fd's in the range
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* orig_start..fdt->next_fd
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* orig_start..fdt->next_fd
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@ -95,9 +96,15 @@ repeat:
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if (error)
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if (error)
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goto repeat;
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goto repeat;
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/*
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* We reacquired files_lock, so we are safe as long as
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* we reacquire the fdtable pointer and use it while holding
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* the lock, no one can free it during that time.
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*/
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fdt = files_fdtable(files);
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if (start <= fdt->next_fd)
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if (start <= fdt->next_fd)
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fdt->next_fd = newfd + 1;
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fdt->next_fd = newfd + 1;
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error = newfd;
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error = newfd;
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out:
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out:
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@ -163,7 +170,7 @@ asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
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if (!tofree && FD_ISSET(newfd, fdt->open_fds))
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if (!tofree && FD_ISSET(newfd, fdt->open_fds))
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goto out_fput;
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goto out_fput;
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fdt->fd[newfd] = file;
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rcu_assign_pointer(fdt->fd[newfd], file);
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FD_SET(newfd, fdt->open_fds);
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FD_SET(newfd, fdt->open_fds);
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FD_CLR(newfd, fdt->close_on_exec);
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FD_CLR(newfd, fdt->close_on_exec);
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spin_unlock(&files->file_lock);
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spin_unlock(&files->file_lock);
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407
fs/file.c
407
fs/file.c
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@ -13,6 +13,25 @@
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#include <linux/vmalloc.h>
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#include <linux/vmalloc.h>
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#include <linux/file.h>
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#include <linux/file.h>
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#include <linux/bitops.h>
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#include <linux/bitops.h>
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#include <linux/interrupt.h>
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#include <linux/spinlock.h>
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#include <linux/rcupdate.h>
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#include <linux/workqueue.h>
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struct fdtable_defer {
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spinlock_t lock;
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struct work_struct wq;
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struct timer_list timer;
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struct fdtable *next;
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};
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/*
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* We use this list to defer free fdtables that have vmalloced
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* sets/arrays. By keeping a per-cpu list, we avoid having to embed
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* the work_struct in fdtable itself which avoids a 64 byte (i386) increase in
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* this per-task structure.
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*/
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static DEFINE_PER_CPU(struct fdtable_defer, fdtable_defer_list);
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/*
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/*
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@ -48,85 +67,143 @@ void free_fd_array(struct file **array, int num)
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vfree(array);
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vfree(array);
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}
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}
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/*
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static void __free_fdtable(struct fdtable *fdt)
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* Expand the fd array in the files_struct. Called with the files
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{
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* spinlock held for write.
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int fdset_size, fdarray_size;
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*/
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fdset_size = fdt->max_fdset / 8;
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static int expand_fd_array(struct files_struct *files, int nr)
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fdarray_size = fdt->max_fds * sizeof(struct file *);
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__releases(files->file_lock)
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free_fdset(fdt->open_fds, fdset_size);
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__acquires(files->file_lock)
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free_fdset(fdt->close_on_exec, fdset_size);
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free_fd_array(fdt->fd, fdarray_size);
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kfree(fdt);
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}
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static void fdtable_timer(unsigned long data)
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{
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struct fdtable_defer *fddef = (struct fdtable_defer *)data;
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spin_lock(&fddef->lock);
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/*
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* If someone already emptied the queue return.
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*/
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if (!fddef->next)
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goto out;
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if (!schedule_work(&fddef->wq))
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mod_timer(&fddef->timer, 5);
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out:
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spin_unlock(&fddef->lock);
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}
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static void free_fdtable_work(struct fdtable_defer *f)
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{
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{
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struct file **new_fds;
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int error, nfds;
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struct fdtable *fdt;
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struct fdtable *fdt;
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spin_lock_bh(&f->lock);
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error = -EMFILE;
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fdt = f->next;
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fdt = files_fdtable(files);
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f->next = NULL;
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if (fdt->max_fds >= NR_OPEN || nr >= NR_OPEN)
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spin_unlock_bh(&f->lock);
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goto out;
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while(fdt) {
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struct fdtable *next = fdt->next;
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nfds = fdt->max_fds;
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__free_fdtable(fdt);
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spin_unlock(&files->file_lock);
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fdt = next;
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/*
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* Expand to the max in easy steps, and keep expanding it until
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* we have enough for the requested fd array size.
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*/
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do {
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#if NR_OPEN_DEFAULT < 256
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if (nfds < 256)
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nfds = 256;
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else
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#endif
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if (nfds < (PAGE_SIZE / sizeof(struct file *)))
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nfds = PAGE_SIZE / sizeof(struct file *);
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else {
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nfds = nfds * 2;
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if (nfds > NR_OPEN)
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nfds = NR_OPEN;
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}
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} while (nfds <= nr);
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error = -ENOMEM;
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new_fds = alloc_fd_array(nfds);
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spin_lock(&files->file_lock);
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if (!new_fds)
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goto out;
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/* Copy the existing array and install the new pointer */
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fdt = files_fdtable(files);
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if (nfds > fdt->max_fds) {
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struct file **old_fds;
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int i;
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old_fds = xchg(&fdt->fd, new_fds);
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i = xchg(&fdt->max_fds, nfds);
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/* Don't copy/clear the array if we are creating a new
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fd array for fork() */
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if (i) {
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memcpy(new_fds, old_fds, i * sizeof(struct file *));
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/* clear the remainder of the array */
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memset(&new_fds[i], 0,
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(nfds-i) * sizeof(struct file *));
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spin_unlock(&files->file_lock);
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free_fd_array(old_fds, i);
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spin_lock(&files->file_lock);
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}
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} else {
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/* Somebody expanded the array while we slept ... */
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spin_unlock(&files->file_lock);
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free_fd_array(new_fds, nfds);
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spin_lock(&files->file_lock);
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}
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}
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error = 0;
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}
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out:
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return error;
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static void free_fdtable_rcu(struct rcu_head *rcu)
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{
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struct fdtable *fdt = container_of(rcu, struct fdtable, rcu);
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int fdset_size, fdarray_size;
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struct fdtable_defer *fddef;
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BUG_ON(!fdt);
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fdset_size = fdt->max_fdset / 8;
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fdarray_size = fdt->max_fds * sizeof(struct file *);
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if (fdt->free_files) {
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/*
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* The this fdtable was embedded in the files structure
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* and the files structure itself was getting destroyed.
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* It is now safe to free the files structure.
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*/
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kmem_cache_free(files_cachep, fdt->free_files);
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return;
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}
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if (fdt->max_fdset <= __FD_SETSIZE && fdt->max_fds <= NR_OPEN_DEFAULT) {
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/*
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* The fdtable was embedded
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*/
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return;
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}
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if (fdset_size <= PAGE_SIZE && fdarray_size <= PAGE_SIZE) {
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kfree(fdt->open_fds);
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kfree(fdt->close_on_exec);
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kfree(fdt->fd);
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kfree(fdt);
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} else {
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fddef = &get_cpu_var(fdtable_defer_list);
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spin_lock(&fddef->lock);
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fdt->next = fddef->next;
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fddef->next = fdt;
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/*
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* vmallocs are handled from the workqueue context.
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* If the per-cpu workqueue is running, then we
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* defer work scheduling through a timer.
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*/
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if (!schedule_work(&fddef->wq))
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mod_timer(&fddef->timer, 5);
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spin_unlock(&fddef->lock);
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put_cpu_var(fdtable_defer_list);
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}
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}
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void free_fdtable(struct fdtable *fdt)
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{
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if (fdt->free_files || fdt->max_fdset > __FD_SETSIZE ||
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fdt->max_fds > NR_OPEN_DEFAULT)
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call_rcu(&fdt->rcu, free_fdtable_rcu);
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}
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/*
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* Expand the fdset in the files_struct. Called with the files spinlock
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* held for write.
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*/
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static void copy_fdtable(struct fdtable *nfdt, struct fdtable *fdt)
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{
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int i;
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int count;
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BUG_ON(nfdt->max_fdset < fdt->max_fdset);
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BUG_ON(nfdt->max_fds < fdt->max_fds);
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/* Copy the existing tables and install the new pointers */
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i = fdt->max_fdset / (sizeof(unsigned long) * 8);
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count = (nfdt->max_fdset - fdt->max_fdset) / 8;
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/*
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* Don't copy the entire array if the current fdset is
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* not yet initialised.
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*/
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if (i) {
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memcpy (nfdt->open_fds, fdt->open_fds,
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fdt->max_fdset/8);
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memcpy (nfdt->close_on_exec, fdt->close_on_exec,
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fdt->max_fdset/8);
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memset (&nfdt->open_fds->fds_bits[i], 0, count);
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memset (&nfdt->close_on_exec->fds_bits[i], 0, count);
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}
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/* Don't copy/clear the array if we are creating a new
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fd array for fork() */
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if (fdt->max_fds) {
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memcpy(nfdt->fd, fdt->fd,
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fdt->max_fds * sizeof(struct file *));
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/* clear the remainder of the array */
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memset(&nfdt->fd[fdt->max_fds], 0,
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(nfdt->max_fds - fdt->max_fds) *
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sizeof(struct file *));
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}
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nfdt->next_fd = fdt->next_fd;
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}
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}
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/*
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/*
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|
@ -157,28 +234,21 @@ void free_fdset(fd_set *array, int num)
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vfree(array);
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vfree(array);
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}
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}
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/*
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static struct fdtable *alloc_fdtable(int nr)
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* Expand the fdset in the files_struct. Called with the files spinlock
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* held for write.
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*/
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static int expand_fdset(struct files_struct *files, int nr)
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__releases(file->file_lock)
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__acquires(file->file_lock)
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{
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{
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fd_set *new_openset = NULL, *new_execset = NULL;
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struct fdtable *fdt = NULL;
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int error, nfds = 0;
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int nfds = 0;
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struct fdtable *fdt;
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fd_set *new_openset = NULL, *new_execset = NULL;
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struct file **new_fds;
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error = -EMFILE;
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fdt = kmalloc(sizeof(*fdt), GFP_KERNEL);
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fdt = files_fdtable(files);
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if (!fdt)
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if (fdt->max_fdset >= NR_OPEN || nr >= NR_OPEN)
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goto out;
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goto out;
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memset(fdt, 0, sizeof(*fdt));
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nfds = fdt->max_fdset;
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nfds = __FD_SETSIZE;
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spin_unlock(&files->file_lock);
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/* Expand to the max in easy steps */
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|
do {
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/* Expand to the max in easy steps */
|
|
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do {
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if (nfds < (PAGE_SIZE * 8))
|
if (nfds < (PAGE_SIZE * 8))
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nfds = PAGE_SIZE * 8;
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nfds = PAGE_SIZE * 8;
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else {
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else {
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|
@ -188,50 +258,88 @@ static int expand_fdset(struct files_struct *files, int nr)
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}
|
}
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} while (nfds <= nr);
|
} while (nfds <= nr);
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error = -ENOMEM;
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new_openset = alloc_fdset(nfds);
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new_openset = alloc_fdset(nfds);
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new_execset = alloc_fdset(nfds);
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new_execset = alloc_fdset(nfds);
|
if (!new_openset || !new_execset)
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spin_lock(&files->file_lock);
|
goto out;
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if (!new_openset || !new_execset)
|
fdt->open_fds = new_openset;
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|
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 out;
|
goto out;
|
||||||
|
fdt->fd = new_fds;
|
||||||
error = 0;
|
fdt->max_fds = nfds;
|
||||||
|
fdt->free_files = NULL;
|
||||||
/* Copy the existing tables and install the new pointers */
|
return fdt;
|
||||||
fdt = files_fdtable(files);
|
|
||||||
if (nfds > fdt->max_fdset) {
|
|
||||||
int i = fdt->max_fdset / (sizeof(unsigned long) * 8);
|
|
||||||
int count = (nfds - fdt->max_fdset) / 8;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* Don't copy the entire array if the current fdset is
|
|
||||||
* not yet initialised.
|
|
||||||
*/
|
|
||||||
if (i) {
|
|
||||||
memcpy (new_openset, fdt->open_fds, fdt->max_fdset/8);
|
|
||||||
memcpy (new_execset, fdt->close_on_exec, fdt->max_fdset/8);
|
|
||||||
memset (&new_openset->fds_bits[i], 0, count);
|
|
||||||
memset (&new_execset->fds_bits[i], 0, count);
|
|
||||||
}
|
|
||||||
|
|
||||||
nfds = xchg(&fdt->max_fdset, nfds);
|
|
||||||
new_openset = xchg(&fdt->open_fds, new_openset);
|
|
||||||
new_execset = xchg(&fdt->close_on_exec, new_execset);
|
|
||||||
spin_unlock(&files->file_lock);
|
|
||||||
free_fdset (new_openset, nfds);
|
|
||||||
free_fdset (new_execset, nfds);
|
|
||||||
spin_lock(&files->file_lock);
|
|
||||||
return 0;
|
|
||||||
}
|
|
||||||
/* Somebody expanded the array while we slept ... */
|
|
||||||
|
|
||||||
out:
|
out:
|
||||||
|
if (new_openset)
|
||||||
|
free_fdset(new_openset, nfds);
|
||||||
|
if (new_execset)
|
||||||
|
free_fdset(new_execset, nfds);
|
||||||
|
kfree(fdt);
|
||||||
|
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.
|
||||||
|
*/
|
||||||
|
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;
|
||||||
|
|
||||||
spin_unlock(&files->file_lock);
|
spin_unlock(&files->file_lock);
|
||||||
if (new_openset)
|
nfdt = alloc_fdtable(nr);
|
||||||
free_fdset(new_openset, nfds);
|
if (!nfdt) {
|
||||||
if (new_execset)
|
error = -ENOMEM;
|
||||||
free_fdset(new_execset, nfds);
|
spin_lock(&files->file_lock);
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
|
||||||
spin_lock(&files->file_lock);
|
spin_lock(&files->file_lock);
|
||||||
|
fdt = files_fdtable(files);
|
||||||
|
/*
|
||||||
|
* 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);
|
||||||
|
} else {
|
||||||
|
/* Somebody expanded while we dropped file_lock */
|
||||||
|
spin_unlock(&files->file_lock);
|
||||||
|
__free_fdtable(nfdt);
|
||||||
|
spin_lock(&files->file_lock);
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
rcu_assign_pointer(files->fdt, nfdt);
|
||||||
|
free_fdtable(fdt);
|
||||||
|
out:
|
||||||
return error;
|
return error;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -246,17 +354,36 @@ int expand_files(struct files_struct *files, int nr)
|
||||||
struct fdtable *fdt;
|
struct fdtable *fdt;
|
||||||
|
|
||||||
fdt = files_fdtable(files);
|
fdt = files_fdtable(files);
|
||||||
if (nr >= fdt->max_fdset) {
|
if (nr >= fdt->max_fdset || nr >= fdt->max_fds) {
|
||||||
expand = 1;
|
if (fdt->max_fdset >= NR_OPEN ||
|
||||||
if ((err = expand_fdset(files, nr)))
|
fdt->max_fds >= NR_OPEN || nr >= NR_OPEN) {
|
||||||
|
err = -EMFILE;
|
||||||
goto out;
|
goto out;
|
||||||
}
|
}
|
||||||
if (nr >= fdt->max_fds) {
|
|
||||||
expand = 1;
|
expand = 1;
|
||||||
if ((err = expand_fd_array(files, nr)))
|
if ((err = expand_fdtable(files, nr)))
|
||||||
goto out;
|
goto out;
|
||||||
}
|
}
|
||||||
err = expand;
|
err = expand;
|
||||||
out:
|
out:
|
||||||
return err;
|
return err;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
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;
|
||||||
|
fddef->next = NULL;
|
||||||
|
}
|
||||||
|
|
||||||
|
void __init files_defer_init(void)
|
||||||
|
{
|
||||||
|
int i;
|
||||||
|
/* Really early - can't use for_each_cpu */
|
||||||
|
for (i = 0; i < NR_CPUS; i++)
|
||||||
|
fdtable_defer_list_init(i);
|
||||||
|
}
|
||||||
|
|
|
@ -14,6 +14,7 @@
|
||||||
#include <linux/fs.h>
|
#include <linux/fs.h>
|
||||||
#include <linux/security.h>
|
#include <linux/security.h>
|
||||||
#include <linux/eventpoll.h>
|
#include <linux/eventpoll.h>
|
||||||
|
#include <linux/rcupdate.h>
|
||||||
#include <linux/mount.h>
|
#include <linux/mount.h>
|
||||||
#include <linux/cdev.h>
|
#include <linux/cdev.h>
|
||||||
#include <linux/fsnotify.h>
|
#include <linux/fsnotify.h>
|
||||||
|
@ -53,9 +54,15 @@ void filp_dtor(void * objp, struct kmem_cache_s *cachep, unsigned long dflags)
|
||||||
spin_unlock_irqrestore(&filp_count_lock, flags);
|
spin_unlock_irqrestore(&filp_count_lock, flags);
|
||||||
}
|
}
|
||||||
|
|
||||||
|
static inline void file_free_rcu(struct rcu_head *head)
|
||||||
|
{
|
||||||
|
struct file *f = container_of(head, struct file, f_rcuhead);
|
||||||
|
kmem_cache_free(filp_cachep, f);
|
||||||
|
}
|
||||||
|
|
||||||
static inline void file_free(struct file *f)
|
static inline void file_free(struct file *f)
|
||||||
{
|
{
|
||||||
kmem_cache_free(filp_cachep, f);
|
call_rcu(&f->f_rcuhead, file_free_rcu);
|
||||||
}
|
}
|
||||||
|
|
||||||
/* Find an unused file structure and return a pointer to it.
|
/* Find an unused file structure and return a pointer to it.
|
||||||
|
@ -110,7 +117,7 @@ EXPORT_SYMBOL(get_empty_filp);
|
||||||
|
|
||||||
void fastcall fput(struct file *file)
|
void fastcall fput(struct file *file)
|
||||||
{
|
{
|
||||||
if (atomic_dec_and_test(&file->f_count))
|
if (rcuref_dec_and_test(&file->f_count))
|
||||||
__fput(file);
|
__fput(file);
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -156,11 +163,17 @@ struct file fastcall *fget(unsigned int fd)
|
||||||
struct file *file;
|
struct file *file;
|
||||||
struct files_struct *files = current->files;
|
struct files_struct *files = current->files;
|
||||||
|
|
||||||
spin_lock(&files->file_lock);
|
rcu_read_lock();
|
||||||
file = fcheck_files(files, fd);
|
file = fcheck_files(files, fd);
|
||||||
if (file)
|
if (file) {
|
||||||
get_file(file);
|
if (!rcuref_inc_lf(&file->f_count)) {
|
||||||
spin_unlock(&files->file_lock);
|
/* File object ref couldn't be taken */
|
||||||
|
rcu_read_unlock();
|
||||||
|
return NULL;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
rcu_read_unlock();
|
||||||
|
|
||||||
return file;
|
return file;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -182,21 +195,25 @@ struct file fastcall *fget_light(unsigned int fd, int *fput_needed)
|
||||||
if (likely((atomic_read(&files->count) == 1))) {
|
if (likely((atomic_read(&files->count) == 1))) {
|
||||||
file = fcheck_files(files, fd);
|
file = fcheck_files(files, fd);
|
||||||
} else {
|
} else {
|
||||||
spin_lock(&files->file_lock);
|
rcu_read_lock();
|
||||||
file = fcheck_files(files, fd);
|
file = fcheck_files(files, fd);
|
||||||
if (file) {
|
if (file) {
|
||||||
get_file(file);
|
if (rcuref_inc_lf(&file->f_count))
|
||||||
*fput_needed = 1;
|
*fput_needed = 1;
|
||||||
|
else
|
||||||
|
/* Didn't get the reference, someone's freed */
|
||||||
|
file = NULL;
|
||||||
}
|
}
|
||||||
spin_unlock(&files->file_lock);
|
rcu_read_unlock();
|
||||||
}
|
}
|
||||||
|
|
||||||
return file;
|
return file;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
||||||
void put_filp(struct file *file)
|
void put_filp(struct file *file)
|
||||||
{
|
{
|
||||||
if (atomic_dec_and_test(&file->f_count)) {
|
if (rcuref_dec_and_test(&file->f_count)) {
|
||||||
security_file_free(file);
|
security_file_free(file);
|
||||||
file_kill(file);
|
file_kill(file);
|
||||||
file_free(file);
|
file_free(file);
|
||||||
|
@ -257,4 +274,5 @@ void __init files_init(unsigned long mempages)
|
||||||
files_stat.max_files = n;
|
files_stat.max_files = n;
|
||||||
if (files_stat.max_files < NR_FILE)
|
if (files_stat.max_files < NR_FILE)
|
||||||
files_stat.max_files = NR_FILE;
|
files_stat.max_files = NR_FILE;
|
||||||
|
files_defer_init();
|
||||||
}
|
}
|
||||||
|
|
|
@ -24,6 +24,7 @@
|
||||||
#include <linux/personality.h>
|
#include <linux/personality.h>
|
||||||
#include <linux/pagemap.h>
|
#include <linux/pagemap.h>
|
||||||
#include <linux/syscalls.h>
|
#include <linux/syscalls.h>
|
||||||
|
#include <linux/rcupdate.h>
|
||||||
|
|
||||||
#include <asm/unistd.h>
|
#include <asm/unistd.h>
|
||||||
|
|
||||||
|
@ -930,9 +931,8 @@ void fastcall fd_install(unsigned int fd, struct file * file)
|
||||||
struct fdtable *fdt;
|
struct fdtable *fdt;
|
||||||
spin_lock(&files->file_lock);
|
spin_lock(&files->file_lock);
|
||||||
fdt = files_fdtable(files);
|
fdt = files_fdtable(files);
|
||||||
if (unlikely(fdt->fd[fd] != NULL))
|
BUG_ON(fdt->fd[fd] != NULL);
|
||||||
BUG();
|
rcu_assign_pointer(fdt->fd[fd], file);
|
||||||
fdt->fd[fd] = file;
|
|
||||||
spin_unlock(&files->file_lock);
|
spin_unlock(&files->file_lock);
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -1024,7 +1024,7 @@ asmlinkage long sys_close(unsigned int fd)
|
||||||
filp = fdt->fd[fd];
|
filp = fdt->fd[fd];
|
||||||
if (!filp)
|
if (!filp)
|
||||||
goto out_unlock;
|
goto out_unlock;
|
||||||
fdt->fd[fd] = NULL;
|
rcu_assign_pointer(fdt->fd[fd], NULL);
|
||||||
FD_CLR(fd, fdt->close_on_exec);
|
FD_CLR(fd, fdt->close_on_exec);
|
||||||
__put_unused_fd(files, fd);
|
__put_unused_fd(files, fd);
|
||||||
spin_unlock(&files->file_lock);
|
spin_unlock(&files->file_lock);
|
||||||
|
|
|
@ -9,6 +9,7 @@
|
||||||
#include <linux/posix_types.h>
|
#include <linux/posix_types.h>
|
||||||
#include <linux/compiler.h>
|
#include <linux/compiler.h>
|
||||||
#include <linux/spinlock.h>
|
#include <linux/spinlock.h>
|
||||||
|
#include <linux/rcupdate.h>
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* The default fd array needs to be at least BITS_PER_LONG,
|
* The default fd array needs to be at least BITS_PER_LONG,
|
||||||
|
@ -23,6 +24,9 @@ struct fdtable {
|
||||||
struct file ** fd; /* current fd array */
|
struct file ** fd; /* current fd array */
|
||||||
fd_set *close_on_exec;
|
fd_set *close_on_exec;
|
||||||
fd_set *open_fds;
|
fd_set *open_fds;
|
||||||
|
struct rcu_head rcu;
|
||||||
|
struct files_struct *free_files;
|
||||||
|
struct fdtable *next;
|
||||||
};
|
};
|
||||||
|
|
||||||
/*
|
/*
|
||||||
|
@ -31,13 +35,14 @@ struct fdtable {
|
||||||
struct files_struct {
|
struct files_struct {
|
||||||
atomic_t count;
|
atomic_t count;
|
||||||
spinlock_t file_lock; /* Protects all the below members. Nests inside tsk->alloc_lock */
|
spinlock_t file_lock; /* Protects all the below members. Nests inside tsk->alloc_lock */
|
||||||
|
struct fdtable *fdt;
|
||||||
struct fdtable fdtab;
|
struct fdtable fdtab;
|
||||||
fd_set close_on_exec_init;
|
fd_set close_on_exec_init;
|
||||||
fd_set open_fds_init;
|
fd_set open_fds_init;
|
||||||
struct file * fd_array[NR_OPEN_DEFAULT];
|
struct file * fd_array[NR_OPEN_DEFAULT];
|
||||||
};
|
};
|
||||||
|
|
||||||
#define files_fdtable(files) (&(files)->fdtab)
|
#define files_fdtable(files) (rcu_dereference((files)->fdt))
|
||||||
|
|
||||||
extern void FASTCALL(__fput(struct file *));
|
extern void FASTCALL(__fput(struct file *));
|
||||||
extern void FASTCALL(fput(struct file *));
|
extern void FASTCALL(fput(struct file *));
|
||||||
|
@ -65,6 +70,8 @@ extern fd_set *alloc_fdset(int);
|
||||||
extern void free_fdset(fd_set *, int);
|
extern void free_fdset(fd_set *, int);
|
||||||
|
|
||||||
extern int expand_files(struct files_struct *, int nr);
|
extern int expand_files(struct files_struct *, int nr);
|
||||||
|
extern void free_fdtable(struct fdtable *fdt);
|
||||||
|
extern void __init files_defer_init(void);
|
||||||
|
|
||||||
static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd)
|
static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd)
|
||||||
{
|
{
|
||||||
|
@ -72,7 +79,7 @@ static inline struct file * fcheck_files(struct files_struct *files, unsigned in
|
||||||
struct fdtable *fdt = files_fdtable(files);
|
struct fdtable *fdt = files_fdtable(files);
|
||||||
|
|
||||||
if (fd < fdt->max_fds)
|
if (fd < fdt->max_fds)
|
||||||
file = fdt->fd[fd];
|
file = rcu_dereference(fdt->fd[fd]);
|
||||||
return file;
|
return file;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
|
@ -9,6 +9,7 @@
|
||||||
#include <linux/config.h>
|
#include <linux/config.h>
|
||||||
#include <linux/limits.h>
|
#include <linux/limits.h>
|
||||||
#include <linux/ioctl.h>
|
#include <linux/ioctl.h>
|
||||||
|
#include <linux/rcuref.h>
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* It's silly to have NR_OPEN bigger than NR_FILE, but you can change
|
* It's silly to have NR_OPEN bigger than NR_FILE, but you can change
|
||||||
|
@ -597,12 +598,13 @@ struct file {
|
||||||
spinlock_t f_ep_lock;
|
spinlock_t f_ep_lock;
|
||||||
#endif /* #ifdef CONFIG_EPOLL */
|
#endif /* #ifdef CONFIG_EPOLL */
|
||||||
struct address_space *f_mapping;
|
struct address_space *f_mapping;
|
||||||
|
struct rcu_head f_rcuhead;
|
||||||
};
|
};
|
||||||
extern spinlock_t files_lock;
|
extern spinlock_t files_lock;
|
||||||
#define file_list_lock() spin_lock(&files_lock);
|
#define file_list_lock() spin_lock(&files_lock);
|
||||||
#define file_list_unlock() spin_unlock(&files_lock);
|
#define file_list_unlock() spin_unlock(&files_lock);
|
||||||
|
|
||||||
#define get_file(x) atomic_inc(&(x)->f_count)
|
#define get_file(x) rcuref_inc(&(x)->f_count)
|
||||||
#define file_count(x) atomic_read(&(x)->f_count)
|
#define file_count(x) atomic_read(&(x)->f_count)
|
||||||
|
|
||||||
#define MAX_NON_LFS ((1UL<<31) - 1)
|
#define MAX_NON_LFS ((1UL<<31) - 1)
|
||||||
|
|
|
@ -2,6 +2,7 @@
|
||||||
#define _LINUX__INIT_TASK_H
|
#define _LINUX__INIT_TASK_H
|
||||||
|
|
||||||
#include <linux/file.h>
|
#include <linux/file.h>
|
||||||
|
#include <linux/rcupdate.h>
|
||||||
|
|
||||||
#define INIT_FDTABLE \
|
#define INIT_FDTABLE \
|
||||||
{ \
|
{ \
|
||||||
|
@ -11,12 +12,16 @@
|
||||||
.fd = &init_files.fd_array[0], \
|
.fd = &init_files.fd_array[0], \
|
||||||
.close_on_exec = &init_files.close_on_exec_init, \
|
.close_on_exec = &init_files.close_on_exec_init, \
|
||||||
.open_fds = &init_files.open_fds_init, \
|
.open_fds = &init_files.open_fds_init, \
|
||||||
|
.rcu = RCU_HEAD_INIT, \
|
||||||
|
.free_files = NULL, \
|
||||||
|
.next = NULL, \
|
||||||
}
|
}
|
||||||
|
|
||||||
#define INIT_FILES \
|
#define INIT_FILES \
|
||||||
{ \
|
{ \
|
||||||
.count = ATOMIC_INIT(1), \
|
.count = ATOMIC_INIT(1), \
|
||||||
.file_lock = SPIN_LOCK_UNLOCKED, \
|
.file_lock = SPIN_LOCK_UNLOCKED, \
|
||||||
|
.fdt = &init_files.fdtab, \
|
||||||
.fdtab = INIT_FDTABLE, \
|
.fdtab = INIT_FDTABLE, \
|
||||||
.close_on_exec_init = { { 0, } }, \
|
.close_on_exec_init = { { 0, } }, \
|
||||||
.open_fds_init = { { 0, } }, \
|
.open_fds_init = { { 0, } }, \
|
||||||
|
|
|
@ -411,15 +411,16 @@ void fastcall put_files_struct(struct files_struct *files)
|
||||||
close_files(files);
|
close_files(files);
|
||||||
/*
|
/*
|
||||||
* Free the fd and fdset arrays if we expanded them.
|
* Free the fd and fdset arrays if we expanded them.
|
||||||
|
* If the fdtable was embedded, pass files for freeing
|
||||||
|
* at the end of the RCU grace period. Otherwise,
|
||||||
|
* you can free files immediately.
|
||||||
*/
|
*/
|
||||||
fdt = files_fdtable(files);
|
fdt = files_fdtable(files);
|
||||||
if (fdt->fd != &files->fd_array[0])
|
if (fdt == &files->fdtab)
|
||||||
free_fd_array(fdt->fd, fdt->max_fds);
|
fdt->free_files = files;
|
||||||
if (fdt->max_fdset > __FD_SETSIZE) {
|
else
|
||||||
free_fdset(fdt->open_fds, fdt->max_fdset);
|
kmem_cache_free(files_cachep, files);
|
||||||
free_fdset(fdt->close_on_exec, fdt->max_fdset);
|
free_fdtable(fdt);
|
||||||
}
|
|
||||||
kmem_cache_free(files_cachep, files);
|
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
|
@ -35,6 +35,7 @@
|
||||||
#include <linux/syscalls.h>
|
#include <linux/syscalls.h>
|
||||||
#include <linux/jiffies.h>
|
#include <linux/jiffies.h>
|
||||||
#include <linux/futex.h>
|
#include <linux/futex.h>
|
||||||
|
#include <linux/rcupdate.h>
|
||||||
#include <linux/ptrace.h>
|
#include <linux/ptrace.h>
|
||||||
#include <linux/mount.h>
|
#include <linux/mount.h>
|
||||||
#include <linux/audit.h>
|
#include <linux/audit.h>
|
||||||
|
@ -565,13 +566,12 @@ static inline int copy_fs(unsigned long clone_flags, struct task_struct * tsk)
|
||||||
return 0;
|
return 0;
|
||||||
}
|
}
|
||||||
|
|
||||||
static int count_open_files(struct files_struct *files, int size)
|
static int count_open_files(struct fdtable *fdt)
|
||||||
{
|
{
|
||||||
|
int size = fdt->max_fdset;
|
||||||
int i;
|
int i;
|
||||||
struct fdtable *fdt;
|
|
||||||
|
|
||||||
/* Find the last open fd */
|
/* Find the last open fd */
|
||||||
fdt = files_fdtable(files);
|
|
||||||
for (i = size/(8*sizeof(long)); i > 0; ) {
|
for (i = size/(8*sizeof(long)); i > 0; ) {
|
||||||
if (fdt->open_fds->fds_bits[--i])
|
if (fdt->open_fds->fds_bits[--i])
|
||||||
break;
|
break;
|
||||||
|
@ -592,13 +592,17 @@ static struct files_struct *alloc_files(void)
|
||||||
atomic_set(&newf->count, 1);
|
atomic_set(&newf->count, 1);
|
||||||
|
|
||||||
spin_lock_init(&newf->file_lock);
|
spin_lock_init(&newf->file_lock);
|
||||||
fdt = files_fdtable(newf);
|
fdt = &newf->fdtab;
|
||||||
fdt->next_fd = 0;
|
fdt->next_fd = 0;
|
||||||
fdt->max_fds = NR_OPEN_DEFAULT;
|
fdt->max_fds = NR_OPEN_DEFAULT;
|
||||||
fdt->max_fdset = __FD_SETSIZE;
|
fdt->max_fdset = __FD_SETSIZE;
|
||||||
fdt->close_on_exec = &newf->close_on_exec_init;
|
fdt->close_on_exec = &newf->close_on_exec_init;
|
||||||
fdt->open_fds = &newf->open_fds_init;
|
fdt->open_fds = &newf->open_fds_init;
|
||||||
fdt->fd = &newf->fd_array[0];
|
fdt->fd = &newf->fd_array[0];
|
||||||
|
INIT_RCU_HEAD(&fdt->rcu);
|
||||||
|
fdt->free_files = NULL;
|
||||||
|
fdt->next = NULL;
|
||||||
|
rcu_assign_pointer(newf->fdt, fdt);
|
||||||
out:
|
out:
|
||||||
return newf;
|
return newf;
|
||||||
}
|
}
|
||||||
|
@ -637,7 +641,7 @@ static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
|
||||||
old_fdt = files_fdtable(oldf);
|
old_fdt = files_fdtable(oldf);
|
||||||
new_fdt = files_fdtable(newf);
|
new_fdt = files_fdtable(newf);
|
||||||
size = old_fdt->max_fdset;
|
size = old_fdt->max_fdset;
|
||||||
open_files = count_open_files(oldf, old_fdt->max_fdset);
|
open_files = count_open_files(old_fdt);
|
||||||
expand = 0;
|
expand = 0;
|
||||||
|
|
||||||
/*
|
/*
|
||||||
|
@ -661,7 +665,14 @@ static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
|
||||||
spin_unlock(&newf->file_lock);
|
spin_unlock(&newf->file_lock);
|
||||||
if (error < 0)
|
if (error < 0)
|
||||||
goto out_release;
|
goto out_release;
|
||||||
|
new_fdt = files_fdtable(newf);
|
||||||
|
/*
|
||||||
|
* Reacquire the oldf lock and a pointer to its fd table
|
||||||
|
* who knows it may have a new bigger fd table. We need
|
||||||
|
* the latest pointer.
|
||||||
|
*/
|
||||||
spin_lock(&oldf->file_lock);
|
spin_lock(&oldf->file_lock);
|
||||||
|
old_fdt = files_fdtable(oldf);
|
||||||
}
|
}
|
||||||
|
|
||||||
old_fds = old_fdt->fd;
|
old_fds = old_fdt->fd;
|
||||||
|
@ -683,7 +694,7 @@ static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
|
||||||
*/
|
*/
|
||||||
FD_CLR(open_files - i, new_fdt->open_fds);
|
FD_CLR(open_files - i, new_fdt->open_fds);
|
||||||
}
|
}
|
||||||
*new_fds++ = f;
|
rcu_assign_pointer(*new_fds++, f);
|
||||||
}
|
}
|
||||||
spin_unlock(&oldf->file_lock);
|
spin_unlock(&oldf->file_lock);
|
||||||
|
|
||||||
|
|
Loading…
Reference in a new issue