Commit fbe38120 authored by Jens Axboe's avatar Jens Axboe
Browse files

signalfd: convert to ->read_iter() 



Rather than use the older style ->read() hook, use ->read_iter() so that
signalfd can support both O_NONBLOCK and IOCB_NOWAIT for non-blocking
read attempts.

Split the fd setup into two parts, so that signalfd can mark the file
mode with FMODE_NOWAIT before installing it into the process table.

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 40f45fe8

fs/signalfd.c

+28 −16
Original line number Diff line number Diff line
@@ -68,8 +68,7 @@ static __poll_t signalfd_poll(struct file *file, poll_table *wait) 
/*

 * Copied from copy_siginfo_to_user() in kernel/signal.c

 */

static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,

			     kernel_siginfo_t const *kinfo)

static int signalfd_copyinfo(struct iov_iter *to, kernel_siginfo_t const *kinfo)

{

	struct signalfd_siginfo new;
@@ -146,10 +145,10 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo, 
		break;

	}



	if (copy_to_user(uinfo, &new, sizeof(struct signalfd_siginfo)))

	if (!copy_to_iter_full(&new, sizeof(struct signalfd_siginfo), to))

		return -EFAULT;



	return sizeof(*uinfo);

	return sizeof(struct signalfd_siginfo);

}



static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, kernel_siginfo_t *info,
@@ -199,28 +198,27 @@ static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, kernel_siginfo_t *info 
 * error code. The "count" parameter must be at least the size of a

 * "struct signalfd_siginfo".

 */

static ssize_t signalfd_read(struct file *file, char __user *buf, size_t count,

			     loff_t *ppos)

static ssize_t signalfd_read_iter(struct kiocb *iocb, struct iov_iter *to)

{

	struct file *file = iocb->ki_filp;

	struct signalfd_ctx *ctx = file->private_data;

	struct signalfd_siginfo __user *siginfo;

	int nonblock = file->f_flags & O_NONBLOCK;

	size_t count = iov_iter_count(to);

	ssize_t ret, total = 0;

	kernel_siginfo_t info;

	bool nonblock;



	count /= sizeof(struct signalfd_siginfo);

	if (!count)

		return -EINVAL;



	siginfo = (struct signalfd_siginfo __user *) buf;

	nonblock = file->f_flags & O_NONBLOCK || iocb->ki_flags & IOCB_NOWAIT;

	do {

		ret = signalfd_dequeue(ctx, &info, nonblock);

		if (unlikely(ret <= 0))

			break;

		ret = signalfd_copyinfo(siginfo, &info);

		ret = signalfd_copyinfo(to, &info);

		if (ret < 0)

			break;

		siginfo++;

		total += ret;

		nonblock = 1;

	} while (--count);
@@ -246,7 +244,7 @@ static const struct file_operations signalfd_fops = { 
#endif

	.release	= signalfd_release,

	.poll		= signalfd_poll,

	.read		= signalfd_read,

	.read_iter	= signalfd_read_iter,

	.llseek		= noop_llseek,

};
@@ -265,20 +263,34 @@ static int do_signalfd4(int ufd, sigset_t *mask, int flags) 
	signotset(mask);



	if (ufd == -1) {

		struct file *file;



		ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);

		if (!ctx)

			return -ENOMEM;



		ctx->sigmask = *mask;



		ufd = get_unused_fd_flags(flags & O_CLOEXEC);

		if (ufd < 0) {

			kfree(ctx);

			return ufd;

		}



		file = anon_inode_getfile("[signalfd]", &signalfd_fops, ctx,

				       O_RDWR | (flags & O_NONBLOCK));

		if (IS_ERR(file)) {

			put_unused_fd(ufd);

			kfree(ctx);

			return ufd;

		}

		file->f_mode |= FMODE_NOWAIT;



		/*

		 * When we call this, the initialization must be complete, since

		 * anon_inode_getfd() will install the fd.

		 */

		ufd = anon_inode_getfd("[signalfd]", &signalfd_fops, ctx,

				       O_RDWR | (flags & (O_CLOEXEC | O_NONBLOCK)));

		if (ufd < 0)

			kfree(ctx);

		fd_install(ufd, file);

	} else {

		struct fd f = fdget(ufd);

		if (!f.file)