io_uring/io-wq: move RLIMIT_FSIZE to io-wq

RLIMIT_SIZE in needed only for execution from an io-wq context, hence
move all preparations from hot path to io-wq work setup.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io-wq.c

@@ -462,6 +462,7 @@ static void io_impersonate_work(struct io_worker *worker,
 		io_wq_switch_mm(worker, work);
 	if (worker->cur_creds != work->creds)
 		io_wq_switch_creds(worker, work);
+	current->signal->rlim[RLIMIT_FSIZE].rlim_cur = work->fsize;
 }
 
 static void io_assign_current_work(struct io_worker *worker,

fs/io-wq.h

@@ -89,6 +89,7 @@ struct io_wq_work {
 	struct mm_struct *mm;
 	const struct cred *creds;
 	struct fs_struct *fs;
+	unsigned long fsize;
 	unsigned flags;
 };
 

fs/io_uring.c

@@ -645,7 +645,6 @@ struct io_kiocb {
 	unsigned int		flags;
 	refcount_t		refs;
 	struct task_struct	*task;
-	unsigned long		fsize;
 	u64			user_data;
 
 	struct list_head	link_list;
@@ -736,6 +735,7 @@ struct io_op_def {
 	unsigned		pollout : 1;
 	/* op supports buffer selection */
 	unsigned		buffer_select : 1;
+	unsigned		needs_fsize : 1;
 };
 
 static const struct io_op_def io_op_defs[] = {
@@ -755,6 +755,7 @@ static const struct io_op_def io_op_defs[] = {
 		.hash_reg_file		= 1,
 		.unbound_nonreg_file	= 1,
 		.pollout		= 1,
+		.needs_fsize		= 1,
 	},
 	[IORING_OP_FSYNC] = {
 		.needs_file		= 1,
@@ -769,6 +770,7 @@ static const struct io_op_def io_op_defs[] = {
 		.hash_reg_file		= 1,
 		.unbound_nonreg_file	= 1,
 		.pollout		= 1,
+		.needs_fsize		= 1,
 	},
 	[IORING_OP_POLL_ADD] = {
 		.needs_file		= 1,
@@ -821,6 +823,7 @@ static const struct io_op_def io_op_defs[] = {
 	},
 	[IORING_OP_FALLOCATE] = {
 		.needs_file		= 1,
+		.needs_fsize		= 1,
 	},
 	[IORING_OP_OPENAT] = {
 		.file_table		= 1,
@@ -852,6 +855,7 @@ static const struct io_op_def io_op_defs[] = {
 		.needs_file		= 1,
 		.unbound_nonreg_file	= 1,
 		.pollout		= 1,
+		.needs_fsize		= 1,
 	},
 	[IORING_OP_FADVISE] = {
 		.needs_file		= 1,
@@ -1169,6 +1173,10 @@ static void io_prep_async_work(struct io_kiocb *req)
 		}
 		spin_unlock(&current->fs->lock);
 	}
+	if (def->needs_fsize)
+		req->work.fsize = rlimit(RLIMIT_FSIZE);
+	else
+		req->work.fsize = RLIM_INFINITY;
 }
 
 static void io_prep_async_link(struct io_kiocb *req)
@@ -3072,8 +3080,6 @@ static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 	if (unlikely(!(req->file->f_mode & FMODE_WRITE)))
 		return -EBADF;
 
-	req->fsize = rlimit(RLIMIT_FSIZE);
-
 	/* either don't need iovec imported or already have it */
 	if (!req->io || req->flags & REQ_F_NEED_CLEANUP)
 		return 0;
@@ -3130,17 +3136,11 @@ static int io_write(struct io_kiocb *req, bool force_nonblock,
 		}
 		kiocb->ki_flags |= IOCB_WRITE;
 
-		if (!force_nonblock)
-			current->signal->rlim[RLIMIT_FSIZE].rlim_cur = req->fsize;
-
 		if (req->file->f_op->write_iter)
 			ret2 = call_write_iter(req->file, kiocb, &iter);
 		else
 			ret2 = loop_rw_iter(WRITE, req->file, kiocb, &iter);
 
-		if (!force_nonblock)
-			current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
-
 		/*
 		 * Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just
 		 * retry them without IOCB_NOWAIT.
@@ -3335,7 +3335,6 @@ static int io_fallocate_prep(struct io_kiocb *req,
 	req->sync.off = READ_ONCE(sqe->off);
 	req->sync.len = READ_ONCE(sqe->addr);
 	req->sync.mode = READ_ONCE(sqe->len);
-	req->fsize = rlimit(RLIMIT_FSIZE);
 	return 0;
 }
 
@@ -3346,11 +3345,8 @@ static int io_fallocate(struct io_kiocb *req, bool force_nonblock)
 	/* fallocate always requiring blocking context */
 	if (force_nonblock)
 		return -EAGAIN;
-
-	current->signal->rlim[RLIMIT_FSIZE].rlim_cur = req->fsize;
 	ret = vfs_fallocate(req->file, req->sync.mode, req->sync.off,
 				req->sync.len);
-	current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
 	if (ret < 0)
 		req_set_fail_links(req);
 	io_req_complete(req, ret);