io_uring: pass required context in as flags

We have a number of bits that decide what context to inherit. Set up
io-wq flags for these instead. This is in preparation for always having
the various members set, but not always needing them for all requests.

No intended functional changes in this patch.
Signed-off-by: NJens Axboe <axboe@kernel.dk>

fs/io-wq.c

@@ -448,6 +448,8 @@ static inline void io_wq_switch_blkcg(struct io_worker *worker,
 				      struct io_wq_work *work)
 {
 #ifdef CONFIG_BLK_CGROUP
+	if (!(work->flags & IO_WQ_WORK_BLKCG))
+		return;
 	if (work->blkcg_css != worker->blkcg_css) {
 		kthread_associate_blkcg(work->blkcg_css);
 		worker->blkcg_css = work->blkcg_css;
@@ -470,17 +472,17 @@ static void io_wq_switch_creds(struct io_worker *worker,
 static void io_impersonate_work(struct io_worker *worker,
 				struct io_wq_work *work)
 {
-	if (work->files && current->files != work->files) {
+	if ((work->flags & IO_WQ_WORK_FILES) && current->files != work->files) {
 		task_lock(current);
 		current->files = work->files;
 		current->nsproxy = work->nsproxy;
 		task_unlock(current);
 	}
-	if (work->fs && current->fs != work->fs)
+	if ((work->flags & IO_WQ_WORK_FS) && current->fs != work->fs)
 		current->fs = work->fs;
-	if (work->mm != worker->mm)
+	if ((work->flags & IO_WQ_WORK_MM) && work->mm != worker->mm)
 		io_wq_switch_mm(worker, work);
-	if (worker->cur_creds != work->creds)
+	if ((work->flags & IO_WQ_WORK_CREDS) && worker->cur_creds != work->creds)
 		io_wq_switch_creds(worker, work);
 	current->signal->rlim[RLIMIT_FSIZE].rlim_cur = work->fsize;
 	io_wq_switch_blkcg(worker, work);

fs/io-wq.h

@@ -10,6 +10,12 @@ enum {
 	IO_WQ_WORK_NO_CANCEL	= 8,
 	IO_WQ_WORK_CONCURRENT	= 16,
 
+	IO_WQ_WORK_FILES	= 32,
+	IO_WQ_WORK_FS		= 64,
+	IO_WQ_WORK_MM		= 128,
+	IO_WQ_WORK_CREDS	= 256,
+	IO_WQ_WORK_BLKCG	= 512,
+
 	IO_WQ_HASH_SHIFT	= 24,	/* upper 8 bits are used for hash key */
 };
 

fs/io_uring.c

@@ -729,8 +729,6 @@ struct io_submit_state {
 };
 
 struct io_op_def {
-	/* needs current->mm setup, does mm access */
-	unsigned		needs_mm : 1;
 	/* needs req->file assigned */
 	unsigned		needs_file : 1;
 	/* don't fail if file grab fails */
@@ -741,10 +739,6 @@ struct io_op_def {
 	unsigned		unbound_nonreg_file : 1;
 	/* opcode is not supported by this kernel */
 	unsigned		not_supported : 1;
-	/* needs file table */
-	unsigned		file_table : 1;
-	/* needs ->fs */
-	unsigned		needs_fs : 1;
 	/* set if opcode supports polled "wait" */
 	unsigned		pollin : 1;
 	unsigned		pollout : 1;
@@ -754,45 +748,42 @@ struct io_op_def {
 	unsigned		needs_fsize : 1;
 	/* must always have async data allocated */
 	unsigned		needs_async_data : 1;
-	/* needs blkcg context, issues async io potentially */
-	unsigned		needs_blkcg : 1;
 	/* size of async data needed, if any */
 	unsigned short		async_size;
+	unsigned		work_flags;
 };
 
 static const struct io_op_def io_op_defs[] = {
 	[IORING_OP_NOP] = {},
 	[IORING_OP_READV] = {
-		.needs_mm		= 1,
 		.needs_file		= 1,
 		.unbound_nonreg_file	= 1,
 		.pollin			= 1,
 		.buffer_select		= 1,
 		.needs_async_data	= 1,
-		.needs_blkcg		= 1,
 		.async_size		= sizeof(struct io_async_rw),
+		.work_flags		= IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG,
 	},
 	[IORING_OP_WRITEV] = {
-		.needs_mm		= 1,
 		.needs_file		= 1,
 		.hash_reg_file		= 1,
 		.unbound_nonreg_file	= 1,
 		.pollout		= 1,
 		.needs_fsize		= 1,
 		.needs_async_data	= 1,
-		.needs_blkcg		= 1,
 		.async_size		= sizeof(struct io_async_rw),
+		.work_flags		= IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG,
 	},
 	[IORING_OP_FSYNC] = {
 		.needs_file		= 1,
-		.needs_blkcg		= 1,
+		.work_flags		= IO_WQ_WORK_BLKCG,
 	},
 	[IORING_OP_READ_FIXED] = {
 		.needs_file		= 1,
 		.unbound_nonreg_file	= 1,
 		.pollin			= 1,
-		.needs_blkcg		= 1,
 		.async_size		= sizeof(struct io_async_rw),
+		.work_flags		= IO_WQ_WORK_BLKCG,
 	},
 	[IORING_OP_WRITE_FIXED] = {
 		.needs_file		= 1,
@@ -800,8 +791,8 @@ static const struct io_op_def io_op_defs[] = {
 		.unbound_nonreg_file	= 1,
 		.pollout		= 1,
 		.needs_fsize		= 1,
-		.needs_blkcg		= 1,
 		.async_size		= sizeof(struct io_async_rw),
+		.work_flags		= IO_WQ_WORK_BLKCG,
 	},
 	[IORING_OP_POLL_ADD] = {
 		.needs_file		= 1,
@@ -810,137 +801,123 @@ static const struct io_op_def io_op_defs[] = {
 	[IORING_OP_POLL_REMOVE] = {},
 	[IORING_OP_SYNC_FILE_RANGE] = {
 		.needs_file		= 1,
-		.needs_blkcg		= 1,
+		.work_flags		= IO_WQ_WORK_BLKCG,
 	},
 	[IORING_OP_SENDMSG] = {
-		.needs_mm		= 1,
 		.needs_file		= 1,
 		.unbound_nonreg_file	= 1,
-		.needs_fs		= 1,
 		.pollout		= 1,
 		.needs_async_data	= 1,
-		.needs_blkcg		= 1,
 		.async_size		= sizeof(struct io_async_msghdr),
+		.work_flags		= IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG |
+						IO_WQ_WORK_FS,
 	},
 	[IORING_OP_RECVMSG] = {
-		.needs_mm		= 1,
 		.needs_file		= 1,
 		.unbound_nonreg_file	= 1,
-		.needs_fs		= 1,
 		.pollin			= 1,
 		.buffer_select		= 1,
 		.needs_async_data	= 1,
-		.needs_blkcg		= 1,
 		.async_size		= sizeof(struct io_async_msghdr),
+		.work_flags		= IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG |
+						IO_WQ_WORK_FS,
 	},
 	[IORING_OP_TIMEOUT] = {
-		.needs_mm		= 1,
 		.needs_async_data	= 1,
 		.async_size		= sizeof(struct io_timeout_data),
+		.work_flags		= IO_WQ_WORK_MM,
 	},
 	[IORING_OP_TIMEOUT_REMOVE] = {},
 	[IORING_OP_ACCEPT] = {
-		.needs_mm		= 1,
 		.needs_file		= 1,
 		.unbound_nonreg_file	= 1,
-		.file_table		= 1,
 		.pollin			= 1,
+		.work_flags		= IO_WQ_WORK_MM | IO_WQ_WORK_FILES,
 	},
 	[IORING_OP_ASYNC_CANCEL] = {},
 	[IORING_OP_LINK_TIMEOUT] = {
-		.needs_mm		= 1,
 		.needs_async_data	= 1,
 		.async_size		= sizeof(struct io_timeout_data),
+		.work_flags		= IO_WQ_WORK_MM,
 	},
 	[IORING_OP_CONNECT] = {
-		.needs_mm		= 1,
 		.needs_file		= 1,
 		.unbound_nonreg_file	= 1,
 		.pollout		= 1,
 		.needs_async_data	= 1,
 		.async_size		= sizeof(struct io_async_connect),
+		.work_flags		= IO_WQ_WORK_MM,
 	},
 	[IORING_OP_FALLOCATE] = {
 		.needs_file		= 1,
 		.needs_fsize		= 1,
-		.needs_blkcg		= 1,
+		.work_flags		= IO_WQ_WORK_BLKCG,
 	},
 	[IORING_OP_OPENAT] = {
-		.file_table		= 1,
-		.needs_fs		= 1,
-		.needs_blkcg		= 1,
+		.work_flags		= IO_WQ_WORK_FILES | IO_WQ_WORK_BLKCG |
+						IO_WQ_WORK_FS,
 	},
 	[IORING_OP_CLOSE] = {
 		.needs_file		= 1,
 		.needs_file_no_error	= 1,
-		.file_table		= 1,
-		.needs_blkcg		= 1,
+		.work_flags		= IO_WQ_WORK_FILES | IO_WQ_WORK_BLKCG,
 	},
 	[IORING_OP_FILES_UPDATE] = {
-		.needs_mm		= 1,
-		.file_table		= 1,
+		.work_flags		= IO_WQ_WORK_FILES | IO_WQ_WORK_MM,
 	},
 	[IORING_OP_STATX] = {
-		.needs_mm		= 1,
-		.needs_fs		= 1,
-		.file_table		= 1,
-		.needs_blkcg		= 1,
+		.work_flags		= IO_WQ_WORK_FILES | IO_WQ_WORK_MM |
+						IO_WQ_WORK_FS | IO_WQ_WORK_BLKCG,
 	},
 	[IORING_OP_READ] = {
-		.needs_mm		= 1,
 		.needs_file		= 1,
 		.unbound_nonreg_file	= 1,
 		.pollin			= 1,
 		.buffer_select		= 1,
-		.needs_blkcg		= 1,
 		.async_size		= sizeof(struct io_async_rw),
+		.work_flags		= IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG,
 	},
 	[IORING_OP_WRITE] = {
-		.needs_mm		= 1,
 		.needs_file		= 1,
 		.unbound_nonreg_file	= 1,
 		.pollout		= 1,
 		.needs_fsize		= 1,
-		.needs_blkcg		= 1,
 		.async_size		= sizeof(struct io_async_rw),
+		.work_flags		= IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG,
 	},
 	[IORING_OP_FADVISE] = {
 		.needs_file		= 1,
-		.needs_blkcg		= 1,
+		.work_flags		= IO_WQ_WORK_BLKCG,
 	},
 	[IORING_OP_MADVISE] = {
-		.needs_mm		= 1,
-		.needs_blkcg		= 1,
+		.work_flags		= IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG,
 	},
 	[IORING_OP_SEND] = {
-		.needs_mm		= 1,
 		.needs_file		= 1,
 		.unbound_nonreg_file	= 1,
 		.pollout		= 1,
-		.needs_blkcg		= 1,
+		.work_flags		= IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG,
 	},
 	[IORING_OP_RECV] = {
-		.needs_mm		= 1,
 		.needs_file		= 1,
 		.unbound_nonreg_file	= 1,
 		.pollin			= 1,
 		.buffer_select		= 1,
-		.needs_blkcg		= 1,
+		.work_flags		= IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG,
 	},
 	[IORING_OP_OPENAT2] = {
-		.file_table		= 1,
-		.needs_fs		= 1,
-		.needs_blkcg		= 1,
+		.work_flags		= IO_WQ_WORK_FILES | IO_WQ_WORK_FS |
+						IO_WQ_WORK_BLKCG,
 	},
 	[IORING_OP_EPOLL_CTL] = {
 		.unbound_nonreg_file	= 1,
-		.file_table		= 1,
+		.work_flags		= IO_WQ_WORK_FILES,
 	},
 	[IORING_OP_SPLICE] = {
 		.needs_file		= 1,
 		.hash_reg_file		= 1,
 		.unbound_nonreg_file	= 1,
-		.needs_blkcg		= 1,
+		.work_flags		= IO_WQ_WORK_BLKCG,
 	},
 	[IORING_OP_PROVIDE_BUFFERS] = {},
 	[IORING_OP_REMOVE_BUFFERS] = {},
@@ -1031,7 +1008,7 @@ static int __io_sq_thread_acquire_mm(struct io_ring_ctx *ctx)
 static int io_sq_thread_acquire_mm(struct io_ring_ctx *ctx,
 				   struct io_kiocb *req)
 {
-	if (!io_op_defs[req->opcode].needs_mm)
+	if (!(io_op_defs[req->opcode].work_flags & IO_WQ_WORK_MM))
 		return 0;
 	return __io_sq_thread_acquire_mm(ctx);
 }
@@ -1224,7 +1201,8 @@ static void io_prep_async_work(struct io_kiocb *req)
 		if (def->unbound_nonreg_file)
 			req->work.flags |= IO_WQ_WORK_UNBOUND;
 	}
-	if (!req->work.files && io_op_defs[req->opcode].file_table &&
+	if (!req->work.files &&
+	    (io_op_defs[req->opcode].work_flags & IO_WQ_WORK_FILES) &&
 	    !(req->flags & REQ_F_NO_FILE_TABLE)) {
 		req->work.files = get_files_struct(current);
 		get_nsproxy(current->nsproxy);
@@ -1235,12 +1213,12 @@ static void io_prep_async_work(struct io_kiocb *req)
 		list_add(&req->inflight_entry, &ctx->inflight_list);
 		spin_unlock_irq(&ctx->inflight_lock);
 	}
-	if (!req->work.mm && def->needs_mm) {
+	if (!req->work.mm && (def->work_flags & IO_WQ_WORK_MM)) {
 		mmgrab(current->mm);
 		req->work.mm = current->mm;
 	}
 #ifdef CONFIG_BLK_CGROUP
-	if (!req->work.blkcg_css && def->needs_blkcg) {
+	if (!req->work.blkcg_css && (def->work_flags & IO_WQ_WORK_BLKCG)) {
 		rcu_read_lock();
 		req->work.blkcg_css = blkcg_css();
 		/*
@@ -1254,7 +1232,7 @@ static void io_prep_async_work(struct io_kiocb *req)
 #endif
 	if (!req->work.creds)
 		req->work.creds = get_current_cred();
-	if (!req->work.fs && def->needs_fs) {
+	if (!req->work.fs && (def->work_flags & IO_WQ_WORK_FS)) {
 		spin_lock(&current->fs->lock);
 		if (!current->fs->in_exec) {
 			req->work.fs = current->fs;
@@ -1268,6 +1246,8 @@ static void io_prep_async_work(struct io_kiocb *req)
 		req->work.fsize = rlimit(RLIMIT_FSIZE);
 	else
 		req->work.fsize = RLIM_INFINITY;
+
+	req->work.flags |= def->work_flags;
 }
 
 static void io_prep_async_link(struct io_kiocb *req)