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From: Jens Axboe <[email protected]>
To: [email protected]
Cc: [email protected], [email protected],
	Jens Axboe <[email protected]>
Subject: [PATCH 2/4] io_uring: add basic fixed file allocator
Date: Sun,  8 May 2022 17:49:07 -0600	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

Applications currently always pick where they want fixed files to go.
In preparation for allowing these types of commands with multishot
support, add a basic allocator in the fixed file table.

Signed-off-by: Jens Axboe <[email protected]>
---
 fs/io_uring.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6eac6629e7d4..6148bd562add 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -258,6 +258,7 @@ struct io_rsrc_put {
 struct io_file_table {
 	struct io_fixed_file *files;
 	unsigned long *bitmap;
+	unsigned int alloc_hint;
 };
 
 struct io_rsrc_node {
@@ -4696,6 +4697,31 @@ static int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	return __io_openat_prep(req, sqe);
 }
 
+static int __maybe_unused io_file_bitmap_get(struct io_ring_ctx *ctx)
+{
+	struct io_file_table *table = &ctx->file_table;
+	unsigned long nr = ctx->nr_user_files;
+	int ret;
+
+	if (table->alloc_hint >= nr)
+		table->alloc_hint = 0;
+
+	do {
+		ret = find_next_zero_bit(table->bitmap, nr, table->alloc_hint);
+		if (ret != nr) {
+			table->alloc_hint = ret + 1;
+			return ret;
+		}
+		if (!table->alloc_hint)
+			break;
+
+		nr = table->alloc_hint;
+		table->alloc_hint = 0;
+	} while (1);
+
+	return -ENFILE;
+}
+
 static int io_openat2(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct open_flags op;
@@ -8665,11 +8691,14 @@ static inline void io_file_bitmap_set(struct io_file_table *table, int bit)
 {
 	WARN_ON_ONCE(test_bit(bit, table->bitmap));
 	__set_bit(bit, table->bitmap);
+	if (bit == table->alloc_hint)
+		table->alloc_hint++;
 }
 
 static inline void io_file_bitmap_clear(struct io_file_table *table, int bit)
 {
 	__clear_bit(bit, table->bitmap);
+	table->alloc_hint = bit;
 }
 
 static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
-- 
2.35.1



  parent reply	other threads:[~2022-05-09  1:25 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-08 23:49 [PATCHSET 0/4] Allow allocated direct descriptors Jens Axboe
2022-05-08 23:49 ` [PATCH 1/4] io_uring: track fixed files with a bitmap Jens Axboe
2022-05-08 23:49 ` Jens Axboe [this message]
2022-05-08 23:49 ` [PATCH 3/4] io_uring: allow allocated fixed files for openat/openat2 Jens Axboe
2022-05-08 23:49 ` [PATCH 4/4] io_uring: allow allocated fixed files for accept Jens Axboe

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