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From: Xiaoguang Wang <[email protected]>
To: [email protected]
Cc: [email protected], [email protected]
Subject: [PATCH v3] io_uring: defer alloc_hint update to io_file_bitmap_set()
Date: Sat, 28 May 2022 09:51:09 +0800	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

io_file_bitmap_get() returns a free bitmap slot, but if it isn't
used later, such as io_queue_rsrc_removal() returns error, in this
case, we should not update alloc_hint at all, which still should
be considered as a valid candidate for next io_file_bitmap_get()
calls.

To fix this issue, only update alloc_hint in io_file_bitmap_set().

Signed-off-by: Xiaoguang Wang <[email protected]>
---
v3:
  Revert io_file_bitmap_set() type changes.
V2:
  Delete unnecessary check against to alloc_hint.
---
 fs/io_uring.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index ff50e5f1753d..8f476e8760bf 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5419,15 +5419,11 @@ static int io_file_bitmap_get(struct io_ring_ctx *ctx)
 	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;
+		if (ret != nr)
 			return ret;
-		}
+
 		if (!table->alloc_hint)
 			break;
 
@@ -9654,8 +9650,7 @@ 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++;
+	table->alloc_hint = bit + 1;
 }
 
 static inline void io_file_bitmap_clear(struct io_file_table *table, int bit)
-- 
2.14.4.44.g2045bb6



  parent reply	other threads:[~2022-05-28  1:51 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-27 16:53 [PATCH 0/2] two bug fixes about direct fd install Xiaoguang Wang
2022-05-27 16:53 ` [PATCH 1/2] io_uring: fix file leaks around io_fixed_fd_install() Xiaoguang Wang
2022-05-27 16:53 ` [PATCH 2/2] io_uring: defer alloc_hint update to io_file_bitmap_set() Xiaoguang Wang
2022-05-27 17:09   ` Jens Axboe
2022-05-27 17:39     ` [PATCH v2] " Xiaoguang Wang
2022-05-27 18:03       ` Jens Axboe
2022-05-28  1:45         ` Xiaoguang Wang
2022-05-28  1:51         ` Xiaoguang Wang [this message]
2022-05-28  2:14           ` [PATCH v3] " Jens Axboe

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