[PATCH 2/2] io_uring: add flag for disabling provided buffer recycling

Jens Axboe
2022-03-23T15:39:56Z

If we need to continue doing this IO, then we don't want a potentially
selected buffer recycled. Add a flag for that.

Set this for recv/recvmsg if they do partial IO.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 2cd67b4ff924..5c6f4abbf294 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -783,6 +783,7 @@ enum {
REQ_F_SKIP_LINK_CQES_BIT,
REQ_F_SINGLE_POLL_BIT,
REQ_F_DOUBLE_POLL_BIT,
+ REQ_F_PARTIAL_IO_BIT,
/* keep async read/write and isreg together and in order */
REQ_F_SUPPORT_NOWAIT_BIT,
REQ_F_ISREG_BIT,
@@ -845,6 +846,8 @@ enum {
REQ_F_SINGLE_POLL = BIT(REQ_F_SINGLE_POLL_BIT),
/* double poll may active */
REQ_F_DOUBLE_POLL = BIT(REQ_F_DOUBLE_POLL_BIT),
+ /* request has already done partial IO */
+ REQ_F_PARTIAL_IO = BIT(REQ_F_PARTIAL_IO_BIT),
};

struct async_poll {
@@ -1392,6 +1395,9 @@ static void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)

if (likely(!(req->flags & REQ_F_BUFFER_SELECTED)))
return;
+ /* don't recycle if we already did IO to this buffer */
+ if (req->flags & REQ_F_PARTIAL_IO)
+ return;

if (issue_flags & IO_URING_F_UNLOCKED)
mutex_lock(&ctx->uring_lock);
@@ -5470,6 +5476,7 @@ static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
ret = -EINTR;
if (ret > 0 && flags & MSG_WAITALL) {
sr->done_io += ret;
+ req->flags |= REQ_F_PARTIAL_IO;
return io_setup_async_msg(req, kmsg);
}
req_set_fail(req);
@@ -5539,6 +5546,7 @@ static int io_recv(struct io_kiocb *req, unsigned int issue_flags)
sr->len -= ret;
sr->buf += ret;
sr->done_io += ret;
+ req->flags |= REQ_F_PARTIAL_IO;
return -EAGAIN;
}
req_set_fail(req);
--
2.35.1