io_uring: add flag for disabling provided buffer recycling

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>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index a70de17..88556e6 100644 (file)
--- 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);
@@ -5477,6 +5483,7 @@ static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
                        ret = -EINTR;
                if (ret > 0 && io_net_retry(sock, flags)) {
                        sr->done_io += ret;
+                       req->flags |= REQ_F_PARTIAL_IO;
                        return io_setup_async_msg(req, kmsg);
                }
                req_set_fail(req);
@@ -5546,6 +5553,7 @@ 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);