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authorJens Axboe <axboe@kernel.dk>2024-04-01 20:27:33 +0300
committerJens Axboe <axboe@kernel.dk>2024-04-01 20:41:50 +0300
commit2a975d426c82ff05ec1f0b773798d909fe4a3105 (patch)
tree9d10f7202d77fd15722ceefa880a9640d1457a78 /io_uring
parent39cd87c4eb2b893354f3b850f916353f2658ae6f (diff)
downloadlinux-2a975d426c82ff05ec1f0b773798d909fe4a3105.tar.xz
io_uring/rw: don't allow multishot reads without NOWAIT support
Supporting multishot reads requires support for NOWAIT, as the alternative would be always having io-wq execute the work item whenever the poll readiness triggered. Any fast file type will have NOWAIT support (eg it understands both O_NONBLOCK and IOCB_NOWAIT). If the given file type does not, then simply resort to single shot execution. Cc: stable@vger.kernel.org Fixes: fc68fcda04910 ("io_uring/rw: add support for IORING_OP_READ_MULTISHOT") Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
-rw-r--r--io_uring/rw.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/io_uring/rw.c b/io_uring/rw.c
index 0585ebcc9773..c8d48287439e 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -937,6 +937,13 @@ int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags)
ret = __io_read(req, issue_flags);
/*
+ * If the file doesn't support proper NOWAIT, then disable multishot
+ * and stay in single shot mode.
+ */
+ if (!io_file_supports_nowait(req))
+ req->flags &= ~REQ_F_APOLL_MULTISHOT;
+
+ /*
* If we get -EAGAIN, recycle our buffer and just let normal poll
* handling arm it.
*/
@@ -955,7 +962,7 @@ int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags)
/*
* Any successful return value will keep the multishot read armed.
*/
- if (ret > 0) {
+ if (ret > 0 && req->flags & REQ_F_APOLL_MULTISHOT) {
/*
* Put our buffer and post a CQE. If we fail to post a CQE, then
* jump to the termination path. This request is then done.