io_uring/advise: support 64-bit lengths

The existing fadvise/madvise support only supports 32-bit lengths. Add
support for 64-bit lengths, enabled by the application setting sqe->off
rather than sqe->len for the length. If sqe->len is set, then that is
used as the 32-bit length. If sqe->len is zero, then sqe->off is read
for full 64-bit support.

Older kernels will return -EINVAL if 64-bit support isn't available.

Fixes: 4840e418c2fc ("io_uring: add IORING_OP_FADVISE")
Fixes: c1ca757bd6f4 ("io_uring: add IORING_OP_MADVISE")
Reported-by: Stefan <source@s.muenzel.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/advise.c b/io_uring/advise.c
index 7085804c513c09aba69c9d04d04bc3f90c3bbf6d..cb7b881665e57ffcfb16aab9fe36ffdb58fa2c43 100644 (file)
--- a/io_uring/advise.c
+++ b/io_uring/advise.c
@@ -17,14 +17,14 @@
 struct io_fadvise {
        struct file                     *file;
        u64                             offset;
-       u32                             len;
+       u64                             len;
        u32                             advice;
 };
 
 struct io_madvise {
        struct file                     *file;
        u64                             addr;
-       u32                             len;
+       u64                             len;
        u32                             advice;
 };
 
@@ -33,11 +33,13 @@ int io_madvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 #if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
        struct io_madvise *ma = io_kiocb_to_cmd(req, struct io_madvise);
 
-       if (sqe->buf_index || sqe->off || sqe->splice_fd_in)
+       if (sqe->buf_index || sqe->splice_fd_in)
                return -EINVAL;
 
        ma->addr = READ_ONCE(sqe->addr);
-       ma->len = READ_ONCE(sqe->len);
+       ma->len = READ_ONCE(sqe->off);
+       if (!ma->len)
+               ma->len = READ_ONCE(sqe->len);
        ma->advice = READ_ONCE(sqe->fadvise_advice);
        req->flags |= REQ_F_FORCE_ASYNC;
        return 0;
@@ -78,11 +80,13 @@ int io_fadvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
        struct io_fadvise *fa = io_kiocb_to_cmd(req, struct io_fadvise);
 
-       if (sqe->buf_index || sqe->addr || sqe->splice_fd_in)
+       if (sqe->buf_index || sqe->splice_fd_in)
                return -EINVAL;
 
        fa->offset = READ_ONCE(sqe->off);
-       fa->len = READ_ONCE(sqe->len);
+       fa->len = READ_ONCE(sqe->addr);
+       if (!fa->len)
+               fa->len = READ_ONCE(sqe->len);
        fa->advice = READ_ONCE(sqe->fadvise_advice);
        if (io_fadvise_force_async(fa))
                req->flags |= REQ_F_FORCE_ASYNC;