From bfc0aa7a512f9a4462a88ca7352b00b83f8d68fd Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 11 Sep 2024 13:54:32 -0600 Subject: [PATCH] io_uring/rsrc: add reference count to struct io_mapped_ubuf Currently there's a single ring owner of a mapped buffer, and hence the reference count will always be 1 when it's torn down and freed. However, in preparation for being able to link io_mapped_ubuf to different spots, add a reference count to manage the lifetime of it. Signed-off-by: Jens Axboe --- io_uring/rsrc.c | 3 +++ io_uring/rsrc.h | 1 + 2 files changed, 4 insertions(+) diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c index d42114845fac..28f98de3c304 100644 --- a/io_uring/rsrc.c +++ b/io_uring/rsrc.c @@ -116,6 +116,8 @@ static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slo *slot = NULL; if (imu != &dummy_ubuf) { + if (!refcount_dec_and_test(&imu->refs)) + return; for (i = 0; i < imu->nr_bvecs; i++) unpin_user_page(imu->bvec[i].bv_page); if (imu->acct_pages) @@ -990,6 +992,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov, imu->folio_shift = data.folio_shift; imu->folio_mask = ~((1UL << data.folio_shift) - 1); } + refcount_set(&imu->refs, 1); off = (unsigned long) iov->iov_base & ~imu->folio_mask; *pimu = imu; ret = 0; diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h index 3d0dda3556e6..98a253172c27 100644 --- a/io_uring/rsrc.h +++ b/io_uring/rsrc.h @@ -47,6 +47,7 @@ struct io_mapped_ubuf { unsigned int folio_shift; unsigned long acct_pages; unsigned long folio_mask; + refcount_t refs; struct bio_vec bvec[] __counted_by(nr_bvecs); };