Commit 25440c3b authored by Thanos Makatos's avatar Thanos Makatos Committed by Tomasz Zawadzki
Browse files

nvmf/vfio-user: don't blindly drain poll group eventfd 



This eventfd may be passed by libvfio-user to the remote process which
might remove the EFD_NONBLOCK flag, in which case we would block
indefinitely.

Signed-off-by: default avatarThanos Makatos <thanos.makatos@nutanix.com>
Change-Id: If9826cd700b4a7b3458a0a8278a96322d99ac08e
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/15385


Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
Reviewed-by: default avatarJohn Levon <levon@movementarian.org>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Reviewed-by: default avatarChangpeng Liu <changpeng.liu@intel.com>
parent 7f236385

lib/nvmf/vfio_user.c

+12 −9
Original line number Diff line number Diff line
@@ -4810,20 +4810,13 @@ _post_completion_msg(void *ctx) 
static int nvmf_vfio_user_poll_group_poll(struct spdk_nvmf_transport_poll_group *group);



static int

vfio_user_poll_group_intr(void *ctx)

vfio_user_poll_group_process(void *ctx)

{

	struct nvmf_vfio_user_poll_group *vu_group = ctx;

	eventfd_t val;

	int ret = 0;



	SPDK_DEBUGLOG(vfio_user_db, "pg:%p got intr\n", vu_group);



	/*

	 * NB: this might fail if called from vfio_user_ctrlr_intr(), but it's

	 * non-blocking, so not an issue.

	 */

	eventfd_read(vu_group->intr_fd, &val);



	ret |= nvmf_vfio_user_poll_group_poll(&vu_group->group);



	/*
@@ -4835,6 +4828,16 @@ vfio_user_poll_group_intr(void *ctx) 
	return ret != 0 ? SPDK_POLLER_BUSY : SPDK_POLLER_IDLE;

}



static int

vfio_user_poll_group_intr(void *ctx)

{

	struct nvmf_vfio_user_poll_group *vu_group = ctx;

	eventfd_t val;



	eventfd_read(vu_group->intr_fd, &val);

	return vfio_user_poll_group_process(ctx);

}



/*

 * Handle an interrupt for the given controller: we must poll the vfu_ctx, and

 * the SQs assigned to our own poll group. Other poll groups are handled via
@@ -4880,7 +4883,7 @@ vfio_user_ctrlr_intr(void *ctx) 
		}

	}



	ret |= vfio_user_poll_group_intr(vu_ctrlr_group);

	ret |= vfio_user_poll_group_process(vu_ctrlr_group);



	return ret;

}