From e3abd46024b653de3bf761696044ba142bbc1ce9 Mon Sep 17 00:00:00 2001 From: Rob Norris Date: Mon, 8 Apr 2024 18:09:11 +1000 Subject: [PATCH] zvol_os: fix compile with blk-mq on Linux 4.x 99741bde5 accesses a cached blk-mq hardware context through the mq_hctx field of struct request. However, this field did not exist until 5.0. Before that, the private function blk_mq_map_queue() was used to dig it out of broader queue context. This commit detects this situation, and handles it with a poor-man's simulation of that function. Sponsored-by: Klara, Inc. Sponsored-by: Wasabi Technology, Inc. Signed-off-by: Rob Norris --- config/kernel-blk-queue.m4 | 15 +++++++++++++++ module/os/linux/zfs/zvol_os.c | 5 +++++ 2 files changed, 20 insertions(+) diff --git a/config/kernel-blk-queue.m4 b/config/kernel-blk-queue.m4 index bb5903b313eb..15dbe1c7dff0 100644 --- a/config/kernel-blk-queue.m4 +++ b/config/kernel-blk-queue.m4 @@ -377,6 +377,14 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_BLK_MQ], [ (void) blk_mq_alloc_tag_set(&tag_set); return BLK_STS_OK; ], []) + ZFS_LINUX_TEST_SRC([blk_mq_rq_hctx], [ + #include + #include + ], [ + struct request rq = {0}; + struct blk_mq_hw_ctx *hctx = NULL; + rq.mq_hctx = hctx; + ], []) ]) AC_DEFUN([ZFS_AC_KERNEL_BLK_MQ], [ @@ -384,6 +392,13 @@ AC_DEFUN([ZFS_AC_KERNEL_BLK_MQ], [ ZFS_LINUX_TEST_RESULT([blk_mq], [ AC_MSG_RESULT(yes) AC_DEFINE(HAVE_BLK_MQ, 1, [block multiqueue is available]) + AC_MSG_CHECKING([whether block multiqueue hardware context is cached in struct request]) + ZFS_LINUX_TEST_RESULT([blk_mq_rq_hctx], [ + AC_MSG_RESULT(yes) + AC_DEFINE(HAVE_BLK_MQ_RQ_HCTX, 1, [block multiqueue hardware context is cached in struct request]) + ], [ + AC_MSG_RESULT(no) + ]) ], [ AC_MSG_RESULT(no) ]) diff --git a/module/os/linux/zfs/zvol_os.c b/module/os/linux/zfs/zvol_os.c index 107776932493..1b96e4b539d2 100644 --- a/module/os/linux/zfs/zvol_os.c +++ b/module/os/linux/zfs/zvol_os.c @@ -550,7 +550,12 @@ zvol_request_impl(zvol_state_t *zv, struct bio *bio, struct request *rq, uint_t taskq_hash; #ifdef HAVE_BLK_MQ if (rq) +#ifdef HAVE_BLK_MQ_RQ_HCTX blk_mq_hw_queue = rq->mq_hctx->queue_num; +#else + blk_mq_hw_queue = + rq->q->queue_hw_ctx[rq->q->mq_map[rq->cpu]]->queue_num; +#endif #endif taskq_hash = cityhash4((uintptr_t)zv, offset >> ZVOL_TASKQ_OFFSET_SHIFT, blk_mq_hw_queue, 0);