From 68ce0b9a35d77d767872dd1a729c50e4695a30a8 Mon Sep 17 00:00:00 2001 From: Lianbo Jiang Date: Thu, 2 Jun 2022 20:12:56 +0800 Subject: [PATCH 10/15] Fix for "dev -d|-D" options to support blk-mq change on Linux v5.18-rc1 Kernel commit 4e5cc99e1e48 ("blk-mq: manage hctx map via xarray") removed the "queue_hw_ctx" member from struct request_queue at Linux v5.18-rc1, and replaced it with a struct xarray "hctx_table". Without the patch, the "dev -d|-D" options will print an error: crash> dev -d MAJOR GENDISK NAME REQUEST_QUEUE TOTAL READ WRITE dev: invalid structure member offset: request_queue_queue_hw_ctx With the patch: crash> dev -d MAJOR GENDISK NAME REQUEST_QUEUE TOTAL READ WRITE 8 ffff8e99d0a1ae00 sda ffff8e9c14c59980 10 6 4 Signed-off-by: Lianbo Jiang --- defs.h | 1 + dev.c | 42 +++++++++++++++++++++++++++++++++--------- symbols.c | 2 ++ 3 files changed, 36 insertions(+), 9 deletions(-) diff --git a/defs.h b/defs.h index 2681586a33dc..7d3b73422f48 100644 --- a/defs.h +++ b/defs.h @@ -2180,6 +2180,7 @@ struct offset_table { /* stash of commonly-used offsets */ long blk_mq_tags_breserved_tags; long blk_mq_tags_nr_reserved_tags; long blk_mq_tags_rqs; + long request_queue_hctx_table; }; struct size_table { /* stash of commonly-used sizes */ diff --git a/dev.c b/dev.c index 4be4c96df8b0..0172c83ffaea 100644 --- a/dev.c +++ b/dev.c @@ -4369,20 +4369,42 @@ static void get_mq_diskio_from_hw_queues(ulong q, struct diskio *dio) uint cnt = 0; ulong addr = 0, hctx_addr = 0; ulong *hctx_array = NULL; + struct list_pair *lp = NULL; + + if (VALID_MEMBER(request_queue_hctx_table)) { + addr = q + OFFSET(request_queue_hctx_table); + cnt = do_xarray(addr, XARRAY_COUNT, NULL); + lp = (struct list_pair *)GETBUF(sizeof(struct list_pair) * (cnt + 1)); + if (!lp) + error(FATAL, "fail to get memory for list_pair.\n"); + lp[0].index = cnt; + cnt = do_xarray(addr, XARRAY_GATHER, lp); + } else { + addr = q + OFFSET(request_queue_nr_hw_queues); + readmem(addr, KVADDR, &cnt, sizeof(uint), + "request_queue.nr_hw_queues", FAULT_ON_ERROR); - addr = q + OFFSET(request_queue_nr_hw_queues); - readmem(addr, KVADDR, &cnt, sizeof(uint), - "request_queue.nr_hw_queues", FAULT_ON_ERROR); - - addr = q + OFFSET(request_queue_queue_hw_ctx); - readmem(addr, KVADDR, &hctx_addr, sizeof(void *), - "request_queue.queue_hw_ctx", FAULT_ON_ERROR); + addr = q + OFFSET(request_queue_queue_hw_ctx); + readmem(addr, KVADDR, &hctx_addr, sizeof(void *), + "request_queue.queue_hw_ctx", FAULT_ON_ERROR); + } hctx_array = (ulong *)GETBUF(sizeof(void *) * cnt); - if (!hctx_array) + if (!hctx_array) { + if (lp) + FREEBUF(lp); error(FATAL, "fail to get memory for the hctx_array\n"); + } + + if (lp && hctx_array) { + uint i; + + /* copy it from list_pair to hctx_array */ + for (i = 0; i < cnt; i++) + hctx_array[i] = (ulong)lp[i].value; - if (!readmem(hctx_addr, KVADDR, hctx_array, sizeof(void *) * cnt, + FREEBUF(lp); + } else if (!readmem(hctx_addr, KVADDR, hctx_array, sizeof(void *) * cnt, "request_queue.queue_hw_ctx[]", RETURN_ON_ERROR)) { FREEBUF(hctx_array); return; @@ -4755,6 +4777,8 @@ void diskio_init(void) "request_queue", "queue_hw_ctx"); MEMBER_OFFSET_INIT(request_queue_nr_hw_queues, "request_queue", "nr_hw_queues"); + MEMBER_OFFSET_INIT(request_queue_hctx_table, + "request_queue", "hctx_table"); MEMBER_OFFSET_INIT(blk_mq_ctx_rq_dispatched, "blk_mq_ctx", "rq_dispatched"); MEMBER_OFFSET_INIT(blk_mq_ctx_rq_completed, "blk_mq_ctx", diff --git a/symbols.c b/symbols.c index c1f09556d710..bee1faf92c83 100644 --- a/symbols.c +++ b/symbols.c @@ -10403,6 +10403,8 @@ dump_offset_table(char *spec, ulong makestruct) OFFSET(request_queue_queue_hw_ctx)); fprintf(fp, " request_queue_nr_hw_queues: %ld\n", OFFSET(request_queue_nr_hw_queues)); + fprintf(fp, " request_queue_hctx_table: %ld\n", + OFFSET(request_queue_hctx_table)); fprintf(fp, " blk_mq_ctx_rq_dispatched: %ld\n", OFFSET(blk_mq_ctx_rq_dispatched)); fprintf(fp, " blk_mq_ctx_rq_completed: %ld\n", -- 2.30.2