Re: [Crash-utility] [PATCH v2] Handle blk_mq_ctx member changes for kernels v5.16-rc1~75^2~44
Hi Lianbo,
thanks for the update,
-----Original Message-----
Subject: [PATCH v2] Handle blk_mq_ctx member changes for kernels
v5.16-rc1~75^2~44
only "5.16-rc1" is fine, as we have the commit id below.
Kernel commit <9a14d6ce4135> ("block: remove debugfs
blk_mq_ctx
dispatched/merged/completed attributes") removed the member
rq_dispatched and rq_completed from struct blk_mq_ctx. Without
this patch, crash will fail with the following error:
crash> dev -d
MAJOR GENDISK NAME REQUEST_QUEUE TOTAL ASYNC SYNC
dev: invalid structure member offset: blk_mq_ctx_rq_dispatched
FILE: dev.c LINE: 4229 FUNCTION: get_one_mctx_diskio()
Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com>
---
change since v1:
[1] display prompt information "(not supported)" instead of the
statistical result if kernel does not support it
dev.c | 56 ++++++++++++++++++++++++++++++++++++++------------------
1 file changed, 38 insertions(+), 18 deletions(-)
diff --git a/dev.c b/dev.c
index effe789f38d8..c5e38e1c5376 100644
--- a/dev.c
+++ b/dev.c
@@ -4246,6 +4246,10 @@ get_mq_diskio(unsigned long q, unsigned long *mq_count)
unsigned long mctx_addr;
struct diskio tmp;
+ if (!MEMBER_EXISTS("blk_mq_ctx", "rq_dispatched") &&
+ !MEMBER_EXISTS("blk_mq_ctx", "rq_completed"))
+ return;
+
It's better to use INVALID_MEMBER() here, because they are in the offset_table and
it doesn't call gdb function. And, both of them should be gone on 5.16 and later,
but let's use 'or' for safe:
if (INVALID_MEMBER(blk_mq_ctx_rq_dispatched) ||
INVALID_MEMBER(blk_mq_ctx_rq_completed))
return;
memset(&tmp, 0x00, sizeof(struct diskio));
readmem(q + OFFSET(request_queue_queue_ctx), KVADDR, &queue_ctx,
@@ -4475,24 +4479,40 @@ display_one_diskio(struct iter *i, unsigned long gendisk, ulong
flags)
&& (io.read + io.write == 0))
return;
- fprintf(fp, "%s%s%s %s%s%s%s %s%5d%s%s%s%s%s",
- mkstring(buf0, 5, RJUST|INT_DEC, (char *)(unsigned long)major),
- space(MINSPACE),
- mkstring(buf1, VADDR_PRLEN, LJUST|LONG_HEX, (char *)gendisk),
- space(MINSPACE),
- mkstring(buf2, 10, LJUST, disk_name),
- space(MINSPACE),
- mkstring(buf3, VADDR_PRLEN <= 11 ? 11 : VADDR_PRLEN,
- LJUST|LONG_HEX, (char *)queue_addr),
- space(MINSPACE),
- io.read + io.write,
- space(MINSPACE),
- mkstring(buf4, 5, RJUST|INT_DEC,
- (char *)(unsigned long)io.read),
- space(MINSPACE),
- mkstring(buf5, 5, RJUST|INT_DEC,
- (char *)(unsigned long)io.write),
- space(MINSPACE));
+ if (!MEMBER_EXISTS("blk_mq_ctx", "rq_dispatched") &&
+ !MEMBER_EXISTS("blk_mq_ctx", "rq_completed"))
Same as above.
And this stops displaying the statistics of all devices on 5.16 kernel.
I think that we can stop only mq devices, so how about this?
if (use_mq_interface(queue_addr) &&
(INVALID_MEMBER(blk_mq_ctx_rq_dispatched) ||
INVALID_MEMBER(blk_mq_ctx_rq_completed)))
With this, on a 5.16-rc2 kernel:
crash-dev> dev -d
MAJOR GENDISK NAME REQUEST_QUEUE TOTAL ASYNC SYNC
8 ffff92bbd102e400 sdb ffff92bbf04e3678 (not supported)
8 ffff92bbd1014400 sdc ffff92bbf04e26e8 (not supported)
8 ffff92bbc9bff200 sdd ffff92bbf04e07c8 (not supported)
8 ffff92bbd9676200 sda ffff92bbf04e0000 (not supported)
11 ffff92c347da5e00 sr0 ffff92bbd9c3e528 (not supported)
253 ffff92bbca726e00 dm-0 ffff92bbcad7dd60 0 0 0
253 ffff92bbe03f1000 dm-1 ffff92bbe1d587c8 0 0 0
253 ffff92bbe02fa800 dm-2 ffff92bc01b11f20 0 0 0
where dm-X devices don't use mq interface.
I've modified the patch and attached, you can merge it if you are OK.
Thanks,
Kazu
Attachments:
- 0001-Handle-blk_mq_ctx-member-changes-for-kernels-5.16-rc.patch (application/octet-stream — 3.4 KB)