user/sven/linux.git/include/linux/blkdev.h, branch v4.13.7

bsg-lib: fix kernel panic resulting from missing allocation of reply-buffer

2017-08-24T14:22:10Z

Since we split the scsi_request out of struct request bsg fails to provide a reply-buffer for the drivers. This was done via the pointer for sense-data, that is not preallocated anymore. Failing to allocate/assign it results in illegal dereferences because LLDs use this pointer unquestioned. An example panic on s390x, using the zFCP driver, looks like this (I had debugging on, otherwise NULL-pointer dereferences wouldn't even panic on s390x): Unable to handle kernel pointer dereference in virtual kernel address space Failing address: 6b6b6b6b6b6b6000 TEID: 6b6b6b6b6b6b6403 Fault in home space mode while using kernel ASCE. AS:0000000001590007 R3:0000000000000024 Oops: 0038 ilc:2 [#1] PREEMPT SMP DEBUG_PAGEALLOC Modules linked in: CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.12.0-bsg-regression+ #3 Hardware name: IBM 2964 N96 702 (z/VM 6.4.0) task: 0000000065cb0100 task.stack: 0000000065cb4000 Krnl PSW : 0704e00180000000 000003ff801e4156 (zfcp_fc_ct_els_job_handler+0x16/0x58 [zfcp]) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3 Krnl GPRS: 0000000000000001 000000005fa9d0d0 000000005fa9d078 0000000000e16866 000003ff00000290 6b6b6b6b6b6b6b6b 0000000059f78f00 000000000000000f 00000000593a0958 00000000593a0958 0000000060d88800 000000005ddd4c38 0000000058b50100 07000000659cba08 000003ff801e8556 00000000659cb9a8 Krnl Code: 000003ff801e4146: e31020500004 lg %r1,80(%r2) 000003ff801e414c: 58402040 l %r4,64(%r2) #000003ff801e4150: e35020200004 lg %r5,32(%r2) >000003ff801e4156: 50405004 st %r4,4(%r5) 000003ff801e415a: e54c50080000 mvhi 8(%r5),0 000003ff801e4160: e33010280012 lt %r3,40(%r1) 000003ff801e4166: a718fffb lhi %r1,-5 000003ff801e416a: 1803 lr %r0,%r3 Call Trace: ([<000003ff801e8556>] zfcp_fsf_req_complete+0x726/0x768 [zfcp]) [<000003ff801ea82a>] zfcp_fsf_reqid_check+0x102/0x180 [zfcp] [<000003ff801eb980>] zfcp_qdio_int_resp+0x230/0x278 [zfcp] [<00000000009b91b6>] qdio_kick_handler+0x2ae/0x2c8 [<00000000009b9e3e>] __tiqdio_inbound_processing+0x406/0xc10 [<00000000001684c2>] tasklet_action+0x15a/0x1d8 [<0000000000bd28ec>] __do_softirq+0x3ec/0x848 [<00000000001675a4>] irq_exit+0x74/0xf8 [<000000000010dd6a>] do_IRQ+0xba/0xf0 [<0000000000bd19e8>] io_int_handler+0x104/0x2d4 [<00000000001033b6>] enabled_wait+0xb6/0x188 ([<000000000010339e>] enabled_wait+0x9e/0x188) [<000000000010396a>] arch_cpu_idle+0x32/0x50 [<0000000000bd0112>] default_idle_call+0x52/0x68 [<00000000001cd0fa>] do_idle+0x102/0x188 [<00000000001cd41e>] cpu_startup_entry+0x3e/0x48 [<0000000000118c64>] smp_start_secondary+0x11c/0x130 [<0000000000bd2016>] restart_int_handler+0x62/0x78 [<0000000000000000>] (null) INFO: lockdep is turned off. Last Breaking-Event-Address: [<000003ff801e41d6>] zfcp_fc_ct_job_handler+0x3e/0x48 [zfcp] Kernel panic - not syncing: Fatal exception in interrupt This patch moves bsg-lib to allocate and setup struct bsg_job ahead of time, including the allocation of a buffer for the reply-data. This means, struct bsg_job is not allocated separately anymore, but as part of struct request allocation - similar to struct scsi_cmd. Reflect this in the function names that used to handle creation/destruction of struct bsg_job. Reported-by: Steffen Maier Suggested-by: Christoph Hellwig Reviewed-by: Christoph Hellwig Signed-off-by: Benjamin Block Fixes: 82ed4db499b8 ("block: split scsi_request out of struct request") Cc: #4.11+ Signed-off-by: Jens Axboe

block: remove the queue_bounce_pfn helper

2017-06-27T18:13:45Z

Only used inside the bounce code, and opencoding it makes it more obvious what is going on. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: move bounce declarations to block/blk.h

2017-06-27T18:13:45Z

Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

blk-mq: expose write hints through debugfs

2017-06-27T18:05:31Z

Useful to verify that things are working the way they should. Reading the file will return number of kb written with each write hint. Writing the file will reset the statistics. No care is taken to ensure that we don't race on updates. Drivers will write to q->write_hints[] if they handle a given write hint. Reviewed-by: Andreas Dilger Reviewed-by: Martin K. Petersen Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: add support for write hints in a bio

2017-06-27T18:05:27Z

No functional changes in this patch, we just use up some holes in the bio and request structures to define a write hint that we psas down the stack. Ensure that we don't merge requests that have different life time hints assigned to them, and that we inherit the write hint when cloning a bio. Reviewed-by: Martin K. Petersen Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe

Merge commit '8e8320c9315c' into for-4.13/block

2017-06-23T03:55:24Z

Pull in the fix for shared tags, as it conflicts with the pending changes in for-4.13/block. We already pulled in v4.12-rc5 to solve other conflicts or get fixes that went into 4.12, so not a lot of changes in this merge. Signed-off-by: Jens Axboe

blk-mq: fix performance regression with shared tags

2017-06-21T16:17:49Z

If we have shared tags enabled, then every IO completion will trigger a full loop of every queue belonging to a tag set, and every hardware queue for each of those queues, even if nothing needs to be done. This causes a massive performance regression if you have a lot of shared devices. Instead of doing this huge full scan on every IO, add an atomic counter to the main queue that tracks how many hardware queues have been marked as needing a restart. With that, we can avoid looking for restartable queues, if we don't have to. Max reports that this restores performance. Before this patch, 4K IOPS was limited to 22-23K IOPS. With the patch, we are running at 950-970K IOPS. Fixes: 6d8c6c0f97ad ("blk-mq: Restart a single queue if tag sets are shared") Reported-by: Max Gurtovoy Tested-by: Max Gurtovoy Reviewed-by: Bart Van Assche Tested-by: Bart Van Assche Signed-off-by: Jens Axboe

block: Add a comment above queue_lockdep_assert_held()

2017-06-21T01:27:14Z

Add a comment above the queue_lockdep_assert_held() macro that explains the purpose of the q->queue_lock test. Signed-off-by: Bart Van Assche Reviewed-by: Christoph Hellwig Cc: Hannes Reinecke Cc: Omar Sandoval Cc: Ming Lei Signed-off-by: Jens Axboe

block: Introduce request_queue.initialize_rq_fn()

2017-06-21T01:27:14Z

Several block drivers need to initialize the driver-private request data after having called blk_get_request() and before .prep_rq_fn() is called, e.g. when submitting a REQ_OP_SCSI_* request. Avoid that that initialization code has to be repeated after every blk_get_request() call by adding new callback functions to struct request_queue and to struct blk_mq_ops. Signed-off-by: Bart Van Assche Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Omar Sandoval Signed-off-by: Jens Axboe

block: Make request operation type argument declarations consistent

2017-06-21T01:27:14Z

Instead of declaring the second argument of blk_*_get_request() as int and passing it to functions that expect an unsigned int, declare that second argument as unsigned int. Also because of consistency, rename that second argument from 'rw' into 'op'. This patch does not change any functionality. Signed-off-by: Bart Van Assche Reviewed-by: Christoph Hellwig Cc: Hannes Reinecke Cc: Omar Sandoval Cc: Ming Lei Signed-off-by: Jens Axboe