Re: [RFC PATCH 1/2] block: introduce helper function to calculate bps budgt

kernel test robot
2024-05-16T10:33:54Z

Hi zhaoyang.huang,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]
[also build test WARNING on v6.9]
[cannot apply to axboe-block/for-next linus/master next-20240516]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/zhaoyang-huang/block-introduce-helper-function-to-calculate-bps-budgt/20240515-092646
base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link: https://lore.kernel.org/r/20240515012350.1166350-2-zhaoyang.huang%40unisoc.com
patch subject: [RFC PATCH 1/2] block: introduce helper function to calculate bps budgt
config: hexagon-allyesconfig (https://download.01.org/0day-ci/archive/20240516/202405161846.6WR9ZYYH-lkp@intel.com/config)
compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project d3455f4ddd16811401fa153298fadd2f59f6914e)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240516/202405161846.6WR9ZYYH-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202405161846.6WR9ZYYH-lkp@intel.com/

All warnings (new ones prefixed by >>):

In file included from block/blk-throttle.c:10:
In file included from include/linux/blkdev.h:9:
In file included from include/linux/blk_types.h:10:
In file included from include/linux/bvec.h:10:
In file included from include/linux/highmem.h:10:
In file included from include/linux/mm.h:2253:
include/linux/vmstat.h:514:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
514 | return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
| ~~~~~~~~~~~ ^ ~~~
In file included from block/blk-throttle.c:10:
In file included from include/linux/blkdev.h:9:
In file included from include/linux/blk_types.h:10:
In file included from include/linux/bvec.h:10:
In file included from include/linux/highmem.h:12:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:14:
In file included from arch/hexagon/include/asm/io.h:328:
include/asm-generic/io.h:548:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
548 | val = __raw_readb(PCI_IOBASE + addr);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:561:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
561 | val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
| ~~~~~~~~~~ ^
include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
| ^
In file included from block/blk-throttle.c:10:
In file included from include/linux/blkdev.h:9:
In file included from include/linux/blk_types.h:10:
In file included from include/linux/bvec.h:10:
In file included from include/linux/highmem.h:12:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:14:
In file included from arch/hexagon/include/asm/io.h:328:
include/asm-generic/io.h:574:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
574 | val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
| ~~~~~~~~~~ ^
include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
| ^
In file included from block/blk-throttle.c:10:
In file included from include/linux/blkdev.h:9:
In file included from include/linux/blk_types.h:10:
In file included from include/linux/bvec.h:10:
In file included from include/linux/highmem.h:12:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:14:
In file included from arch/hexagon/include/asm/io.h:328:
include/asm-generic/io.h:585:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
585 | __raw_writeb(value, PCI_IOBASE + addr);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:595:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
595 | __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:605:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
605 | __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
| ~~~~~~~~~~ ^
>> block/blk-throttle.c:2380:10: warning: implicit conversion from 'u64' (aka 'unsigned long long') to 'unsigned long' changes value from 18446744073709551615 to 4294967295 [-Wconstant-conversion]
2380 | return U64_MAX;
| ~~~~~~ ^~~~~~~
include/linux/limits.h:25:19: note: expanded from macro 'U64_MAX'
25 | #define U64_MAX ((u64)~0ULL)
| ^~~~~~~~~~
8 warnings generated.

vim +2380 block/blk-throttle.c

2368
2369 unsigned long blk_throttle_budgt(struct block_device *bdev)
2370 {
2371 struct request_queue *q = bdev_get_queue(bdev);
2372 struct blkcg *blkcg;
2373 struct blkcg_gq *blkg;
2374 struct throtl_grp *tg;
2375 long long bytes_allowed = 0;
2376 unsigned long jiffy_elapsed, jiffy_elapsed_rnd;
2377 u64 bps_limit;
2378
2379 if (!q)
> 2380 return U64_MAX;
2381
2382 rcu_read_lock();
2383 spin_lock_irq(&q->queue_lock);
2384 blkcg = css_to_blkcg(task_css(current, io_cgrp_id));
2385 if (!blkcg)
2386 goto out;
2387
2388 blkg = blkg_lookup(blkcg, q);
2389 if (!blkg || !blkg_tryget(blkg))
2390 goto out;
2391
2392 tg = blkg_to_tg(blkg);
2393 bps_limit = tg_bps_limit(tg, READ);
2394 if (bps_limit == U64_MAX)
2395 goto out;
2396
2397 jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[READ];
2398 if (!jiffy_elapsed)
2399 jiffy_elapsed_rnd = tg->td->throtl_slice;
2400
2401 jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, tg->td->throtl_slice);
2402 bytes_allowed = calculate_bytes_allowed(bps_limit, jiffy_elapsed_rnd) +
2403 tg->carryover_bytes[READ];
2404 blkg_put(blkg);
2405 out:
2406 spin_unlock_irq(&q->queue_lock);
2407 rcu_read_unlock();
2408 return bytes_allowed;
2409 }
2410

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