Re: [PATCH v14 11/11] null_blk: add support for copy offload

From: kernel test robot
Date: Fri Aug 11 2023 - 13:16:56 EST

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In reply to: Nitesh Shetty: "[PATCH v14 11/11] null_blk: add support for copy offload"
Next in thread: kernel test robot: "Re: [PATCH v14 11/11] null_blk: add support for copy offload"
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Hi Nitesh,

kernel test robot noticed the following build warnings:

[auto build test WARNING on f7dc24b3413851109c4047b22997bd0d95ed52a2]

url: https://github.com/intel-lab-lkp/linux/commits/Nitesh-Shetty/block-Introduce-queue-limits-and-sysfs-for-copy-offload-support/20230811-192259
base: f7dc24b3413851109c4047b22997bd0d95ed52a2
patch link: https://lore.kernel.org/r/20230811105300.15889-12-nj.shetty%40samsung.com
patch subject: [PATCH v14 11/11] null_blk: add support for copy offload
config: hexagon-randconfig-r032-20230811 (https://download.01.org/0day-ci/archive/20230812/202308120029.elW3y1RM-lkp@xxxxxxxxx/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce: (https://download.01.org/0day-ci/archive/20230812/202308120029.elW3y1RM-lkp@xxxxxxxxx/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@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202308120029.elW3y1RM-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

In file included from drivers/block/null_blk/main.c:12:
In file included from drivers/block/null_blk/null_blk.h:8:
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:13:
In file included from arch/hexagon/include/asm/io.h:337:
include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
547 | val = __raw_readb(PCI_IOBASE + addr);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
560 | 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 drivers/block/null_blk/main.c:12:
In file included from drivers/block/null_blk/null_blk.h:8:
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:13:
In file included from arch/hexagon/include/asm/io.h:337:
include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
573 | 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 drivers/block/null_blk/main.c:12:
In file included from drivers/block/null_blk/null_blk.h:8:
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:13:
In file included from arch/hexagon/include/asm/io.h:337:
include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
584 | __raw_writeb(value, PCI_IOBASE + addr);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
594 | __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
604 | __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
| ~~~~~~~~~~ ^
>> drivers/block/null_blk/main.c:1303:2: warning: variable 'sector_in' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
1303 | __rq_for_each_bio(bio, req) {
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/blk-mq.h:1008:6: note: expanded from macro '__rq_for_each_bio'
1008 | if ((rq->bio)) \
| ^~~~~~~~~
drivers/block/null_blk/main.c:1316:8: note: uninitialized use occurs here
1316 | sector_in << SECTOR_SHIFT, rem);
| ^~~~~~~~~
drivers/block/null_blk/main.c:1303:2: note: remove the 'if' if its condition is always true
1303 | __rq_for_each_bio(bio, req) {
| ^
include/linux/blk-mq.h:1008:2: note: expanded from macro '__rq_for_each_bio'
1008 | if ((rq->bio)) \
| ^
drivers/block/null_blk/main.c:1287:20: note: initialize the variable 'sector_in' to silence this warning
1287 | sector_t sector_in, sector_out;
| ^
| = 0
>> drivers/block/null_blk/main.c:1303:2: warning: variable 'sector_out' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
1303 | __rq_for_each_bio(bio, req) {
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/blk-mq.h:1008:6: note: expanded from macro '__rq_for_each_bio'
1008 | if ((rq->bio)) \
| ^~~~~~~~~
drivers/block/null_blk/main.c:1315:27: note: uninitialized use occurs here
1315 | trace_nullb_copy_op(req, sector_out << SECTOR_SHIFT,
| ^~~~~~~~~~
drivers/block/null_blk/main.c:1303:2: note: remove the 'if' if its condition is always true
1303 | __rq_for_each_bio(bio, req) {
| ^
include/linux/blk-mq.h:1008:2: note: expanded from macro '__rq_for_each_bio'
1008 | if ((rq->bio)) \
| ^
drivers/block/null_blk/main.c:1287:32: note: initialize the variable 'sector_out' to silence this warning
1287 | sector_t sector_in, sector_out;
| ^
| = 0
8 warnings generated.

vim +1303 drivers/block/null_blk/main.c

1283
1284 static inline int nullb_setup_copy(struct nullb *nullb, struct request *req,
1285 bool is_fua)
1286 {
1287 sector_t sector_in, sector_out;
1288 loff_t offset_in, offset_out;
1289 void *in, *out;
1290 ssize_t chunk, rem = 0;
1291 struct bio *bio;
1292 struct nullb_page *t_page_in, *t_page_out;
1293 u16 seg = 1;
1294 int status = -EIO;
1295
1296 if (blk_rq_nr_phys_segments(req) != COPY_MAX_SEGMENTS)
1297 return status;
1298
1299 /*
1300 * First bio contains information about source and last bio contains
1301 * information about destination.
1302 */
> 1303 __rq_for_each_bio(bio, req) {
1304 if (seg == blk_rq_nr_phys_segments(req)) {
1305 sector_out = bio->bi_iter.bi_sector;
1306 if (rem != bio->bi_iter.bi_size)
1307 return status;
1308 } else {
1309 sector_in = bio->bi_iter.bi_sector;
1310 rem = bio->bi_iter.bi_size;
1311 }
1312 seg++;
1313 }
1314
1315 trace_nullb_copy_op(req, sector_out << SECTOR_SHIFT,
1316 sector_in << SECTOR_SHIFT, rem);
1317
1318 spin_lock_irq(&nullb->lock);
1319 while (rem > 0) {
1320 chunk = min_t(size_t, nullb->dev->blocksize, rem);
1321 offset_in = (sector_in & SECTOR_MASK) << SECTOR_SHIFT;
1322 offset_out = (sector_out & SECTOR_MASK) << SECTOR_SHIFT;
1323
1324 if (null_cache_active(nullb) && !is_fua)
1325 null_make_cache_space(nullb, PAGE_SIZE);
1326
1327 t_page_in = null_lookup_page(nullb, sector_in, false,
1328 !null_cache_active(nullb));
1329 if (!t_page_in)
1330 goto err;
1331 t_page_out = null_insert_page(nullb, sector_out,
1332 !null_cache_active(nullb) ||
1333 is_fua);
1334 if (!t_page_out)
1335 goto err;
1336
1337 in = kmap_local_page(t_page_in->page);
1338 out = kmap_local_page(t_page_out->page);
1339
1340 memcpy(out + offset_out, in + offset_in, chunk);
1341 kunmap_local(out);
1342 kunmap_local(in);
1343 __set_bit(sector_out & SECTOR_MASK, t_page_out->bitmap);
1344
1345 if (is_fua)
1346 null_free_sector(nullb, sector_out, true);
1347
1348 rem -= chunk;
1349 sector_in += chunk >> SECTOR_SHIFT;
1350 sector_out += chunk >> SECTOR_SHIFT;
1351 }
1352
1353 status = 0;
1354 err:
1355 spin_unlock_irq(&nullb->lock);
1356 return status;
1357 }
1358

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Next message: Eric DeVolder: "Re: linux-next: build failure after merge of the mm tree"
Previous message: Sean Christopherson: "Re: [RFC PATCH v2 5/5] KVM: Unmap pages only when it's indeed protected for NUMA migration"
In reply to: Nitesh Shetty: "[PATCH v14 11/11] null_blk: add support for copy offload"
Next in thread: kernel test robot: "Re: [PATCH v14 11/11] null_blk: add support for copy offload"
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