On Thu, Mar 23, 2023 at 10:48:09AM +0800, kernel test robot wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable > head: 39aca4f17e02ee4076b6ab327577c9b1be23775d > commit: d9cab54f77377439e766e1c5916f79ec2ee27a6c [288/290] mm: vmalloc: convert vread() to vread_iter() > config: i386-randconfig-a002 (https://download.01.org/0day-ci/archive/20230323/202303231055.DeninwHS-lkp@xxxxxxxxx/config) > compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1) > reproduce (this is a W=1 build): > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross > chmod +x ~/bin/make.cross > # https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/commit/?id=d9cab54f77377439e766e1c5916f79ec2ee27a6c > git remote add akpm-mm https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git > git fetch --no-tags akpm-mm mm-unstable > git checkout d9cab54f77377439e766e1c5916f79ec2ee27a6c > # save the config file > mkdir build_dir && cp config build_dir/.config > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 olddefconfig > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash > > If you fix the issue, kindly add following tag where applicable > | Reported-by: kernel test robot <lkp@xxxxxxxxx> > | Link: https://lore.kernel.org/oe-kbuild-all/202303231055.DeninwHS-lkp@xxxxxxxxx/ > > All warnings (new ones prefixed by >>): > > >> mm/vmalloc.c:3448:8: warning: no previous prototype for function 'zero_iter' [-Wmissing-prototypes] > size_t zero_iter(struct iov_iter *iter, size_t count) > ^ > mm/vmalloc.c:3448:1: note: declare 'static' if the function is not intended to be used outside of this translation unit > size_t zero_iter(struct iov_iter *iter, size_t count) > ^ > static Ack, will fix + respin. > >> mm/vmalloc.c:3543:6: warning: variable 'remains' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized] > if (bitmap_empty(vb->used_map, VMAP_BBMAP_BITS)) { > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > mm/vmalloc.c:3587:17: note: uninitialized use occurs here > return count - remains + zero_iter(iter, remains); > ^~~~~~~ > mm/vmalloc.c:3543:2: note: remove the 'if' if its condition is always false > if (bitmap_empty(vb->used_map, VMAP_BBMAP_BITS)) { > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > mm/vmalloc.c:3539:6: warning: variable 'remains' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized] > if (!vb) > ^~~ > mm/vmalloc.c:3587:17: note: uninitialized use occurs here > return count - remains + zero_iter(iter, remains); > ^~~~~~~ > mm/vmalloc.c:3539:2: note: remove the 'if' if its condition is always false > if (!vb) > ^~~~~~~~ > mm/vmalloc.c:3524:16: note: initialize the variable 'remains' to silence this warning > size_t remains, n; > ^ > = 0 > 3 warnings generated. > Remaining warnings have all already been fixed in latest version of this patch series. > > vim +/zero_iter +3448 mm/vmalloc.c > > 3442 > 3443 /* > 3444 * Atomically zero bytes in the iterator. > 3445 * > 3446 * Returns the number of zeroed bytes. > 3447 */ > > 3448 size_t zero_iter(struct iov_iter *iter, size_t count) > 3449 { > 3450 size_t remains = count; > 3451 > 3452 while (remains > 0) { > 3453 size_t num, copied; > 3454 > 3455 num = remains < PAGE_SIZE ? remains : PAGE_SIZE; > 3456 copied = copy_page_to_iter_atomic(ZERO_PAGE(0), 0, num, iter); > 3457 remains -= copied; > 3458 > 3459 if (copied < num) > 3460 break; > 3461 } > 3462 > 3463 return count - remains; > 3464 } > 3465 > 3466 /* > 3467 * small helper routine, copy contents to iter from addr. > 3468 * If the page is not present, fill zero. > 3469 * > 3470 * Returns the number of copied bytes. > 3471 */ > 3472 static size_t aligned_vread_iter(struct iov_iter *iter, > 3473 const char *addr, size_t count) > 3474 { > 3475 size_t remains = count; > 3476 struct page *page; > 3477 > 3478 while (remains > 0) { > 3479 unsigned long offset, length; > 3480 size_t copied = 0; > 3481 > 3482 offset = offset_in_page(addr); > 3483 length = PAGE_SIZE - offset; > 3484 if (length > remains) > 3485 length = remains; > 3486 page = vmalloc_to_page(addr); > 3487 /* > 3488 * To do safe access to this _mapped_ area, we need lock. But > 3489 * adding lock here means that we need to add overhead of > 3490 * vmalloc()/vfree() calls for this _debug_ interface, rarely > 3491 * used. Instead of that, we'll use an local mapping via > 3492 * copy_page_to_iter_atomic() and accept a small overhead in > 3493 * this access function. > 3494 */ > 3495 if (page) > 3496 copied = copy_page_to_iter_atomic(page, offset, length, > 3497 iter); > 3498 > 3499 /* Zero anything we were unable to copy. */ > 3500 copied += zero_iter(iter, length - copied); > 3501 > 3502 addr += copied; > 3503 remains -= copied; > 3504 > 3505 if (copied != length) > 3506 break; > 3507 } > 3508 > 3509 return count - remains; > 3510 } > 3511 > 3512 /* > 3513 * Read from a vm_map_ram region of memory. > 3514 * > 3515 * Returns the number of copied bytes. > 3516 */ > 3517 static size_t vmap_ram_vread_iter(struct iov_iter *iter, const char *addr, > 3518 size_t count, unsigned long flags) > 3519 { > 3520 char *start; > 3521 struct vmap_block *vb; > 3522 unsigned long offset; > 3523 unsigned int rs, re; > 3524 size_t remains, n; > 3525 > 3526 /* > 3527 * If it's area created by vm_map_ram() interface directly, but > 3528 * not further subdividing and delegating management to vmap_block, > 3529 * handle it here. > 3530 */ > 3531 if (!(flags & VMAP_BLOCK)) > 3532 return aligned_vread_iter(iter, addr, count); > 3533 > 3534 /* > 3535 * Area is split into regions and tracked with vmap_block, read out > 3536 * each region and zero fill the hole between regions. > 3537 */ > 3538 vb = xa_load(&vmap_blocks, addr_to_vb_idx((unsigned long)addr)); > 3539 if (!vb) > 3540 goto finished_zero; > 3541 > 3542 spin_lock(&vb->lock); > > 3543 if (bitmap_empty(vb->used_map, VMAP_BBMAP_BITS)) { > 3544 spin_unlock(&vb->lock); > 3545 goto finished_zero; > 3546 } > 3547 > 3548 remains = count; > 3549 for_each_set_bitrange(rs, re, vb->used_map, VMAP_BBMAP_BITS) { > 3550 size_t copied; > 3551 > 3552 if (remains == 0) > 3553 goto finished; > 3554 > 3555 start = vmap_block_vaddr(vb->va->va_start, rs); > 3556 > 3557 if (addr < start) { > 3558 size_t to_zero = min_t(size_t, start - addr, remains); > 3559 size_t zeroed = zero_iter(iter, to_zero); > 3560 > 3561 addr += zeroed; > 3562 remains -= zeroed; > 3563 > 3564 if (remains == 0 || zeroed != to_zero) > 3565 goto finished; > 3566 } > 3567 > 3568 /*it could start reading from the middle of used region*/ > 3569 offset = offset_in_page(addr); > 3570 n = ((re - rs + 1) << PAGE_SHIFT) - offset; > 3571 if (n > remains) > 3572 n = remains; > 3573 > 3574 copied = aligned_vread_iter(iter, start + offset, n); > 3575 > 3576 addr += copied; > 3577 remains -= copied; > 3578 > 3579 if (copied != n) > 3580 goto finished; > 3581 } > 3582 > 3583 spin_unlock(&vb->lock); > 3584 > 3585 finished_zero: > 3586 /* zero-fill the left dirty or free regions */ > 3587 return count - remains + zero_iter(iter, remains); > 3588 finished: > 3589 /* We couldn't copy/zero everything */ > 3590 spin_unlock(&vb->lock); > 3591 return count - remains; > 3592 } > 3593 > > -- > 0-DAY CI Kernel Test Service > https://github.com/intel/lkp-tests
