/* * mm/percpu-km.c - kernel memory based chunk allocation * * Copyright (C) 2010 SUSE Linux Products GmbH * Copyright (C) 2010 Tejun Heo * * This file is released under the GPLv2. * * Chunks are allocated as a contiguous kernel memory using gfp * allocation. This is to be used on nommu architectures. * * To use percpu-km, * * - define CONFIG_NEED_PER_CPU_KM from the arch Kconfig. * * - CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK must not be defined. It's * not compatible with PER_CPU_KM. EMBED_FIRST_CHUNK should work * fine. * * - NUMA is not supported. When setting up the first chunk, * @cpu_distance_fn should be NULL or report all CPUs to be nearer * than or at LOCAL_DISTANCE. * * - It's best if the chunk size is power of two multiple of * PAGE_SIZE. Because each chunk is allocated as a contiguous * kernel memory block using alloc_pages(), memory will be wasted if * chunk size is not aligned. percpu-km code will whine about it. */ #if defined(CONFIG_SMP) && defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK) #error "contiguous percpu allocation is incompatible with paged first chunk" #endif #include static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int page_start, int page_end) { return 0; } static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int page_start, int page_end) { /* nada */ } static struct pcpu_chunk *pcpu_create_chunk(void) { const int nr_pages = pcpu_group_sizes[0] >> PAGE_SHIFT; struct pcpu_chunk *chunk; struct page *pages; int i; chunk = pcpu_alloc_chunk(); if (!chunk) return NULL; pages = alloc_pages(GFP_KERNEL, order_base_2(nr_pages)); if (!pages) { pcpu_free_chunk(chunk); return NULL; } for (i = 0; i < nr_pages; i++) pcpu_set_page_chunk(nth_page(pages, i), chunk); chunk->data = pages; chunk->base_addr = page_address(pages) - pcpu_group_offsets[0]; spin_lock_irq(&pcpu_lock); pcpu_chunk_populated(chunk, 0, nr_pages); spin_unlock_irq(&pcpu_lock); return chunk; } static void pcpu_destroy_chunk(struct pcpu_chunk *chunk) { const int nr_pages = pcpu_group_sizes[0] >> PAGE_SHIFT; if (chunk && chunk->data) __free_pages(chunk->data, order_base_2(nr_pages)); pcpu_free_chunk(chunk); } static struct page *pcpu_addr_to_page(void *addr) { return virt_to_page(addr); } static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai) { size_t nr_pages, alloc_pages; /* all units must be in a single group */ if (ai->nr_groups != 1) { pr_crit("can't handle more than one group\n"); return -EINVAL; } nr_pages = (ai->groups[0].nr_units * ai->unit_size) >> PAGE_SHIFT; alloc_pages = roundup_pow_of_two(nr_pages); if (alloc_pages > nr_pages) pr_warn("wasting %zu pages per chunk\n", alloc_pages - nr_pages); return 0; } 6cc1b2b10e752'>root/drivers/usb/misc/rio500_usb.h
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authorLinus Torvalds <torvalds@linux-foundation.org>2017-02-02 12:34:27 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-02 12:34:27 -0800
commitf2557779e1a9cfbf69c99b74da26cc1b2b10e752 (patch)
tree8ddca65c897199add553948c429072b8bd463692 /drivers/usb/misc/rio500_usb.h
parent6d04dfc8966019b8b0977b2cb942351f13d2b178 (diff)
parent030305d69fc6963c16003f50d7e8d74b02d0a143 (diff)
Merge tag 'pci-v4.10-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci
Pull PCI fix from Bjorn Helgaas: "Configure ASPM on the link from a PCI-to-PCIe bridge (avoids a NULL pointer dereference on topologies including these bridges)" * tag 'pci-v4.10-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: PCI/ASPM: Handle PCI-to-PCIe bridges as roots of PCIe hierarchies
Diffstat (limited to 'drivers/usb/misc/rio500_usb.h')