cregit-Linux how code gets into the kernel

Release 4.15 fs/aio.c

Directory: fs
/*
 *      An async IO implementation for Linux
 *      Written by Benjamin LaHaise <bcrl@kvack.org>
 *
 *      Implements an efficient asynchronous io interface.
 *
 *      Copyright 2000, 2001, 2002 Red Hat, Inc.  All Rights Reserved.
 *
 *      See ../COPYING for licensing terms.
 */

#define pr_fmt(fmt) "%s: " fmt, __func__

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/aio_abi.h>
#include <linux/export.h>
#include <linux/syscalls.h>
#include <linux/backing-dev.h>
#include <linux/uio.h>

#include <linux/sched/signal.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/mmu_context.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/aio.h>
#include <linux/highmem.h>
#include <linux/workqueue.h>
#include <linux/security.h>
#include <linux/eventfd.h>
#include <linux/blkdev.h>
#include <linux/compat.h>
#include <linux/migrate.h>
#include <linux/ramfs.h>
#include <linux/percpu-refcount.h>
#include <linux/mount.h>

#include <asm/kmap_types.h>
#include <linux/uaccess.h>

#include "internal.h"


#define AIO_RING_MAGIC			0xa10a10a1

#define AIO_RING_COMPAT_FEATURES	1

#define AIO_RING_INCOMPAT_FEATURES	0

struct aio_ring {
	
unsigned	id;	/* kernel internal index number */
	
unsigned	nr;	/* number of io_events */
	
unsigned	head;	/* Written to by userland or under ring_lock
                                 * mutex by aio_read_events_ring(). */
	
unsigned	tail;

	
unsigned	magic;
	
unsigned	compat_features;
	
unsigned	incompat_features;
	
unsigned	header_length;	/* size of aio_ring */


	
struct io_event		io_events[0];
}; /* 128 bytes + ring size */


#define AIO_RING_PAGES	8


struct kioctx_table {
	
struct rcu_head	rcu;
	
unsigned	nr;
	
struct kioctx	*table[];
};


struct kioctx_cpu {
	
unsigned		reqs_available;
};


struct ctx_rq_wait {
	
struct completion comp;
	
atomic_t count;
};


struct kioctx {
	
struct percpu_ref	users;
	
atomic_t		dead;

	
struct percpu_ref	reqs;

	
unsigned long		user_id;

	
struct __percpu kioctx_cpu *cpu;

	/*
         * For percpu reqs_available, number of slots we move to/from global
         * counter at a time:
         */
	
unsigned		req_batch;
	/*
         * This is what userspace passed to io_setup(), it's not used for
         * anything but counting against the global max_reqs quota.
         *
         * The real limit is nr_events - 1, which will be larger (see
         * aio_setup_ring())
         */
	
unsigned		max_reqs;

	/* Size of ringbuffer, in units of struct io_event */
	
unsigned		nr_events;

	
unsigned long		mmap_base;
	
unsigned long		mmap_size;

	
struct page		**ring_pages;
	
long			nr_pages;

	
struct work_struct	free_work;

	/*
         * signals when all in-flight requests are done
         */
	
struct ctx_rq_wait	*rq_wait;

	struct {
		/*
                 * This counts the number of available slots in the ringbuffer,
                 * so we avoid overflowing it: it's decremented (if positive)
                 * when allocating a kiocb and incremented when the resulting
                 * io_event is pulled off the ringbuffer.
                 *
                 * We batch accesses to it with a percpu version.
                 */
		
atomic_t	reqs_available;
	
} ____cacheline_aligned_in_smp;

	struct {
		
spinlock_t	ctx_lock;
		
struct list_head active_reqs;	/* used for cancellation */
	
} ____cacheline_aligned_in_smp;

	struct {
		
struct mutex	ring_lock;
		
wait_queue_head_t wait;
	
} ____cacheline_aligned_in_smp;

	struct {
		
unsigned	tail;
		
unsigned	completed_events;
		
spinlock_t	completion_lock;
	
} ____cacheline_aligned_in_smp;

	
struct page		*internal_pages[AIO_RING_PAGES];
	
struct file		*aio_ring_file;

	
unsigned		id;
};

/*
 * We use ki_cancel == KIOCB_CANCELLED to indicate that a kiocb has been either
 * cancelled or completed (this makes a certain amount of sense because
 * successful cancellation - io_cancel() - does deliver the completion to
 * userspace).
 *
 * And since most things don't implement kiocb cancellation and we'd really like
 * kiocb completion to be lockless when possible, we use ki_cancel to
 * synchronize cancellation and completion - we only set it to KIOCB_CANCELLED
 * with xchg() or cmpxchg(), see batch_complete_aio() and kiocb_cancel().
 */

#define KIOCB_CANCELLED		((void *) (~0ULL))


struct aio_kiocb {
	
struct kiocb		common;

	
struct kioctx		*ki_ctx;
	
kiocb_cancel_fn		*ki_cancel;

	
struct iocb __user	*ki_user_iocb;	/* user's aiocb */
	
__u64			ki_user_data;	/* user's data for completion */

	
struct list_head	ki_list;	/* the aio core uses this
                                                 * for cancellation */

	/*
         * If the aio_resfd field of the userspace iocb is not zero,
         * this is the underlying eventfd context to deliver events to.
         */
	
struct eventfd_ctx	*ki_eventfd;
};

/*------ sysctl variables----*/
static DEFINE_SPINLOCK(aio_nr_lock);

unsigned long aio_nr;		
/* current system wide number of aio requests */

unsigned long aio_max_nr = 0x10000; 
/* system wide maximum number of aio requests */
/*----end sysctl variables---*/


static struct kmem_cache	*kiocb_cachep;

static struct kmem_cache	*kioctx_cachep;


static struct vfsmount *aio_mnt;


static const struct file_operations aio_ring_fops;

static const struct address_space_operations aio_ctx_aops;


static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages) { struct qstr this = QSTR_INIT("[aio]", 5); struct file *file; struct path path; struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb); if (IS_ERR(inode)) return ERR_CAST(inode); inode->i_mapping->a_ops = &aio_ctx_aops; inode->i_mapping->private_data = ctx; inode->i_size = PAGE_SIZE * nr_pages; path.dentry = d_alloc_pseudo(aio_mnt->mnt_sb, &this); if (!path.dentry) { iput(inode); return ERR_PTR(-ENOMEM); } path.mnt = mntget(aio_mnt); d_instantiate(path.dentry, inode); file = alloc_file(&path, FMODE_READ | FMODE_WRITE, &aio_ring_fops); if (IS_ERR(file)) { path_put(&path); return file; } file->f_flags = O_RDWR; return file; }

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Benjamin LaHaise17697.24%150.00%
Dan Carpenter52.76%150.00%
Total181100.00%2100.00%


static struct dentry *aio_mount(struct file_system_type *fs_type, int flags, const char *dev_name, void *data) { static const struct dentry_operations ops = { .d_dname = simple_dname, }; struct dentry *root = mount_pseudo(fs_type, "aio:", NULL, &ops, AIO_RING_MAGIC); if (!IS_ERR(root)) root->d_sb->s_iflags |= SB_I_NOEXEC; return root; }

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Benjamin LaHaise5167.11%133.33%
Jann Horn2431.58%133.33%
Gu Zheng11.32%133.33%
Total76100.00%3100.00%

/* aio_setup * Creates the slab caches used by the aio routines, panic on * failure as this is done early during the boot sequence. */
static int __init aio_setup(void) { static struct file_system_type aio_fs = { .name = "aio", .mount = aio_mount, .kill_sb = kill_anon_super, }; aio_mnt = kern_mount(&aio_fs); if (IS_ERR(aio_mnt)) panic("Failed to create aio fs mount."); kiocb_cachep = KMEM_CACHE(aio_kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC); kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC); pr_debug("sizeof(struct page) = %zu\n", sizeof(struct page)); return 0; }

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Benjamin LaHaise7889.66%228.57%
Andrew Morton44.60%114.29%
Christoph Lameter22.30%114.29%
Christoph Hellwig11.15%114.29%
Kent Overstreet11.15%114.29%
Stephen Hemminger11.15%114.29%
Total87100.00%7100.00%

__initcall(aio_setup);
static void put_aio_ring_file(struct kioctx *ctx) { struct file *aio_ring_file = ctx->aio_ring_file; struct address_space *i_mapping; if (aio_ring_file) { truncate_setsize(file_inode(aio_ring_file), 0); /* Prevent further access to the kioctx from migratepages */ i_mapping = aio_ring_file->f_mapping; spin_lock(&i_mapping->private_lock); i_mapping->private_data = NULL; ctx->aio_ring_file = NULL; spin_unlock(&i_mapping->private_lock); fput(aio_ring_file); } }

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Benjamin LaHaise5669.14%240.00%
Rasmus Villemoes1214.81%120.00%
Gu Zheng911.11%120.00%
Al Viro44.94%120.00%
Total81100.00%5100.00%


static void aio_free_ring(struct kioctx *ctx) { int i; /* Disconnect the kiotx from the ring file. This prevents future * accesses to the kioctx from page migration. */ put_aio_ring_file(ctx); for (i = 0; i < ctx->nr_pages; i++) { struct page *page; pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i, page_count(ctx->ring_pages[i])); page = ctx->ring_pages[i]; if (!page) continue; ctx->ring_pages[i] = NULL; put_page(page); } if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) { kfree(ctx->ring_pages); ctx->ring_pages = NULL; } }

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Benjamin LaHaise8368.60%457.14%
Gu Zheng2419.83%114.29%
Sasha Levin86.61%114.29%
Kent Overstreet64.96%114.29%
Total121100.00%7100.00%


static int aio_ring_mremap(struct vm_area_struct *vma) { struct file *file = vma->vm_file; struct mm_struct *mm = vma->vm_mm; struct kioctx_table *table; int i, res = -EINVAL; spin_lock(&mm->ioctx_lock); rcu_read_lock(); table = rcu_dereference(mm->ioctx_table); for (i = 0; i < table->nr; i++) { struct kioctx *ctx; ctx = table->table[i]; if (ctx && ctx->aio_ring_file == file) { if (!atomic_read(&ctx->dead)) { ctx->user_id = ctx->mmap_base = vma->vm_start; res = 0; } break; } } rcu_read_unlock(); spin_unlock(&mm->ioctx_lock); return res; }

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Pavel Emelyanov11073.83%125.00%
Al Viro2516.78%125.00%
Gu Zheng96.04%125.00%
Oleg Nesterov53.36%125.00%
Total149100.00%4100.00%

static const struct vm_operations_struct aio_ring_vm_ops = { .mremap = aio_ring_mremap, #if IS_ENABLED(CONFIG_MMU) .fault = filemap_fault, .map_pages = filemap_map_pages, .page_mkwrite = filemap_page_mkwrite, #endif };
static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma) { vma->vm_flags |= VM_DONTEXPAND; vma->vm_ops = &aio_ring_vm_ops; return 0; }

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Oleg Nesterov32100.00%1100.00%
Total32100.00%1100.00%

static const struct file_operations aio_ring_fops = { .mmap = aio_ring_mmap, }; #if IS_ENABLED(CONFIG_MIGRATION)
static int aio_migratepage(struct address_space *mapping, struct page *new, struct page *old, enum migrate_mode mode) { struct kioctx *ctx; unsigned long flags; pgoff_t idx; int rc; /* * We cannot support the _NO_COPY case here, because copy needs to * happen under the ctx->completion_lock. That does not work with the * migration workflow of MIGRATE_SYNC_NO_COPY. */ if (mode == MIGRATE_SYNC_NO_COPY) return -EINVAL; rc = 0; /* mapping->private_lock here protects against the kioctx teardown. */ spin_lock(&mapping->private_lock); ctx = mapping->private_data; if (!ctx) { rc = -EINVAL; goto out; } /* The ring_lock mutex. The prevents aio_read_events() from writing * to the ring's head, and prevents page migration from mucking in * a partially initialized kiotx. */ if (!mutex_trylock(&ctx->ring_lock)) { rc = -EAGAIN; goto out; } idx = old->index; if (idx < (pgoff_t)ctx->nr_pages) { /* Make sure the old page hasn't already been changed */ if (ctx->ring_pages[idx] != old) rc = -EAGAIN; } else rc = -EINVAL; if (rc != 0) goto out_unlock; /* Writeback must be complete */ BUG_ON(PageWriteback(old)); get_page(new); rc = migrate_page_move_mapping(mapping, new, old, NULL, mode, 1); if (rc != MIGRATEPAGE_SUCCESS) { put_page(new); goto out_unlock; } /* Take completion_lock to prevent other writes to the ring buffer * while the old page is copied to the new. This prevents new * events from being lost. */ spin_lock_irqsave(&ctx->completion_lock, flags); migrate_page_copy(new, old); BUG_ON(ctx->ring_pages[idx] != old); ctx->ring_pages[idx] = new; spin_unlock_irqrestore(&ctx->completion_lock, flags); /* The old page is no longer accessible. */ put_page(old); out_unlock: mutex_unlock(&ctx->ring_lock); out: spin_unlock(&mapping->private_lock); return rc; }

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Benjamin LaHaise15855.83%360.00%
Gu Zheng11440.28%120.00%
Jérôme Glisse113.89%120.00%
Total283100.00%5100.00%

#endif static const struct address_space_operations aio_ctx_aops = { .set_page_dirty = __set_page_dirty_no_writeback, #if IS_ENABLED(CONFIG_MIGRATION) .migratepage = aio_migratepage, #endif };
static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events) { struct aio_ring *ring; struct mm_struct *mm = current->mm; unsigned long size, unused; int nr_pages; int i; struct file *file; /* Compensate for the ring buffer's head/tail overlap entry */ nr_events += 2; /* 1 is required, 2 for good luck */ size = sizeof(struct aio_ring); size += sizeof(struct io_event) * nr_events; nr_pages = PFN_UP(size); if (nr_pages < 0) return -EINVAL; file = aio_private_file(ctx, nr_pages); if (IS_ERR(file)) { ctx->aio_ring_file = NULL; return -ENOMEM; } ctx->aio_ring_file = file; nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event); ctx->ring_pages = ctx->internal_pages; if (nr_pages > AIO_RING_PAGES) { ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL); if (!ctx->ring_pages) { put_aio_ring_file(ctx); return -ENOMEM; } } for (i = 0; i < nr_pages; i++) { struct page *page; page = find_or_create_page(file->f_mapping, i, GFP_HIGHUSER | __GFP_ZERO); if (!page) break; pr_debug("pid(%d) page[%d]->count=%d\n", current->pid, i, page_count(page)); SetPageUptodate(page); unlock_page(page); ctx->ring_pages[i] = page; } ctx->nr_pages = i; if (unlikely(i != nr_pages)) { aio_free_ring(ctx); return -ENOMEM; } ctx->mmap_size = nr_pages * PAGE_SIZE; pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size); if (down_write_killable(&mm->mmap_sem)) { ctx->mmap_size = 0; aio_free_ring(ctx); return -EINTR; } ctx->mmap_base = do_mmap_pgoff(ctx->aio_ring_file, 0, ctx->mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, 0, &unused, NULL); up_write(&mm->mmap_sem); if (IS_ERR((void *)ctx->mmap_base)) { ctx->mmap_size = 0; aio_free_ring(ctx); return -ENOMEM; } pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base); ctx->user_id = ctx->mmap_base; ctx->nr_events = nr_events; /* trusted copy */ ring = kmap_atomic(ctx->ring_pages[0]); ring->nr = nr_events; /* user copy */ ring->id = ~0U; ring->head = ring->tail = 0; ring->magic = AIO_RING_MAGIC; ring->compat_features = AIO_RING_COMPAT_FEATURES; ring->incompat_features = AIO_RING_INCOMPAT_FEATURES; ring->header_length = sizeof(struct aio_ring); kunmap_atomic(ring); flush_dcache_page(ctx->ring_pages[0]); return 0; }

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Benjamin LaHaise23646.00%421.05%
Gu Zheng11221.83%210.53%
Linus Torvalds10019.49%15.26%
Kent Overstreet244.68%315.79%
Michal Hocko203.90%15.26%
Zach Brown91.75%15.26%
Mauricio Faria de Oliveira40.78%15.26%
Michel Lespinasse30.58%210.53%
Al Viro20.39%210.53%
Mike Rapoport20.39%15.26%
Oliver Neukum10.19%15.26%
Total513100.00%19100.00%

#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event)) #define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event)) #define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel) { struct aio_kiocb *req = container_of(iocb, struct aio_kiocb, common); struct kioctx *ctx = req->ki_ctx; unsigned long flags; spin_lock_irqsave(&ctx->ctx_lock, flags); if (!req->ki_list.next) list_add(&req->ki_list, &ctx->active_reqs); req->ki_cancel = cancel; spin_unlock_irqrestore(&ctx->ctx_lock, flags); }

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Kent Overstreet7482.22%150.00%
Christoph Hellwig1617.78%150.00%
Total90100.00%2100.00%

EXPORT_SYMBOL(kiocb_set_cancel_fn);
static int kiocb_cancel(struct aio_kiocb *kiocb) { kiocb_cancel_fn *old, *cancel; /* * Don't want to set kiocb->ki_cancel = KIOCB_CANCELLED unless it * actually has a cancel function, hence the cmpxchg() */ cancel = READ_ONCE(kiocb->ki_cancel); do { if (!cancel || cancel == KIOCB_CANCELLED) return -EINVAL; old = cancel; cancel = cmpxchg(&kiocb->ki_cancel, old, KIOCB_CANCELLED); } while (cancel != old); return cancel(&kiocb->common); }

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Kent Overstreet7393.59%360.00%
Christoph Hellwig45.13%120.00%
Mark Rutland11.28%120.00%
Total78100.00%5100.00%


static void free_ioctx(struct work_struct *work) { struct kioctx *ctx = container_of(work, struct kioctx, free_work); pr_debug("freeing %p\n", ctx); aio_free_ring(ctx); free_percpu(ctx->cpu); percpu_ref_exit(&ctx->reqs); percpu_ref_exit(&ctx->users); kmem_cache_free(kioctx_cachep, ctx); }

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Kent Overstreet3855.88%350.00%
Tejun Heo1623.53%116.67%
Benjamin LaHaise1319.12%116.67%
Jens Axboe11.47%116.67%
Total68100.00%6100.00%


static void free_ioctx_reqs(struct percpu_ref *ref) { struct kioctx *ctx = container_of(ref, struct kioctx, reqs); /* At this point we know that there are no any in-flight requests */ if (ctx->rq_wait && atomic_dec_and_test(&ctx->rq_wait->count)) complete(&ctx->rq_wait->comp); INIT_WORK(&ctx->free_work, free_ioctx); schedule_work(&ctx->free_work); }

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Kent Overstreet4461.97%133.33%
Jens Axboe1521.13%133.33%
Anatol Pomozov1216.90%133.33%
Total71100.00%3100.00%

/* * When this function runs, the kioctx has been removed from the "hash table" * and ctx->users has dropped to 0, so we know no more kiocbs can be submitted - * now it's safe to cancel any that need to be. */
static void free_ioctx_users(struct percpu_ref *ref) { struct kioctx *ctx = container_of(ref, struct kioctx, users); struct aio_kiocb *req; spin_lock_irq(&ctx->ctx_lock); while (!list_empty(&ctx->active_reqs)) { req = list_first_entry(&ctx->active_reqs, struct aio_kiocb, ki_list); list_del_init(&req->ki_list); kiocb_cancel(req); } spin_unlock_irq(&ctx->ctx_lock); percpu_ref_kill(&ctx->reqs); percpu_ref_put(&ctx->reqs); }

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Kent Overstreet8985.58%360.00%
Benjamin LaHaise1312.50%120.00%
Christoph Hellwig21.92%120.00%
Total104100.00%5100.00%


static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm) { unsigned i, new_nr; struct kioctx_table *table, *old; struct aio_ring *ring; spin_lock(&mm->ioctx_lock); table = rcu_dereference_raw(mm->ioctx_table); while (1) { if (table) for (i = 0; i < table->nr; i++) if (!table->table[i]) { ctx->id = i; table->table[i] = ctx; spin_unlock(&mm->ioctx_lock); /* While kioctx setup is in progress, * we are protected from page migration * changes ring_pages by ->ring_lock. */ ring = kmap_atomic(ctx->ring_pages[0]); ring->id = ctx->id; kunmap_atomic(ring); return 0; } new_nr = (table ? table->nr : 1) * 4; spin_unlock(&mm->ioctx_lock); table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) * new_nr, GFP_KERNEL); if (!table) return -ENOMEM; table->nr = new_nr; spin_lock(&mm->ioctx_lock); old = rcu_dereference_raw(mm->ioctx_table); if (!old) { rcu_assign_pointer(mm->ioctx_table, table); } else if (table->nr > old->nr) { memcpy(table->table, old->table, old->nr * sizeof(struct kioctx *)); rcu_assign_pointer(mm->ioctx_table, table); kfree_rcu(old, rcu); } else { kfree(table); table = old; } } }

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Benjamin LaHaise28596.61%350.00%
Kent Overstreet82.71%233.33%
Oleg Nesterov20.68%116.67%
Total295100.00%6100.00%


static void aio_nr_sub(unsigned nr) { spin_lock(&aio_nr_lock); if (WARN_ON(aio_nr - nr > aio_nr)) aio_nr = 0; else aio_nr -= nr; spin_unlock(&aio_nr_lock); }

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Kent Overstreet41100.00%1100.00%
Total41100.00%1100.00%

/* ioctx_alloc * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed. */
static struct kioctx *ioctx_alloc(unsigned nr_events) { struct mm_struct *mm = current->mm; struct kioctx *ctx; int err = -ENOMEM; /* * Store the original nr_events -- what userspace passed to io_setup(), * for counting against the global limit -- before it changes. */ unsigned int max_reqs = nr_events; /* * We keep track of the number of available ringbuffer slots, to prevent * overflow (reqs_available), and we also use percpu counters for this. * * So since up to half the slots might be on other cpu's percpu counters * and unavailable, double nr_events so userspace sees what they * expected: additionally, we move req_batch slots to/from percpu * counters at a time, so make sure that isn't 0: */ nr_events = max(nr_events, num_possible_cpus() * 4); nr_events *= 2; /* Prevent overflows */ if (nr_events > (0x10000000U / sizeof(struct io_event))) { pr_debug("ENOMEM: nr_events too high\n"); return ERR_PTR(-EINVAL); } if (!nr_events || (unsigned long)max_reqs > aio_max_nr) return ERR_PTR(-EAGAIN); ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL); if (!ctx) return ERR_PTR(-ENOMEM); ctx->max_reqs = max_reqs; spin_lock_init(&ctx->ctx_lock); spin_lock_init(&ctx->completion_lock); mutex_init(&ctx->ring_lock); /* Protect against page migration throughout kiotx setup by keeping * the ring_lock mutex held until setup is complete. */ mutex_lock(&ctx->ring_lock); init_waitqueue_head(&ctx->wait); INIT_LIST_HEAD(&ctx->active_reqs); if (percpu_ref_init(&ctx->users, free_ioctx_users, 0, GFP_KERNEL)) goto err; if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs, 0, GFP_KERNEL)) goto err; ctx->cpu = alloc_percpu(struct kioctx_cpu); if (!ctx->cpu) goto err; err = aio_setup_ring(ctx, nr_events); if (err < 0) goto err; atomic_set(&ctx->reqs_available, ctx->nr_events - 1); ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4); if (ctx->req_batch < 1) ctx->req_batch = 1; /* limit the number of system wide aios */ spin_lock(&aio_nr_lock); if (aio_nr + ctx->max_reqs > aio_max_nr || aio_nr + ctx->max_reqs < aio_nr) { spin_unlock(&aio_nr_lock); err = -EAGAIN; goto err_ctx; } aio_nr += ctx->max_reqs; spin_unlock(&aio_nr_lock); percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */ percpu_ref_get(&ctx->reqs); /* free_ioctx_users() will drop this */ err = ioctx_add_table(ctx, mm); if (err) goto err_cleanup; /* Release the ring_lock mutex now that all setup is complete. */ mutex_unlock(&ctx->ring_lock); pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n", ctx, ctx->user_id, mm, ctx->nr_events); return ctx; err_cleanup: aio_nr_sub(ctx->max_reqs); err_ctx: atomic_set(&ctx->dead, 1); if (ctx->mmap_size) vm_munmap(ctx->mmap_base, ctx->mmap_size); aio_free_ring(ctx); err: mutex_unlock(&ctx->ring_lock); free_percpu(ctx->cpu); percpu_ref_exit(&ctx->reqs); percpu_ref_exit(&ctx->users); kmem_cache_free(kioctx_cachep, ctx); pr_debug("error allocating ioctx %d\n", err); return ERR_PTR(err); }

Contributors

PersonTokensPropCommitsCommitProp
Benjamin LaHaise23445.44%622.22%
Kent Overstreet16932.82%829.63%
Al Viro479.13%414.81%
Zach Brown234.47%13.70%
Mauricio Faria de Oliveira173.30%13.70%
Tejun Heo122.33%414.81%
Gu Zheng122.33%27.41%
Robert P. J. Day10.19%13.70%
Total515100.00%27100.00%

/* kill_ioctx * Cancels all outstanding aio requests on an aio context. Used * when the processes owning a context have all exited to encourage * the rapid destruction of the kioctx. */
static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx, struct ctx_rq_wait *wait) { struct kioctx_table *table; spin_lock(&mm->ioctx_lock); if (atomic_xchg(&ctx->dead, 1)) { spin_unlock(&mm->ioctx_lock); return -EINVAL; } table = rcu_dereference_raw(mm->ioctx_table); WARN_ON(ctx != table->table[ctx->id]); table->table[ctx->id] = NULL; spin_unlock(&mm->ioctx_lock); /* percpu_ref_kill() will do the necessary call_rcu() */ wake_up_all(&ctx->wait); /* * It'd be more correct to do this in free_ioctx(), after all * the outstanding kiocbs have finished - but by then io_destroy * has already returned, so io_setup() could potentially return * -EAGAIN with no ioctxs actually in use (as far as userspace * could tell). */ aio_nr_sub(ctx->max_reqs); if (ctx->mmap_size) vm_munmap(ctx->mmap_base, ctx->mmap_size); ctx->rq_wait = wait; percpu_ref_kill(&ctx->users); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Benjamin LaHaise6643.14%533.33%
Kent Overstreet5032.68%533.33%
Al Viro159.80%16.67%
Ken Chen106.54%16.67%
Anatol Pomozov74.58%16.67%
Jens Axboe42.61%16.67%
Oleg Nesterov10.65%16.67%
Total153100.00%15100.00%

/* * exit_aio: called when the last user of mm goes away. At this point, there is * no way for any new requests to be submited or any of the io_* syscalls to be * called on the context. * * There may be outstanding kiocbs, but free_ioctx() will explicitly wait on * them. */
void exit_aio(struct mm_struct *mm) { struct kioctx_table *table = rcu_dereference_raw(mm->ioctx_table); struct ctx_rq_wait wait; int i, skipped; if (!table) return; atomic_set(&wait.count, table->nr); init_completion(&wait.comp); skipped = 0; for (i = 0; i < table->nr; ++i) { struct kioctx *ctx = table->table[i]; if (!ctx) { skipped++; continue; } /* * We don't need to bother with munmap() here - exit_mmap(mm) * is coming and it'll unmap everything. And we simply can't, * this is not necessarily our ->mm. * Since kill_ioctx() uses non-zero ->mmap_size as indicator * that it needs to unmap the area, just set it to 0. */ ctx->mmap_size = 0; kill_ioctx(mm, ctx, &wait); } if (!atomic_sub_and_test(skipped, &wait.count)) { /* Wait until all IO for the context are done. */ wait_for_completion(&wait.comp); } RCU_INIT_POINTER(mm->ioctx_table, NULL); kfree(table); }

Contributors

PersonTokensPropCommitsCommitProp
Jens Axboe5434.62%111.11%
Benjamin LaHaise4528.85%222.22%
Oleg Nesterov4025.64%111.11%
Gu Zheng74.49%111.11%
Al Viro63.85%111.11%
Kent Overstreet31.92%222.22%
Anatol Pomozov10.64%111.11%
Total156100.00%9100.00%


static void put_reqs_available(struct kioctx *ctx, unsigned nr) { struct kioctx_cpu *kcpu; unsigned long flags; local_irq_save(flags); kcpu = this_cpu_ptr(ctx->cpu); kcpu->reqs_available += nr; while (kcpu->reqs_available >= ctx->req_batch * 2) { kcpu->reqs_available -= ctx->req_batch; atomic_add(ctx->req_batch, &ctx->reqs_available); } local_irq_restore(flags); }

Contributors

PersonTokensPropCommitsCommitProp
Kent Overstreet6984.15%133.33%
Benjamin LaHaise1315.85%266.67%
Total82100.00%3100.00%


static bool get_reqs_available(struct kioctx *ctx) { struct kioctx_cpu *kcpu; bool ret = false; unsigned long flags; local_irq_save(flags); kcpu = this_cpu_ptr(ctx->cpu); if (!kcpu->reqs_available) { int old, avail = atomic_read(&ctx->reqs_available); do { if (avail < ctx->req_batch) goto out; old = avail; avail = atomic_cmpxchg(&ctx->reqs_available, avail, avail - ctx->req_batch); } while (avail != old); kcpu->reqs_available += ctx->req_batch; } ret = true; kcpu->reqs_available--; out: local_irq_restore(flags); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Kent Overstreet11890.08%133.33%
Benjamin LaHaise139.92%266.67%
Total131100.00%3100.00%

/* refill_reqs_available * Updates the reqs_available reference counts used for tracking the * number of free slots in the completion ring. This can be called * from aio_complete() (to optimistically update reqs_available) or * from aio_get_req() (the we're out of events case). It must be * called holding ctx->completion_lock. */
static void refill_reqs_available(struct kioctx *ctx, unsigned head, unsigned tail) { unsigned events_in_ring, completed; /* Clamp head since userland can write to it. */ head %= ctx->nr_events; if (head <= tail) events_in_ring = tail - head; else events_in_ring = ctx->nr_events - (head - tail); completed = ctx->completed_events; if (events_in_ring < completed) completed -= events_in_ring; else completed = 0; if (!completed) return; ctx->completed_events -= completed; put_reqs_available(ctx, completed); }

Contributors

PersonTokensPropCommitsCommitProp
Benjamin LaHaise94100.00%1100.00%
Total94100.00%1100.00%

/* user_refill_reqs_available * Called to refill reqs_available when aio_get_req() encounters an * out of space in the completion ring. */
static void user_refill_reqs_available(struct kioctx *ctx) { spin_lock_irq(&ctx->completion_lock); if (ctx->completed_events) { struct aio_ring *ring; unsigned head; /* Access of ring->head may race with aio_read_events_ring() * here, but that's okay since whether we read the old version * or the new version, and either will be valid. The important * part is that head cannot pass tail since we prevent * aio_complete() from updating tail by holding * ctx->completion_lock. Even if head is invalid, the check * against ctx->completed_events below will make sure we do the * safe/right thing. */ ring = kmap_atomic(ctx->ring_pages[0]); head = ring->head; kunmap_atomic(ring); refill_reqs_available(ctx, head, ctx->tail); } spin_unlock_irq(&ctx->completion_lock); }

Contributors

PersonTokensPropCommitsCommitProp
Benjamin LaHaise78100.00%1100.00%
Total78100.00%1100.00%

/* aio_get_req * Allocate a slot for an aio request. * Returns NULL if no requests are free. */
static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx) { struct aio_kiocb *req; if (!get_reqs_available(ctx)) { user_refill_reqs_available(ctx); if (!get_reqs_available(ctx)) return NULL; } req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL|__GFP_ZERO); if (unlikely(!req)) goto out_put; percpu_ref_get(&ctx->reqs); req->ki_ctx = ctx; return req; out_put: put_reqs_available(ctx, 1); return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Kent Overstreet4142.71%444.44%
Benjamin LaHaise2728.12%222.22%
Jeff Moyer2020.83%111.11%
Gleb Natapov66.25%111.11%
Christoph Hellwig22.08%111.11%
Total96100.00%9100.00%


static void kiocb_free(struct aio_kiocb *req) { if (req->common.ki_filp) fput(req->common.ki_filp); if (req->ki_eventfd != NULL) eventfd_ctx_put(req->ki_eventfd); kmem_cache_free(kiocb_cachep, req); }

Contributors

PersonTokensPropCommitsCommitProp
Benjamin LaHaise1632.00%116.67%
Kent Overstreet1428.00%233.33%
Davide Libenzi1122.00%116.67%
Christoph Hellwig510.00%116.67%
William Lee Irwin III48.00%116.67%
Total50100.00%6100.00%


static struct kioctx *lookup_ioctx(unsigned long ctx_id) { struct aio_ring __user *ring = (void __user *)ctx_id; struct mm_struct *mm = current->mm; struct kioctx *ctx, *ret = NULL; struct kioctx_table *table; unsigned id; if (get_user(id, &ring->id)) return NULL; rcu_read_lock(); table = rcu_dereference(mm->ioctx_table); if (!table || id >= table->nr) goto out; ctx = table->table[id]; if (ctx && ctx->user_id == ctx_id) { percpu_ref_get(&ctx->users); ret = ctx; } out: rcu_read_unlock(); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Benjamin LaHaise7354.48%342.86%
Zach Brown4634.33%114.29%
Suparna Bhattacharya85.97%114.29%
Kent Overstreet75.22%228.57%
Total134100.00%7100.00%

/* aio_complete * Called when the io request on the given iocb is complete. */
static void aio_complete(struct kiocb *kiocb, long res, long res2) { struct aio_kiocb *iocb = container_of(kiocb, struct aio_kiocb, common); struct kioctx *ctx = iocb->ki_ctx; struct aio_ring *ring; struct io_event *ev_page, *event; unsigned tail, pos, head; unsigned long flags; if (kiocb->ki_flags & IOCB_WRITE) { struct file *file = kiocb->ki_filp; /* * Tell lockdep we inherited freeze protection from submission * thread. */ if (S_ISREG(file_inode(file)->i_mode)) __sb_writers_acquired(file_inode(file)->i_sb, SB_FREEZE_WRITE); file_end_write(file); } /* * Special case handling for sync iocbs: * - events go directly into the iocb for fast handling * - the sync task with the iocb in its stack holds the single iocb * ref, no other paths have a way to get another ref * - the sync task helpfully left a reference to itself in the iocb */ BUG_ON(is_sync_kiocb(kiocb)); if (iocb->ki_list.next) { unsigned long flags; spin_lock_irqsave(&ctx->ctx_lock, flags); list_del(&iocb->ki_list); spin_unlock_irqrestore(&ctx->ctx_lock, flags); } /* * Add a completion event to the ring buffer. Must be done holding * ctx->completion_lock to prevent other code from messing with the tail * pointer since we might be called from irq context. */ spin_lock_irqsave(&ctx->completion_lock, flags); tail = ctx->tail; pos = tail + AIO_EVENTS_OFFSET; if (++tail >= ctx->nr_events) tail = 0; ev_page = kmap_atomic(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]); event = ev_page + pos % AIO_EVENTS_PER_PAGE; event->obj = (u64)(unsigned long)iocb->ki_user_iocb; event->data = iocb->ki_user_data; event->res = res; event->res2 = res2; kunmap_atomic(ev_page); flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]); pr_debug("%p[%u]: %p: %p %Lx %lx %lx\n", ctx, tail, iocb, iocb->ki_user_iocb, iocb->ki_user_data, res, res2); /* after flagging the request as done, we * must never even look at it again */ smp_wmb(); /* make event visible before updating tail */ ctx->tail = tail; ring = kmap_atomic(ctx->ring_pages[0]); head = ring->head; ring->tail = tail; kunmap_atomic(ring); flush_dcache_page(ctx->ring_pages[0]); ctx->completed_events++; if (ctx->completed_events > 1) refill_reqs_available(ctx, head, tail); spin_unlock_irqrestore(&ctx->completion_lock, flags); pr_debug("added to ring %p at [%u]\n", iocb, tail); /* * Check if the user asked us to deliver the result through an * eventfd. The eventfd_signal() function is safe to be called * from IRQ context. */ if (iocb->ki_eventfd != NULL) eventfd_signal(iocb->ki_eventfd, 1); /* everything turned out well, dispose of the aiocb. */ kiocb_free(iocb); /* * We have to order our ring_info tail store above and test * of the wait list below outside the wait lock. This is * like in wake_up_bit() where clearing a bit has to be * ordered with the unlocked test. */ smp_mb(); if (waitqueue_active(&ctx->wait)) wake_up(&ctx->wait); percpu_ref_put(&ctx->reqs); }

Contributors

PersonTokensPropCommitsCommitProp
Kent Overstreet13931.38%940.91%
Suparna Bhattacharya13330.02%14.55%
Benjamin LaHaise6915.58%29.09%
Jan Kara378.35%14.55%
Christoph Hellwig214.74%29.09%
Davide Libenzi184.06%29.09%
Shaohua Li122.71%14.55%
Kenneth W. Chen81.81%14.55%
Quentin Barnes40.90%14.55%
Zach Brown10.23%14.55%
Tang Chen10.23%14.55%
Total443100.00%22100.00%

/* aio_read_events_ring * Pull an event off of the ioctx's event ring. Returns the number of * events fetched */
static long aio_read_events_ring(struct kioctx *ctx, struct io_event __user *event, long nr) { struct aio_ring *ring; unsigned head, tail, pos; long ret = 0; int copy_ret; /* * The mutex can block and wake us up and that will cause * wait_event_interruptible_hrtimeout() to schedule without sleeping * and repeat. This should be rare enough that it doesn't cause * peformance issues. See the comment in read_events() for more detail. */ sched_annotate_sleep(); mutex_lock(&ctx->ring_lock); /* Access to ->ring_pages here is protected by ctx->ring_lock. */ ring = kmap_atomic(ctx->ring_pages[0]); head = ring->head; tail = ring->tail; kunmap_atomic(ring); /* * Ensure that once we've read the current tail pointer, that * we also see the events that were stored up to the tail. */ smp_rmb(); pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events); if (head == tail) goto out; head %= ctx->nr_events; tail %= ctx->nr_events; while (ret < nr) { long avail; struct io_event *ev; struct page *page; avail = (head <= tail ? tail : ctx->nr_events) - head; if (head == tail) break; avail = min(avail, nr - ret); avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - ((head + AIO_EVENTS_OFFSET) % AIO_EVENTS_PER_PAGE)); pos = head + AIO_EVENTS_OFFSET; page = ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]; pos %= AIO_EVENTS_PER_PAGE; ev = kmap(page); copy_ret = copy_to_user(event + ret, ev + pos, sizeof(*ev) * avail); kunmap(page); if (unlikely(copy_ret)) { ret = -EFAULT; goto out; } ret += avail; head += avail; head %= ctx->nr_events; } ring = kmap_atomic(ctx->ring_pages[0]); ring->head = head; kunmap_atomic(ring); flush_dcache_page(ctx->ring_pages[0]); pr_debug("%li h%u t%u\n", ret, head, tail); out: mutex_unlock(&ctx->ring_lock); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Kent Overstreet22065.09%541.67%
Suparna Bhattacharya9427.81%18.33%
Benjamin LaHaise154.44%325.00%
Dave Chinner41.18%18.33%
Jeff Moyer41.18%18.33%
Zhao Hongjiang10.30%18.33%
Total338100.00%12100.00%


static bool aio_read_events(struct kioctx *ctx, long min_nr, long nr, struct io_event __user *event, long *i) { long ret = aio_read_events_ring(ctx, event + *i, nr - *i); if (ret > 0) *i += ret; if (unlikely(atomic_read(&ctx->dead))) ret = -EINVAL; if (!*i) *i = ret; return ret < 0 || *i >= min_nr; }

Contributors

PersonTokensPropCommitsCommitProp
Kent Overstreet6871.58%150.00%
Suparna Bhattacharya2728.42%150.00%
Total95100.00%2100.00%


static long read_events(struct kioctx *ctx, long min_nr, long nr, struct io_event __user *event, ktime_t until) { long ret = 0; /* * Note that aio_read_events() is being called as the conditional - i.e. * we're calling it after prepare_to_wait() has set task state to * TASK_INTERRUPTIBLE. * * But aio_read_events() can block, and if it blocks it's going to flip * the task state back to TASK_RUNNING. * * This should be ok, provided it doesn't flip the state back to * TASK_RUNNING and return 0 too much - that causes us to spin. That * will only happen if the mutex_lock() call blocks, and we then find * the ringbuffer empty. So in practice we should be ok, but it's * something to be aware of when touching this code. */ if (until == 0) aio_read_events(ctx, min_nr, nr, event, &ret); else wait_event_interruptible_hrtimeout(ctx->wait, aio_read_events(ctx, min_nr, nr, event, &ret), until); if (!ret && signal_pending(current)) ret = -EINTR; return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Suparna Bhattacharya4446.81%114.29%
Kent Overstreet2223.40%228.57%
Fam Zheng2122.34%114.29%
Benjamin LaHaise44.26%114.29%
Deepa Dinamani22.13%114.29%
Thomas Gleixner11.06%114.29%
Total94100.00%7100.00%

/* sys_io_setup: * Create an aio_context capable of receiving at least nr_events. * ctxp must not point to an aio_context that already exists, and * must be initialized to 0 prior to the call. On successful * creation of the aio_context, *ctxp is filled in with the resulting * handle. May fail with -EINVAL if *ctxp is not initialized, * if the specified nr_events exceeds internal limits. May fail * with -EAGAIN if the specified nr_events exceeds the user's limit * of available events. May fail with -ENOMEM if insufficient kernel * resources are available. May fail with -EFAULT if an invalid * pointer is passed for ctxp. Will fail with -ENOSYS if not * implemented. */ SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp) { struct kioctx *ioctx = NULL; unsigned long ctx; long ret; ret = get_user(ctx, ctxp); if (unlikely(ret)) goto out; ret = -EINVAL; if (unlikely(ctx || nr_events == 0)) { pr_debug("EINVAL: ctx %lu nr_events %u\n", ctx, nr_events); goto out; } ioctx = ioctx_alloc(nr_events); ret = PTR_ERR(ioctx); if (!IS_ERR(ioctx)) { ret = put_user(ioctx->user_id, ctxp); if (ret) kill_ioctx(current->mm, ioctx, NULL); percpu_ref_put(&ioctx->users); } out: return ret; } #ifdef CONFIG_COMPAT COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p) { struct kioctx *ioctx = NULL; unsigned long ctx; long ret; ret = get_user(ctx, ctx32p); if (unlikely(ret)) goto out; ret = -EINVAL; if (unlikely(ctx || nr_events == 0)) { pr_debug("EINVAL: ctx %lu nr_events %u\n", ctx, nr_events); goto out; } ioctx = ioctx_alloc(nr_events); ret = PTR_ERR(ioctx); if (!IS_ERR(ioctx)) { /* truncating is ok because it's a user address */ ret = put_user((u32)ioctx->user_id, ctx32p); if (ret) kill_ioctx(current->mm, ioctx, NULL); percpu_ref_put(&ioctx->users); } out: return ret; } #endif /* sys_io_destroy: * Destroy the aio_context specified. May cancel any outstanding * AIOs and block on completion. Will fail with -ENOSYS if not * implemented. May fail with -EINVAL if the context pointed to * is invalid. */ SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx) { struct kioctx *ioctx = lookup_ioctx(ctx); if (likely(NULL != ioctx)) { struct ctx_rq_wait wait; int ret; init_completion(&wait.comp); atomic_set(&wait.count, 1); /* Pass requests_done to kill_ioctx() where it can be set * in a thread-safe way. If we try to set it here then we have * a race condition if two io_destroy() called simultaneously. */ ret = kill_ioctx(current->mm, ioctx, &wait); percpu_ref_put(&ioctx->users); /* Wait until all IO for the context are done. Otherwise kernel * keep using user-space buffers even if user thinks the context * is destroyed. */ if (!ret) wait_for_completion(&wait.comp); return ret; } pr_debug("EINVAL: invalid context id\n"); return -EINVAL; }
static int aio_setup_rw(int rw, struct iocb *iocb, struct iovec **iovec, bool vectored, bool compat, struct iov_iter *iter) { void __user *buf = (void __user *)(uintptr_t)iocb->aio_buf; size_t len = iocb->aio_nbytes; if (!vectored) { ssize_t ret = import_single_range(rw, buf, len, *iovec, iter); *iovec = NULL; return ret; } #ifdef CONFIG_COMPAT if (compat) return compat_import_iovec(rw, buf, len, UIO_FASTIOV, iovec, iter); #endif return import_iovec(rw, buf, len, UIO_FASTIOV, iovec, iter); }

Contributors

PersonTokensPropCommitsCommitProp
Christoph Hellwig6349.22%19.09%
Jeff Moyer1914.84%19.09%
Al Viro1511.72%327.27%
Kent Overstreet129.38%218.18%
Badari Pulavarty97.03%19.09%
Suparna Bhattacharya64.69%19.09%
Gu Zheng21.56%19.09%
Linus Torvalds21.56%19.09%
Total128100.00%11100.00%


static inline ssize_t aio_ret(struct kiocb *req, ssize_t ret) { switch (ret) { case -EIOCBQUEUED: return ret; case -ERESTARTSYS: case -ERESTARTNOINTR: case -ERESTARTNOHAND: case -ERESTART_RESTARTBLOCK: /* * There's no easy way to restart the syscall since other AIO's * may be already running. Just fail this IO with EINTR. */ ret = -EINTR; /*FALLTHRU*/ default: aio_complete(req, ret, 0); return 0; } }

Contributors

PersonTokensPropCommitsCommitProp
Christoph Hellwig5687.50%116.67%
Suparna Bhattacharya34.69%116.67%
Benjamin LaHaise23.12%116.67%
Adrian Bunk11.56%116.67%
Kent Overstreet11.56%116.67%
Jeff Moyer11.56%116.67%
Total64100.00%6100.00%


static ssize_t aio_read(struct kiocb *req, struct iocb *iocb, bool vectored, bool compat) { struct file *file = req->ki_filp; struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct iov_iter iter; ssize_t ret; if (unlikely(!(file->f_mode & FMODE_READ))) return -EBADF; if (unlikely(!file->f_op->read_iter)) return -EINVAL; ret = aio_setup_rw(READ, iocb, &iovec, vectored, compat, &iter); if (ret) return ret; ret = rw_verify_area(READ, file, &req->ki_pos, iov_iter_count(&iter)); if (!ret) ret = aio_ret(req, call_read_iter(file, req, &iter)); kfree(iovec); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Christoph Hellwig11270.00%216.67%
Al Viro116.88%18.33%
Kent Overstreet116.88%216.67%
Suparna Bhattacharya63.75%18.33%
Benjamin LaHaise63.75%216.67%
Gu Zheng53.12%18.33%
Badari Pulavarty42.50%18.33%
Miklos Szeredi31.88%18.33%
Jeff Moyer21.25%18.33%
Total160100.00%12100.00%


static ssize_t aio_write(struct kiocb *req, struct iocb *iocb, bool vectored, bool compat) { struct file *file = req->ki_filp; struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct iov_iter iter; ssize_t ret; if (unlikely(!(file->f_mode & FMODE_WRITE))) return -EBADF; if (unlikely(!file->f_op->write_iter)) return -EINVAL; ret = aio_setup_rw(WRITE, iocb, &iovec, vectored, compat, &iter); if (ret) return ret; ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter)); if (!ret) { req->ki_flags |= IOCB_WRITE; file_start_write(file); ret = aio_ret(req, call_write_iter(file, req, &iter)); /* * We release freeze protection in aio_complete(). Fool lockdep * by telling it the lock got released so that it doesn't * complain about held lock when we return to userspace. */ if (S_ISREG(file_inode(file)->i_mode)) __sb_writers_release(file_inode(file)->i_sb, SB_FREEZE_WRITE); } kfree(iovec); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Christoph Hellwig8241.41%317.65%
Kent Overstreet3718.69%317.65%
Badari Pulavarty2110.61%15.88%
Al Viro2110.61%423.53%
Jan Kara157.58%15.88%
Shaohua Li126.06%15.88%
Suparna Bhattacharya52.53%15.88%
Miklos Szeredi31.52%15.88%
Jeff Moyer10.51%15.88%
Benjamin LaHaise10.51%15.88%
Total198100.00%17100.00%


static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, struct iocb *iocb, bool compat) { struct aio_kiocb *req; struct file *file; ssize_t ret; /* enforce forwards compatibility on users */ if (unlikely(iocb->aio_reserved2)) { pr_debug("EINVAL: reserve field set\n"); return -EINVAL; } /* prevent overflows */ if (unlikely( (iocb->aio_buf != (unsigned long)iocb->aio_buf) || (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) || ((ssize_t)iocb->aio_nbytes < 0) )) { pr_debug("EINVAL: overflow check\n"); return -EINVAL; } req = aio_get_req(ctx); if (unlikely(!req)) return -EAGAIN; req->common.ki_filp = file = fget(iocb->aio_fildes); if (unlikely(!req->common.ki_filp)) { ret = -EBADF; goto out_put_req; } req->common.ki_pos = iocb->aio_offset; req->common.ki_complete = aio_complete; req->common.ki_flags = iocb_flags(req->common.ki_filp); req->common.ki_hint = file_write_hint(file); if (iocb->aio_flags & IOCB_FLAG_RESFD) { /* * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an * instance of the file* now. The file descriptor must be * an eventfd() fd, and will be signaled for each completed * event using the eventfd_signal() function. */ req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd); if (IS_ERR(req->ki_eventfd)) { ret = PTR_ERR(req->ki_eventfd); req->ki_eventfd = NULL; goto out_put_req; } req->common.ki_flags |= IOCB_EVENTFD; } ret = kiocb_set_rw_flags(&req->common, iocb->aio_rw_flags); if (unlikely(ret)) { pr_debug("EINVAL: aio_rw_flags\n"); goto out_put_req; } ret = put_user(KIOCB_KEY, &user_iocb->aio_key); if (unlikely(ret)) { pr_debug("EFAULT: aio_key\n"); goto out_put_req; } req->ki_user_iocb = user_iocb; req->ki_user_data = iocb->aio_data; get_file(file); switch (iocb->aio_lio_opcode) { case IOCB_CMD_PREAD: ret = aio_read(&req->common, iocb, false, compat); break; case IOCB_CMD_PWRITE: ret = aio_write(&req->common, iocb, false, compat); break; case IOCB_CMD_PREADV: ret = aio_read(&req->common, iocb, true, compat); break; case IOCB_CMD_PWRITEV: ret = aio_write(&req->common, iocb, true, compat); break; default: pr_debug("invalid aio operation %d\n", iocb->aio_lio_opcode); ret = -EINVAL; break; } fput(file); if (ret && ret != -EIOCBQUEUED) goto out_put_req; return 0; out_put_req: put_reqs_available(ctx, 1); percpu_ref_put(&ctx->reqs); kiocb_free(req); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Benjamin LaHaise16031.75%27.41%
Christoph Hellwig15129.96%311.11%
Davide Libenzi5410.71%311.11%
Kent Overstreet479.33%829.63%
Goldwyn Rodrigues316.15%13.70%
Suparna Bhattacharya254.96%13.70%
Jens Axboe112.18%13.70%
Al Viro81.59%13.70%
James Morris71.39%13.70%
Jeff Moyer50.99%27.41%
Yan Zheng20.40%13.70%
Andrew Morton10.20%13.70%
Kinglong Mee10.20%13.70%
Adrian Bunk10.20%13.70%
Total504100.00%27100.00%


static long do_io_submit(aio_context_t ctx_id, long nr, struct iocb __user *__user *iocbpp, bool compat) { struct kioctx *ctx; long ret = 0; int i = 0; struct blk_plug plug; if (unlikely(nr < 0)) return -EINVAL; if (unlikely(nr > LONG_MAX/sizeof(*iocbpp))) nr = LONG_MAX/sizeof(*iocbpp); if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp))))) return -EFAULT; ctx = lookup_ioctx(ctx_id); if (unlikely(!ctx)) { pr_debug("EINVAL: invalid context id\n"); return -EINVAL; } blk_start_plug(&plug); /* * AKPM: should this return a partial result if some of the IOs were * successfully submitted? */ for (i=0; i<nr; i++) { struct iocb __user *user_iocb; struct iocb tmp; if (unlikely(__get_user(user_iocb, iocbpp + i))) { ret = -EFAULT; break; } if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) { ret = -EFAULT; break; } ret = io_submit_one(ctx, user_iocb, &tmp, compat); if (ret) break; } blk_finish_plug(&plug); percpu_ref_put(&ctx->users); return i ? i : ret; }

Contributors

PersonTokensPropCommitsCommitProp
Benjamin LaHaise17669.57%216.67%
Jeff Moyer5421.34%433.33%
David Shaohua Li114.35%18.33%
Kent Overstreet51.98%216.67%
Andrew Morton51.98%18.33%
Andrea Arcangeli10.40%18.33%
Al Viro10.40%18.33%
Total253100.00%12100.00%

/* sys_io_submit: * Queue the nr iocbs pointed to by iocbpp for processing. Returns * the number of iocbs queued. May return -EINVAL if the aio_context * specified by ctx_id is invalid, if nr is < 0, if the iocb at * *iocbpp[0] is not properly initialized, if the operation specified * is invalid for the file descriptor in the iocb. May fail with * -EFAULT if any of the data structures point to invalid data. May * fail with -EBADF if the file descriptor specified in the first * iocb is invalid. May fail with -EAGAIN if insufficient resources * are available to queue any iocbs. Will return 0 if nr is 0. Will * fail with -ENOSYS if not implemented. */ SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr, struct iocb __user * __user *, iocbpp) { return do_io_submit(ctx_id, nr, iocbpp, 0); } #ifdef CONFIG_COMPAT
static inline long copy_iocb(long nr, u32 __user *ptr32, struct iocb __user * __user *ptr64) { compat_uptr_t uptr; int i; for (i = 0; i < nr; ++i) { if (get_user(uptr, ptr32 + i)) return -EFAULT; if (put_user(compat_ptr(uptr), ptr64 + i)) return -EFAULT; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro80100.00%1100.00%
Total80100.00%1100.00%

#define MAX_AIO_SUBMITS (PAGE_SIZE/sizeof(struct iocb *)) COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id, int, nr, u32 __user *, iocb) { struct iocb __user * __user *iocb64; long ret; if (unlikely(nr < 0)) return -EINVAL; if (nr > MAX_AIO_SUBMITS) nr = MAX_AIO_SUBMITS; iocb64 = compat_alloc_user_space(nr * sizeof(*iocb64)); ret = copy_iocb(nr, iocb, iocb64); if (!ret) ret = do_io_submit(ctx_id, nr, iocb64, 1); return ret; } #endif /* lookup_kiocb * Finds a given iocb for cancellation. */
static struct aio_kiocb * lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, u32 key) { struct aio_kiocb *kiocb; assert_spin_locked(&ctx->ctx_lock); if (key != KIOCB_KEY) return NULL; /* TODO: use a hash or array, this sucks. */ list_for_each_entry(kiocb, &ctx->active_reqs, ki_list) { if (kiocb->ki_user_iocb == iocb) return kiocb; } return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Benjamin LaHaise4260.87%228.57%
Kent Overstreet913.04%114.29%
Christoph Hellwig811.59%114.29%
Zach Brown811.59%114.29%
Adrian Bunk11.45%114.29%
Linus Torvalds11.45%114.29%
Total69100.00%7100.00%

/* sys_io_cancel: * Attempts to cancel an iocb previously passed to io_submit. If * the operation is successfully cancelled, the resulting event is * copied into the memory pointed to by result without being placed * into the completion queue and 0 is returned. May fail with * -EFAULT if any of the data structures pointed to are invalid. * May fail with -EINVAL if aio_context specified by ctx_id is * invalid. May fail with -EAGAIN if the iocb specified was not * cancelled. Will fail with -ENOSYS if not implemented. */ SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, struct io_event __user *, result) { struct kioctx *ctx; struct aio_kiocb *kiocb; u32 key; int ret; ret = get_user(key, &iocb->aio_key); if (unlikely(ret)) return -EFAULT; ctx = lookup_ioctx(ctx_id); if (unlikely(!ctx)) return -EINVAL; spin_lock_irq(&ctx->ctx_lock); kiocb = lookup_kiocb(ctx, iocb, key); if (kiocb) ret = kiocb_cancel(kiocb); else ret = -EINVAL; spin_unlock_irq(&ctx->ctx_lock); if (!ret) { /* * The result argument is no longer used - the io_event is * always delivered via the ring buffer. -EINPROGRESS indicates * cancellation is progress: */ ret = -EINPROGRESS; } percpu_ref_put(&ctx->users); return ret; }
static long do_io_getevents(aio_context_t ctx_id, long min_nr, long nr, struct io_event __user *events, struct timespec64 *ts) { ktime_t until = ts ? timespec64_to_ktime(*ts) : KTIME_MAX; struct kioctx *ioctx = lookup_ioctx(ctx_id); long ret = -EINVAL; if (likely(ioctx)) { if (likely(min_nr <= nr && min_nr >= 0)) ret = read_events(ioctx, min_nr, nr, events, until); percpu_ref_put(&ioctx->users); } return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Benjamin LaHaise5048.54%233.33%
Deepa Dinamani3735.92%116.67%
Andrew Morton109.71%116.67%
Kent Overstreet43.88%116.67%
Heiko Carstens21.94%116.67%
Total103100.00%6100.00%

/* io_getevents: * Attempts to read at least min_nr events and up to nr events from * the completion queue for the aio_context specified by ctx_id. If * it succeeds, the number of read events is returned. May fail with * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is * out of range, if timeout is out of range. May fail with -EFAULT * if any of the memory specified is invalid. May return 0 or * < min_nr if the timeout specified by timeout has elapsed * before sufficient events are available, where timeout == NULL * specifies an infinite timeout. Note that the timeout pointed to by * timeout is relative. Will fail with -ENOSYS if not implemented. */ SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id, long, min_nr, long, nr, struct io_event __user *, events, struct timespec __user *, timeout) { struct timespec64 ts; if (timeout) { if (unlikely(get_timespec64(&ts, timeout))) return -EFAULT; } return do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL); } #ifdef CONFIG_COMPAT COMPAT_SYSCALL_DEFINE5(io_getevents, compat_aio_context_t, ctx_id, compat_long_t, min_nr, compat_long_t, nr, struct io_event __user *, events, struct compat_timespec __user *, timeout) { struct timespec64 t; if (timeout) { if (compat_get_timespec64(&t, timeout)) return -EFAULT; } return do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL); } #endif

Overall Contributors

PersonTokensPropCommitsCommitProp
Benjamin LaHaise267034.88%2213.50%
Kent Overstreet166421.74%2515.34%
Christoph Hellwig5697.43%53.07%
Al Viro5677.41%169.82%
Suparna Bhattacharya4325.64%10.61%
Gu Zheng3374.40%74.29%
Jeff Moyer1431.87%53.07%
Jens Axboe1261.65%42.45%
Oleg Nesterov1171.53%31.84%
Deepa Dinamani1161.52%10.61%
Pavel Emelyanov1101.44%10.61%
Linus Torvalds1061.38%53.07%
Zach Brown1021.33%42.45%
Davide Libenzi861.12%42.45%
Jan Kara520.68%10.61%
Heiko Carstens380.50%10.61%
Badari Pulavarty370.48%21.23%
Anatol Pomozov370.48%10.61%
Goldwyn Rodrigues310.41%10.61%
Tejun Heo280.37%42.45%
Andrew Morton260.34%53.07%
Shaohua Li240.31%10.61%
Jann Horn240.31%10.61%
Fam Zheng210.27%10.61%
Mauricio Faria de Oliveira210.27%10.61%
Michal Hocko200.26%10.61%
Rasmus Villemoes120.16%10.61%
Jérôme Glisse110.14%10.61%
David Shaohua Li110.14%10.61%
James Morris100.13%10.61%
Ken Chen100.13%10.61%
Kenneth W. Chen80.10%10.61%
Sasha Levin80.10%10.61%
Miklos Szeredi60.08%10.61%
Christoph Lameter60.08%21.23%
Gleb Natapov60.08%10.61%
Dan Carpenter50.07%10.61%
H Hartley Sweeten50.07%10.61%
Dave Chinner40.05%10.61%
Darrick J. Wong40.05%10.61%
Quentin Barnes40.05%10.61%
Adrian Bunk40.05%31.84%
William Lee Irwin III40.05%10.61%
Michel Lespinasse30.04%21.23%
Ingo Molnar30.04%21.23%
Arnd Bergmann30.04%10.61%
Michael S. Tsirkin30.04%10.61%
Kinglong Mee30.04%10.61%
John Myers30.04%10.61%
Yan Zheng20.03%10.61%
Mike Rapoport20.03%10.61%
Thomas Gleixner10.01%10.61%
Satoru Takeuchi10.01%10.61%
Oliver Neukum10.01%10.61%
Andrea Arcangeli10.01%10.61%
Robert P. J. Day10.01%10.61%
Stephen Hemminger10.01%10.61%
Paul Gortmaker10.01%10.61%
Zhao Hongjiang10.01%10.61%
Mark Rutland10.01%10.61%
Tang Chen10.01%10.61%
Total7654100.00%163100.00%
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