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Merge tag 'for-4.21/aio-20181221' of git://git.kernel.dk/linux-block
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Pull aio updates from Jens Axboe:
 "Flushing out pre-patches for the buffered/polled aio series. Some
  fixes in here, but also optimizations"

* tag 'for-4.21/aio-20181221' of git://git.kernel.dk/linux-block:
  aio: abstract out io_event filler helper
  aio: split out iocb copy from io_submit_one()
  aio: use iocb_put() instead of open coding it
  aio: only use blk plugs for > 2 depth submissions
  aio: don't zero entire aio_kiocb aio_get_req()
  aio: separate out ring reservation from req allocation
  aio: use assigned completion handler
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@torvalds
torvalds committed Dec 28, 2018
2 parents 0e9da3f + 875736b commit 956eb6c
Showing 1 changed file with 88 additions and 56 deletions.
144 changes: 88 additions & 56 deletions fs/aio.c
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Original file line number Diff line number Diff line change
Expand Up @@ -70,6 +70,12 @@ struct aio_ring {
struct io_event io_events[0];
}; /* 128 bytes + ring size */

/*
* Plugging is meant to work with larger batches of IOs. If we don't
* have more than the below, then don't bother setting up a plug.
*/
#define AIO_PLUG_THRESHOLD 2

#define AIO_RING_PAGES 8

struct kioctx_table {
Expand Down Expand Up @@ -902,7 +908,7 @@ static void put_reqs_available(struct kioctx *ctx, unsigned nr)
local_irq_restore(flags);
}

static bool get_reqs_available(struct kioctx *ctx)
static bool __get_reqs_available(struct kioctx *ctx)
{
struct kioctx_cpu *kcpu;
bool ret = false;
Expand Down Expand Up @@ -994,6 +1000,14 @@ static void user_refill_reqs_available(struct kioctx *ctx)
spin_unlock_irq(&ctx->completion_lock);
}

static bool get_reqs_available(struct kioctx *ctx)
{
if (__get_reqs_available(ctx))
return true;
user_refill_reqs_available(ctx);
return __get_reqs_available(ctx);
}

/* aio_get_req
* Allocate a slot for an aio request.
* Returns NULL if no requests are free.
Expand All @@ -1002,24 +1016,16 @@ 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);
req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
if (unlikely(!req))
goto out_put;
return NULL;

percpu_ref_get(&ctx->reqs);
req->ki_ctx = ctx;
INIT_LIST_HEAD(&req->ki_list);
refcount_set(&req->ki_refcnt, 0);
req->ki_ctx = ctx;
req->ki_eventfd = NULL;
return req;
out_put:
put_reqs_available(ctx, 1);
return NULL;
}

static struct kioctx *lookup_ioctx(unsigned long ctx_id)
Expand Down Expand Up @@ -1059,6 +1065,15 @@ static inline void iocb_put(struct aio_kiocb *iocb)
}
}

static void aio_fill_event(struct io_event *ev, struct aio_kiocb *iocb,
long res, long res2)
{
ev->obj = (u64)(unsigned long)iocb->ki_user_iocb;
ev->data = iocb->ki_user_data;
ev->res = res;
ev->res2 = res2;
}

/* aio_complete
* Called when the io request on the given iocb is complete.
*/
Expand Down Expand Up @@ -1086,10 +1101,7 @@ static void aio_complete(struct aio_kiocb *iocb, long res, long res2)
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;
aio_fill_event(event, iocb, res, res2);

kunmap_atomic(ev_page);
flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
Expand Down Expand Up @@ -1416,7 +1428,7 @@ static void aio_complete_rw(struct kiocb *kiocb, long res, long res2)
aio_complete(iocb, res, res2);
}

static int aio_prep_rw(struct kiocb *req, struct iocb *iocb)
static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb)
{
int ret;

Expand Down Expand Up @@ -1457,7 +1469,7 @@ static int aio_prep_rw(struct kiocb *req, struct iocb *iocb)
return ret;
}

static int aio_setup_rw(int rw, struct iocb *iocb, struct iovec **iovec,
static int aio_setup_rw(int rw, const struct iocb *iocb, struct iovec **iovec,
bool vectored, bool compat, struct iov_iter *iter)
{
void __user *buf = (void __user *)(uintptr_t)iocb->aio_buf;
Expand Down Expand Up @@ -1492,12 +1504,12 @@ static inline void aio_rw_done(struct kiocb *req, ssize_t ret)
ret = -EINTR;
/*FALLTHRU*/
default:
aio_complete_rw(req, ret, 0);
req->ki_complete(req, ret, 0);
}
}

static ssize_t aio_read(struct kiocb *req, struct iocb *iocb, bool vectored,
bool compat)
static ssize_t aio_read(struct kiocb *req, const struct iocb *iocb,
bool vectored, bool compat)
{
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
struct iov_iter iter;
Expand Down Expand Up @@ -1529,8 +1541,8 @@ static ssize_t aio_read(struct kiocb *req, struct iocb *iocb, bool vectored,
return ret;
}

static ssize_t aio_write(struct kiocb *req, struct iocb *iocb, bool vectored,
bool compat)
static ssize_t aio_write(struct kiocb *req, const struct iocb *iocb,
bool vectored, bool compat)
{
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
struct iov_iter iter;
Expand Down Expand Up @@ -1585,7 +1597,8 @@ static void aio_fsync_work(struct work_struct *work)
aio_complete(container_of(req, struct aio_kiocb, fsync), ret, 0);
}

static int aio_fsync(struct fsync_iocb *req, struct iocb *iocb, bool datasync)
static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb,
bool datasync)
{
if (unlikely(iocb->aio_buf || iocb->aio_offset || iocb->aio_nbytes ||
iocb->aio_rw_flags))
Expand Down Expand Up @@ -1713,7 +1726,7 @@ aio_poll_queue_proc(struct file *file, struct wait_queue_head *head,
add_wait_queue(head, &pt->iocb->poll.wait);
}

static ssize_t aio_poll(struct aio_kiocb *aiocb, struct iocb *iocb)
static ssize_t aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)
{
struct kioctx *ctx = aiocb->ki_ctx;
struct poll_iocb *req = &aiocb->poll;
Expand All @@ -1733,6 +1746,10 @@ static ssize_t aio_poll(struct aio_kiocb *aiocb, struct iocb *iocb)
if (unlikely(!req->file))
return -EBADF;

req->head = NULL;
req->woken = false;
req->cancelled = false;

apt.pt._qproc = aio_poll_queue_proc;
apt.pt._key = req->events;
apt.iocb = aiocb;
Expand Down Expand Up @@ -1781,44 +1798,44 @@ static ssize_t aio_poll(struct aio_kiocb *aiocb, struct iocb *iocb)
return 0;
}

static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
bool compat)
static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,
struct iocb __user *user_iocb, bool compat)
{
struct aio_kiocb *req;
struct iocb iocb;
ssize_t ret;

if (unlikely(copy_from_user(&iocb, user_iocb, sizeof(iocb))))
return -EFAULT;

/* enforce forwards compatibility on users */
if (unlikely(iocb.aio_reserved2)) {
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)
(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;
}

if (!get_reqs_available(ctx))
return -EAGAIN;

ret = -EAGAIN;
req = aio_get_req(ctx);
if (unlikely(!req))
return -EAGAIN;
goto out_put_reqs_available;

if (iocb.aio_flags & IOCB_FLAG_RESFD) {
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);
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;
Expand All @@ -1833,32 +1850,32 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
}

req->ki_user_iocb = user_iocb;
req->ki_user_data = iocb.aio_data;
req->ki_user_data = iocb->aio_data;

switch (iocb.aio_lio_opcode) {
switch (iocb->aio_lio_opcode) {
case IOCB_CMD_PREAD:
ret = aio_read(&req->rw, &iocb, false, compat);
ret = aio_read(&req->rw, iocb, false, compat);
break;
case IOCB_CMD_PWRITE:
ret = aio_write(&req->rw, &iocb, false, compat);
ret = aio_write(&req->rw, iocb, false, compat);
break;
case IOCB_CMD_PREADV:
ret = aio_read(&req->rw, &iocb, true, compat);
ret = aio_read(&req->rw, iocb, true, compat);
break;
case IOCB_CMD_PWRITEV:
ret = aio_write(&req->rw, &iocb, true, compat);
ret = aio_write(&req->rw, iocb, true, compat);
break;
case IOCB_CMD_FSYNC:
ret = aio_fsync(&req->fsync, &iocb, false);
ret = aio_fsync(&req->fsync, iocb, false);
break;
case IOCB_CMD_FDSYNC:
ret = aio_fsync(&req->fsync, &iocb, true);
ret = aio_fsync(&req->fsync, iocb, true);
break;
case IOCB_CMD_POLL:
ret = aio_poll(req, &iocb);
ret = aio_poll(req, iocb);
break;
default:
pr_debug("invalid aio operation %d\n", iocb.aio_lio_opcode);
pr_debug("invalid aio operation %d\n", iocb->aio_lio_opcode);
ret = -EINVAL;
break;
}
Expand All @@ -1872,14 +1889,25 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
goto out_put_req;
return 0;
out_put_req:
put_reqs_available(ctx, 1);
percpu_ref_put(&ctx->reqs);
if (req->ki_eventfd)
eventfd_ctx_put(req->ki_eventfd);
kmem_cache_free(kiocb_cachep, req);
iocb_put(req);
out_put_reqs_available:
put_reqs_available(ctx, 1);
return ret;
}

static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
bool compat)
{
struct iocb iocb;

if (unlikely(copy_from_user(&iocb, user_iocb, sizeof(iocb))))
return -EFAULT;

return __io_submit_one(ctx, &iocb, user_iocb, compat);
}

/* 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
Expand Down Expand Up @@ -1912,7 +1940,8 @@ SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
if (nr > ctx->nr_events)
nr = ctx->nr_events;

blk_start_plug(&plug);
if (nr > AIO_PLUG_THRESHOLD)
blk_start_plug(&plug);
for (i = 0; i < nr; i++) {
struct iocb __user *user_iocb;

Expand All @@ -1925,7 +1954,8 @@ SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
if (ret)
break;
}
blk_finish_plug(&plug);
if (nr > AIO_PLUG_THRESHOLD)
blk_finish_plug(&plug);

percpu_ref_put(&ctx->users);
return i ? i : ret;
Expand All @@ -1952,7 +1982,8 @@ COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id,
if (nr > ctx->nr_events)
nr = ctx->nr_events;

blk_start_plug(&plug);
if (nr > AIO_PLUG_THRESHOLD)
blk_start_plug(&plug);
for (i = 0; i < nr; i++) {
compat_uptr_t user_iocb;

Expand All @@ -1965,7 +1996,8 @@ COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id,
if (ret)
break;
}
blk_finish_plug(&plug);
if (nr > AIO_PLUG_THRESHOLD)
blk_finish_plug(&plug);

percpu_ref_put(&ctx->users);
return i ? i : ret;
Expand Down

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