* Re: [PATCH 03/32] timens: Introduce CLOCK_MONOTONIC offsets
From: Thomas Gleixner @ 2019-02-08 9:46 UTC (permalink / raw)
To: Dmitry Safonov
Cc: linux-kernel, Andrei Vagin, Adrian Reber, Andrei Vagin,
Andy Lutomirski, Andy Tucker, Arnd Bergmann, Christian Brauner,
Cyrill Gorcunov, Dmitry Safonov, Eric W. Biederman,
H. Peter Anvin, Ingo Molnar, Jeff Dike, Oleg Nesterov,
Pavel Emelyanov, Shuah Khan, containers, criu, linux-api, x86
In-Reply-To: <alpine.DEB.2.21.1902072225420.1645@nanos.tec.linutronix.de>
On Thu, 7 Feb 2019, Thomas Gleixner wrote:
> Does this really need to be an out of line call? If you stick this into the
> clock_get() implementations then it boils down to:
>
> static inline void timens_add_monotonic(struct timespec64 *ts)
> {
> struct timens_offsets *ns_offsets = current->nsproxy->time_ns->offsets;
>
> if (ns_offsets)
> *ts = timespec64_add(*ts, ns_offsets->monotonic_time_offset);
And this needs to be a special variant of
timespec64-add_safe(). timespec64_add_safe() is not sufficient, because it
assumes that both values are positive, which is not the case here..
In timer_set() implementations you move the timespec_valid() check after
the add. That's wrong because you really want to check the input value from
user space.
Assume that the caller supplied value is valid and the adjustment brings it
out of range then how should the caller understand why it it rejected?
So timespec64_add_namespace() must check for under and overflow. But doing
this with timespecs is a pain. I rather suggest to rework the whole thing
so hrtimer_nanosleep() takes a ktime_t expiry value and move the conversion
to the call sites. Then the whole offset magic becomes:
expires = timespec64_to_ktime(rqtp);
if (abstime)
expires = timens_to_host_mono(expires);
and that function can nicely do the underflow and overflow detection and
cap the values to 0 on underflow and KTIME_MAX on overflow.
Hmm?
Thanks,
tglx
^ permalink raw reply
* Re: [PATCH 03/32] timens: Introduce CLOCK_MONOTONIC offsets
From: Andrei Vagin @ 2019-02-08 9:02 UTC (permalink / raw)
To: Thomas Gleixner
Cc: Dmitry Safonov, linux-kernel, Andrei Vagin, Adrian Reber,
Andy Lutomirski, Andy Tucker, Arnd Bergmann, Christian Brauner,
Cyrill Gorcunov, Dmitry Safonov, Eric W. Biederman,
H. Peter Anvin, Ingo Molnar, Jeff Dike, Oleg Nesterov,
Pavel Emelyanov, Shuah Khan, containers, criu, linux-api, x86
In-Reply-To: <alpine.DEB.2.21.1902072225420.1645@nanos.tec.linutronix.de>
On Thu, Feb 07, 2019 at 10:40:55PM +0100, Thomas Gleixner wrote:
> On Wed, 6 Feb 2019, Dmitry Safonov wrote:
> > #include "timekeeping.h"
> > #include "posix-timers.h"
> > @@ -1041,6 +1042,9 @@ SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
> >
> > error = kc->clock_get(which_clock, &kernel_tp);
> >
> > + if (!error && kc->clock_timens_adjust)
> > + timens_clock_from_host(which_clock, &kernel_tp);
>
> Why are you adding this conditional instead of sticking the offset
> magic into the affected ->clock_get() implementations?
>
> That spares you the switch() and the !offsets conditional.
>
> > +static void clock_timens_fixup(int clockid, struct timespec64 *val, bool to_ns)
> > +{
> > + struct timens_offsets *ns_offsets = current->nsproxy->time_ns->offsets;
> > + struct timespec64 *offsets = NULL;
> > +
> > + if (!ns_offsets)
> > + return;
> > +
> > + if (val->tv_sec == 0 && val->tv_nsec == 0)
> > + return;
>
> I have no idea why 0/0 is special.
Initially this function was introduced to apply timens offsets in
do_timer_settime and there it is special and means that the timer should
be disarmed.
Now this functions is used in many other places and this check defenetly
sould not be here.
>
> > +
> > + switch (clockid) {
> > + case CLOCK_MONOTONIC:
> > + case CLOCK_MONOTONIC_RAW:
> > + case CLOCK_MONOTONIC_COARSE:
> > + offsets = &ns_offsets->monotonic_time_offset;
> > + break;
> > + }
> > +
> > + if (!offsets)
> > + return;
> > +
> > + if (to_ns)
> > + *val = timespec64_add(*val, *offsets);
> > + else
> > + *val = timespec64_sub(*val, *offsets);
> > +}
> > +
> > +void timens_clock_to_host(int clockid, struct timespec64 *val)
>
> Does this really need to be an out of line call?
The idea was to collect all the logic about timens offsets in one place.
clock_timens_fixup() is used in all places where we need apply timens
offsets (clock_gettim, posix timers, clock_nanosleep, timerfd, uptime_proc_show).
> If you stick this into the
> clock_get() implementations then it boils down to:
clock_get() is called from clock_gettime and from common_timer_get(). In
common_timer_get(), we expect to get time in the root time namespace.
but I think we can handle this. For example, we can introduce a new flag
CLOCL_TIMENS and
kc->clock_get(which_clock | CLOCK_TIMENS, &tp) will return time in a
current time namespace.
kc->clock_get(which_clock, &tp) will return time in the root time
namespace.
>
> static inline void timens_add_monotonic(struct timespec64 *ts)
> {
> struct timens_offsets *ns_offsets = current->nsproxy->time_ns->offsets;
>
> if (ns_offsets)
> *ts = timespec64_add(*ts, ns_offsets->monotonic_time_offset);
> }
>
> and
>
> static int posix_ktime_get_ts(clockid_t which_clock, struct timespec64 *tp)
> {
> ktime_get_ts64(tp);
> timens_add_monotonic(tp);
> return 0;
> }
>
> Hmm?
Yes, we can do this. I like this idea. This will allow us to remove
timens_clock_to_host(), but I am not sure that we will be able to do
something similar with timens_clock_from_host, which is used to apply
offsets for timers. I need to look at the timer code again.
Thanks,
Andrei
>
> Thanks,
>
> tglx
>
^ permalink raw reply
* Re: [PATCH 07/32] timens/kernel: Take into account timens clock offsets in clock_nanosleep
From: Thomas Gleixner @ 2019-02-08 7:56 UTC (permalink / raw)
To: Dmitry Safonov
Cc: linux-kernel, Andrei Vagin, Adrian Reber, Andrei Vagin,
Andy Lutomirski, Andy Tucker, Arnd Bergmann, Christian Brauner,
Cyrill Gorcunov, Dmitry Safonov, Eric W. Biederman,
H. Peter Anvin, Ingo Molnar, Jeff Dike, Oleg Nesterov,
Pavel Emelyanov, Shuah Khan, containers, criu, linux-api, x86
In-Reply-To: <20190206001107.16488-8-dima@arista.com>
On Wed, 6 Feb 2019, Dmitry Safonov wrote:
>
> @@ -1721,9 +1722,16 @@ long hrtimer_nanosleep(const struct timespec64 *rqtp,
> {
> struct restart_block *restart;
> struct hrtimer_sleeper t;
> + struct timespec64 tp;
> int ret = 0;
> u64 slack;
>
> + if (!(mode & HRTIMER_MODE_REL)) {
> + tp = *rqtp;
> + rqtp = &tp;
So every invocation of hrtimer_nanosleep() gains a copy of the timespec64
even if the namespace muck is disabled.
The only relevant caller of this is common_nsleep(). So it might make sense
to have common_nsleep() separated for CLOCK_MONOTONIC/BOOTTIME and handle
the thing there. That again avoids the switch() to and out of line calls.
Thanks,
tglx
^ permalink raw reply
* Re: [PATCH 12/18] io_uring: add support for pre-mapped user IO buffers
From: Jens Axboe @ 2019-02-07 22:47 UTC (permalink / raw)
To: Jeff Moyer; +Cc: linux-aio, linux-block, linux-api, hch, avi, jannh, viro
In-Reply-To: <x49zhr7442d.fsf@segfault.boston.devel.redhat.com>
On 2/7/19 3:38 PM, Jeff Moyer wrote:
> Hi, Jens,
>
> Jens Axboe <axboe@kernel.dk> writes:
>
>> For now, buffers must not be file backed. If file backed buffers are
>> passed in, the registration will fail with -1/EOPNOTSUPP. This
>> restriction may be relaxed in the future.
>
> [...]
>
>> + down_write(¤t->mm->mmap_sem);
>> + pret = get_user_pages_longterm(ubuf, nr_pages, FOLL_WRITE,
>> + pages, vmas);
>> + if (pret == nr_pages) {
>> + /* don't support file backed memory */
>> + for (j = 0; j < nr_pages; j++) {
>> + struct vm_area_struct *vma = vmas[j];
>> +
>> + if (vma->vm_file) {
>> + ret = -EOPNOTSUPP;
>> + break;
>> + }
>> + }
>
> Unfortunately, this suffers the same problem as FOLL_ANON. Huge pages
> are backed by hugetlbfs, and vma->vm_file will be filled in.
>
> I guess you could check is_file_hugepages(vma->vm_file):
>
> if (vma->vm_file &&
> !is_file_hugepages(vma->vm_file)) {
> ret = -EOPNOTSUPP;
> break;
> }
>
> That works for me.
Thanks, that looks better. Fixed!
--
Jens Axboe
--
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^ permalink raw reply
* Re: [PATCH 12/18] io_uring: add support for pre-mapped user IO buffers
From: Jeff Moyer @ 2019-02-07 22:38 UTC (permalink / raw)
To: Jens Axboe; +Cc: linux-aio, linux-block, linux-api, hch, avi, jannh, viro
In-Reply-To: <20190207195552.22770-13-axboe@kernel.dk>
Hi, Jens,
Jens Axboe <axboe@kernel.dk> writes:
> For now, buffers must not be file backed. If file backed buffers are
> passed in, the registration will fail with -1/EOPNOTSUPP. This
> restriction may be relaxed in the future.
[...]
> + down_write(¤t->mm->mmap_sem);
> + pret = get_user_pages_longterm(ubuf, nr_pages, FOLL_WRITE,
> + pages, vmas);
> + if (pret == nr_pages) {
> + /* don't support file backed memory */
> + for (j = 0; j < nr_pages; j++) {
> + struct vm_area_struct *vma = vmas[j];
> +
> + if (vma->vm_file) {
> + ret = -EOPNOTSUPP;
> + break;
> + }
> + }
Unfortunately, this suffers the same problem as FOLL_ANON. Huge pages
are backed by hugetlbfs, and vma->vm_file will be filled in.
I guess you could check is_file_hugepages(vma->vm_file):
if (vma->vm_file &&
!is_file_hugepages(vma->vm_file)) {
ret = -EOPNOTSUPP;
break;
}
That works for me.
-Jeff
--
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^ permalink raw reply
* Re: [PATCH 16/18] io_uring: add support for IORING_OP_POLL
From: Jens Axboe @ 2019-02-07 22:18 UTC (permalink / raw)
To: Jeff Moyer; +Cc: linux-aio, linux-block, linux-api, hch, avi, jannh, viro
In-Reply-To: <x497eeb5jtq.fsf@segfault.boston.devel.redhat.com>
On 2/7/19 3:12 PM, Jeff Moyer wrote:
> Hi, Jens,
>
>> +static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe)
>> +{
>
> [...]
>
>> + /* one for removal from waitqueue, one for this function */
>> + refcount_set(&req->refs, 2);
>> +
>> + mask = vfs_poll(poll->file, &ipt.pt) & poll->events;
>> + if (unlikely(!poll->head)) {
>> + /* we did not manage to set up a waitqueue, done */
>> + goto out;
>> + }
>> +
>> + spin_lock_irq(&ctx->completion_lock);
>> + spin_lock(&poll->head->lock);
>> + if (poll->woken) {
>> + /* wake_up context handles the rest */
>> + mask = 0;
>> + ipt.error = 0;
>> + } else if (mask || ipt.error) {
>> + /* if we get an error or a mask we are done */
>> + WARN_ON_ONCE(list_empty(&poll->wait.entry));
>> + list_del_init(&poll->wait.entry);
>> + } else {
>> + /* actually waiting for an event */
>> + list_add_tail(&req->list, &ctx->cancel_list);
>> + }
>> + spin_unlock(&poll->head->lock);
>> + spin_unlock_irq(&ctx->completion_lock);
>> +
>> +out:
>> + if (unlikely(ipt.error)) {
>> + if (!(flags & IOSQE_FIXED_FILE))
>> + fput(poll->file);
>> + return ipt.error;
>> + }
>
> You need to drop the reference count on the req inside that if block.
Ah good point, because it's elevated. Fixed, thanks Jeff.
--
Jens Axboe
--
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^ permalink raw reply
* Re: [PATCH 16/18] io_uring: add support for IORING_OP_POLL
From: Jeff Moyer @ 2019-02-07 22:12 UTC (permalink / raw)
To: Jens Axboe; +Cc: linux-aio, linux-block, linux-api, hch, avi, jannh, viro
In-Reply-To: <20190207195552.22770-17-axboe@kernel.dk>
Hi, Jens,
> +static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe)
> +{
[...]
> + /* one for removal from waitqueue, one for this function */
> + refcount_set(&req->refs, 2);
> +
> + mask = vfs_poll(poll->file, &ipt.pt) & poll->events;
> + if (unlikely(!poll->head)) {
> + /* we did not manage to set up a waitqueue, done */
> + goto out;
> + }
> +
> + spin_lock_irq(&ctx->completion_lock);
> + spin_lock(&poll->head->lock);
> + if (poll->woken) {
> + /* wake_up context handles the rest */
> + mask = 0;
> + ipt.error = 0;
> + } else if (mask || ipt.error) {
> + /* if we get an error or a mask we are done */
> + WARN_ON_ONCE(list_empty(&poll->wait.entry));
> + list_del_init(&poll->wait.entry);
> + } else {
> + /* actually waiting for an event */
> + list_add_tail(&req->list, &ctx->cancel_list);
> + }
> + spin_unlock(&poll->head->lock);
> + spin_unlock_irq(&ctx->completion_lock);
> +
> +out:
> + if (unlikely(ipt.error)) {
> + if (!(flags & IOSQE_FIXED_FILE))
> + fput(poll->file);
> + return ipt.error;
> + }
You need to drop the reference count on the req inside that if block.
-Jeff
> +
> + if (mask)
> + io_poll_complete(req, mask);
> + io_free_req(req);
> + return 0;
> +}
--
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^ permalink raw reply
* Re: [PATCH 03/32] timens: Introduce CLOCK_MONOTONIC offsets
From: Thomas Gleixner @ 2019-02-07 21:40 UTC (permalink / raw)
To: Dmitry Safonov
Cc: linux-kernel, Andrei Vagin, Adrian Reber, Andrei Vagin,
Andy Lutomirski, Andy Tucker, Arnd Bergmann, Christian Brauner,
Cyrill Gorcunov, Dmitry Safonov, Eric W. Biederman,
H. Peter Anvin, Ingo Molnar, Jeff Dike, Oleg Nesterov,
Pavel Emelyanov, Shuah Khan, containers, criu, linux-api, x86
In-Reply-To: <20190206001107.16488-4-dima@arista.com>
On Wed, 6 Feb 2019, Dmitry Safonov wrote:
> #include "timekeeping.h"
> #include "posix-timers.h"
> @@ -1041,6 +1042,9 @@ SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
>
> error = kc->clock_get(which_clock, &kernel_tp);
>
> + if (!error && kc->clock_timens_adjust)
> + timens_clock_from_host(which_clock, &kernel_tp);
Why are you adding this conditional instead of sticking the offset
magic into the affected ->clock_get() implementations?
That spares you the switch() and the !offsets conditional.
> +static void clock_timens_fixup(int clockid, struct timespec64 *val, bool to_ns)
> +{
> + struct timens_offsets *ns_offsets = current->nsproxy->time_ns->offsets;
> + struct timespec64 *offsets = NULL;
> +
> + if (!ns_offsets)
> + return;
> +
> + if (val->tv_sec == 0 && val->tv_nsec == 0)
> + return;
I have no idea why 0/0 is special.
> +
> + switch (clockid) {
> + case CLOCK_MONOTONIC:
> + case CLOCK_MONOTONIC_RAW:
> + case CLOCK_MONOTONIC_COARSE:
> + offsets = &ns_offsets->monotonic_time_offset;
> + break;
> + }
> +
> + if (!offsets)
> + return;
> +
> + if (to_ns)
> + *val = timespec64_add(*val, *offsets);
> + else
> + *val = timespec64_sub(*val, *offsets);
> +}
> +
> +void timens_clock_to_host(int clockid, struct timespec64 *val)
Does this really need to be an out of line call? If you stick this into the
clock_get() implementations then it boils down to:
static inline void timens_add_monotonic(struct timespec64 *ts)
{
struct timens_offsets *ns_offsets = current->nsproxy->time_ns->offsets;
if (ns_offsets)
*ts = timespec64_add(*ts, ns_offsets->monotonic_time_offset);
}
and
static int posix_ktime_get_ts(clockid_t which_clock, struct timespec64 *tp)
{
ktime_get_ts64(tp);
timens_add_monotonic(tp);
return 0;
}
Hmm?
Thanks,
tglx
^ permalink raw reply
* Re: [PATCH 12/18] io_uring: add support for pre-mapped user IO buffers
From: Jens Axboe @ 2019-02-07 21:02 UTC (permalink / raw)
To: Jeff Moyer; +Cc: linux-aio, linux-block, linux-api, hch, avi, jannh, viro
In-Reply-To: <x49mun75nam.fsf@segfault.boston.devel.redhat.com>
On 2/7/19 1:57 PM, Jeff Moyer wrote:
> Hi, Jens,
>
> Jens Axboe <axboe@kernel.dk> writes:
>
>> +static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx)
>> +{
>> + int i, j;
>> +
>> + if (!ctx->user_bufs)
>> + return -ENXIO;
>> +
>> + for (i = 0; i < ctx->sq_entries; i++) {
>> + struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
>> +
>> + for (j = 0; j < imu->nr_bvecs; j++)
>> + put_page(imu->bvec[j].bv_page);
>> +
>> + io_unaccount_mem(ctx->user, imu->nr_bvecs);
>> + kfree(imu->bvec);
>> + imu->nr_bvecs = 0;
>> + }
>> +
>> + kfree(ctx->user_bufs);
>> + ctx->user_bufs = NULL;
>> + free_uid(ctx->user);
> ^^^^^^^^^^^^^^^^^^^
>> + ctx->user = NULL;
> ^^^^^^^^^^^^^^^^^
>
> I don't think you want to do that here. If you do an
> IORING_REGISTER_BUFFERS, followed by IORING_UNREGISTER_BUFFERS, and then
> follow that up with IORING_REGISTER_FILES, you'll get a null pointer
> dereference trying to bump the reference count of the (now NULL)
> ctx->user (io_uring.c:1944):
>
> [ 216.927990] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
> [ 216.935825] #PF error: [WRITE]
> [ 216.938883] PGD 5f39244067 P4D 5f39244067 PUD 5f043ca067 PMD 0
> [ 216.944803] Oops: 0002 [#1] SMP
> [ 216.947949] CPU: 79 PID: 3371 Comm: io_uring_regist Not tainted 5.0.0-rc5.io_uring.4+ #26
> [ 216.956119] Hardware name: Intel Corporation S2600WFD/S2600WFD, BIOS SE5C620.86B.0D.01.0108.091420182119 09/14/2018
> [ 216.966553] RIP: 0010:__io_uring_register+0x1c2/0x7c0
> [ 216.971606] Code: 49 89 c6 48 85 c0 0f 84 9b 05 00 00 48 8b 83 20 02 00 00 48 8b 40 20 49 c7 46 60 60 89 1d 96 49 89 46 18 48 8b 83 18 01 00 00 <f0> ff 00 0f 88 1a a0 52 00 45 31 e4 66 83 7d 00 00 48 89 45 08 7e
> [ 216.990355] RSP: 0018:ffffb296087e3e70 EFLAGS: 00010286
> [ 216.995578] RAX: 0000000000000000 RBX: ffff9aacbbff3800 RCX: 0000000000000000
> [ 217.002711] RDX: ffff9aacbbaf1ac0 RSI: 00000000ffffffff RDI: ffff9aacb9a8f6b0
> [ 217.009842] RBP: ffff9aacbb45e800 R08: 00000000000000c0 R09: ffff9a4e87c07000
> [ 217.016977] R10: 0000000000000006 R11: ffff9aac97da9b00 R12: 00007efdc3dbd1fc
> [ 217.024107] R13: ffff9aacbb45ec08 R14: ffff9aacb9a8f600 R15: ffff9aac97da9a00
> [ 217.031241] FS: 00007f01c439e500(0000) GS:ffff9aacbf7c0000(0000) knlGS:0000000000000000
> [ 217.039326] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 217.045075] CR2: 0000000000000000 CR3: 0000005f08d85002 CR4: 00000000007606e0
> [ 217.052207] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 217.059340] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [ 217.066472] PKRU: 55555554
> [ 217.069183] Call Trace:
> [ 217.071638] __x64_sys_io_uring_register+0x91/0xb0
> [ 217.076433] do_syscall_64+0x4f/0x190
> [ 217.080110] entry_SYSCALL_64_after_hwframe+0x44/0xa9
> [ 217.085167] RIP: 0033:0x7f01c3eb42bd
> [ 217.088743] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 9b 6b 2c 00 f7 d8 64 89 01 48
>
> I'd expect ctx->user to live as long as the io_uring context itself,
> right?
Yes, it used to just be used for the buffers, now we use it generally. I've
fixed that up, thanks Jeff!
--
Jens Axboe
--
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^ permalink raw reply
* Re: [PATCH 12/18] io_uring: add support for pre-mapped user IO buffers
From: Jeff Moyer @ 2019-02-07 20:57 UTC (permalink / raw)
To: Jens Axboe; +Cc: linux-aio, linux-block, linux-api, hch, avi, jannh, viro
In-Reply-To: <20190207195552.22770-13-axboe@kernel.dk>
Hi, Jens,
Jens Axboe <axboe@kernel.dk> writes:
> +static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx)
> +{
> + int i, j;
> +
> + if (!ctx->user_bufs)
> + return -ENXIO;
> +
> + for (i = 0; i < ctx->sq_entries; i++) {
> + struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
> +
> + for (j = 0; j < imu->nr_bvecs; j++)
> + put_page(imu->bvec[j].bv_page);
> +
> + io_unaccount_mem(ctx->user, imu->nr_bvecs);
> + kfree(imu->bvec);
> + imu->nr_bvecs = 0;
> + }
> +
> + kfree(ctx->user_bufs);
> + ctx->user_bufs = NULL;
> + free_uid(ctx->user);
^^^^^^^^^^^^^^^^^^^
> + ctx->user = NULL;
^^^^^^^^^^^^^^^^^
I don't think you want to do that here. If you do an
IORING_REGISTER_BUFFERS, followed by IORING_UNREGISTER_BUFFERS, and then
follow that up with IORING_REGISTER_FILES, you'll get a null pointer
dereference trying to bump the reference count of the (now NULL)
ctx->user (io_uring.c:1944):
[ 216.927990] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
[ 216.935825] #PF error: [WRITE]
[ 216.938883] PGD 5f39244067 P4D 5f39244067 PUD 5f043ca067 PMD 0
[ 216.944803] Oops: 0002 [#1] SMP
[ 216.947949] CPU: 79 PID: 3371 Comm: io_uring_regist Not tainted 5.0.0-rc5.io_uring.4+ #26
[ 216.956119] Hardware name: Intel Corporation S2600WFD/S2600WFD, BIOS SE5C620.86B.0D.01.0108.091420182119 09/14/2018
[ 216.966553] RIP: 0010:__io_uring_register+0x1c2/0x7c0
[ 216.971606] Code: 49 89 c6 48 85 c0 0f 84 9b 05 00 00 48 8b 83 20 02 00 00 48 8b 40 20 49 c7 46 60 60 89 1d 96 49 89 46 18 48 8b 83 18 01 00 00 <f0> ff 00 0f 88 1a a0 52 00 45 31 e4 66 83 7d 00 00 48 89 45 08 7e
[ 216.990355] RSP: 0018:ffffb296087e3e70 EFLAGS: 00010286
[ 216.995578] RAX: 0000000000000000 RBX: ffff9aacbbff3800 RCX: 0000000000000000
[ 217.002711] RDX: ffff9aacbbaf1ac0 RSI: 00000000ffffffff RDI: ffff9aacb9a8f6b0
[ 217.009842] RBP: ffff9aacbb45e800 R08: 00000000000000c0 R09: ffff9a4e87c07000
[ 217.016977] R10: 0000000000000006 R11: ffff9aac97da9b00 R12: 00007efdc3dbd1fc
[ 217.024107] R13: ffff9aacbb45ec08 R14: ffff9aacb9a8f600 R15: ffff9aac97da9a00
[ 217.031241] FS: 00007f01c439e500(0000) GS:ffff9aacbf7c0000(0000) knlGS:0000000000000000
[ 217.039326] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 217.045075] CR2: 0000000000000000 CR3: 0000005f08d85002 CR4: 00000000007606e0
[ 217.052207] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 217.059340] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 217.066472] PKRU: 55555554
[ 217.069183] Call Trace:
[ 217.071638] __x64_sys_io_uring_register+0x91/0xb0
[ 217.076433] do_syscall_64+0x4f/0x190
[ 217.080110] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 217.085167] RIP: 0033:0x7f01c3eb42bd
[ 217.088743] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 9b 6b 2c 00 f7 d8 64 89 01 48
I'd expect ctx->user to live as long as the io_uring context itself,
right?
-Jeff
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^ permalink raw reply
* Re: [PATCH 05/18] Add io_uring IO interface
From: Jens Axboe @ 2019-02-07 20:16 UTC (permalink / raw)
To: Keith Busch
Cc: linux-aio, linux-block, linux-api, hch, jmoyer, avi, jannh, viro
In-Reply-To: <20190207201508.GA31594@localhost.localdomain>
On 2/7/19 1:15 PM, Keith Busch wrote:
> On Thu, Feb 07, 2019 at 12:55:39PM -0700, Jens Axboe wrote:
>> IO submissions use the io_uring_sqe data structure, and completions
>> are generated in the form of io_uring_sqe data structures.
> ^^^
>
> Completions use _cqe, right?
They do indeed... Fixed the typo, thanks Keith.
--
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^ permalink raw reply
* Re: [PATCH 05/18] Add io_uring IO interface
From: Keith Busch @ 2019-02-07 20:15 UTC (permalink / raw)
To: Jens Axboe
Cc: linux-aio, linux-block, linux-api, hch, jmoyer, avi, jannh, viro
In-Reply-To: <20190207195552.22770-6-axboe@kernel.dk>
On Thu, Feb 07, 2019 at 12:55:39PM -0700, Jens Axboe wrote:
> IO submissions use the io_uring_sqe data structure, and completions
> are generated in the form of io_uring_sqe data structures.
^^^
Completions use _cqe, right?
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^ permalink raw reply
* [PATCH 18/18] io_uring: add io_uring_event cache hit information
From: Jens Axboe @ 2019-02-07 19:55 UTC (permalink / raw)
To: linux-aio, linux-block, linux-api
Cc: hch, jmoyer, avi, jannh, viro, Jens Axboe
In-Reply-To: <20190207195552.22770-1-axboe@kernel.dk>
Add hint on whether a read was served out of the page cache, or if it
hit media. This is useful for buffered async IO, O_DIRECT reads would
never have this set (for obvious reasons).
If the read hit page cache, cqe->flags will have IOCQE_FLAG_CACHEHIT
set.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 7 ++++++-
include/uapi/linux/io_uring.h | 5 +++++
2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index af063145f901..69ab3f134b6d 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -579,11 +579,16 @@ static void io_fput(struct io_kiocb *req)
static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
{
struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
+ unsigned ev_flags = 0;
kiocb_end_write(kiocb);
io_fput(req);
- io_cqring_add_event(req->ctx, req->user_data, res, 0);
+
+ if (res > 0 && (req->flags & REQ_F_FORCE_NONBLOCK))
+ ev_flags = IOCQE_FLAG_CACHEHIT;
+
+ io_cqring_add_event(req->ctx, req->user_data, res, ev_flags);
io_free_req(req);
}
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index e23408692118..24906e99fdc7 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -69,6 +69,11 @@ struct io_uring_cqe {
__u32 flags;
};
+/*
+ * io_uring_event->flags
+ */
+#define IOCQE_FLAG_CACHEHIT (1U << 0) /* IO did not hit media */
+
/*
* Magic offsets for the application to mmap the data it needs
*/
--
2.17.1
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^ permalink raw reply related
* [PATCH 17/18] io_uring: allow workqueue item to handle multiple buffered requests
From: Jens Axboe @ 2019-02-07 19:55 UTC (permalink / raw)
To: linux-aio, linux-block, linux-api
Cc: hch, jmoyer, avi, jannh, viro, Jens Axboe
In-Reply-To: <20190207195552.22770-1-axboe@kernel.dk>
Right now we punt any buffered request that ends up triggering an
-EAGAIN to an async workqueue. This works fine in terms of providing
async execution of them, but it also can create quite a lot of work
queue items. For sequentially buffered IO, it's advantageous to
serialize the issue of them. For reads, the first one will trigger a
read-ahead, and subsequent request merely end up waiting on later pages
to complete. For writes, devices usually respond better to streamed
sequential writes.
Add state to track the last buffered request we punted to a work queue,
and if the next one is sequential to the previous, attempt to get the
previous work item to handle it. We limit the number of sequential
add-ons to the a multiple (8) of the max read-ahead size of the file.
This should be a good number for both reads and wries, as it defines the
max IO size the device can do directly.
This drastically cuts down on the number of context switches we need to
handle buffered sequential IO, and a basic test case of copying a big
file with io_uring sees a 5x speedup.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 267 ++++++++++++++++++++++++++++++++++++++++----------
1 file changed, 216 insertions(+), 51 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index cd456fd65af7..af063145f901 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -72,6 +72,16 @@ struct io_mapped_ubuf {
unsigned int nr_bvecs;
};
+struct async_list {
+ spinlock_t lock;
+ atomic_t cnt;
+ struct list_head list;
+
+ struct file *file;
+ off_t io_end;
+ size_t io_pages;
+};
+
struct io_ring_ctx {
struct {
struct percpu_ref refs;
@@ -140,6 +150,8 @@ struct io_ring_ctx {
struct list_head cancel_list;
} ____cacheline_aligned_in_smp;
+ struct async_list pending_async[2];
+
#if defined(CONFIG_NET)
struct socket *ring_sock;
#endif
@@ -177,6 +189,7 @@ struct io_kiocb {
#define REQ_F_FORCE_NONBLOCK 1 /* inline submission attempt */
#define REQ_F_IOPOLL_COMPLETED 2 /* polled IO has completed */
#define REQ_F_FIXED_FILE 4 /* ctx owns file */
+#define REQ_F_SEQ_PREV 8 /* sequential with previous */
u64 user_data;
u64 error;
@@ -232,6 +245,7 @@ static void io_ring_ctx_ref_free(struct percpu_ref *ref)
static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
{
struct io_ring_ctx *ctx;
+ int i;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
@@ -247,6 +261,11 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
init_completion(&ctx->ctx_done);
mutex_init(&ctx->uring_lock);
init_waitqueue_head(&ctx->wait);
+ for (i = 0; i < ARRAY_SIZE(ctx->pending_async); i++) {
+ spin_lock_init(&ctx->pending_async[i].lock);
+ INIT_LIST_HEAD(&ctx->pending_async[i].list);
+ atomic_set(&ctx->pending_async[i].cnt, 0);
+ }
spin_lock_init(&ctx->completion_lock);
INIT_LIST_HEAD(&ctx->poll_list);
INIT_LIST_HEAD(&ctx->cancel_list);
@@ -843,6 +862,39 @@ static int io_import_iovec(struct io_ring_ctx *ctx, int rw,
return import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter);
}
+static void io_async_list_note(int rw, struct io_kiocb *req, size_t len)
+{
+ struct async_list *async_list = &req->ctx->pending_async[rw];
+ struct kiocb *kiocb = &req->rw;
+ struct file *filp = kiocb->ki_filp;
+ off_t io_end = kiocb->ki_pos + len;
+
+ if (filp == async_list->file && kiocb->ki_pos == async_list->io_end) {
+ unsigned long max_pages;
+
+ /* Use 8x RA size as a decent limiter for both reads/writes */
+ max_pages = filp->f_ra.ra_pages;
+ if (!max_pages)
+ max_pages = VM_MAX_READAHEAD >> (PAGE_SHIFT - 10);
+ max_pages *= 8;
+
+ len >>= PAGE_SHIFT;
+ if (async_list->io_pages + len <= max_pages) {
+ req->flags |= REQ_F_SEQ_PREV;
+ async_list->io_pages += len;
+ } else {
+ io_end = 0;
+ async_list->io_pages = 0;
+ }
+ }
+
+ if (async_list->file != filp) {
+ async_list->io_pages = 0;
+ async_list->file = filp;
+ }
+ async_list->io_end = io_end;
+}
+
static ssize_t io_read(struct io_kiocb *req, const struct sqe_submit *s,
bool force_nonblock, struct io_submit_state *state)
{
@@ -850,6 +902,7 @@ static ssize_t io_read(struct io_kiocb *req, const struct sqe_submit *s,
struct kiocb *kiocb = &req->rw;
struct iov_iter iter;
struct file *file;
+ size_t iov_count;
ssize_t ret;
ret = io_prep_rw(req, s, force_nonblock, state);
@@ -868,16 +921,24 @@ static ssize_t io_read(struct io_kiocb *req, const struct sqe_submit *s,
if (ret)
goto out_fput;
- ret = rw_verify_area(READ, file, &kiocb->ki_pos, iov_iter_count(&iter));
+ iov_count = iov_iter_count(&iter);
+ ret = rw_verify_area(READ, file, &kiocb->ki_pos, iov_count);
if (!ret) {
ssize_t ret2;
/* Catch -EAGAIN return for forced non-blocking submission */
ret2 = call_read_iter(file, kiocb, &iter);
- if (!force_nonblock || ret2 != -EAGAIN)
+ if (!force_nonblock || ret2 != -EAGAIN) {
io_rw_done(kiocb, ret2);
- else
+ } else {
+ /*
+ * If ->needs_lock is true, we're already in async
+ * context.
+ */
+ if (!s->needs_lock)
+ io_async_list_note(READ, req, iov_count);
ret = -EAGAIN;
+ }
}
kfree(iovec);
out_fput:
@@ -894,14 +955,12 @@ static ssize_t io_write(struct io_kiocb *req, const struct sqe_submit *s,
struct kiocb *kiocb = &req->rw;
struct iov_iter iter;
struct file *file;
+ size_t iov_count;
ssize_t ret;
ret = io_prep_rw(req, s, force_nonblock, state);
if (ret)
return ret;
- /* Hold on to the file for -EAGAIN */
- if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT))
- return -EAGAIN;
ret = -EBADF;
file = kiocb->ki_filp;
@@ -915,8 +974,17 @@ static ssize_t io_write(struct io_kiocb *req, const struct sqe_submit *s,
if (ret)
goto out_fput;
- ret = rw_verify_area(WRITE, file, &kiocb->ki_pos,
- iov_iter_count(&iter));
+ iov_count = iov_iter_count(&iter);
+
+ ret = -EAGAIN;
+ if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT)) {
+ /* If ->needs_lock is true, we're already in async context. */
+ if (!s->needs_lock)
+ io_async_list_note(WRITE, req, iov_count);
+ goto out_free;
+ }
+
+ ret = rw_verify_area(WRITE, file, &kiocb->ki_pos, iov_count);
if (!ret) {
/*
* Open-code file_start_write here to grab freeze protection,
@@ -934,9 +1002,11 @@ static ssize_t io_write(struct io_kiocb *req, const struct sqe_submit *s,
kiocb->ki_flags |= IOCB_WRITE;
io_rw_done(kiocb, call_write_iter(file, kiocb, &iter));
}
+out_free:
kfree(iovec);
out_fput:
- if (unlikely(ret))
+ /* Hold on to the file for -EAGAIN */
+ if (unlikely(ret && ret != -EAGAIN))
io_fput(req);
return ret;
}
@@ -1300,6 +1370,21 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
return 0;
}
+static struct async_list *io_async_list_from_sqe(struct io_ring_ctx *ctx,
+ const struct io_uring_sqe *sqe)
+{
+ switch (sqe->opcode) {
+ case IORING_OP_READV:
+ case IORING_OP_READ_FIXED:
+ return &ctx->pending_async[READ];
+ case IORING_OP_WRITEV:
+ case IORING_OP_WRITE_FIXED:
+ return &ctx->pending_async[WRITE];
+ default:
+ return NULL;
+ }
+}
+
static inline bool io_sqe_needs_user(const struct io_uring_sqe *sqe)
{
u8 opcode = READ_ONCE(sqe->opcode);
@@ -1311,60 +1396,133 @@ static inline bool io_sqe_needs_user(const struct io_uring_sqe *sqe)
static void io_sq_wq_submit_work(struct work_struct *work)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
- struct sqe_submit *s = &req->submit;
struct io_ring_ctx *ctx = req->ctx;
+ struct mm_struct *cur_mm = NULL;
+ struct async_list *async_list;
+ LIST_HEAD(req_list);
mm_segment_t old_fs;
- bool needs_user;
- u64 user_data;
int ret;
- /* Ensure we clear previously set forced non-block flag */
- req->flags &= ~REQ_F_FORCE_NONBLOCK;
- req->rw.ki_flags &= ~IOCB_NOWAIT;
+ async_list = io_async_list_from_sqe(ctx, req->submit.sqe);
+restart:
+ do {
+ struct sqe_submit *s = &req->submit;
+ u64 user_data = READ_ONCE(s->sqe->user_data);
+
+ /* Ensure we clear previously set forced non-block flag */
+ req->flags &= ~REQ_F_FORCE_NONBLOCK;
+ req->rw.ki_flags &= ~IOCB_NOWAIT;
- user_data = READ_ONCE(s->sqe->user_data);
- s->needs_lock = true;
- s->has_user = false;
- s->needs_fixed_file = false;
+ ret = 0;
+ if (io_sqe_needs_user(s->sqe) && !cur_mm) {
+ if (!mmget_not_zero(ctx->sqo_mm)) {
+ ret = -EFAULT;
+ } else {
+ cur_mm = ctx->sqo_mm;
+ use_mm(ctx->sqo_mm);
+ old_fs = get_fs();
+ set_fs(USER_DS);
+ }
+ }
+
+ if (!ret) {
+ s->has_user = cur_mm != NULL;
+ s->needs_lock = true;
+ s->needs_fixed_file = false;
+ do {
+ ret = __io_submit_sqe(ctx, req, s, false, NULL);
+ /*
+ * We can get EAGAIN for polled IO even though
+ * we're forcing a sync submission from here,
+ * since we can't wait for request slots on the
+ * block side.
+ */
+ if (ret != -EAGAIN)
+ break;
+ cond_resched();
+ } while (1);
+ }
+ if (ret) {
+ io_cqring_add_event(ctx, user_data, ret, 0);
+ io_free_req(req);
+ }
+ if (!async_list)
+ break;
+ if (!list_empty(&req_list)) {
+ req = list_first_entry(&req_list, struct io_kiocb,
+ list);
+ list_del(&req->list);
+ continue;
+ }
+ if (list_empty(&async_list->list))
+ break;
+
+ req = NULL;
+ spin_lock(&async_list->lock);
+ if (list_empty(&async_list->list)) {
+ spin_unlock(&async_list->lock);
+ break;
+ }
+ list_splice_init(&async_list->list, &req_list);
+ spin_unlock(&async_list->lock);
+
+ req = list_first_entry(&req_list, struct io_kiocb, list);
+ list_del(&req->list);
+ } while (req);
/*
- * If we're doing IO to fixed buffers, we don't need to get/set
- * user context
+ * Rare case of racing with a submitter. If we find the count has
+ * dropped to zero AND we have pending work items, then restart
+ * the processing. This is a tiny race window.
*/
- needs_user = io_sqe_needs_user(s->sqe);
- if (needs_user) {
- if (!mmget_not_zero(ctx->sqo_mm)) {
- ret = -EFAULT;
- goto err;
+ ret = atomic_dec_return(&async_list->cnt);
+ while (!ret && !list_empty(&async_list->list)) {
+ spin_lock(&async_list->lock);
+ atomic_inc(&async_list->cnt);
+ list_splice_init(&async_list->list, &req_list);
+ spin_unlock(&async_list->lock);
+
+ if (!list_empty(&req_list)) {
+ req = list_first_entry(&req_list, struct io_kiocb,
+ list);
+ list_del(&req->list);
+ goto restart;
}
- use_mm(ctx->sqo_mm);
- old_fs = get_fs();
- set_fs(USER_DS);
- s->has_user = true;
+ ret = atomic_dec_return(&async_list->cnt);
}
- do {
- ret = __io_submit_sqe(ctx, req, s, false, NULL);
- /*
- * We can get EAGAIN for polled IO even though we're forcing
- * a sync submission from here, since we can't wait for
- * request slots on the block side.
- */
- if (ret != -EAGAIN)
- break;
- cond_resched();
- } while (1);
-
- if (needs_user) {
+ if (cur_mm) {
set_fs(old_fs);
- unuse_mm(ctx->sqo_mm);
- mmput(ctx->sqo_mm);
+ unuse_mm(cur_mm);
+ mmput(cur_mm);
}
-err:
- if (ret) {
- io_cqring_add_event(ctx, user_data, ret, 0);
- io_free_req(req);
+}
+
+/*
+ * See if we can piggy back onto previously submitted work, that is still
+ * running. We currently only allow this if the new request is sequential
+ * to the previous one we punted.
+ */
+static bool io_add_to_prev_work(struct async_list *list, struct io_kiocb *req)
+{
+ bool ret = false;
+
+ if (!list)
+ return false;
+ if (!(req->flags & REQ_F_SEQ_PREV))
+ return false;
+ if (!atomic_read(&list->cnt))
+ return false;
+
+ ret = true;
+ spin_lock(&list->lock);
+ list_add_tail(&req->list, &list->list);
+ if (!atomic_read(&list->cnt)) {
+ list_del_init(&req->list);
+ ret = false;
}
+ spin_unlock(&list->lock);
+ return ret;
}
static int io_submit_sqe(struct io_ring_ctx *ctx, const struct sqe_submit *s,
@@ -1385,9 +1543,16 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, const struct sqe_submit *s,
ret = __io_submit_sqe(ctx, req, s, true, state);
if (ret == -EAGAIN) {
+ struct async_list *list;
+
+ list = io_async_list_from_sqe(ctx, s->sqe);
memcpy(&req->submit, s, sizeof(*s));
- INIT_WORK(&req->work, io_sq_wq_submit_work);
- queue_work(ctx->sqo_wq, &req->work);
+ if (!io_add_to_prev_work(list, req)) {
+ if (list)
+ atomic_inc(&list->cnt);
+ INIT_WORK(&req->work, io_sq_wq_submit_work);
+ queue_work(ctx->sqo_wq, &req->work);
+ }
ret = 0;
}
if (ret)
--
2.17.1
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* [PATCH 16/18] io_uring: add support for IORING_OP_POLL
From: Jens Axboe @ 2019-02-07 19:55 UTC (permalink / raw)
To: linux-aio, linux-block, linux-api
Cc: hch, jmoyer, avi, jannh, viro, Jens Axboe
In-Reply-To: <20190207195552.22770-1-axboe@kernel.dk>
This is basically a direct port of bfe4037e722e, which implements a
one-shot poll command through aio. Description below is based on that
commit as well. However, instead of adding a POLL command and relying
on io_cancel(2) to remove it, we mimic the epoll(2) interface of
having a command to add a poll notification, IORING_OP_POLL_ADD,
and one to remove it again, IORING_OP_POLL_REMOVE.
To poll for a file descriptor the application should submit an sqe of
type IORING_OP_POLL. It will poll the fd for the events specified in the
poll_events field.
Unlike poll or epoll without EPOLLONESHOT this interface always works in
one shot mode, that is once the sqe is completed, it will have to be
resubmitted.
Based-on-code-from: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 256 +++++++++++++++++++++++++++++++++-
include/uapi/linux/io_uring.h | 3 +
2 files changed, 258 insertions(+), 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index b54c70f8f8af..cd456fd65af7 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -137,6 +137,7 @@ struct io_ring_ctx {
* manipulate the list, hence no extra locking is needed there.
*/
struct list_head poll_list;
+ struct list_head cancel_list;
} ____cacheline_aligned_in_smp;
#if defined(CONFIG_NET)
@@ -152,8 +153,20 @@ struct sqe_submit {
bool needs_fixed_file;
};
+struct io_poll_iocb {
+ struct file *file;
+ struct wait_queue_head *head;
+ __poll_t events;
+ bool woken;
+ bool canceled;
+ struct wait_queue_entry wait;
+};
+
struct io_kiocb {
- struct kiocb rw;
+ union {
+ struct kiocb rw;
+ struct io_poll_iocb poll;
+ };
struct sqe_submit submit;
@@ -236,6 +249,7 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
init_waitqueue_head(&ctx->wait);
spin_lock_init(&ctx->completion_lock);
INIT_LIST_HEAD(&ctx->poll_list);
+ INIT_LIST_HEAD(&ctx->cancel_list);
return ctx;
}
@@ -989,6 +1003,239 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe,
return 0;
}
+static void io_poll_remove_one(struct io_kiocb *req)
+{
+ struct io_poll_iocb *poll = &req->poll;
+
+ spin_lock(&poll->head->lock);
+ WRITE_ONCE(poll->canceled, true);
+ if (!list_empty(&poll->wait.entry)) {
+ list_del_init(&poll->wait.entry);
+ queue_work(req->ctx->sqo_wq, &req->work);
+ }
+ spin_unlock(&poll->head->lock);
+
+ list_del_init(&req->list);
+}
+
+static void io_poll_remove_all(struct io_ring_ctx *ctx)
+{
+ struct io_kiocb *req;
+
+ spin_lock_irq(&ctx->completion_lock);
+ while (!list_empty(&ctx->cancel_list)) {
+ req = list_first_entry(&ctx->cancel_list, struct io_kiocb,list);
+ io_poll_remove_one(req);
+ }
+ spin_unlock_irq(&ctx->completion_lock);
+}
+
+/*
+ * Find a running poll command that matches one specified in sqe->addr,
+ * and remove it if found.
+ */
+static int io_poll_remove(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+ struct io_kiocb *poll_req, *next;
+ int ret = -ENOENT;
+
+ if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+ return -EINVAL;
+ if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index ||
+ sqe->poll_events)
+ return -EINVAL;
+
+ spin_lock_irq(&ctx->completion_lock);
+ list_for_each_entry_safe(poll_req, next, &ctx->cancel_list, list) {
+ if (READ_ONCE(sqe->addr) == poll_req->user_data) {
+ io_poll_remove_one(poll_req);
+ ret = 0;
+ break;
+ }
+ }
+ spin_unlock_irq(&ctx->completion_lock);
+
+ io_cqring_add_event(req->ctx, sqe->user_data, ret, 0);
+ io_free_req(req);
+ return 0;
+}
+
+static void io_poll_complete(struct io_kiocb *req, __poll_t mask)
+{
+ io_cqring_add_event(req->ctx, req->user_data, mangle_poll(mask), 0);
+ io_fput(req);
+ io_free_req(req);
+}
+
+static void io_poll_complete_work(struct work_struct *work)
+{
+ struct io_kiocb *req = container_of(work, struct io_kiocb, work);
+ struct io_poll_iocb *poll = &req->poll;
+ struct poll_table_struct pt = { ._key = poll->events };
+ struct io_ring_ctx *ctx = req->ctx;
+ __poll_t mask = 0;
+
+ if (!READ_ONCE(poll->canceled))
+ mask = vfs_poll(poll->file, &pt) & poll->events;
+
+ /*
+ * Note that ->ki_cancel callers also delete iocb from active_reqs after
+ * calling ->ki_cancel. We need the ctx_lock roundtrip here to
+ * synchronize with them. In the cancellation case the list_del_init
+ * itself is not actually needed, but harmless so we keep it in to
+ * avoid further branches in the fast path.
+ */
+ spin_lock_irq(&ctx->completion_lock);
+ if (!mask && !READ_ONCE(poll->canceled)) {
+ add_wait_queue(poll->head, &poll->wait);
+ spin_unlock_irq(&ctx->completion_lock);
+ return;
+ }
+ list_del_init(&req->list);
+ spin_unlock_irq(&ctx->completion_lock);
+
+ io_poll_complete(req, mask);
+}
+
+static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
+ void *key)
+{
+ struct io_poll_iocb *poll = container_of(wait, struct io_poll_iocb,
+ wait);
+ struct io_kiocb *req = container_of(poll, struct io_kiocb, poll);
+ struct io_ring_ctx *ctx = req->ctx;
+ __poll_t mask = key_to_poll(key);
+
+ poll->woken = true;
+
+ /* for instances that support it check for an event match first: */
+ if (mask) {
+ if (!(mask & poll->events))
+ return 0;
+
+ /* try to complete the iocb inline if we can: */
+ if (spin_trylock(&ctx->completion_lock)) {
+ list_del(&req->list);
+ spin_unlock(&ctx->completion_lock);
+
+ list_del_init(&poll->wait.entry);
+ io_poll_complete(req, mask);
+ return 1;
+ }
+ }
+
+ list_del_init(&poll->wait.entry);
+ queue_work(ctx->sqo_wq, &req->work);
+ return 1;
+}
+
+struct io_poll_table {
+ struct poll_table_struct pt;
+ struct io_kiocb *req;
+ int error;
+};
+
+static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head,
+ struct poll_table_struct *p)
+{
+ struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
+
+ if (unlikely(pt->req->poll.head)) {
+ pt->error = -EINVAL;
+ return;
+ }
+
+ pt->error = 0;
+ pt->req->poll.head = head;
+ add_wait_queue(head, &pt->req->poll.wait);
+}
+
+static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+ struct io_poll_iocb *poll = &req->poll;
+ struct io_ring_ctx *ctx = req->ctx;
+ struct io_poll_table ipt;
+ unsigned flags;
+ __poll_t mask;
+ u16 events;
+ int fd;
+
+ if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+ return -EINVAL;
+ if (sqe->addr || sqe->ioprio || sqe->off || sqe->len || sqe->buf_index)
+ return -EINVAL;
+
+ INIT_WORK(&req->work, io_poll_complete_work);
+ events = READ_ONCE(sqe->poll_events);
+ poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP;
+
+ flags = READ_ONCE(sqe->flags);
+ fd = READ_ONCE(sqe->fd);
+
+ if (flags & IOSQE_FIXED_FILE) {
+ if (unlikely(!ctx->user_files || fd >= ctx->user_files->count))
+ return -EBADF;
+ poll->file = ctx->user_files->fp[fd];
+ req->flags |= REQ_F_FIXED_FILE;
+ } else {
+ poll->file = fget(fd);
+ }
+ if (unlikely(!poll->file))
+ return -EBADF;
+
+ poll->head = NULL;
+ poll->woken = false;
+ poll->canceled = false;
+
+ ipt.pt._qproc = io_poll_queue_proc;
+ ipt.pt._key = poll->events;
+ ipt.req = req;
+ ipt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */
+
+ /* initialized the list so that we can do list_empty checks */
+ INIT_LIST_HEAD(&poll->wait.entry);
+ init_waitqueue_func_entry(&poll->wait, io_poll_wake);
+
+ /* one for removal from waitqueue, one for this function */
+ refcount_set(&req->refs, 2);
+
+ mask = vfs_poll(poll->file, &ipt.pt) & poll->events;
+ if (unlikely(!poll->head)) {
+ /* we did not manage to set up a waitqueue, done */
+ goto out;
+ }
+
+ spin_lock_irq(&ctx->completion_lock);
+ spin_lock(&poll->head->lock);
+ if (poll->woken) {
+ /* wake_up context handles the rest */
+ mask = 0;
+ ipt.error = 0;
+ } else if (mask || ipt.error) {
+ /* if we get an error or a mask we are done */
+ WARN_ON_ONCE(list_empty(&poll->wait.entry));
+ list_del_init(&poll->wait.entry);
+ } else {
+ /* actually waiting for an event */
+ list_add_tail(&req->list, &ctx->cancel_list);
+ }
+ spin_unlock(&poll->head->lock);
+ spin_unlock_irq(&ctx->completion_lock);
+
+out:
+ if (unlikely(ipt.error)) {
+ if (!(flags & IOSQE_FIXED_FILE))
+ fput(poll->file);
+ return ipt.error;
+ }
+
+ if (mask)
+ io_poll_complete(req, mask);
+ io_free_req(req);
+ return 0;
+}
+
static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
const struct sqe_submit *s, bool force_nonblock,
struct io_submit_state *state)
@@ -1024,6 +1271,12 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
case IORING_OP_FSYNC:
ret = io_fsync(req, s->sqe, force_nonblock);
break;
+ case IORING_OP_POLL_ADD:
+ ret = io_poll_add(req, s->sqe);
+ break;
+ case IORING_OP_POLL_REMOVE:
+ ret = io_poll_remove(req, s->sqe);
+ break;
default:
ret = -EINVAL;
break;
@@ -1933,6 +2186,7 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
percpu_ref_kill(&ctx->refs);
mutex_unlock(&ctx->uring_lock);
+ io_poll_remove_all(ctx);
io_iopoll_reap_events(ctx);
wait_for_completion(&ctx->ctx_done);
io_ring_ctx_free(ctx);
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 0ec74bab8dbe..e23408692118 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -25,6 +25,7 @@ struct io_uring_sqe {
union {
__kernel_rwf_t rw_flags;
__u32 fsync_flags;
+ __u16 poll_events;
};
__u64 user_data; /* data to be passed back at completion time */
union {
@@ -51,6 +52,8 @@ struct io_uring_sqe {
#define IORING_OP_FSYNC 3
#define IORING_OP_READ_FIXED 4
#define IORING_OP_WRITE_FIXED 5
+#define IORING_OP_POLL_ADD 6
+#define IORING_OP_POLL_REMOVE 7
/*
* sqe->fsync_flags
--
2.17.1
--
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^ permalink raw reply related
* [PATCH 15/18] io_uring: add io_kiocb ref count
From: Jens Axboe @ 2019-02-07 19:55 UTC (permalink / raw)
To: linux-aio, linux-block, linux-api
Cc: hch, jmoyer, avi, jannh, viro, Jens Axboe
In-Reply-To: <20190207195552.22770-1-axboe@kernel.dk>
We'll use this for the POLL implementation. Regular requests will
NOT be using references, so initialize it to 0. Any real use of
the io_kiocb ref will initialize it to at least 2.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 200631cf3955..b54c70f8f8af 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -160,6 +160,7 @@ struct io_kiocb {
struct io_ring_ctx *ctx;
struct list_head list;
unsigned int flags;
+ refcount_t refs;
#define REQ_F_FORCE_NONBLOCK 1 /* inline submission attempt */
#define REQ_F_IOPOLL_COMPLETED 2 /* polled IO has completed */
#define REQ_F_FIXED_FILE 4 /* ctx owns file */
@@ -345,6 +346,7 @@ static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx,
req->ctx = ctx;
req->flags = 0;
+ refcount_set(&req->refs, 0);
return req;
out:
io_ring_drop_ctx_refs(ctx, 1);
@@ -362,8 +364,10 @@ static void io_free_req_many(struct io_ring_ctx *ctx, void **reqs, int *nr)
static void io_free_req(struct io_kiocb *req)
{
- io_ring_drop_ctx_refs(req->ctx, 1);
- kmem_cache_free(req_cachep, req);
+ if (!refcount_read(&req->refs) || refcount_dec_and_test(&req->refs)) {
+ io_ring_drop_ctx_refs(req->ctx, 1);
+ kmem_cache_free(req_cachep, req);
+ }
}
/*
--
2.17.1
--
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^ permalink raw reply related
* [PATCH 14/18] io_uring: add submission polling
From: Jens Axboe @ 2019-02-07 19:55 UTC (permalink / raw)
To: linux-aio, linux-block, linux-api
Cc: hch, jmoyer, avi, jannh, viro, Jens Axboe
In-Reply-To: <20190207195552.22770-1-axboe@kernel.dk>
This enables an application to do IO, without ever entering the kernel.
By using the SQ ring to fill in new sqes and watching for completions
on the CQ ring, we can submit and reap IOs without doing a single system
call. The kernel side thread will poll for new submissions, and in case
of HIPRI/polled IO, it'll also poll for completions.
By default, we allow 1 second of active spinning. This can by changed
by passing in a different grace period at io_uring_register(2) time.
If the thread exceeds this idle time without having any work to do, it
will set:
sq_ring->flags |= IORING_SQ_NEED_WAKEUP.
The application will have to call io_uring_enter() to start things back
up again. If IO is kept busy, that will never be needed. Basically an
application that has this feature enabled will guard it's
io_uring_enter(2) call with:
read_barrier();
if (*sq_ring->flags & IORING_SQ_NEED_WAKEUP)
io_uring_enter(fd, 0, 0, IORING_ENTER_SQ_WAKEUP);
instead of calling it unconditionally.
It's mandatory to use fixed files with this feature. Failure to do so
will result in the application getting an -EBADF CQ entry when
submitting IO.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 249 +++++++++++++++++++++++++++++++++-
include/uapi/linux/io_uring.h | 12 +-
2 files changed, 253 insertions(+), 8 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index f2550efec60d..200631cf3955 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -24,6 +24,7 @@
#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
+#include <linux/kthread.h>
#include <linux/blkdev.h>
#include <linux/bvec.h>
#include <linux/net.h>
@@ -85,12 +86,16 @@ struct io_ring_ctx {
unsigned cached_sq_head;
unsigned sq_entries;
unsigned sq_mask;
+ unsigned sq_thread_idle;
struct io_uring_sqe *sq_sqes;
} ____cacheline_aligned_in_smp;
/* IO offload */
struct workqueue_struct *sqo_wq;
+ struct task_struct *sqo_thread; /* if using sq thread polling */
struct mm_struct *sqo_mm;
+ wait_queue_head_t sqo_wait;
+ unsigned sqo_stop;
struct {
/* CQ ring */
@@ -144,6 +149,7 @@ struct sqe_submit {
unsigned short index;
bool has_user;
bool needs_lock;
+ bool needs_fixed_file;
};
struct io_kiocb {
@@ -295,6 +301,8 @@ static void io_cqring_add_event(struct io_ring_ctx *ctx, u64 ki_user_data,
if (waitqueue_active(&ctx->wait))
wake_up(&ctx->wait);
+ if (waitqueue_active(&ctx->sqo_wait))
+ wake_up(&ctx->sqo_wait);
}
static void io_ring_drop_ctx_refs(struct io_ring_ctx *ctx, unsigned refs)
@@ -648,9 +656,10 @@ static bool io_file_supports_async(struct file *file)
return false;
}
-static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
+static int io_prep_rw(struct io_kiocb *req, const struct sqe_submit *s,
bool force_nonblock, struct io_submit_state *state)
{
+ const struct io_uring_sqe *sqe = s->sqe;
struct io_ring_ctx *ctx = req->ctx;
struct kiocb *kiocb = &req->rw;
unsigned ioprio, flags;
@@ -670,6 +679,8 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
kiocb->ki_filp = ctx->user_files->fp[fd];
req->flags |= REQ_F_FIXED_FILE;
} else {
+ if (s->needs_fixed_file)
+ return -EBADF;
kiocb->ki_filp = io_file_get(state, fd);
if (unlikely(!kiocb->ki_filp))
return -EBADF;
@@ -823,7 +834,7 @@ static ssize_t io_read(struct io_kiocb *req, const struct sqe_submit *s,
struct file *file;
ssize_t ret;
- ret = io_prep_rw(req, s->sqe, force_nonblock, state);
+ ret = io_prep_rw(req, s, force_nonblock, state);
if (ret)
return ret;
file = kiocb->ki_filp;
@@ -867,7 +878,7 @@ static ssize_t io_write(struct io_kiocb *req, const struct sqe_submit *s,
struct file *file;
ssize_t ret;
- ret = io_prep_rw(req, s->sqe, force_nonblock, state);
+ ret = io_prep_rw(req, s, force_nonblock, state);
if (ret)
return ret;
/* Hold on to the file for -EAGAIN */
@@ -1057,6 +1068,7 @@ static void io_sq_wq_submit_work(struct work_struct *work)
user_data = READ_ONCE(s->sqe->user_data);
s->needs_lock = true;
s->has_user = false;
+ s->needs_fixed_file = false;
/*
* If we're doing IO to fixed buffers, we don't need to get/set
@@ -1211,6 +1223,170 @@ static bool io_get_sqring(struct io_ring_ctx *ctx, struct sqe_submit *s)
return false;
}
+static int io_submit_sqes(struct io_ring_ctx *ctx, struct sqe_submit *sqes,
+ unsigned int nr, bool has_user, bool mm_fault)
+{
+ struct io_submit_state state, *statep = NULL;
+ int ret, i, submitted = 0;
+
+ if (nr > IO_PLUG_THRESHOLD) {
+ io_submit_state_start(&state, ctx, nr);
+ statep = &state;
+ }
+
+ for (i = 0; i < nr; i++) {
+ if (unlikely(mm_fault)) {
+ ret = -EFAULT;
+ } else {
+ sqes[i].has_user = has_user;
+ sqes[i].needs_lock = true;
+ sqes[i].needs_fixed_file = true;
+ ret = io_submit_sqe(ctx, &sqes[i], statep);
+ }
+ if (!ret) {
+ submitted++;
+ continue;
+ }
+
+ io_cqring_add_event(ctx, sqes[i].sqe->user_data, ret, 0);
+ }
+
+ if (statep)
+ io_submit_state_end(&state);
+
+ return submitted;
+}
+
+static int io_sq_thread(void *data)
+{
+ struct sqe_submit sqes[IO_IOPOLL_BATCH];
+ struct io_ring_ctx *ctx = data;
+ struct mm_struct *cur_mm = NULL;
+ mm_segment_t old_fs;
+ DEFINE_WAIT(wait);
+ unsigned inflight;
+ unsigned long timeout;
+
+ old_fs = get_fs();
+ set_fs(USER_DS);
+
+ timeout = inflight = 0;
+ while (!kthread_should_stop() && !ctx->sqo_stop) {
+ bool all_fixed, mm_fault = false;
+ int i;
+
+ if (inflight) {
+ unsigned nr_events = 0;
+
+ if (ctx->flags & IORING_SETUP_IOPOLL) {
+ /*
+ * We disallow the app entering submit/complete
+ * with polling, but we still need to lock the
+ * ring to prevent racing with polled issue
+ * that got punted to a workqueue.
+ */
+ mutex_lock(&ctx->uring_lock);
+ io_iopoll_check(ctx, &nr_events, 0);
+ mutex_unlock(&ctx->uring_lock);
+ } else {
+ /*
+ * Normal IO, just pretend everything completed.
+ * We don't have to poll completions for that.
+ */
+ nr_events = inflight;
+ }
+
+ inflight -= nr_events;
+ if (!inflight)
+ timeout = jiffies + ctx->sq_thread_idle;
+ }
+
+ if (!io_get_sqring(ctx, &sqes[0])) {
+ /*
+ * We're polling. If we're within the defined idle
+ * period, then let us spin without work before going
+ * to sleep.
+ */
+ if (inflight || !time_after(jiffies, timeout)) {
+ cpu_relax();
+ continue;
+ }
+
+ /*
+ * Drop cur_mm before scheduling, we can't hold it for
+ * long periods (or over schedule()). Do this before
+ * adding ourselves to the waitqueue, as the unuse/drop
+ * may sleep.
+ */
+ if (cur_mm) {
+ unuse_mm(cur_mm);
+ mmput(cur_mm);
+ cur_mm = NULL;
+ }
+
+ prepare_to_wait(&ctx->sqo_wait, &wait,
+ TASK_INTERRUPTIBLE);
+
+ /* Tell userspace we may need a wakeup call */
+ ctx->sq_ring->flags |= IORING_SQ_NEED_WAKEUP;
+ smp_wmb();
+
+ if (!io_get_sqring(ctx, &sqes[0])) {
+ if (kthread_should_stop()) {
+ finish_wait(&ctx->sqo_wait, &wait);
+ break;
+ }
+ if (signal_pending(current))
+ flush_signals(current);
+ schedule();
+ finish_wait(&ctx->sqo_wait, &wait);
+
+ ctx->sq_ring->flags &= ~IORING_SQ_NEED_WAKEUP;
+ smp_wmb();
+ continue;
+ }
+ finish_wait(&ctx->sqo_wait, &wait);
+
+ ctx->sq_ring->flags &= ~IORING_SQ_NEED_WAKEUP;
+ smp_wmb();
+ }
+
+ i = 0;
+ all_fixed = true;
+ do {
+ if (all_fixed && io_sqe_needs_user(sqes[i].sqe))
+ all_fixed = false;
+
+ i++;
+ if (i == ARRAY_SIZE(sqes))
+ break;
+ } while (io_get_sqring(ctx, &sqes[i]));
+
+ io_commit_sqring(ctx);
+
+ /* Unless all new commands are FIXED regions, grab mm */
+ if (!all_fixed && !cur_mm) {
+ mm_fault = !mmget_not_zero(ctx->sqo_mm);
+ if (!mm_fault) {
+ use_mm(ctx->sqo_mm);
+ cur_mm = ctx->sqo_mm;
+ }
+ }
+
+ inflight += io_submit_sqes(ctx, sqes, i, cur_mm != NULL,
+ mm_fault);
+ }
+
+ io_iopoll_reap_events(ctx);
+
+ set_fs(old_fs);
+ if (cur_mm) {
+ unuse_mm(cur_mm);
+ mmput(cur_mm);
+ }
+ return 0;
+}
+
static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit)
{
struct io_submit_state state, *statep = NULL;
@@ -1229,6 +1405,7 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit)
s.has_user = true;
s.needs_lock = false;
+ s.needs_fixed_file = false;
ret = io_submit_sqe(ctx, &s, statep);
if (ret) {
@@ -1391,13 +1568,47 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
return ret;
}
-static int io_sq_offload_start(struct io_ring_ctx *ctx)
+static int io_sq_offload_start(struct io_ring_ctx *ctx,
+ struct io_uring_params *p)
{
int ret;
+ init_waitqueue_head(&ctx->sqo_wait);
mmgrab(current->mm);
ctx->sqo_mm = current->mm;
+ ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle);
+ if (!ctx->sq_thread_idle)
+ ctx->sq_thread_idle = HZ;
+
+ ret = -EINVAL;
+ if (!cpu_possible(p->sq_thread_cpu))
+ goto err;
+
+ if (ctx->flags & IORING_SETUP_SQPOLL) {
+ if (p->flags & IORING_SETUP_SQ_AFF) {
+ int cpu;
+
+ cpu = array_index_nospec(p->sq_thread_cpu, NR_CPUS);
+ ctx->sqo_thread = kthread_create_on_cpu(io_sq_thread,
+ ctx, cpu,
+ "io_uring-sq");
+ } else {
+ ctx->sqo_thread = kthread_create(io_sq_thread, ctx,
+ "io_uring-sq");
+ }
+ if (IS_ERR(ctx->sqo_thread)) {
+ ret = PTR_ERR(ctx->sqo_thread);
+ ctx->sqo_thread = NULL;
+ goto err;
+ }
+ wake_up_process(ctx->sqo_thread);
+ } else if (p->flags & IORING_SETUP_SQ_AFF) {
+ /* Can't have SQ_AFF without SQPOLL */
+ ret = -EINVAL;
+ goto err;
+ }
+
/* Do QD, or 2 * CPUS, whatever is smallest */
ctx->sqo_wq = alloc_workqueue("io_ring-wq", WQ_UNBOUND | WQ_FREEZABLE,
min(ctx->sq_entries - 1, 2 * num_online_cpus()));
@@ -1408,6 +1619,12 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx)
return 0;
err:
+ if (ctx->sqo_thread) {
+ ctx->sqo_stop = 1;
+ mb();
+ kthread_stop(ctx->sqo_thread);
+ ctx->sqo_thread = NULL;
+ }
mmdrop(ctx->sqo_mm);
ctx->sqo_mm = NULL;
return ret;
@@ -1654,6 +1871,11 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
static void io_ring_ctx_free(struct io_ring_ctx *ctx)
{
+ if (ctx->sqo_thread) {
+ ctx->sqo_stop = 1;
+ mb();
+ kthread_stop(ctx->sqo_thread);
+ }
if (ctx->sqo_wq)
destroy_workqueue(ctx->sqo_wq);
if (ctx->sqo_mm)
@@ -1761,7 +1983,7 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
int submitted = 0;
struct fd f;
- if (flags & ~IORING_ENTER_GETEVENTS)
+ if (flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP))
return -EINVAL;
f = fdget(fd);
@@ -1777,6 +1999,18 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
if (!percpu_ref_tryget(&ctx->refs))
goto out_fput;
+ /*
+ * For SQ polling, the thread will do all submissions and completions.
+ * Just return the requested submit count, and wake the thread if
+ * we were asked to.
+ */
+ if (ctx->flags & IORING_SETUP_SQPOLL) {
+ if (flags & IORING_ENTER_SQ_WAKEUP)
+ wake_up(&ctx->sqo_wait);
+ submitted = to_submit;
+ goto out_ctx;
+ }
+
if (to_submit) {
to_submit = min(to_submit, ctx->sq_entries);
@@ -1940,7 +2174,7 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p)
if (ret)
goto err;
- ret = io_sq_offload_start(ctx);
+ ret = io_sq_offload_start(ctx, p);
if (ret)
goto err;
@@ -1988,7 +2222,8 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
return -EINVAL;
}
- if (p.flags & ~IORING_SETUP_IOPOLL)
+ if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL |
+ IORING_SETUP_SQ_AFF))
return -EINVAL;
ret = io_uring_create(entries, &p);
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 6257478d55e9..0ec74bab8dbe 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -42,6 +42,8 @@ struct io_uring_sqe {
* io_uring_setup() flags
*/
#define IORING_SETUP_IOPOLL (1U << 0) /* io_context is polled */
+#define IORING_SETUP_SQPOLL (1U << 1) /* SQ poll thread */
+#define IORING_SETUP_SQ_AFF (1U << 2) /* sq_thread_cpu is valid */
#define IORING_OP_NOP 0
#define IORING_OP_READV 1
@@ -86,6 +88,11 @@ struct io_sqring_offsets {
__u64 resv2;
};
+/*
+ * sq_ring->flags
+ */
+#define IORING_SQ_NEED_WAKEUP (1U << 0) /* needs io_uring_enter wakeup */
+
struct io_cqring_offsets {
__u32 head;
__u32 tail;
@@ -100,6 +107,7 @@ struct io_cqring_offsets {
* io_uring_enter(2) flags
*/
#define IORING_ENTER_GETEVENTS (1U << 0)
+#define IORING_ENTER_SQ_WAKEUP (1U << 1)
/*
* Passed in for io_uring_setup(2). Copied back with updated info on success
@@ -108,7 +116,9 @@ struct io_uring_params {
__u32 sq_entries;
__u32 cq_entries;
__u32 flags;
- __u32 resv[7];
+ __u32 sq_thread_cpu;
+ __u32 sq_thread_idle;
+ __u32 resv[5];
struct io_sqring_offsets sq_off;
struct io_cqring_offsets cq_off;
};
--
2.17.1
--
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^ permalink raw reply related
* [PATCH 13/18] io_uring: add file set registration
From: Jens Axboe @ 2019-02-07 19:55 UTC (permalink / raw)
To: linux-aio, linux-block, linux-api
Cc: hch, jmoyer, avi, jannh, viro, Jens Axboe
In-Reply-To: <20190207195552.22770-1-axboe@kernel.dk>
We normally have to fget/fput for each IO we do on a file. Even with
the batching we do, the cost of the atomic inc/dec of the file usage
count adds up.
This adds IORING_REGISTER_FILES, and IORING_UNREGISTER_FILES opcodes
for the io_uring_register(2) system call. The arguments passed in must
be an array of __s32 holding file descriptors, and nr_args should hold
the number of file descriptors the application wishes to pin for the
duration of the io_uring context (or until IORING_UNREGISTER_FILES is
called).
When used, the application must set IOSQE_FIXED_FILE in the sqe->flags
member. Then, instead of setting sqe->fd to the real fd, it sets sqe->fd
to the index in the array passed in to IORING_REGISTER_FILES.
Files are automatically unregistered when the io_uring context is
torn down. An application need only unregister if it wishes to
register a new set of fds.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 207 +++++++++++++++++++++++++++++-----
include/net/af_unix.h | 1 +
include/uapi/linux/io_uring.h | 9 +-
net/unix/af_unix.c | 2 +-
4 files changed, 188 insertions(+), 31 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 9d6233dc35ca..f2550efec60d 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -29,6 +29,7 @@
#include <linux/net.h>
#include <net/sock.h>
#include <net/af_unix.h>
+#include <net/scm.h>
#include <linux/anon_inodes.h>
#include <linux/sched/mm.h>
#include <linux/uaccess.h>
@@ -101,6 +102,13 @@ struct io_ring_ctx {
struct fasync_struct *cq_fasync;
} ____cacheline_aligned_in_smp;
+ /*
+ * If used, fixed file set. Writers must ensure that ->refs is dead,
+ * readers must ensure that ->refs is alive as long as the file* is
+ * used. Only updated through io_uring_register(2).
+ */
+ struct scm_fp_list *user_files;
+
/* if used, fixed mapped user buffers */
unsigned nr_user_bufs;
struct io_mapped_ubuf *user_bufs;
@@ -148,6 +156,7 @@ struct io_kiocb {
unsigned int flags;
#define REQ_F_FORCE_NONBLOCK 1 /* inline submission attempt */
#define REQ_F_IOPOLL_COMPLETED 2 /* polled IO has completed */
+#define REQ_F_FIXED_FILE 4 /* ctx owns file */
u64 user_data;
u64 error;
@@ -374,15 +383,17 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
* Batched puts of the same file, to avoid dirtying the
* file usage count multiple times, if avoidable.
*/
- if (!file) {
- file = req->rw.ki_filp;
- file_count = 1;
- } else if (file == req->rw.ki_filp) {
- file_count++;
- } else {
- fput_many(file, file_count);
- file = req->rw.ki_filp;
- file_count = 1;
+ if (!(req->flags & REQ_F_FIXED_FILE)) {
+ if (!file) {
+ file = req->rw.ki_filp;
+ file_count = 1;
+ } else if (file == req->rw.ki_filp) {
+ file_count++;
+ } else {
+ fput_many(file, file_count);
+ file = req->rw.ki_filp;
+ file_count = 1;
+ }
}
if (to_free == ARRAY_SIZE(reqs))
@@ -514,13 +525,19 @@ static void kiocb_end_write(struct kiocb *kiocb)
}
}
+static void io_fput(struct io_kiocb *req)
+{
+ if (!(req->flags & REQ_F_FIXED_FILE))
+ fput(req->rw.ki_filp);
+}
+
static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
{
struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
kiocb_end_write(kiocb);
- fput(kiocb->ki_filp);
+ io_fput(req);
io_cqring_add_event(req->ctx, req->user_data, res, 0);
io_free_req(req);
}
@@ -636,19 +653,29 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
{
struct io_ring_ctx *ctx = req->ctx;
struct kiocb *kiocb = &req->rw;
- unsigned ioprio;
+ unsigned ioprio, flags;
int fd, ret;
/* For -EAGAIN retry, everything is already prepped */
if (kiocb->ki_filp)
return 0;
+ flags = READ_ONCE(sqe->flags);
fd = READ_ONCE(sqe->fd);
- kiocb->ki_filp = io_file_get(state, fd);
- if (unlikely(!kiocb->ki_filp))
- return -EBADF;
- if (force_nonblock && !io_file_supports_async(kiocb->ki_filp))
- force_nonblock = false;
+
+ if (flags & IOSQE_FIXED_FILE) {
+ if (unlikely(!ctx->user_files ||
+ (unsigned) fd >= ctx->user_files->count))
+ return -EBADF;
+ kiocb->ki_filp = ctx->user_files->fp[fd];
+ req->flags |= REQ_F_FIXED_FILE;
+ } else {
+ kiocb->ki_filp = io_file_get(state, fd);
+ if (unlikely(!kiocb->ki_filp))
+ return -EBADF;
+ if (force_nonblock && !io_file_supports_async(kiocb->ki_filp))
+ force_nonblock = false;
+ }
kiocb->ki_pos = READ_ONCE(sqe->off);
kiocb->ki_flags = iocb_flags(kiocb->ki_filp);
kiocb->ki_hint = ki_hint_validate(file_write_hint(kiocb->ki_filp));
@@ -688,10 +715,14 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
}
return 0;
out_fput:
- /* in case of error, we didn't use this file reference. drop it. */
- if (state)
- state->used_refs--;
- io_file_put(state, kiocb->ki_filp);
+ if (!(flags & IOSQE_FIXED_FILE)) {
+ /*
+ * in case of error, we didn't use this file reference. drop it.
+ */
+ if (state)
+ state->used_refs--;
+ io_file_put(state, kiocb->ki_filp);
+ }
return ret;
}
@@ -823,7 +854,7 @@ static ssize_t io_read(struct io_kiocb *req, const struct sqe_submit *s,
out_fput:
/* Hold on to the file for -EAGAIN */
if (unlikely(ret && ret != -EAGAIN))
- fput(file);
+ io_fput(req);
return ret;
}
@@ -877,7 +908,7 @@ static ssize_t io_write(struct io_kiocb *req, const struct sqe_submit *s,
kfree(iovec);
out_fput:
if (unlikely(ret))
- fput(file);
+ io_fput(req);
return ret;
}
@@ -903,7 +934,7 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe,
loff_t sqe_off = READ_ONCE(sqe->off);
loff_t sqe_len = READ_ONCE(sqe->len);
loff_t end = sqe_off + sqe_len;
- unsigned fsync_flags;
+ unsigned fsync_flags, flags;
struct file *file;
int ret, fd;
@@ -921,14 +952,23 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe,
return -EINVAL;
fd = READ_ONCE(sqe->fd);
- file = fget(fd);
+ flags = READ_ONCE(sqe->flags);
+
+ if (flags & IOSQE_FIXED_FILE) {
+ if (unlikely(!ctx->user_files || fd >= ctx->user_files->count))
+ return -EBADF;
+ file = ctx->user_files->fp[fd];
+ } else {
+ file = fget(fd);
+ }
if (unlikely(!file))
return -EBADF;
ret = vfs_fsync_range(file, sqe_off, end > 0 ? end : LLONG_MAX,
fsync_flags & IORING_FSYNC_DATASYNC);
- fput(file);
+ if (!(flags & IOSQE_FIXED_FILE))
+ fput(file);
io_cqring_add_event(ctx, sqe->user_data, ret, 0);
io_free_req(req);
return 0;
@@ -1065,7 +1105,7 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, const struct sqe_submit *s,
ssize_t ret;
/* enforce forwards compatibility on users */
- if (unlikely(s->sqe->flags))
+ if (unlikely(s->sqe->flags & ~IOSQE_FIXED_FILE))
return -EINVAL;
req = io_get_req(ctx, state);
@@ -1253,6 +1293,104 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
return ring->r.head == ring->r.tail ? ret : 0;
}
+static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
+{
+#if defined(CONFIG_NET)
+ if (ctx->ring_sock) {
+ struct sock *sock = ctx->ring_sock->sk;
+ struct sk_buff *skb;
+
+ while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
+ kfree_skb(skb);
+ }
+#else
+ int i;
+
+ for (i = 0; i < ctx->user_files->count; i++)
+ fput(ctx->user_files->fp[i]);
+
+ kfree(ctx->user_files);
+#endif
+}
+
+static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
+{
+ if (!ctx->user_files)
+ return -ENXIO;
+
+ __io_sqe_files_unregister(ctx);
+ ctx->user_files = NULL;
+ return 0;
+}
+
+static int io_sqe_files_scm(struct io_ring_ctx *ctx)
+{
+#if defined(CONFIG_NET)
+ struct scm_fp_list *fpl = ctx->user_files;
+ struct sk_buff *skb;
+ int i;
+
+ skb = __alloc_skb(0, GFP_KERNEL, 0, NUMA_NO_NODE);
+ if (!skb)
+ return -ENOMEM;
+
+ skb->sk = ctx->ring_sock->sk;
+ skb->destructor = unix_destruct_scm;
+
+ fpl->user = get_uid(ctx->user);
+ for (i = 0; i < fpl->count; i++) {
+ get_file(fpl->fp[i]);
+ unix_inflight(fpl->user, fpl->fp[i]);
+ fput(fpl->fp[i]);
+ }
+
+ UNIXCB(skb).fp = fpl;
+ skb_queue_head(&ctx->ring_sock->sk->sk_receive_queue, skb);
+#endif
+ return 0;
+}
+
+static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
+ unsigned nr_args)
+{
+ __s32 __user *fds = (__s32 __user *) arg;
+ struct scm_fp_list *fpl;
+ int fd, ret = 0;
+ unsigned i;
+
+ if (ctx->user_files)
+ return -EBUSY;
+ if (!nr_args || nr_args > SCM_MAX_FD)
+ return -EINVAL;
+
+ fpl = kzalloc(sizeof(*ctx->user_files), GFP_KERNEL);
+ if (!fpl)
+ return -ENOMEM;
+ fpl->max = nr_args;
+
+ for (i = 0; i < nr_args; i++) {
+ ret = -EFAULT;
+ if (copy_from_user(&fd, &fds[i], sizeof(fd)))
+ break;
+
+ fpl->fp[i] = fget(fd);
+
+ ret = -EBADF;
+ if (!fpl->fp[i])
+ break;
+ fpl->count++;
+ ret = 0;
+ }
+
+ ctx->user_files = fpl;
+ if (!ret)
+ ret = io_sqe_files_scm(ctx);
+ if (ret)
+ io_sqe_files_unregister(ctx);
+
+ return ret;
+}
+
static int io_sq_offload_start(struct io_ring_ctx *ctx)
{
int ret;
@@ -1520,14 +1658,16 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx)
destroy_workqueue(ctx->sqo_wq);
if (ctx->sqo_mm)
mmdrop(ctx->sqo_mm);
+
+ io_iopoll_reap_events(ctx);
+ io_sqe_buffer_unregister(ctx);
+ io_sqe_files_unregister(ctx);
+
#if defined(CONFIG_NET)
if (ctx->ring_sock)
sock_release(ctx->ring_sock);
#endif
- io_iopoll_reap_events(ctx);
- io_sqe_buffer_unregister(ctx);
-
io_mem_free(ctx->sq_ring);
io_mem_free(ctx->sq_sqes);
io_mem_free(ctx->cq_ring);
@@ -1885,6 +2025,15 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
break;
ret = io_sqe_buffer_unregister(ctx);
break;
+ case IORING_REGISTER_FILES:
+ ret = io_sqe_files_register(ctx, arg, nr_args);
+ break;
+ case IORING_UNREGISTER_FILES:
+ ret = -EINVAL;
+ if (arg || nr_args)
+ break;
+ ret = io_sqe_files_unregister(ctx);
+ break;
default:
ret = -EINVAL;
break;
diff --git a/include/net/af_unix.h b/include/net/af_unix.h
index ddbba838d048..3426d6dacc45 100644
--- a/include/net/af_unix.h
+++ b/include/net/af_unix.h
@@ -10,6 +10,7 @@
void unix_inflight(struct user_struct *user, struct file *fp);
void unix_notinflight(struct user_struct *user, struct file *fp);
+void unix_destruct_scm(struct sk_buff *skb);
void unix_gc(void);
void wait_for_unix_gc(void);
struct sock *unix_get_socket(struct file *filp);
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index cf28f7a11f12..6257478d55e9 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -16,7 +16,7 @@
*/
struct io_uring_sqe {
__u8 opcode; /* type of operation for this sqe */
- __u8 flags; /* as of now unused */
+ __u8 flags; /* IOSQE_ flags */
__u16 ioprio; /* ioprio for the request */
__s32 fd; /* file descriptor to do IO on */
__u64 off; /* offset into file */
@@ -33,6 +33,11 @@ struct io_uring_sqe {
};
};
+/*
+ * sqe->flags
+ */
+#define IOSQE_FIXED_FILE (1U << 0) /* use fixed fileset */
+
/*
* io_uring_setup() flags
*/
@@ -113,5 +118,7 @@ struct io_uring_params {
*/
#define IORING_REGISTER_BUFFERS 0
#define IORING_UNREGISTER_BUFFERS 1
+#define IORING_REGISTER_FILES 2
+#define IORING_UNREGISTER_FILES 3
#endif
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 74d1eed7cbd4..9b1bbf74c4ea 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1497,7 +1497,7 @@ static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
unix_notinflight(scm->fp->user, scm->fp->fp[i]);
}
-static void unix_destruct_scm(struct sk_buff *skb)
+void unix_destruct_scm(struct sk_buff *skb)
{
struct scm_cookie scm;
memset(&scm, 0, sizeof(scm));
--
2.17.1
--
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^ permalink raw reply related
* [PATCH 12/18] io_uring: add support for pre-mapped user IO buffers
From: Jens Axboe @ 2019-02-07 19:55 UTC (permalink / raw)
To: linux-aio, linux-block, linux-api
Cc: hch, jmoyer, avi, jannh, viro, Jens Axboe
In-Reply-To: <20190207195552.22770-1-axboe@kernel.dk>
If we have fixed user buffers, we can map them into the kernel when we
setup the io_context. That avoids the need to do get_user_pages() for
each and every IO.
To utilize this feature, the application must call io_uring_register()
after having setup an io_uring context, passing in
IORING_REGISTER_BUFFERS as the opcode. The argument must be a pointer
to an iovec array, and the nr_args should contain how many iovecs the
application wishes to map.
If successful, these buffers are now mapped into the kernel, eligible
for IO. To use these fixed buffers, the application must use the
IORING_OP_READ_FIXED and IORING_OP_WRITE_FIXED opcodes, and then
set sqe->index to the desired buffer index. sqe->addr..sqe->addr+seq->len
must point to somewhere inside the indexed buffer.
The application may register buffers throughout the lifetime of the
io_uring context. It can call io_uring_register() with
IORING_UNREGISTER_BUFFERS as the opcode to unregister the current set of
buffers, and then register a new set. The application need not
unregister buffers explicitly before shutting down the io_uring context.
It's perfectly valid to setup a larger buffer, and then sometimes only
use parts of it for an IO. As long as the range is within the originally
mapped region, it will work just fine.
For now, buffers must not be file backed. If file backed buffers are
passed in, the registration will fail with -1/EOPNOTSUPP. This
restriction may be relaxed in the future.
RLIMIT_MEMLOCK is used to check how much memory we can pin. A somewhat
arbitrary 1G per buffer size is also imposed.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
fs/io_uring.c | 356 ++++++++++++++++++++++++-
include/linux/sched/user.h | 2 +-
include/linux/syscalls.h | 2 +
include/uapi/asm-generic/unistd.h | 4 +-
include/uapi/linux/io_uring.h | 13 +-
kernel/sys_ni.c | 1 +
8 files changed, 363 insertions(+), 17 deletions(-)
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 481c126259e9..2eefd2a7c1ce 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -400,3 +400,4 @@
386 i386 rseq sys_rseq __ia32_sys_rseq
425 i386 io_uring_setup sys_io_uring_setup __ia32_sys_io_uring_setup
426 i386 io_uring_enter sys_io_uring_enter __ia32_sys_io_uring_enter
+427 i386 io_uring_register sys_io_uring_register __ia32_sys_io_uring_register
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 6a32a430c8e0..65c026185e61 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -345,6 +345,7 @@
334 common rseq __x64_sys_rseq
425 common io_uring_setup __x64_sys_io_uring_setup
426 common io_uring_enter __x64_sys_io_uring_enter
+427 common io_uring_register __x64_sys_io_uring_register
#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 1369cb95e1b5..9d6233dc35ca 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -25,6 +25,7 @@
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/blkdev.h>
+#include <linux/bvec.h>
#include <linux/net.h>
#include <net/sock.h>
#include <net/af_unix.h>
@@ -32,6 +33,7 @@
#include <linux/sched/mm.h>
#include <linux/uaccess.h>
#include <linux/nospec.h>
+#include <linux/sizes.h>
#include <uapi/linux/io_uring.h>
@@ -61,6 +63,13 @@ struct io_cq_ring {
struct io_uring_cqe cqes[];
};
+struct io_mapped_ubuf {
+ u64 ubuf;
+ size_t len;
+ struct bio_vec *bvec;
+ unsigned int nr_bvecs;
+};
+
struct io_ring_ctx {
struct {
struct percpu_ref refs;
@@ -92,6 +101,10 @@ struct io_ring_ctx {
struct fasync_struct *cq_fasync;
} ____cacheline_aligned_in_smp;
+ /* if used, fixed mapped user buffers */
+ unsigned nr_user_bufs;
+ struct io_mapped_ubuf *user_bufs;
+
struct user_struct *user;
struct completion ctx_done;
@@ -703,6 +716,44 @@ static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
}
}
+static int io_import_fixed(struct io_ring_ctx *ctx, int rw,
+ const struct io_uring_sqe *sqe,
+ struct iov_iter *iter)
+{
+ size_t len = READ_ONCE(sqe->len);
+ struct io_mapped_ubuf *imu;
+ unsigned index, buf_index;
+ size_t offset;
+ u64 buf_addr;
+
+ /* attempt to use fixed buffers without having provided iovecs */
+ if (unlikely(!ctx->user_bufs))
+ return -EFAULT;
+
+ buf_index = READ_ONCE(sqe->buf_index);
+ if (unlikely(buf_index >= ctx->nr_user_bufs))
+ return -EFAULT;
+
+ index = array_index_nospec(buf_index, ctx->nr_user_bufs);
+ imu = &ctx->user_bufs[index];
+ buf_addr = READ_ONCE(sqe->addr);
+
+ if (buf_addr + len < buf_addr)
+ return -EFAULT;
+ if (buf_addr < imu->ubuf || buf_addr + len > imu->ubuf + imu->len)
+ return -EFAULT;
+
+ /*
+ * May not be a start of buffer, set size appropriately
+ * and advance us to the beginning.
+ */
+ offset = buf_addr - imu->ubuf;
+ iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len);
+ if (offset)
+ iov_iter_advance(iter, offset);
+ return 0;
+}
+
static int io_import_iovec(struct io_ring_ctx *ctx, int rw,
const struct sqe_submit *s, struct iovec **iovec,
struct iov_iter *iter)
@@ -710,6 +761,15 @@ static int io_import_iovec(struct io_ring_ctx *ctx, int rw,
const struct io_uring_sqe *sqe = s->sqe;
void __user *buf = u64_to_user_ptr(READ_ONCE(sqe->addr));
size_t sqe_len = READ_ONCE(sqe->len);
+ u8 opcode;
+
+ opcode = READ_ONCE(sqe->opcode);
+ if (opcode == IORING_OP_READ_FIXED ||
+ opcode == IORING_OP_WRITE_FIXED) {
+ ssize_t ret = io_import_fixed(ctx, rw, sqe, iter);
+ *iovec = NULL;
+ return ret;
+ }
if (!s->has_user)
return EFAULT;
@@ -853,7 +913,7 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe,
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
- if (unlikely(sqe->addr || sqe->ioprio))
+ if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index))
return -EINVAL;
fsync_flags = READ_ONCE(sqe->fsync_flags);
@@ -891,9 +951,19 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
ret = io_nop(req, req->user_data);
break;
case IORING_OP_READV:
+ if (unlikely(s->sqe->buf_index))
+ return -EINVAL;
ret = io_read(req, s, force_nonblock, state);
break;
case IORING_OP_WRITEV:
+ if (unlikely(s->sqe->buf_index))
+ return -EINVAL;
+ ret = io_write(req, s, force_nonblock, state);
+ break;
+ case IORING_OP_READ_FIXED:
+ ret = io_read(req, s, force_nonblock, state);
+ break;
+ case IORING_OP_WRITE_FIXED:
ret = io_write(req, s, force_nonblock, state);
break;
case IORING_OP_FSYNC:
@@ -922,28 +992,47 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
return 0;
}
+static inline bool io_sqe_needs_user(const struct io_uring_sqe *sqe)
+{
+ u8 opcode = READ_ONCE(sqe->opcode);
+
+ return !(opcode == IORING_OP_READ_FIXED ||
+ opcode == IORING_OP_WRITE_FIXED);
+}
+
static void io_sq_wq_submit_work(struct work_struct *work)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
struct sqe_submit *s = &req->submit;
- u64 user_data = READ_ONCE(s->sqe->user_data);
struct io_ring_ctx *ctx = req->ctx;
- mm_segment_t old_fs = get_fs();
+ mm_segment_t old_fs;
+ bool needs_user;
+ u64 user_data;
int ret;
/* Ensure we clear previously set forced non-block flag */
req->flags &= ~REQ_F_FORCE_NONBLOCK;
req->rw.ki_flags &= ~IOCB_NOWAIT;
- if (!mmget_not_zero(ctx->sqo_mm)) {
- ret = -EFAULT;
- goto err;
- }
-
- use_mm(ctx->sqo_mm);
- set_fs(USER_DS);
- s->has_user = true;
+ user_data = READ_ONCE(s->sqe->user_data);
s->needs_lock = true;
+ s->has_user = false;
+
+ /*
+ * If we're doing IO to fixed buffers, we don't need to get/set
+ * user context
+ */
+ needs_user = io_sqe_needs_user(s->sqe);
+ if (needs_user) {
+ if (!mmget_not_zero(ctx->sqo_mm)) {
+ ret = -EFAULT;
+ goto err;
+ }
+ use_mm(ctx->sqo_mm);
+ old_fs = get_fs();
+ set_fs(USER_DS);
+ s->has_user = true;
+ }
do {
ret = __io_submit_sqe(ctx, req, s, false, NULL);
@@ -957,9 +1046,11 @@ static void io_sq_wq_submit_work(struct work_struct *work)
cond_resched();
} while (1);
- set_fs(old_fs);
- unuse_mm(ctx->sqo_mm);
- mmput(ctx->sqo_mm);
+ if (needs_user) {
+ set_fs(old_fs);
+ unuse_mm(ctx->sqo_mm);
+ mmput(ctx->sqo_mm);
+ }
err:
if (ret) {
io_cqring_add_event(ctx, user_data, ret, 0);
@@ -1241,6 +1332,188 @@ static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries)
return (bytes + PAGE_SIZE - 1) / PAGE_SIZE;
}
+static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx)
+{
+ int i, j;
+
+ if (!ctx->user_bufs)
+ return -ENXIO;
+
+ for (i = 0; i < ctx->sq_entries; i++) {
+ struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
+
+ for (j = 0; j < imu->nr_bvecs; j++)
+ put_page(imu->bvec[j].bv_page);
+
+ io_unaccount_mem(ctx->user, imu->nr_bvecs);
+ kfree(imu->bvec);
+ imu->nr_bvecs = 0;
+ }
+
+ kfree(ctx->user_bufs);
+ ctx->user_bufs = NULL;
+ free_uid(ctx->user);
+ ctx->user = NULL;
+ return 0;
+}
+
+static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
+ void __user *arg, unsigned index)
+{
+ struct iovec __user *src;
+
+#ifdef CONFIG_COMPAT
+ if (ctx->compat) {
+ struct compat_iovec __user *ciovs;
+ struct compat_iovec ciov;
+
+ ciovs = (struct compat_iovec __user *) arg;
+ if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
+ return -EFAULT;
+
+ dst->iov_base = (void __user *) (unsigned long) ciov.iov_base;
+ dst->iov_len = ciov.iov_len;
+ return 0;
+ }
+#endif
+ src = (struct iovec __user *) arg;
+ if (copy_from_user(dst, &src[index], sizeof(*dst)))
+ return -EFAULT;
+ return 0;
+}
+
+static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
+ unsigned nr_args)
+{
+ struct vm_area_struct **vmas = NULL;
+ struct page **pages = NULL;
+ int i, j, got_pages = 0;
+ int ret = -EINVAL;
+
+ if (ctx->user_bufs)
+ return -EBUSY;
+ if (!nr_args || nr_args > UIO_MAXIOV)
+ return -EINVAL;
+
+ ctx->user_bufs = kcalloc(nr_args, sizeof(struct io_mapped_ubuf),
+ GFP_KERNEL);
+ if (!ctx->user_bufs)
+ return -ENOMEM;
+
+ for (i = 0; i < nr_args; i++) {
+ struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
+ unsigned long off, start, end, ubuf;
+ int pret, nr_pages;
+ struct iovec iov;
+ size_t size;
+
+ ret = io_copy_iov(ctx, &iov, arg, i);
+ if (ret)
+ break;
+
+ /*
+ * Don't impose further limits on the size and buffer
+ * constraints here, we'll -EINVAL later when IO is
+ * submitted if they are wrong.
+ */
+ ret = -EFAULT;
+ if (!iov.iov_base || !iov.iov_len)
+ goto err;
+
+ /* arbitrary limit, but we need something */
+ if (iov.iov_len > SZ_1G)
+ goto err;
+
+ ubuf = (unsigned long) iov.iov_base;
+ end = (ubuf + iov.iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ start = ubuf >> PAGE_SHIFT;
+ nr_pages = end - start;
+
+ ret = io_account_mem(ctx->user, nr_pages);
+ if (ret)
+ goto err;
+
+ if (!pages || nr_pages > got_pages) {
+ kfree(vmas);
+ kfree(pages);
+ pages = kmalloc_array(nr_pages, sizeof(struct page *),
+ GFP_KERNEL);
+ vmas = kmalloc_array(nr_pages,
+ sizeof(struct vma_area_struct *),
+ GFP_KERNEL);
+ if (!pages || !vmas) {
+ ret = -ENOMEM;
+ io_unaccount_mem(ctx->user, nr_pages);
+ goto err;
+ }
+ got_pages = nr_pages;
+ }
+
+ imu->bvec = kmalloc_array(nr_pages, sizeof(struct bio_vec),
+ GFP_KERNEL);
+ if (!imu->bvec) {
+ io_unaccount_mem(ctx->user, nr_pages);
+ goto err;
+ }
+
+ down_write(¤t->mm->mmap_sem);
+ pret = get_user_pages_longterm(ubuf, nr_pages, FOLL_WRITE,
+ pages, vmas);
+ if (pret == nr_pages) {
+ /* don't support file backed memory */
+ for (j = 0; j < nr_pages; j++) {
+ struct vm_area_struct *vma = vmas[j];
+
+ if (vma->vm_file) {
+ ret = -EOPNOTSUPP;
+ break;
+ }
+ }
+ } else {
+ ret = pret < 0 ? pret : -EFAULT;
+ }
+ up_write(¤t->mm->mmap_sem);
+ if (ret) {
+ /*
+ * if we did partial map, or found file backed vmas,
+ * release any pages we did get
+ */
+ if (pret > 0) {
+ for (j = 0; j < pret; j++)
+ put_page(pages[j]);
+ }
+ io_unaccount_mem(ctx->user, nr_pages);
+ goto err;
+ }
+
+ off = ubuf & ~PAGE_MASK;
+ size = iov.iov_len;
+ for (j = 0; j < nr_pages; j++) {
+ size_t vec_len;
+
+ vec_len = min_t(size_t, size, PAGE_SIZE - off);
+ imu->bvec[j].bv_page = pages[j];
+ imu->bvec[j].bv_len = vec_len;
+ imu->bvec[j].bv_offset = off;
+ off = 0;
+ size -= vec_len;
+ }
+ /* store original address for later verification */
+ imu->ubuf = ubuf;
+ imu->len = iov.iov_len;
+ imu->nr_bvecs = nr_pages;
+ }
+ kfree(pages);
+ kfree(vmas);
+ ctx->nr_user_bufs = nr_args;
+ return 0;
+err:
+ kfree(pages);
+ kfree(vmas);
+ io_sqe_buffer_unregister(ctx);
+ return ret;
+}
+
static void io_ring_ctx_free(struct io_ring_ctx *ctx)
{
if (ctx->sqo_wq)
@@ -1253,6 +1526,7 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx)
#endif
io_iopoll_reap_events(ctx);
+ io_sqe_buffer_unregister(ctx);
io_mem_free(ctx->sq_ring);
io_mem_free(ctx->sq_sqes);
@@ -1593,6 +1867,60 @@ SYSCALL_DEFINE2(io_uring_setup, u32, entries,
return io_uring_setup(entries, params);
}
+static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
+ void __user *arg, unsigned nr_args)
+{
+ int ret;
+
+ percpu_ref_kill(&ctx->refs);
+ wait_for_completion(&ctx->ctx_done);
+
+ switch (opcode) {
+ case IORING_REGISTER_BUFFERS:
+ ret = io_sqe_buffer_register(ctx, arg, nr_args);
+ break;
+ case IORING_UNREGISTER_BUFFERS:
+ ret = -EINVAL;
+ if (arg || nr_args)
+ break;
+ ret = io_sqe_buffer_unregister(ctx);
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ /* bring the ctx back to life */
+ reinit_completion(&ctx->ctx_done);
+ percpu_ref_reinit(&ctx->refs);
+ return ret;
+}
+
+SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode,
+ void __user *, arg, unsigned int, nr_args)
+{
+ struct io_ring_ctx *ctx;
+ long ret = -EBADF;
+ struct fd f;
+
+ f = fdget(fd);
+ if (!f.file)
+ return -EBADF;
+
+ ret = -EOPNOTSUPP;
+ if (f.file->f_op != &io_uring_fops)
+ goto out_fput;
+
+ ctx = f.file->private_data;
+
+ mutex_lock(&ctx->uring_lock);
+ ret = __io_uring_register(ctx, opcode, arg, nr_args);
+ mutex_unlock(&ctx->uring_lock);
+out_fput:
+ fdput(f);
+ return ret;
+}
+
static int __init io_uring_init(void)
{
req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC);
diff --git a/include/linux/sched/user.h b/include/linux/sched/user.h
index 39ad98c09c58..c7b5f86b91a1 100644
--- a/include/linux/sched/user.h
+++ b/include/linux/sched/user.h
@@ -40,7 +40,7 @@ struct user_struct {
kuid_t uid;
#if defined(CONFIG_PERF_EVENTS) || defined(CONFIG_BPF_SYSCALL) || \
- defined(CONFIG_NET)
+ defined(CONFIG_NET) || defined(CONFIG_IO_URING)
atomic_long_t locked_vm;
#endif
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 3072dbaa7869..3681c05ac538 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -315,6 +315,8 @@ asmlinkage long sys_io_uring_setup(u32 entries,
asmlinkage long sys_io_uring_enter(unsigned int fd, u32 to_submit,
u32 min_complete, u32 flags,
const sigset_t __user *sig, size_t sigsz);
+asmlinkage long sys_io_uring_register(unsigned int fd, unsigned int op,
+ void __user *arg, unsigned int nr_args);
/* fs/xattr.c */
asmlinkage long sys_setxattr(const char __user *path, const char __user *name,
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 87871e7b7ea7..d346229a1eb0 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -744,9 +744,11 @@ __SYSCALL(__NR_kexec_file_load, sys_kexec_file_load)
__SYSCALL(__NR_io_uring_setup, sys_io_uring_setup)
#define __NR_io_uring_enter 426
__SYSCALL(__NR_io_uring_enter, sys_io_uring_enter)
+#define __NR_io_uring_register 427
+__SYSCALL(__NR_io_uring_register, sys_io_uring_register)
#undef __NR_syscalls
-#define __NR_syscalls 427
+#define __NR_syscalls 428
/*
* 32 bit systems traditionally used different
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 5c457ea396e6..cf28f7a11f12 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -27,7 +27,10 @@ struct io_uring_sqe {
__u32 fsync_flags;
};
__u64 user_data; /* data to be passed back at completion time */
- __u64 __pad2[3];
+ union {
+ __u16 buf_index; /* index into fixed buffers, if used */
+ __u64 __pad2[3];
+ };
};
/*
@@ -39,6 +42,8 @@ struct io_uring_sqe {
#define IORING_OP_READV 1
#define IORING_OP_WRITEV 2
#define IORING_OP_FSYNC 3
+#define IORING_OP_READ_FIXED 4
+#define IORING_OP_WRITE_FIXED 5
/*
* sqe->fsync_flags
@@ -103,4 +108,10 @@ struct io_uring_params {
struct io_cqring_offsets cq_off;
};
+/*
+ * io_uring_register(2) opcodes and arguments
+ */
+#define IORING_REGISTER_BUFFERS 0
+#define IORING_UNREGISTER_BUFFERS 1
+
#endif
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index ee5e523564bb..1bb6604dc19f 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -48,6 +48,7 @@ COND_SYSCALL_COMPAT(io_getevents);
COND_SYSCALL_COMPAT(io_pgetevents);
COND_SYSCALL(io_uring_setup);
COND_SYSCALL(io_uring_enter);
+COND_SYSCALL(io_uring_register);
/* fs/xattr.c */
--
2.17.1
--
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^ permalink raw reply related
* [PATCH 11/18] block: implement bio helper to add iter bvec pages to bio
From: Jens Axboe @ 2019-02-07 19:55 UTC (permalink / raw)
To: linux-aio, linux-block, linux-api
Cc: hch, jmoyer, avi, jannh, viro, Jens Axboe
In-Reply-To: <20190207195552.22770-1-axboe@kernel.dk>
For an ITER_BVEC, we can just iterate the iov and add the pages
to the bio directly. This requires that the caller doesn't releases
the pages on IO completion, we add a BIO_NO_PAGE_REF flag for that.
The current two callers of bio_iov_iter_get_pages() are updated to
check if they need to release pages on completion. This makes them
work with bvecs that contain kernel mapped pages already.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
block/bio.c | 59 ++++++++++++++++++++++++++++++++-------
fs/block_dev.c | 5 ++--
fs/iomap.c | 5 ++--
include/linux/blk_types.h | 1 +
4 files changed, 56 insertions(+), 14 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 4db1008309ed..330df572cfb8 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -828,6 +828,23 @@ int bio_add_page(struct bio *bio, struct page *page,
}
EXPORT_SYMBOL(bio_add_page);
+static int __bio_iov_bvec_add_pages(struct bio *bio, struct iov_iter *iter)
+{
+ const struct bio_vec *bv = iter->bvec;
+ unsigned int len;
+ size_t size;
+
+ len = min_t(size_t, bv->bv_len, iter->count);
+ size = bio_add_page(bio, bv->bv_page, len,
+ bv->bv_offset + iter->iov_offset);
+ if (size == len) {
+ iov_iter_advance(iter, size);
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
#define PAGE_PTRS_PER_BVEC (sizeof(struct bio_vec) / sizeof(struct page *))
/**
@@ -876,23 +893,43 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
}
/**
- * bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio
+ * bio_iov_iter_get_pages - add user or kernel pages to a bio
* @bio: bio to add pages to
- * @iter: iov iterator describing the region to be mapped
+ * @iter: iov iterator describing the region to be added
+ *
+ * This takes either an iterator pointing to user memory, or one pointing to
+ * kernel pages (BVEC iterator). If we're adding user pages, we pin them and
+ * map them into the kernel. On IO completion, the caller should put those
+ * pages. If we're adding kernel pages, we just have to add the pages to the
+ * bio directly. We don't grab an extra reference to those pages (the user
+ * should already have that), and we don't put the page on IO completion.
+ * The caller needs to check if the bio is flagged BIO_NO_PAGE_REF on IO
+ * completion. If it isn't, then pages should be released.
*
- * Pins pages from *iter and appends them to @bio's bvec array. The
- * pages will have to be released using put_page() when done.
* The function tries, but does not guarantee, to pin as many pages as
- * fit into the bio, or are requested in *iter, whatever is smaller.
- * If MM encounters an error pinning the requested pages, it stops.
- * Error is returned only if 0 pages could be pinned.
+ * fit into the bio, or are requested in *iter, whatever is smaller. If
+ * MM encounters an error pinning the requested pages, it stops. Error
+ * is returned only if 0 pages could be pinned.
*/
int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
{
+ const bool is_bvec = iov_iter_is_bvec(iter);
unsigned short orig_vcnt = bio->bi_vcnt;
+ /*
+ * If this is a BVEC iter, then the pages are kernel pages. Don't
+ * release them on IO completion.
+ */
+ if (is_bvec)
+ bio_set_flag(bio, BIO_NO_PAGE_REF);
+
do {
- int ret = __bio_iov_iter_get_pages(bio, iter);
+ int ret;
+
+ if (is_bvec)
+ ret = __bio_iov_bvec_add_pages(bio, iter);
+ else
+ ret = __bio_iov_iter_get_pages(bio, iter);
if (unlikely(ret))
return bio->bi_vcnt > orig_vcnt ? 0 : ret;
@@ -1634,7 +1671,8 @@ static void bio_dirty_fn(struct work_struct *work)
next = bio->bi_private;
bio_set_pages_dirty(bio);
- bio_release_pages(bio);
+ if (!bio_flagged(bio, BIO_NO_PAGE_REF))
+ bio_release_pages(bio);
bio_put(bio);
}
}
@@ -1650,7 +1688,8 @@ void bio_check_pages_dirty(struct bio *bio)
goto defer;
}
- bio_release_pages(bio);
+ if (!bio_flagged(bio, BIO_NO_PAGE_REF))
+ bio_release_pages(bio);
bio_put(bio);
return;
defer:
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 392e2bfb636f..051ab41d1c61 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -338,8 +338,9 @@ static void blkdev_bio_end_io(struct bio *bio)
struct bio_vec *bvec;
int i;
- bio_for_each_segment_all(bvec, bio, i)
- put_page(bvec->bv_page);
+ if (!bio_flagged(bio, BIO_NO_PAGE_REF))
+ bio_for_each_segment_all(bvec, bio, i)
+ put_page(bvec->bv_page);
bio_put(bio);
}
}
diff --git a/fs/iomap.c b/fs/iomap.c
index 2ac9eb746d44..9389cf0a1c6f 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -1591,8 +1591,9 @@ static void iomap_dio_bio_end_io(struct bio *bio)
struct bio_vec *bvec;
int i;
- bio_for_each_segment_all(bvec, bio, i)
- put_page(bvec->bv_page);
+ if (!bio_flagged(bio, BIO_NO_PAGE_REF))
+ bio_for_each_segment_all(bvec, bio, i)
+ put_page(bvec->bv_page);
bio_put(bio);
}
}
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index d66bf5f32610..791fee35df88 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -215,6 +215,7 @@ struct bio {
/*
* bio flags
*/
+#define BIO_NO_PAGE_REF 0 /* don't put release vec pages */
#define BIO_SEG_VALID 1 /* bi_phys_segments valid */
#define BIO_CLONED 2 /* doesn't own data */
#define BIO_BOUNCED 3 /* bio is a bounce bio */
--
2.17.1
--
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^ permalink raw reply related
* [PATCH 10/18] io_uring: batch io_kiocb allocation
From: Jens Axboe @ 2019-02-07 19:55 UTC (permalink / raw)
To: linux-aio, linux-block, linux-api
Cc: hch, jmoyer, avi, jannh, viro, Jens Axboe
In-Reply-To: <20190207195552.22770-1-axboe@kernel.dk>
Similarly to how we use the state->ios_left to know how many references
to get to a file, we can use it to allocate the io_kiocb's we need in
bulk.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 45 ++++++++++++++++++++++++++++++++++++++-------
1 file changed, 38 insertions(+), 7 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index e23e639a4ff0..1369cb95e1b5 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -147,6 +147,13 @@ struct io_kiocb {
struct io_submit_state {
struct blk_plug plug;
+ /*
+ * io_kiocb alloc cache
+ */
+ void *reqs[IO_IOPOLL_BATCH];
+ unsigned int free_reqs;
+ unsigned int cur_req;
+
/*
* File reference cache
*/
@@ -276,20 +283,40 @@ static void io_ring_drop_ctx_refs(struct io_ring_ctx *ctx, unsigned refs)
wake_up(&ctx->wait);
}
-static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx)
+static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx,
+ struct io_submit_state *state)
{
struct io_kiocb *req;
if (!percpu_ref_tryget(&ctx->refs))
return NULL;
- req = kmem_cache_alloc(req_cachep, __GFP_NOWARN);
- if (req) {
- req->ctx = ctx;
- req->flags = 0;
- return req;
+ if (!state) {
+ req = kmem_cache_alloc(req_cachep, __GFP_NOWARN);
+ if (unlikely(!req))
+ goto out;
+ } else if (!state->free_reqs) {
+ size_t sz;
+ int ret;
+
+ sz = min_t(size_t, state->ios_left, ARRAY_SIZE(state->reqs));
+ ret = kmem_cache_alloc_bulk(req_cachep, __GFP_NOWARN, sz,
+ state->reqs);
+ if (unlikely(ret <= 0))
+ goto out;
+ state->free_reqs = ret - 1;
+ state->cur_req = 1;
+ req = state->reqs[0];
+ } else {
+ req = state->reqs[state->cur_req];
+ state->free_reqs--;
+ state->cur_req++;
}
+ req->ctx = ctx;
+ req->flags = 0;
+ return req;
+out:
io_ring_drop_ctx_refs(ctx, 1);
return NULL;
}
@@ -950,7 +977,7 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, const struct sqe_submit *s,
if (unlikely(s->sqe->flags))
return -EINVAL;
- req = io_get_req(ctx);
+ req = io_get_req(ctx, state);
if (unlikely(!req))
return -EAGAIN;
@@ -976,6 +1003,9 @@ static void io_submit_state_end(struct io_submit_state *state)
{
blk_finish_plug(&state->plug);
io_file_put(state, NULL);
+ if (state->free_reqs)
+ kmem_cache_free_bulk(req_cachep, state->free_reqs,
+ &state->reqs[state->cur_req]);
}
/*
@@ -985,6 +1015,7 @@ static void io_submit_state_start(struct io_submit_state *state,
struct io_ring_ctx *ctx, unsigned max_ios)
{
blk_start_plug(&state->plug);
+ state->free_reqs = 0;
state->file = NULL;
state->ios_left = max_ios;
}
--
2.17.1
--
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^ permalink raw reply related
* [PATCH 09/18] io_uring: use fget/fput_many() for file references
From: Jens Axboe @ 2019-02-07 19:55 UTC (permalink / raw)
To: linux-aio, linux-block, linux-api
Cc: hch, jmoyer, avi, jannh, viro, Jens Axboe
In-Reply-To: <20190207195552.22770-1-axboe@kernel.dk>
Add a separate io_submit_state structure, to cache some of the things
we need for IO submission.
One such example is file reference batching. io_submit_state. We get as
many references as the number of sqes we are submitting, and drop
unused ones if we end up switching files. The assumption here is that
we're usually only dealing with one fd, and if there are multiple,
hopefuly they are at least somewhat ordered. Could trivially be extended
to cover multiple fds, if needed.
On the completion side we do the same thing, except this is trivially
done just locally in io_iopoll_reap().
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 142 ++++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 121 insertions(+), 21 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 5e83391dc538..e23e639a4ff0 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -144,6 +144,19 @@ struct io_kiocb {
#define IO_PLUG_THRESHOLD 2
#define IO_IOPOLL_BATCH 8
+struct io_submit_state {
+ struct blk_plug plug;
+
+ /*
+ * File reference cache
+ */
+ struct file *file;
+ unsigned int fd;
+ unsigned int has_refs;
+ unsigned int used_refs;
+ unsigned int ios_left;
+};
+
static struct kmem_cache *req_cachep;
static const struct file_operations io_uring_fops;
@@ -303,9 +316,11 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
struct list_head *done)
{
void *reqs[IO_IOPOLL_BATCH];
+ int file_count, to_free;
+ struct file *file = NULL;
struct io_kiocb *req;
- int to_free = 0;
+ file_count = to_free = 0;
while (!list_empty(done)) {
req = list_first_entry(done, struct io_kiocb, list);
list_del(&req->list);
@@ -315,12 +330,28 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
reqs[to_free++] = req;
(*nr_events)++;
- fput(req->rw.ki_filp);
+ /*
+ * Batched puts of the same file, to avoid dirtying the
+ * file usage count multiple times, if avoidable.
+ */
+ if (!file) {
+ file = req->rw.ki_filp;
+ file_count = 1;
+ } else if (file == req->rw.ki_filp) {
+ file_count++;
+ } else {
+ fput_many(file, file_count);
+ file = req->rw.ki_filp;
+ file_count = 1;
+ }
+
if (to_free == ARRAY_SIZE(reqs))
io_free_req_many(ctx, reqs, &to_free);
}
io_commit_cqring(ctx);
+ if (file)
+ fput_many(file, file_count);
io_free_req_many(ctx, reqs, &to_free);
}
@@ -501,6 +532,48 @@ static void io_iopoll_req_issued(struct io_kiocb *req)
list_add_tail(&req->list, &ctx->poll_list);
}
+static void io_file_put(struct io_submit_state *state, struct file *file)
+{
+ if (!state) {
+ fput(file);
+ } else if (state->file) {
+ int diff = state->has_refs - state->used_refs;
+
+ if (diff)
+ fput_many(state->file, diff);
+ state->file = NULL;
+ }
+}
+
+/*
+ * Get as many references to a file as we have IOs left in this submission,
+ * assuming most submissions are for one file, or at least that each file
+ * has more than one submission.
+ */
+static struct file *io_file_get(struct io_submit_state *state, int fd)
+{
+ if (!state)
+ return fget(fd);
+
+ if (state->file) {
+ if (state->fd == fd) {
+ state->used_refs++;
+ state->ios_left--;
+ return state->file;
+ }
+ io_file_put(state, NULL);
+ }
+ state->file = fget_many(fd, state->ios_left);
+ if (!state->file)
+ return NULL;
+
+ state->fd = fd;
+ state->has_refs = state->ios_left;
+ state->used_refs = 1;
+ state->ios_left--;
+ return state->file;
+}
+
/*
* If we tracked the file through the SCM inflight mechanism, we could support
* any file. For now, just ensure that anything potentially problematic is done
@@ -519,7 +592,7 @@ static bool io_file_supports_async(struct file *file)
}
static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
- bool force_nonblock)
+ bool force_nonblock, struct io_submit_state *state)
{
struct io_ring_ctx *ctx = req->ctx;
struct kiocb *kiocb = &req->rw;
@@ -531,7 +604,7 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
return 0;
fd = READ_ONCE(sqe->fd);
- kiocb->ki_filp = fget(fd);
+ kiocb->ki_filp = io_file_get(state, fd);
if (unlikely(!kiocb->ki_filp))
return -EBADF;
if (force_nonblock && !io_file_supports_async(kiocb->ki_filp))
@@ -575,7 +648,10 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
}
return 0;
out_fput:
- fput(kiocb->ki_filp);
+ /* in case of error, we didn't use this file reference. drop it. */
+ if (state)
+ state->used_refs--;
+ io_file_put(state, kiocb->ki_filp);
return ret;
}
@@ -621,7 +697,7 @@ static int io_import_iovec(struct io_ring_ctx *ctx, int rw,
}
static ssize_t io_read(struct io_kiocb *req, const struct sqe_submit *s,
- bool force_nonblock)
+ bool force_nonblock, struct io_submit_state *state)
{
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
struct kiocb *kiocb = &req->rw;
@@ -629,7 +705,7 @@ static ssize_t io_read(struct io_kiocb *req, const struct sqe_submit *s,
struct file *file;
ssize_t ret;
- ret = io_prep_rw(req, s->sqe, force_nonblock);
+ ret = io_prep_rw(req, s->sqe, force_nonblock, state);
if (ret)
return ret;
file = kiocb->ki_filp;
@@ -665,7 +741,7 @@ static ssize_t io_read(struct io_kiocb *req, const struct sqe_submit *s,
}
static ssize_t io_write(struct io_kiocb *req, const struct sqe_submit *s,
- bool force_nonblock)
+ bool force_nonblock, struct io_submit_state *state)
{
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
struct kiocb *kiocb = &req->rw;
@@ -673,7 +749,7 @@ static ssize_t io_write(struct io_kiocb *req, const struct sqe_submit *s,
struct file *file;
ssize_t ret;
- ret = io_prep_rw(req, s->sqe, force_nonblock);
+ ret = io_prep_rw(req, s->sqe, force_nonblock, state);
if (ret)
return ret;
/* Hold on to the file for -EAGAIN */
@@ -772,7 +848,8 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe,
}
static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
- const struct sqe_submit *s, bool force_nonblock)
+ const struct sqe_submit *s, bool force_nonblock,
+ struct io_submit_state *state)
{
ssize_t ret;
int opcode;
@@ -787,10 +864,10 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
ret = io_nop(req, req->user_data);
break;
case IORING_OP_READV:
- ret = io_read(req, s, force_nonblock);
+ ret = io_read(req, s, force_nonblock, state);
break;
case IORING_OP_WRITEV:
- ret = io_write(req, s, force_nonblock);
+ ret = io_write(req, s, force_nonblock, state);
break;
case IORING_OP_FSYNC:
ret = io_fsync(req, s->sqe, force_nonblock);
@@ -842,7 +919,7 @@ static void io_sq_wq_submit_work(struct work_struct *work)
s->needs_lock = true;
do {
- ret = __io_submit_sqe(ctx, req, s, false);
+ ret = __io_submit_sqe(ctx, req, s, false, NULL);
/*
* We can get EAGAIN for polled IO even though we're forcing
* a sync submission from here, since we can't wait for
@@ -863,7 +940,8 @@ static void io_sq_wq_submit_work(struct work_struct *work)
}
}
-static int io_submit_sqe(struct io_ring_ctx *ctx, const struct sqe_submit *s)
+static int io_submit_sqe(struct io_ring_ctx *ctx, const struct sqe_submit *s,
+ struct io_submit_state *state)
{
struct io_kiocb *req;
ssize_t ret;
@@ -878,7 +956,7 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, const struct sqe_submit *s)
req->rw.ki_filp = NULL;
- ret = __io_submit_sqe(ctx, req, s, true);
+ ret = __io_submit_sqe(ctx, req, s, true, state);
if (ret == -EAGAIN) {
memcpy(&req->submit, s, sizeof(*s));
INIT_WORK(&req->work, io_sq_wq_submit_work);
@@ -891,6 +969,26 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, const struct sqe_submit *s)
return ret;
}
+/*
+ * Batched submission is done, ensure local IO is flushed out.
+ */
+static void io_submit_state_end(struct io_submit_state *state)
+{
+ blk_finish_plug(&state->plug);
+ io_file_put(state, NULL);
+}
+
+/*
+ * Start submission side cache.
+ */
+static void io_submit_state_start(struct io_submit_state *state,
+ struct io_ring_ctx *ctx, unsigned max_ios)
+{
+ blk_start_plug(&state->plug);
+ state->file = NULL;
+ state->ios_left = max_ios;
+}
+
static void io_commit_sqring(struct io_ring_ctx *ctx)
{
struct io_sq_ring *ring = ctx->sq_ring;
@@ -953,11 +1051,13 @@ static bool io_get_sqring(struct io_ring_ctx *ctx, struct sqe_submit *s)
static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit)
{
+ struct io_submit_state state, *statep = NULL;
int i, ret = 0, submit = 0;
- struct blk_plug plug;
- if (to_submit > IO_PLUG_THRESHOLD)
- blk_start_plug(&plug);
+ if (to_submit > IO_PLUG_THRESHOLD) {
+ io_submit_state_start(&state, ctx, to_submit);
+ statep = &state;
+ }
for (i = 0; i < to_submit; i++) {
struct sqe_submit s;
@@ -968,7 +1068,7 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit)
s.has_user = true;
s.needs_lock = false;
- ret = io_submit_sqe(ctx, &s);
+ ret = io_submit_sqe(ctx, &s, statep);
if (ret) {
io_drop_sqring(ctx);
break;
@@ -978,8 +1078,8 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit)
}
io_commit_sqring(ctx);
- if (to_submit > IO_PLUG_THRESHOLD)
- blk_finish_plug(&plug);
+ if (statep)
+ io_submit_state_end(statep);
return submit ? submit : ret;
}
--
2.17.1
--
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^ permalink raw reply related
* [PATCH 08/18] fs: add fget_many() and fput_many()
From: Jens Axboe @ 2019-02-07 19:55 UTC (permalink / raw)
To: linux-aio, linux-block, linux-api
Cc: hch, jmoyer, avi, jannh, viro, Jens Axboe
In-Reply-To: <20190207195552.22770-1-axboe@kernel.dk>
Some uses cases repeatedly get and put references to the same file, but
the only exposed interface is doing these one at the time. As each of
these entail an atomic inc or dec on a shared structure, that cost can
add up.
Add fget_many(), which works just like fget(), except it takes an
argument for how many references to get on the file. Ditto fput_many(),
which can drop an arbitrary number of references to a file.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/file.c | 15 ++++++++++-----
fs/file_table.c | 9 +++++++--
include/linux/file.h | 2 ++
include/linux/fs.h | 4 +++-
4 files changed, 22 insertions(+), 8 deletions(-)
diff --git a/fs/file.c b/fs/file.c
index 3209ee271c41..97df385d6ab0 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -705,7 +705,7 @@ void do_close_on_exec(struct files_struct *files)
spin_unlock(&files->file_lock);
}
-static struct file *__fget(unsigned int fd, fmode_t mask)
+static struct file *__fget(unsigned int fd, fmode_t mask, unsigned int refs)
{
struct files_struct *files = current->files;
struct file *file;
@@ -720,7 +720,7 @@ static struct file *__fget(unsigned int fd, fmode_t mask)
*/
if (file->f_mode & mask)
file = NULL;
- else if (!get_file_rcu(file))
+ else if (!get_file_rcu_many(file, refs))
goto loop;
}
rcu_read_unlock();
@@ -728,15 +728,20 @@ static struct file *__fget(unsigned int fd, fmode_t mask)
return file;
}
+struct file *fget_many(unsigned int fd, unsigned int refs)
+{
+ return __fget(fd, FMODE_PATH, refs);
+}
+
struct file *fget(unsigned int fd)
{
- return __fget(fd, FMODE_PATH);
+ return __fget(fd, FMODE_PATH, 1);
}
EXPORT_SYMBOL(fget);
struct file *fget_raw(unsigned int fd)
{
- return __fget(fd, 0);
+ return __fget(fd, 0, 1);
}
EXPORT_SYMBOL(fget_raw);
@@ -767,7 +772,7 @@ static unsigned long __fget_light(unsigned int fd, fmode_t mask)
return 0;
return (unsigned long)file;
} else {
- file = __fget(fd, mask);
+ file = __fget(fd, mask, 1);
if (!file)
return 0;
return FDPUT_FPUT | (unsigned long)file;
diff --git a/fs/file_table.c b/fs/file_table.c
index 5679e7fcb6b0..155d7514a094 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -326,9 +326,9 @@ void flush_delayed_fput(void)
static DECLARE_DELAYED_WORK(delayed_fput_work, delayed_fput);
-void fput(struct file *file)
+void fput_many(struct file *file, unsigned int refs)
{
- if (atomic_long_dec_and_test(&file->f_count)) {
+ if (atomic_long_sub_and_test(refs, &file->f_count)) {
struct task_struct *task = current;
if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) {
@@ -347,6 +347,11 @@ void fput(struct file *file)
}
}
+void fput(struct file *file)
+{
+ fput_many(file, 1);
+}
+
/*
* synchronous analog of fput(); for kernel threads that might be needed
* in some umount() (and thus can't use flush_delayed_fput() without
diff --git a/include/linux/file.h b/include/linux/file.h
index 6b2fb032416c..3fcddff56bc4 100644
--- a/include/linux/file.h
+++ b/include/linux/file.h
@@ -13,6 +13,7 @@
struct file;
extern void fput(struct file *);
+extern void fput_many(struct file *, unsigned int);
struct file_operations;
struct vfsmount;
@@ -44,6 +45,7 @@ static inline void fdput(struct fd fd)
}
extern struct file *fget(unsigned int fd);
+extern struct file *fget_many(unsigned int fd, unsigned int refs);
extern struct file *fget_raw(unsigned int fd);
extern unsigned long __fdget(unsigned int fd);
extern unsigned long __fdget_raw(unsigned int fd);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 61aa210f0c2b..80e1b199a4b1 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -952,7 +952,9 @@ static inline struct file *get_file(struct file *f)
atomic_long_inc(&f->f_count);
return f;
}
-#define get_file_rcu(x) atomic_long_inc_not_zero(&(x)->f_count)
+#define get_file_rcu_many(x, cnt) \
+ atomic_long_add_unless(&(x)->f_count, (cnt), 0)
+#define get_file_rcu(x) get_file_rcu_many((x), 1)
#define fput_atomic(x) atomic_long_add_unless(&(x)->f_count, -1, 1)
#define file_count(x) atomic_long_read(&(x)->f_count)
--
2.17.1
--
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^ permalink raw reply related
* [PATCH 07/18] io_uring: support for IO polling
From: Jens Axboe @ 2019-02-07 19:55 UTC (permalink / raw)
To: linux-aio, linux-block, linux-api
Cc: hch, jmoyer, avi, jannh, viro, Jens Axboe
In-Reply-To: <20190207195552.22770-1-axboe@kernel.dk>
Add support for a polled io_uring context. When a read or write is
submitted to a polled context, the application must poll for completions
on the CQ ring through io_uring_enter(2). Polled IO may not generate
IRQ completions, hence they need to be actively found by the application
itself.
To use polling, io_uring_setup() must be used with the
IORING_SETUP_IOPOLL flag being set. It is illegal to mix and match
polled and non-polled IO on an io_uring.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 274 ++++++++++++++++++++++++++++++++--
include/uapi/linux/io_uring.h | 5 +
2 files changed, 270 insertions(+), 9 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index e92ae7abffce..5e83391dc538 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -103,6 +103,14 @@ struct io_ring_ctx {
struct {
spinlock_t completion_lock;
+ bool poll_multi_file;
+ /*
+ * ->poll_list is protected by the ctx->uring_lock for
+ * io_uring instances that don't use IORING_SETUP_SQPOLL.
+ * For SQPOLL, only the single threaded io_sq_thread() will
+ * manipulate the list, hence no extra locking is needed there.
+ */
+ struct list_head poll_list;
} ____cacheline_aligned_in_smp;
#if defined(CONFIG_NET)
@@ -114,6 +122,7 @@ struct sqe_submit {
const struct io_uring_sqe *sqe;
unsigned short index;
bool has_user;
+ bool needs_lock;
};
struct io_kiocb {
@@ -125,12 +134,15 @@ struct io_kiocb {
struct list_head list;
unsigned int flags;
#define REQ_F_FORCE_NONBLOCK 1 /* inline submission attempt */
+#define REQ_F_IOPOLL_COMPLETED 2 /* polled IO has completed */
u64 user_data;
+ u64 error;
struct work_struct work;
};
#define IO_PLUG_THRESHOLD 2
+#define IO_IOPOLL_BATCH 8
static struct kmem_cache *req_cachep;
@@ -174,6 +186,7 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
mutex_init(&ctx->uring_lock);
init_waitqueue_head(&ctx->wait);
spin_lock_init(&ctx->completion_lock);
+ INIT_LIST_HEAD(&ctx->poll_list);
return ctx;
}
@@ -268,12 +281,153 @@ static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx)
return NULL;
}
+static void io_free_req_many(struct io_ring_ctx *ctx, void **reqs, int *nr)
+{
+ if (*nr) {
+ kmem_cache_free_bulk(req_cachep, *nr, reqs);
+ io_ring_drop_ctx_refs(ctx, *nr);
+ *nr = 0;
+ }
+}
+
static void io_free_req(struct io_kiocb *req)
{
io_ring_drop_ctx_refs(req->ctx, 1);
kmem_cache_free(req_cachep, req);
}
+/*
+ * Find and free completed poll iocbs
+ */
+static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
+ struct list_head *done)
+{
+ void *reqs[IO_IOPOLL_BATCH];
+ struct io_kiocb *req;
+ int to_free = 0;
+
+ while (!list_empty(done)) {
+ req = list_first_entry(done, struct io_kiocb, list);
+ list_del(&req->list);
+
+ io_cqring_fill_event(ctx, req->user_data, req->error, 0);
+
+ reqs[to_free++] = req;
+ (*nr_events)++;
+
+ fput(req->rw.ki_filp);
+ if (to_free == ARRAY_SIZE(reqs))
+ io_free_req_many(ctx, reqs, &to_free);
+ }
+ io_commit_cqring(ctx);
+
+ io_free_req_many(ctx, reqs, &to_free);
+}
+
+static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
+ long min)
+{
+ struct io_kiocb *req, *tmp;
+ LIST_HEAD(done);
+ bool spin;
+ int ret;
+
+ /*
+ * Only spin for completions if we don't have multiple devices hanging
+ * off our complete list, and we're under the requested amount.
+ */
+ spin = !ctx->poll_multi_file && *nr_events < min;
+
+ ret = 0;
+ list_for_each_entry_safe(req, tmp, &ctx->poll_list, list) {
+ struct kiocb *kiocb = &req->rw;
+
+ /*
+ * Move completed entries to our local list. If we find a
+ * request that requires polling, break out and complete
+ * the done list first, if we have entries there.
+ */
+ if (req->flags & REQ_F_IOPOLL_COMPLETED) {
+ list_move_tail(&req->list, &done);
+ continue;
+ }
+ if (!list_empty(&done))
+ break;
+
+ ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin);
+ if (ret < 0)
+ break;
+
+ if (ret && spin)
+ spin = false;
+ ret = 0;
+ }
+
+ if (!list_empty(&done))
+ io_iopoll_complete(ctx, nr_events, &done);
+
+ return ret;
+}
+
+/*
+ * Poll for a mininum of 'min' events. Note that if min == 0 we consider that a
+ * non-spinning poll check - we'll still enter the driver poll loop, but only
+ * as a non-spinning completion check.
+ */
+static int io_iopoll_getevents(struct io_ring_ctx *ctx, unsigned int *nr_events,
+ long min)
+{
+ while (!list_empty(&ctx->poll_list)) {
+ int ret;
+
+ ret = io_do_iopoll(ctx, nr_events, min);
+ if (ret < 0)
+ return ret;
+ if (!min || *nr_events >= min)
+ return 0;
+ }
+
+ return 1;
+}
+
+/*
+ * We can't just wait for polled events to come to us, we have to actively
+ * find and complete them.
+ */
+static void io_iopoll_reap_events(struct io_ring_ctx *ctx)
+{
+ if (!(ctx->flags & IORING_SETUP_IOPOLL))
+ return;
+
+ mutex_lock(&ctx->uring_lock);
+ while (!list_empty(&ctx->poll_list)) {
+ unsigned int nr_events = 0;
+
+ io_iopoll_getevents(ctx, &nr_events, 1);
+ }
+ mutex_unlock(&ctx->uring_lock);
+}
+
+static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events,
+ long min)
+{
+ int ret = 0;
+
+ do {
+ int tmin = 0;
+
+ if (*nr_events < min)
+ tmin = min - *nr_events;
+
+ ret = io_iopoll_getevents(ctx, nr_events, tmin);
+ if (ret <= 0)
+ break;
+ ret = 0;
+ } while (min && !*nr_events && !need_resched());
+
+ return ret;
+}
+
static void kiocb_end_write(struct kiocb *kiocb)
{
if (kiocb->ki_flags & IOCB_WRITE) {
@@ -300,6 +454,53 @@ static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
io_free_req(req);
}
+static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2)
+{
+ struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
+
+ kiocb_end_write(kiocb);
+
+ req->error = res;
+ if (res != -EAGAIN)
+ req->flags |= REQ_F_IOPOLL_COMPLETED;
+}
+
+/*
+ * After the iocb has been issued, it's safe to be found on the poll list.
+ * Adding the kiocb to the list AFTER submission ensures that we don't
+ * find it from a io_iopoll_getevents() thread before the issuer is done
+ * accessing the kiocb cookie.
+ */
+static void io_iopoll_req_issued(struct io_kiocb *req)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+
+ /*
+ * Track whether we have multiple files in our lists. This will impact
+ * how we do polling eventually, not spinning if we're on potentially
+ * different devices.
+ */
+ if (list_empty(&ctx->poll_list)) {
+ ctx->poll_multi_file = false;
+ } else if (!ctx->poll_multi_file) {
+ struct io_kiocb *list_req;
+
+ list_req = list_first_entry(&ctx->poll_list, struct io_kiocb,
+ list);
+ if (list_req->rw.ki_filp != req->rw.ki_filp)
+ ctx->poll_multi_file = true;
+ }
+
+ /*
+ * For fast devices, IO may have already completed. If it has, add
+ * it to the front so we find it first.
+ */
+ if (req->flags & REQ_F_IOPOLL_COMPLETED)
+ list_add(&req->list, &ctx->poll_list);
+ else
+ list_add_tail(&req->list, &ctx->poll_list);
+}
+
/*
* If we tracked the file through the SCM inflight mechanism, we could support
* any file. For now, just ensure that anything potentially problematic is done
@@ -320,6 +521,7 @@ static bool io_file_supports_async(struct file *file)
static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
bool force_nonblock)
{
+ struct io_ring_ctx *ctx = req->ctx;
struct kiocb *kiocb = &req->rw;
unsigned ioprio;
int fd, ret;
@@ -355,12 +557,22 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
kiocb->ki_flags |= IOCB_NOWAIT;
req->flags |= REQ_F_FORCE_NONBLOCK;
}
- if (kiocb->ki_flags & IOCB_HIPRI) {
- ret = -EINVAL;
- goto out_fput;
- }
+ if (ctx->flags & IORING_SETUP_IOPOLL) {
+ ret = -EOPNOTSUPP;
+ if (!(kiocb->ki_flags & IOCB_DIRECT) ||
+ !kiocb->ki_filp->f_op->iopoll)
+ goto out_fput;
- kiocb->ki_complete = io_complete_rw;
+ req->error = 0;
+ kiocb->ki_flags |= IOCB_HIPRI;
+ kiocb->ki_complete = io_complete_rw_iopoll;
+ } else {
+ if (kiocb->ki_flags & IOCB_HIPRI) {
+ ret = -EINVAL;
+ goto out_fput;
+ }
+ kiocb->ki_complete = io_complete_rw;
+ }
return 0;
out_fput:
fput(kiocb->ki_filp);
@@ -513,6 +725,9 @@ static int io_nop(struct io_kiocb *req, u64 user_data)
{
struct io_ring_ctx *ctx = req->ctx;
+ if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
+ return -EINVAL;
+
io_cqring_add_event(ctx, user_data, 0, 0);
io_free_req(req);
return 0;
@@ -533,6 +748,8 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe,
if (force_nonblock)
return -EAGAIN;
+ if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+ return -EINVAL;
if (unlikely(sqe->addr || sqe->ioprio))
return -EINVAL;
@@ -583,7 +800,22 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
break;
}
- return ret;
+ if (ret)
+ return ret;
+
+ if (ctx->flags & IORING_SETUP_IOPOLL) {
+ if (req->error == -EAGAIN)
+ return -EAGAIN;
+
+ /* workqueue context doesn't hold uring_lock, grab it now */
+ if (s->needs_lock)
+ mutex_lock(&ctx->uring_lock);
+ io_iopoll_req_issued(req);
+ if (s->needs_lock)
+ mutex_unlock(&ctx->uring_lock);
+ }
+
+ return 0;
}
static void io_sq_wq_submit_work(struct work_struct *work)
@@ -607,8 +839,19 @@ static void io_sq_wq_submit_work(struct work_struct *work)
use_mm(ctx->sqo_mm);
set_fs(USER_DS);
s->has_user = true;
+ s->needs_lock = true;
- ret = __io_submit_sqe(ctx, req, s, false);
+ do {
+ ret = __io_submit_sqe(ctx, req, s, false);
+ /*
+ * We can get EAGAIN for polled IO even though we're forcing
+ * a sync submission from here, since we can't wait for
+ * request slots on the block side.
+ */
+ if (ret != -EAGAIN)
+ break;
+ cond_resched();
+ } while (1);
set_fs(old_fs);
unuse_mm(ctx->sqo_mm);
@@ -723,6 +966,8 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit)
break;
s.has_user = true;
+ s.needs_lock = false;
+
ret = io_submit_sqe(ctx, &s);
if (ret) {
io_drop_sqring(ctx);
@@ -876,6 +1121,8 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx)
sock_release(ctx->ring_sock);
#endif
+ io_iopoll_reap_events(ctx);
+
io_mem_free(ctx->sq_ring);
io_mem_free(ctx->sq_sqes);
io_mem_free(ctx->cq_ring);
@@ -915,6 +1162,7 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
percpu_ref_kill(&ctx->refs);
mutex_unlock(&ctx->uring_lock);
+ io_iopoll_reap_events(ctx);
wait_for_completion(&ctx->ctx_done);
io_ring_ctx_free(ctx);
}
@@ -995,6 +1243,8 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
goto out_ctx;
}
if (flags & IORING_ENTER_GETEVENTS) {
+ unsigned nr_events = 0;
+
/*
* The application could have included the 'to_submit' count
* in how many events it wanted to wait for. If we failed to
@@ -1004,7 +1254,13 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
if (submitted < to_submit)
min_complete = min_t(unsigned, submitted, min_complete);
- ret = io_cqring_wait(ctx, min_complete, sig, sigsz);
+ if (ctx->flags & IORING_SETUP_IOPOLL) {
+ mutex_lock(&ctx->uring_lock);
+ ret = io_iopoll_check(ctx, &nr_events, min_complete);
+ mutex_unlock(&ctx->uring_lock);
+ } else {
+ ret = io_cqring_wait(ctx, min_complete, sig, sigsz);
+ }
}
out_ctx:
@@ -1187,7 +1443,7 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
return -EINVAL;
}
- if (p.flags)
+ if (p.flags & ~IORING_SETUP_IOPOLL)
return -EINVAL;
ret = io_uring_create(entries, &p);
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 4589d56d0b68..5c457ea396e6 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -30,6 +30,11 @@ struct io_uring_sqe {
__u64 __pad2[3];
};
+/*
+ * io_uring_setup() flags
+ */
+#define IORING_SETUP_IOPOLL (1U << 0) /* io_context is polled */
+
#define IORING_OP_NOP 0
#define IORING_OP_READV 1
#define IORING_OP_WRITEV 2
--
2.17.1
--
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^ permalink raw reply related
* [PATCH 06/18] io_uring: add fsync support
From: Jens Axboe @ 2019-02-07 19:55 UTC (permalink / raw)
To: linux-aio, linux-block, linux-api
Cc: hch, jmoyer, avi, jannh, viro, Jens Axboe
In-Reply-To: <20190207195552.22770-1-axboe@kernel.dk>
From: Christoph Hellwig <hch@lst.de>
Add a new fsync opcode, which either syncs a range if one is passed,
or the whole file if the offset and length fields are both cleared
to zero. A flag is provided to use fdatasync semantics, that is only
force out metadata which is required to retrieve the file data, but
not others like metadata.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 40 +++++++++++++++++++++++++++++++++++
include/uapi/linux/io_uring.h | 8 ++++++-
2 files changed, 47 insertions(+), 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 39a6cd14f0ec..e92ae7abffce 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4,6 +4,7 @@
* supporting fast/efficient IO.
*
* Copyright (C) 2018-2019 Jens Axboe
+ * Copyright (c) 2018-2019 Christoph Hellwig
*/
#include <linux/kernel.h>
#include <linux/init.h>
@@ -517,6 +518,42 @@ static int io_nop(struct io_kiocb *req, u64 user_data)
return 0;
}
+static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe,
+ bool force_nonblock)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+ loff_t sqe_off = READ_ONCE(sqe->off);
+ loff_t sqe_len = READ_ONCE(sqe->len);
+ loff_t end = sqe_off + sqe_len;
+ unsigned fsync_flags;
+ struct file *file;
+ int ret, fd;
+
+ /* fsync always requires a blocking context */
+ if (force_nonblock)
+ return -EAGAIN;
+
+ if (unlikely(sqe->addr || sqe->ioprio))
+ return -EINVAL;
+
+ fsync_flags = READ_ONCE(sqe->fsync_flags);
+ if (unlikely(fsync_flags & ~IORING_FSYNC_DATASYNC))
+ return -EINVAL;
+
+ fd = READ_ONCE(sqe->fd);
+ file = fget(fd);
+ if (unlikely(!file))
+ return -EBADF;
+
+ ret = vfs_fsync_range(file, sqe_off, end > 0 ? end : LLONG_MAX,
+ fsync_flags & IORING_FSYNC_DATASYNC);
+
+ fput(file);
+ io_cqring_add_event(ctx, sqe->user_data, ret, 0);
+ io_free_req(req);
+ return 0;
+}
+
static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
const struct sqe_submit *s, bool force_nonblock)
{
@@ -538,6 +575,9 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
case IORING_OP_WRITEV:
ret = io_write(req, s, force_nonblock);
break;
+ case IORING_OP_FSYNC:
+ ret = io_fsync(req, s->sqe, force_nonblock);
+ break;
default:
ret = -EINVAL;
break;
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index ac692823d6f4..4589d56d0b68 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -24,7 +24,7 @@ struct io_uring_sqe {
__u32 len; /* buffer size or number of iovecs */
union {
__kernel_rwf_t rw_flags;
- __u32 __resv;
+ __u32 fsync_flags;
};
__u64 user_data; /* data to be passed back at completion time */
__u64 __pad2[3];
@@ -33,6 +33,12 @@ struct io_uring_sqe {
#define IORING_OP_NOP 0
#define IORING_OP_READV 1
#define IORING_OP_WRITEV 2
+#define IORING_OP_FSYNC 3
+
+/*
+ * sqe->fsync_flags
+ */
+#define IORING_FSYNC_DATASYNC (1U << 0)
/*
* IO completion data structure (Completion Queue Entry)
--
2.17.1
--
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