I like this idea, but there are a couple issues here.
First the flag per command really doesn't work - we need a creation
time flag. Unfortunately the existing io_setup system call doesn't
take flags, so we'll need to add a new one.
Second we need a check that the polling mode is actually supported
for a given file descriptor.
Third this hardcodes block device knowlege into the block layer. We
really need move it into a method. See my third attached patch
for an (untested) idea how to make that work. The first two are
just cleanups.
Fourth we already have aio ->poll support. So this needs a different
naming scheme, e.g. *iopoll*.
>From 8b0d8f2e723bcf52d010c46130eb759770a0dc11 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@xxxxxx>
Date: Mon, 19 Nov 2018 08:13:19 +0100
Subject: aio: split get_reqs_available from aio_get_req
This makes the polled case nice to handle, and matches the put side.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
fs/aio.c | 41 ++++++++++++++++++++++-------------------
1 file changed, 22 insertions(+), 19 deletions(-)
diff --git a/fs/aio.c b/fs/aio.c
index e02085fe10d7..348f04129035 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -935,7 +935,7 @@ static void put_reqs_available(struct kioctx *ctx, unsigned nr)
local_irq_restore(flags);
}
-static bool get_reqs_available(struct kioctx *ctx)
+static bool __get_reqs_available(struct kioctx *ctx)
{
struct kioctx_cpu *kcpu;
bool ret = false;
@@ -1027,23 +1027,25 @@ static void user_refill_reqs_available(struct kioctx *ctx)
spin_unlock_irq(&ctx->completion_lock);
}
+static bool get_reqs_available(struct kioctx *ctx)
+{
+ if (__get_reqs_available(ctx))
+ return true;
+ user_refill_reqs_available(ctx);
+ return __get_reqs_available(ctx);
+}
+
/* aio_get_req
* Allocate a slot for an aio request.
* Returns NULL if no requests are free.
*/
-static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx, bool needs_ring)
+static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)
{
struct aio_kiocb *req;
- if (needs_ring && !get_reqs_available(ctx)) {
- user_refill_reqs_available(ctx);
- if (!get_reqs_available(ctx))
- return NULL;
- }
-
req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL|__GFP_ZERO);
if (unlikely(!req))
- goto out_put;
+ return NULL;
percpu_ref_get(&ctx->reqs);
INIT_LIST_HEAD(&req->ki_list);
@@ -1051,10 +1053,6 @@ static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx, bool needs_ring)
refcount_set(&req->ki_refcnt, 0);
req->ki_ctx = ctx;
return req;
-out_put:
- if (needs_ring)
- put_reqs_available(ctx, 1);
- return NULL;
}
static struct kioctx *lookup_ioctx(unsigned long ctx_id)
@@ -2200,17 +2198,21 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
return -EINVAL;
}
- if (iocb.aio_flags & IOCB_FLAG_HIPRI)
+ if (iocb.aio_flags & IOCB_FLAG_HIPRI) {
ctx_type = CTX_TYPE_POLLED;
- else
+ } else {
ctx_type = CTX_TYPE_NORMAL;
+ if (!get_reqs_available(ctx))
+ return -EAGAIN;
+ }
/*
* Polled IO doesn't need ring reservations
*/
- req = aio_get_req(ctx, ctx_type == CTX_TYPE_NORMAL);
+ ret = -EAGAIN;
+ req = aio_get_req(ctx);
if (unlikely(!req))
- return -EAGAIN;
+ goto out_put_reqs_available;
if (iocb.aio_flags & IOCB_FLAG_RESFD) {
/*
@@ -2294,12 +2296,13 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
return 0;
out_put_req:
- if (ctx_type == CTX_TYPE_NORMAL)
- put_reqs_available(ctx, 1);
percpu_ref_put(&ctx->reqs);
if (req->ki_eventfd)
eventfd_ctx_put(req->ki_eventfd);
kmem_cache_free(kiocb_cachep, req);
+out_put_reqs_available:
+ if (ctx_type == CTX_TYPE_NORMAL)
+ put_reqs_available(ctx, 1);
return ret;
}
--
2.19.1
>From a42c0af6c96b47d9b915e4efdaa0211e9b6b5253 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@xxxxxx>
Date: Sun, 18 Nov 2018 16:24:22 +0100
Subject: cleanup the aio_poll_reap related flow
Should not change behavior except for fixing a bug where the number
of returned iocbs was incorrectly overwritten when we actually loop
on poll_done for the first call.
I don't really understand why we loop there but not the second time
we call it. Nor do I really understand the nested loop in the callers
of __aio_check_polled, but that is for another time..
---
fs/aio.c | 152 ++++++++++++++++++-------------------------------------
1 file changed, 50 insertions(+), 102 deletions(-)
diff --git a/fs/aio.c b/fs/aio.c
index 348f04129035..d9198f99ed97 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1091,7 +1091,7 @@ static inline void iocb_put(struct aio_kiocb *iocb)
}
}
-static void iocb_put_many(struct kioctx *ctx, void **iocbs, int nr)
+static void iocb_put_many(struct kioctx *ctx, void **iocbs, int nr)
{
if (nr) {
kmem_cache_free_bulk(kiocb_cachep, nr, iocbs);
@@ -1316,42 +1316,33 @@ static struct block_device *aio_bdev_host(struct kiocb *req)
#define AIO_POLL_STACK 8
-struct aio_poll_data {
- struct io_event __user *evs;
- int off;
- long max;
- void *iocbs[AIO_POLL_STACK];
- int to_free;
-};
-
/*
- * Process the done_list of iocbs, copy to user space, and free them.
- * Migh return with data->iocbs holding entries, in which case
- * data->to_free is non-zero and the caller should free them.
+ * Process the done_list of iocbs, copy to user space, and free them. Might
+ * return with iocbs holding entries, in which case *to_free is non-zero and
+ * the caller should free them.
*/
-static long aio_poll_reap(struct kioctx *ctx, struct aio_poll_data *data)
+static long aio_poll_reap(struct kioctx *ctx, struct io_event __user *evs,
+ int off, long max, void **iocbs, int *to_free)
__releases(&ctx->poll_lock)
__acquires(&ctx->poll_lock)
{
struct aio_kiocb *iocb;
int ret, nr = 0;
-restart:
- while (!list_empty(&ctx->poll_done)) {
+ while ((iocb = list_first_entry_or_null(&ctx->poll_done,
+ struct aio_kiocb, ki_poll_list))) {
struct io_event __user *uev;
struct io_event ev;
- if (data->to_free == ARRAY_SIZE(data->iocbs)) {
- iocb_put_many(ctx, data->iocbs, data->to_free);
- data->to_free = 0;
+ if (*to_free == AIO_POLL_STACK) {
+ iocb_put_many(ctx, iocbs, *to_free);
+ *to_free = 0;
}
- iocb = list_first_entry(&ctx->poll_done, struct aio_kiocb,
- ki_poll_list);
list_del(&iocb->ki_poll_list);
+ iocbs[*to_free++] = iocb;
- data->iocbs[data->to_free++] = iocb;
- if (!data->evs) {
+ if (!evs) {
nr++;
continue;
}
@@ -1361,65 +1352,26 @@ static long aio_poll_reap(struct kioctx *ctx, struct aio_poll_data *data)
ev.res = iocb->ki_poll_res;
ev.res2 = iocb->ki_poll_res2;
- uev = data->evs + nr + data->off;
- if (!__copy_to_user_inatomic(uev, &ev, sizeof(*uev))) {
- nr++;
- if (nr + data->off < data->max)
- continue;
- break;
+ uev = evs + nr + off;
+ if (unlikely(__copy_to_user_inatomic(uev, &ev, sizeof(*uev)))) {
+ /*
+ * Unexpected slow path, drop lock and attempt copy
+ * again. If this also fails we are done.
+ */
+ spin_unlock_irq(&ctx->poll_lock);
+ ret = copy_to_user(uev, &ev, sizeof(*uev));
+ spin_lock_irq(&ctx->poll_lock);
+ if (ret)
+ return nr ? nr : -EFAULT;
}
- /*
- * Unexpected slow path, drop lock and attempt copy. If this
- * also fails, we're done. If it worked, we got another event
- * and we restart the list check since we dropped the lock.
- */
- spin_unlock_irq(&ctx->poll_lock);
- ret = copy_to_user(uev, &ev, sizeof(*uev));
- spin_lock_irq(&ctx->poll_lock);
- if (!ret) {
- nr++;
- if (nr + data->off < data->max)
- goto restart;
-
+ if (++nr + off == max)
break;
- }
-
- if (!nr)
- nr = -EFAULT;
- break;
}
return nr;
}
-/*
- * Reap done events, if any
- */
-static long aio_poll_find(struct kioctx *ctx, struct io_event __user *evs,
- int off, long max)
-{
- struct aio_poll_data data = {
- .evs = evs,
- .off = off,
- .max = max,
- .to_free = 0
- };
- int ret;
-
- if (list_empty_careful(&ctx->poll_done))
- return 0;
-
- spin_lock_irq(&ctx->poll_lock);
- ret = aio_poll_reap(ctx, &data);
- spin_unlock_irq(&ctx->poll_lock);
-
- if (data.to_free)
- iocb_put_many(ctx, data.iocbs, data.to_free);
-
- return ret;
-}
-
static void aio_poll_for_events(struct kioctx *ctx, struct aio_iopoll_data *pd,
unsigned int nr_pd, int off, long min, long max)
{
@@ -1448,42 +1400,32 @@ static int __aio_check_polled(struct kioctx *ctx, struct io_event __user *event,
int off, unsigned int *entries, long min, long max)
{
struct aio_iopoll_data pd[AIO_POLL_STACK];
+ void *iocbs[AIO_POLL_STACK];
+ int to_free = 0;
struct aio_kiocb *iocb;
unsigned int nr_pd;
- int ret, pre = 0;
+ int ret, found = 0;
if (list_empty_careful(&ctx->poll_pending))
goto out;
- spin_lock_irq(&ctx->poll_lock);
-
/*
* Check if we already have done events that satisfy what we need
*/
- while (!list_empty(&ctx->poll_done)) {
- struct aio_poll_data data = {
- .evs = event,
- .off = off,
- .max = max,
- .to_free = 0
- };
-
- ret = aio_poll_reap(ctx, &data);
- if (!ret)
- break;
- else if (ret < 0 || ret + off >= min) {
+ spin_lock_irq(&ctx->poll_lock);
+ while ((ret = aio_poll_reap(ctx, event, off, max, iocbs, &to_free))) {
+ if (ret < 0 || ret + off >= min) {
spin_unlock_irq(&ctx->poll_lock);
-
- if (data.to_free)
- iocb_put_many(ctx, data.iocbs, data.to_free);
-
+ if (to_free)
+ iocb_put_many(ctx, iocbs, to_free);
return ret;
}
- if (data.to_free)
- iocb_put_many(ctx, data.iocbs, data.to_free);
-
- pre = ret;
+ if (to_free) {
+ iocb_put_many(ctx, iocbs, to_free);
+ to_free = 0;
+ }
+ found += ret;
off += ret;
}
@@ -1518,13 +1460,19 @@ static int __aio_check_polled(struct kioctx *ctx, struct io_event __user *event,
}
out:
- ret = aio_poll_find(ctx, event, off, max);
- if (ret >= 0)
- return pre + ret;
- else if (pre)
- return pre;
+ if (!list_empty_careful(&ctx->poll_done)) {
+ spin_lock_irq(&ctx->poll_lock);
+ ret = aio_poll_reap(ctx, event, off, max, iocbs, &to_free);
+ spin_unlock_irq(&ctx->poll_lock);
+
+ if (to_free)
+ iocb_put_many(ctx, iocbs, to_free);
+ if (ret < 0)
+ return ret;
+ found += ret;
+ }
- return ret;
+ return found;
}
/*
--
2.19.1
>From f44b92fc87f2f83946af12db9faea5916016a486 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@xxxxxx>
Date: Sun, 18 Nov 2018 17:17:55 +0100
Subject: use array of iocbs
XXX: will need some protection against concurrent reaps
---
fs/aio.c | 121 +++++++++++++-----------------------------
fs/block_dev.c | 20 +++++--
fs/direct-io.c | 4 +-
fs/iomap.c | 53 +++++++++++-------
fs/xfs/xfs_file.c | 1 +
include/linux/fs.h | 2 +-
include/linux/iomap.h | 1 +
7 files changed, 90 insertions(+), 112 deletions(-)
diff --git a/fs/aio.c b/fs/aio.c
index d9198f99ed97..cb2fead2ab7c 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -89,6 +89,9 @@ struct ctx_rq_wait {
enum {
CTX_TYPE_NORMAL = 0,
CTX_TYPE_POLLED,
+
+ /* currently undergoing a polling io_getevents */
+ CTX_TYPE_POLLING,
};
struct kioctx {
@@ -1282,38 +1285,6 @@ static bool aio_read_events(struct kioctx *ctx, long min_nr, long nr,
return ret < 0 || *i >= min_nr;
}
-struct aio_iopoll_data {
- unsigned int blk_qc;
- struct block_device *bdev;
-};
-
-static int aio_io_poll(struct aio_iopoll_data *pd, bool wait)
-{
-#ifdef CONFIG_BLOCK
- /*
- * Should only happen if someone sets ->ki_blk_qc at random,
- * not being a blockdev target. We'll just ignore it, the IO
- * will complete normally without being polled.
- */
- if (pd->bdev)
- return blk_poll(bdev_get_queue(pd->bdev), pd->blk_qc, wait);
-#endif
-
- return 0;
-}
-
-static struct block_device *aio_bdev_host(struct kiocb *req)
-{
- struct inode *inode = req->ki_filp->f_mapping->host;
-
- if (S_ISBLK(inode->i_mode))
- return I_BDEV(inode);
- else if (inode->i_sb && inode->i_sb->s_bdev)
- return inode->i_sb->s_bdev;
-
- return NULL;
-}
-
#define AIO_POLL_STACK 8
/*
@@ -1372,39 +1343,12 @@ static long aio_poll_reap(struct kioctx *ctx, struct io_event __user *evs,
return nr;
}
-static void aio_poll_for_events(struct kioctx *ctx, struct aio_iopoll_data *pd,
- unsigned int nr_pd, int off, long min, long max)
-{
- int i, polled = 0;
-
- /*
- * Poll for needed events with wait == true, anything
- * after that we just check if we have more, up to max.
- */
- for (i = 0; i < nr_pd; i++) {
- bool wait = polled + off >= min;
-
- polled += aio_io_poll(&pd[i], wait);
- if (polled + off >= max)
- break;
-
- /*
- * If we have entries waiting to be reaped, stop polling
- */
- if (!list_empty_careful(&ctx->poll_done))
- break;
- }
-}
-
static int __aio_check_polled(struct kioctx *ctx, struct io_event __user *event,
- int off, unsigned int *entries, long min, long max)
+ int off, unsigned int *to_poll, long min, long max)
{
- struct aio_iopoll_data pd[AIO_POLL_STACK];
void *iocbs[AIO_POLL_STACK];
- int to_free = 0;
struct aio_kiocb *iocb;
- unsigned int nr_pd;
- int ret, found = 0;
+ int to_free = 0, found = 0, polled = 0, ret, i;
if (list_empty_careful(&ctx->poll_pending))
goto out;
@@ -1433,30 +1377,27 @@ static int __aio_check_polled(struct kioctx *ctx, struct io_event __user *event,
* Find up to 'max_nr' worth of events to poll for, including the
* events we already successfully polled
*/
- nr_pd = 0;
list_for_each_entry(iocb, &ctx->poll_pending, ki_poll_list) {
- struct kiocb *kiocb = &iocb->rw;
- blk_qc_t qc;
-
- /*
- * Not submitted yet, don't poll for it
- */
- qc = READ_ONCE(kiocb->ki_blk_qc);
- if (qc == BLK_QC_T_NONE)
- continue;
-
- pd[nr_pd].blk_qc = qc;
- pd[nr_pd].bdev = aio_bdev_host(kiocb);
-
- ++nr_pd;
- if (nr_pd == ARRAY_SIZE(pd) || nr_pd + off >= max)
+ iocbs[*to_poll] = iocb;
+ (*to_poll)++;
+ if (*to_poll == AIO_POLL_STACK || *to_poll + off >= max)
break;
}
spin_unlock_irq(&ctx->poll_lock);
- if (nr_pd) {
- *entries = nr_pd;
- aio_poll_for_events(ctx, pd, nr_pd, off, min, max);
+ /*
+ * Poll for needed events with wait == true, anything after that we just
+ * check if we have more, up to max.
+ *
+ * If we have entries waiting to be reaped, stop polling
+ */
+ for (i = 0; i < *to_poll; i++) {
+ bool wait = polled + off >= min;
+
+ iocb = iocbs[*to_poll];
+ polled += iocb->rw.ki_filp->f_op->iopoll(&iocb->rw, wait);
+ if (polled + off >= max || !list_empty_careful(&ctx->poll_done))
+ break;
}
out:
@@ -1502,6 +1443,10 @@ static int aio_check_polled(struct kioctx *ctx, long min_nr, long nr,
unsigned int found;
int this, ret = 0;
+ /* We can only allow a single thread to poll a context at a time */
+ if (test_and_set_bit(CTX_TYPE_POLLING, &ctx->io_type))
+ return -EBUSY;
+
if (!access_ok(VERIFY_WRITE, event, nr * sizeof(*event)))
return -EFAULT;
@@ -1522,6 +1467,7 @@ static int aio_check_polled(struct kioctx *ctx, long min_nr, long nr,
ret += this;
} while (found && ret < min_nr);
+ clear_bit(CTX_TYPE_POLLING, &ctx->io_type);
return ret;
}
@@ -1737,14 +1683,19 @@ static int aio_prep_rw(struct aio_kiocb *kiocb, struct iocb *iocb)
if (iocb->aio_flags & IOCB_FLAG_HIPRI) {
struct kioctx *ctx = kiocb->ki_ctx;
+ ret = -EOPNOTSUPP;
+ if (!(req->ki_flags & IOCB_DIRECT) ||
+ !req->ki_filp->f_op->iopoll)
+ goto out_fput;
+
req->ki_flags |= IOCB_HIPRI;
- req->ki_blk_qc = BLK_QC_T_NONE;
req->ki_complete = aio_complete_rw_poll;
spin_lock_irq(&ctx->poll_lock);
list_add_tail(&kiocb->ki_poll_list, &ctx->poll_pending);
spin_unlock_irq(&ctx->poll_lock);
} else {
+ req->ki_flags &= ~IOCB_HIPRI;
req->ki_complete = aio_complete_rw;
}
@@ -1761,8 +1712,7 @@ static int aio_prep_rw(struct aio_kiocb *kiocb, struct iocb *iocb)
ret = ioprio_check_cap(iocb->aio_reqprio);
if (ret) {
pr_debug("aio ioprio check cap error: %d\n", ret);
- fput(req->ki_filp);
- return ret;
+ goto out_fput;
}
req->ki_ioprio = iocb->aio_reqprio;
@@ -1771,7 +1721,10 @@ static int aio_prep_rw(struct aio_kiocb *kiocb, struct iocb *iocb)
ret = kiocb_set_rw_flags(req, iocb->aio_rw_flags);
if (unlikely(ret))
- fput(req->ki_filp);
+ goto out_fput;
+ return 0;
+out_fput:
+ fput(req->ki_filp);
return ret;
}
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 8a2fed18e3fc..8ba58e280ac6 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -236,7 +236,6 @@ __blkdev_direct_IO_simple(struct kiocb *iocb, struct iov_iter *iter,
bio.bi_opf |= REQ_HIPRI;
qc = submit_bio(&bio);
- WRITE_ONCE(iocb->ki_blk_qc, qc);
for (;;) {
__set_current_state(TASK_UNINTERRUPTIBLE);
@@ -274,6 +273,7 @@ struct blkdev_dio {
};
size_t size;
atomic_t ref;
+ blk_qc_t qc;
bool multi_bio : 1;
bool should_dirty : 1;
bool is_sync : 1;
@@ -282,6 +282,14 @@ struct blkdev_dio {
static struct bio_set blkdev_dio_pool;
+static bool blkdev_iopoll(struct kiocb *kiocb, bool wait)
+{
+ struct blkdev_dio *dio = kiocb->private;
+ struct block_device *bdev = I_BDEV(kiocb->ki_filp->f_mapping->host);
+
+ return blk_poll(bdev_get_queue(bdev), READ_ONCE(dio->qc), wait);
+}
+
static void blkdev_bio_end_io(struct bio *bio)
{
struct blkdev_dio *dio = bio->bi_private;
@@ -336,7 +344,6 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
bool is_poll = (iocb->ki_flags & IOCB_HIPRI) != 0;
bool is_read = (iov_iter_rw(iter) == READ), is_sync;
loff_t pos = iocb->ki_pos;
- blk_qc_t qc = BLK_QC_T_NONE;
int ret = 0;
if ((pos | iov_iter_alignment(iter)) &
@@ -356,6 +363,9 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
dio->size = 0;
dio->multi_bio = false;
dio->should_dirty = is_read && iter_is_iovec(iter);
+ dio->qc = BLK_QC_T_NONE;
+
+ iocb->private = dio;
/*
* Don't plug for HIPRI/polled IO, as those should go straight
@@ -396,8 +406,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
if (iocb->ki_flags & IOCB_HIPRI)
bio->bi_opf |= REQ_HIPRI;
- qc = submit_bio(bio);
- WRITE_ONCE(iocb->ki_blk_qc, qc);
+ WRITE_ONCE(dio->qc, submit_bio(bio));
break;
}
@@ -425,7 +434,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
break;
if (!(iocb->ki_flags & IOCB_HIPRI) ||
- !blk_poll(bdev_get_queue(bdev), qc, true))
+ !blk_poll(bdev_get_queue(bdev), dio->qc, true))
io_schedule();
}
__set_current_state(TASK_RUNNING);
@@ -2063,6 +2072,7 @@ const struct file_operations def_blk_fops = {
.llseek = block_llseek,
.read_iter = blkdev_read_iter,
.write_iter = blkdev_write_iter,
+ .iopoll = blkdev_iopoll,
.mmap = generic_file_mmap,
.fsync = blkdev_fsync,
.unlocked_ioctl = block_ioctl,
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 34de494e9061..a5a4e5a1423e 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -477,10 +477,8 @@ static inline void dio_bio_submit(struct dio *dio, struct dio_submit *sdio)
if (sdio->submit_io) {
sdio->submit_io(bio, dio->inode, sdio->logical_offset_in_bio);
dio->bio_cookie = BLK_QC_T_NONE;
- } else {
+ } else
dio->bio_cookie = submit_bio(bio);
- WRITE_ONCE(dio->iocb->ki_blk_qc, dio->bio_cookie);
- }
sdio->bio = NULL;
sdio->boundary = 0;
diff --git a/fs/iomap.c b/fs/iomap.c
index 4cf412b6230a..e5cd9dbe78a8 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -1419,14 +1419,14 @@ struct iomap_dio {
unsigned flags;
int error;
bool wait_for_completion;
+ blk_qc_t cookie;
+ struct request_queue *last_queue;
union {
/* used during submission and for synchronous completion: */
struct {
struct iov_iter *iter;
struct task_struct *waiter;
- struct request_queue *last_queue;
- blk_qc_t cookie;
} submit;
/* used for aio completion: */
@@ -1436,6 +1436,30 @@ struct iomap_dio {
};
};
+bool iomap_dio_iopoll(struct kiocb *kiocb, bool wait)
+{
+ struct iomap_dio *dio = kiocb->private;
+ struct request_queue *q = READ_ONCE(dio->last_queue);
+
+ if (!q)
+ return false;
+ return blk_poll(q, READ_ONCE(dio->cookie), wait);
+}
+EXPORT_SYMBOL_GPL(iomap_dio_iopoll);
+
+static void iomap_dio_submit_bio(struct iomap_dio *dio, struct iomap *iomap,
+ struct bio *bio)
+{
+ atomic_inc(&dio->ref);
+
+ /*
+ * iomap_dio_iopoll can race with us. A non-zero last_queue marks that
+ * we are ready to poll.
+ */
+ WRITE_ONCE(dio->cookie, submit_bio(bio));
+ WRITE_ONCE(dio->last_queue, bdev_get_queue(iomap->bdev));
+}
+
static ssize_t iomap_dio_complete(struct iomap_dio *dio)
{
struct kiocb *iocb = dio->iocb;
@@ -1548,14 +1572,13 @@ static void iomap_dio_bio_end_io(struct bio *bio)
}
}
-static blk_qc_t
+static void
iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos,
unsigned len)
{
struct page *page = ZERO_PAGE(0);
int flags = REQ_SYNC | REQ_IDLE;
struct bio *bio;
- blk_qc_t qc;
bio = bio_alloc(GFP_KERNEL, 1);
bio_set_dev(bio, iomap->bdev);
@@ -1569,11 +1592,7 @@ iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos,
get_page(page);
__bio_add_page(bio, page, len, 0);
bio_set_op_attrs(bio, REQ_OP_WRITE, flags);
-
- atomic_inc(&dio->ref);
- qc = submit_bio(bio);
- WRITE_ONCE(dio->iocb->ki_blk_qc, qc);
- return qc;
+ iomap_dio_submit_bio(dio, iomap, bio);
}
static loff_t
@@ -1679,11 +1698,7 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
copied += n;
nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES);
-
- atomic_inc(&dio->ref);
-
- dio->submit.last_queue = bdev_get_queue(iomap->bdev);
- dio->iocb->ki_blk_qc = dio->submit.cookie = submit_bio(bio);
+ iomap_dio_submit_bio(dio, iomap, bio);
} while (nr_pages);
if (need_zeroout) {
@@ -1785,6 +1800,7 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
dio = kmalloc(sizeof(*dio), GFP_KERNEL);
if (!dio)
return -ENOMEM;
+ iocb->private = dio;
dio->iocb = iocb;
atomic_set(&dio->ref, 1);
@@ -1794,11 +1810,11 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
dio->error = 0;
dio->flags = 0;
dio->wait_for_completion = is_sync_kiocb(iocb);
+ dio->cookie = BLK_QC_T_NONE;
+ dio->last_queue = NULL;
dio->submit.iter = iter;
dio->submit.waiter = current;
- dio->submit.cookie = BLK_QC_T_NONE;
- dio->submit.last_queue = NULL;
if (iov_iter_rw(iter) == READ) {
if (pos >= dio->i_size)
@@ -1897,9 +1913,8 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
break;
if (!(iocb->ki_flags & IOCB_HIPRI) ||
- !dio->submit.last_queue ||
- !blk_poll(dio->submit.last_queue,
- dio->submit.cookie, true))
+ !dio->last_queue ||
+ !blk_poll(dio->last_queue, dio->cookie, true))
io_schedule();
}
__set_current_state(TASK_RUNNING);
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 53c9ab8fb777..603e705781a4 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1203,6 +1203,7 @@ const struct file_operations xfs_file_operations = {
.write_iter = xfs_file_write_iter,
.splice_read = generic_file_splice_read,
.splice_write = iter_file_splice_write,
+ .iopoll = iomap_dio_iopoll,
.unlocked_ioctl = xfs_file_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = xfs_file_compat_ioctl,
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 032761d9b218..1d46a10aef6c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -310,7 +310,6 @@ struct kiocb {
int ki_flags;
u16 ki_hint;
u16 ki_ioprio; /* See linux/ioprio.h */
- u32 ki_blk_qc;
} __randomize_layout;
static inline bool is_sync_kiocb(struct kiocb *kiocb)
@@ -1782,6 +1781,7 @@ struct file_operations {
ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
+ bool (*iopoll)(struct kiocb *kiocb, bool wait);
int (*iterate) (struct file *, struct dir_context *);
int (*iterate_shared) (struct file *, struct dir_context *);
__poll_t (*poll) (struct file *, struct poll_table_struct *);
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 9a4258154b25..2cbe87ad1878 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -162,6 +162,7 @@ typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret,
unsigned flags);
ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
const struct iomap_ops *ops, iomap_dio_end_io_t end_io);
+bool iomap_dio_iopoll(struct kiocb *kiocb, bool wait);
#ifdef CONFIG_SWAP
struct file;
--
2.19.1
