Merge tag 'io_uring-20190323' of git://git.kernel.dk/linux-block
Pull io_uring fixes and improvements from Jens Axboe:
"The first five in this series are heavily inspired by the work Al did
on the aio side to fix the races there.
The last two re-introduce a feature that was in io_uring before it got
merged, but which I pulled since we didn't have a good way to have
BVEC iters that already have a stable reference. These aren't
necessarily related to block, it's just how io_uring pins fixed
buffers"
* tag 'io_uring-20190323' of git://git.kernel.dk/linux-block:
block: add BIO_NO_PAGE_REF flag
iov_iter: add ITER_BVEC_FLAG_NO_REF flag
io_uring: mark me as the maintainer
io_uring: retry bulk slab allocs as single allocs
io_uring: fix poll races
io_uring: fix fget/fput handling
io_uring: add prepped flag
io_uring: make io_read/write return an integer
io_uring: use regular request ref counts
diff --git a/MAINTAINERS b/MAINTAINERS
index e17ebf7..3e5a5d2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8096,6 +8096,16 @@
F: include/linux/of_iommu.h
F: include/linux/iova.h
+IO_URING
+M: Jens Axboe <axboe@kernel.dk>
+L: linux-block@vger.kernel.org
+L: linux-fsdevel@vger.kernel.org
+T: git git://git.kernel.dk/linux-block
+T: git git://git.kernel.dk/liburing
+S: Maintained
+F: fs/io_uring.c
+F: include/uapi/linux/io_uring.h
+
IP MASQUERADING
M: Juanjo Ciarlante <jjciarla@raiz.uncu.edu.ar>
S: Maintained
diff --git a/block/bio.c b/block/bio.c
index 71a78d9..b64cedc 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -849,20 +849,14 @@
size = bio_add_page(bio, bv->bv_page, len,
bv->bv_offset + iter->iov_offset);
if (size == len) {
- struct page *page;
- int i;
+ if (!bio_flagged(bio, BIO_NO_PAGE_REF)) {
+ struct page *page;
+ int i;
- /*
- * For the normal O_DIRECT case, we could skip grabbing this
- * reference and then not have to put them again when IO
- * completes. But this breaks some in-kernel users, like
- * splicing to/from a loop device, where we release the pipe
- * pages unconditionally. If we can fix that case, we can
- * get rid of the get here and the need to call
- * bio_release_pages() at IO completion time.
- */
- mp_bvec_for_each_page(page, bv, i)
- get_page(page);
+ mp_bvec_for_each_page(page, bv, i)
+ get_page(page);
+ }
+
iov_iter_advance(iter, size);
return 0;
}
@@ -925,10 +919,12 @@
* 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. For now, when adding kernel pages, we still grab a reference to the
- * page. This isn't strictly needed for the common case, but some call paths
- * end up releasing pages from eg a pipe and we can't easily control these.
- * See comment in __bio_iov_bvec_add_pages().
+ * pages. If we're adding kernel pages, and the caller told us it's safe to
+ * do so, 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.
*
* 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
@@ -940,6 +936,13 @@
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 the caller asked us to.
+ */
+ if (is_bvec && iov_iter_bvec_no_ref(iter))
+ bio_set_flag(bio, BIO_NO_PAGE_REF);
+
do {
int ret;
@@ -1696,7 +1699,8 @@
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);
}
}
@@ -1713,7 +1717,8 @@
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 e9faa52..78d3257 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -336,12 +336,14 @@
if (should_dirty) {
bio_check_pages_dirty(bio);
} else {
- struct bio_vec *bvec;
- int i;
- struct bvec_iter_all iter_all;
+ if (!bio_flagged(bio, BIO_NO_PAGE_REF)) {
+ struct bvec_iter_all iter_all;
+ struct bio_vec *bvec;
+ int i;
- bio_for_each_segment_all(bvec, bio, i, iter_all)
- put_page(bvec->bv_page);
+ bio_for_each_segment_all(bvec, bio, i, iter_all)
+ put_page(bvec->bv_page);
+ }
bio_put(bio);
}
}
diff --git a/fs/io_uring.c b/fs/io_uring.c
index c88088d..6aaa3058 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -189,17 +189,28 @@
bool needs_fixed_file;
};
+/*
+ * First field must be the file pointer in all the
+ * iocb unions! See also 'struct kiocb' in <linux/fs.h>
+ */
struct io_poll_iocb {
struct file *file;
struct wait_queue_head *head;
__poll_t events;
- bool woken;
+ bool done;
bool canceled;
struct wait_queue_entry wait;
};
+/*
+ * NOTE! Each of the iocb union members has the file pointer
+ * as the first entry in their struct definition. So you can
+ * access the file pointer through any of the sub-structs,
+ * or directly as just 'ki_filp' in this struct.
+ */
struct io_kiocb {
union {
+ struct file *file;
struct kiocb rw;
struct io_poll_iocb poll;
};
@@ -214,6 +225,7 @@
#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 */
+#define REQ_F_PREPPED 16 /* prep already done */
u64 user_data;
u64 error;
@@ -355,20 +367,25 @@
}
}
-static void io_cqring_add_event(struct io_ring_ctx *ctx, u64 ki_user_data,
+static void io_cqring_ev_posted(struct io_ring_ctx *ctx)
+{
+ if (waitqueue_active(&ctx->wait))
+ wake_up(&ctx->wait);
+ if (waitqueue_active(&ctx->sqo_wait))
+ wake_up(&ctx->sqo_wait);
+}
+
+static void io_cqring_add_event(struct io_ring_ctx *ctx, u64 user_data,
long res, unsigned ev_flags)
{
unsigned long flags;
spin_lock_irqsave(&ctx->completion_lock, flags);
- io_cqring_fill_event(ctx, ki_user_data, res, ev_flags);
+ io_cqring_fill_event(ctx, user_data, res, ev_flags);
io_commit_cqring(ctx);
spin_unlock_irqrestore(&ctx->completion_lock, flags);
- if (waitqueue_active(&ctx->wait))
- wake_up(&ctx->wait);
- if (waitqueue_active(&ctx->sqo_wait))
- wake_up(&ctx->sqo_wait);
+ io_cqring_ev_posted(ctx);
}
static void io_ring_drop_ctx_refs(struct io_ring_ctx *ctx, unsigned refs)
@@ -382,13 +399,14 @@
static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx,
struct io_submit_state *state)
{
+ gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
struct io_kiocb *req;
if (!percpu_ref_tryget(&ctx->refs))
return NULL;
if (!state) {
- req = kmem_cache_alloc(req_cachep, __GFP_NOWARN);
+ req = kmem_cache_alloc(req_cachep, gfp);
if (unlikely(!req))
goto out;
} else if (!state->free_reqs) {
@@ -396,10 +414,18 @@
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;
+ ret = kmem_cache_alloc_bulk(req_cachep, gfp, sz, state->reqs);
+
+ /*
+ * Bulk alloc is all-or-nothing. If we fail to get a batch,
+ * retry single alloc to be on the safe side.
+ */
+ if (unlikely(ret <= 0)) {
+ state->reqs[0] = kmem_cache_alloc(req_cachep, gfp);
+ if (!state->reqs[0])
+ goto out;
+ ret = 1;
+ }
state->free_reqs = ret - 1;
state->cur_req = 1;
req = state->reqs[0];
@@ -411,7 +437,8 @@
req->ctx = ctx;
req->flags = 0;
- refcount_set(&req->refs, 0);
+ /* one is dropped after submission, the other at completion */
+ refcount_set(&req->refs, 2);
return req;
out:
io_ring_drop_ctx_refs(ctx, 1);
@@ -429,10 +456,16 @@
static void io_free_req(struct io_kiocb *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);
- }
+ if (req->file && !(req->flags & REQ_F_FIXED_FILE))
+ fput(req->file);
+ io_ring_drop_ctx_refs(req->ctx, 1);
+ kmem_cache_free(req_cachep, req);
+}
+
+static void io_put_req(struct io_kiocb *req)
+{
+ if (refcount_dec_and_test(&req->refs))
+ io_free_req(req);
}
/*
@@ -442,44 +475,34 @@
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;
- file_count = to_free = 0;
+ 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)++;
- /*
- * Batched puts of the same file, to avoid dirtying the
- * file usage count multiple times, if avoidable.
- */
- 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++;
+ if (refcount_dec_and_test(&req->refs)) {
+ /* If we're not using fixed files, we have to pair the
+ * completion part with the file put. Use regular
+ * completions for those, only batch free for fixed
+ * file.
+ */
+ if (req->flags & REQ_F_FIXED_FILE) {
+ reqs[to_free++] = req;
+ if (to_free == ARRAY_SIZE(reqs))
+ io_free_req_many(ctx, reqs, &to_free);
} else {
- fput_many(file, file_count);
- file = req->rw.ki_filp;
- file_count = 1;
+ io_free_req(req);
}
}
-
- 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_commit_cqring(ctx);
io_free_req_many(ctx, reqs, &to_free);
}
@@ -602,21 +625,14 @@
}
}
-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);
- io_fput(req);
io_cqring_add_event(req->ctx, req->user_data, res, 0);
- io_free_req(req);
+ io_put_req(req);
}
static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2)
@@ -731,31 +747,18 @@
const struct io_uring_sqe *sqe = s->sqe;
struct io_ring_ctx *ctx = req->ctx;
struct kiocb *kiocb = &req->rw;
- unsigned ioprio, flags;
- int fd, ret;
+ unsigned ioprio;
+ int ret;
+ if (!req->file)
+ return -EBADF;
/* For -EAGAIN retry, everything is already prepped */
- if (kiocb->ki_filp)
+ if (req->flags & REQ_F_PREPPED)
return 0;
- flags = READ_ONCE(sqe->flags);
- fd = READ_ONCE(sqe->fd);
+ if (force_nonblock && !io_file_supports_async(req->file))
+ force_nonblock = false;
- if (flags & IOSQE_FIXED_FILE) {
- if (unlikely(!ctx->user_files ||
- (unsigned) fd >= ctx->nr_user_files))
- return -EBADF;
- kiocb->ki_filp = ctx->user_files[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;
- 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));
@@ -764,7 +767,7 @@
if (ioprio) {
ret = ioprio_check_cap(ioprio);
if (ret)
- goto out_fput;
+ return ret;
kiocb->ki_ioprio = ioprio;
} else
@@ -772,38 +775,26 @@
ret = kiocb_set_rw_flags(kiocb, READ_ONCE(sqe->rw_flags));
if (unlikely(ret))
- goto out_fput;
+ return ret;
if (force_nonblock) {
kiocb->ki_flags |= IOCB_NOWAIT;
req->flags |= REQ_F_FORCE_NONBLOCK;
}
if (ctx->flags & IORING_SETUP_IOPOLL) {
- ret = -EOPNOTSUPP;
if (!(kiocb->ki_flags & IOCB_DIRECT) ||
!kiocb->ki_filp->f_op->iopoll)
- goto out_fput;
+ return -EOPNOTSUPP;
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;
- }
+ if (kiocb->ki_flags & IOCB_HIPRI)
+ return -EINVAL;
kiocb->ki_complete = io_complete_rw;
}
+ req->flags |= REQ_F_PREPPED;
return 0;
-out_fput:
- 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;
}
static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
@@ -864,6 +855,9 @@
iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len);
if (offset)
iov_iter_advance(iter, offset);
+
+ /* don't drop a reference to these pages */
+ iter->type |= ITER_BVEC_FLAG_NO_REF;
return 0;
}
@@ -887,7 +881,7 @@
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);
+ int ret = io_import_fixed(ctx, rw, sqe, iter);
*iovec = NULL;
return ret;
}
@@ -945,31 +939,29 @@
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)
+static int io_read(struct io_kiocb *req, const struct sqe_submit *s,
+ bool force_nonblock, struct io_submit_state *state)
{
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
struct kiocb *kiocb = &req->rw;
struct iov_iter iter;
struct file *file;
size_t iov_count;
- ssize_t ret;
+ int ret;
ret = io_prep_rw(req, s, force_nonblock, state);
if (ret)
return ret;
file = kiocb->ki_filp;
- ret = -EBADF;
if (unlikely(!(file->f_mode & FMODE_READ)))
- goto out_fput;
- ret = -EINVAL;
+ return -EBADF;
if (unlikely(!file->f_op->read_iter))
- goto out_fput;
+ return -EINVAL;
ret = io_import_iovec(req->ctx, READ, s, &iovec, &iter);
if (ret)
- goto out_fput;
+ return ret;
iov_count = iov_iter_count(&iter);
ret = rw_verify_area(READ, file, &kiocb->ki_pos, iov_count);
@@ -991,38 +983,32 @@
}
}
kfree(iovec);
-out_fput:
- /* Hold on to the file for -EAGAIN */
- if (unlikely(ret && ret != -EAGAIN))
- io_fput(req);
return ret;
}
-static ssize_t io_write(struct io_kiocb *req, const struct sqe_submit *s,
- bool force_nonblock, struct io_submit_state *state)
+static int io_write(struct io_kiocb *req, const struct sqe_submit *s,
+ bool force_nonblock, struct io_submit_state *state)
{
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
struct kiocb *kiocb = &req->rw;
struct iov_iter iter;
struct file *file;
size_t iov_count;
- ssize_t ret;
+ int ret;
ret = io_prep_rw(req, s, force_nonblock, state);
if (ret)
return ret;
- ret = -EBADF;
file = kiocb->ki_filp;
if (unlikely(!(file->f_mode & FMODE_WRITE)))
- goto out_fput;
- ret = -EINVAL;
+ return -EBADF;
if (unlikely(!file->f_op->write_iter))
- goto out_fput;
+ return -EINVAL;
ret = io_import_iovec(req->ctx, WRITE, s, &iovec, &iter);
if (ret)
- goto out_fput;
+ return ret;
iov_count = iov_iter_count(&iter);
@@ -1054,10 +1040,6 @@
}
out_free:
kfree(iovec);
-out_fput:
- /* Hold on to the file for -EAGAIN */
- if (unlikely(ret && ret != -EAGAIN))
- io_fput(req);
return ret;
}
@@ -1072,29 +1054,19 @@
if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
- /*
- * Twilight zone - it's possible that someone issued an opcode that
- * has a file attached, then got -EAGAIN on submission, and changed
- * the sqe before we retried it from async context. Avoid dropping
- * a file reference for this malicious case, and flag the error.
- */
- if (req->rw.ki_filp) {
- err = -EBADF;
- io_fput(req);
- }
io_cqring_add_event(ctx, user_data, err, 0);
- io_free_req(req);
+ io_put_req(req);
return 0;
}
static int io_prep_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_ring_ctx *ctx = req->ctx;
- unsigned flags;
- int fd;
- /* Prep already done */
- if (req->rw.ki_filp)
+ if (!req->file)
+ return -EBADF;
+ /* Prep already done (EAGAIN retry) */
+ if (req->flags & REQ_F_PREPPED)
return 0;
if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
@@ -1102,20 +1074,7 @@
if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index))
return -EINVAL;
- fd = READ_ONCE(sqe->fd);
- flags = READ_ONCE(sqe->flags);
-
- if (flags & IOSQE_FIXED_FILE) {
- if (unlikely(!ctx->user_files || fd >= ctx->nr_user_files))
- return -EBADF;
- req->rw.ki_filp = ctx->user_files[fd];
- req->flags |= REQ_F_FIXED_FILE;
- } else {
- req->rw.ki_filp = fget(fd);
- if (unlikely(!req->rw.ki_filp))
- return -EBADF;
- }
-
+ req->flags |= REQ_F_PREPPED;
return 0;
}
@@ -1144,9 +1103,8 @@
end > 0 ? end : LLONG_MAX,
fsync_flags & IORING_FSYNC_DATASYNC);
- io_fput(req);
io_cqring_add_event(req->ctx, sqe->user_data, ret, 0);
- io_free_req(req);
+ io_put_req(req);
return 0;
}
@@ -1204,15 +1162,16 @@
spin_unlock_irq(&ctx->completion_lock);
io_cqring_add_event(req->ctx, sqe->user_data, ret, 0);
- io_free_req(req);
+ io_put_req(req);
return 0;
}
-static void io_poll_complete(struct io_kiocb *req, __poll_t mask)
+static void io_poll_complete(struct io_ring_ctx *ctx, 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);
+ req->poll.done = true;
+ io_cqring_fill_event(ctx, req->user_data, mangle_poll(mask), 0);
+ io_commit_cqring(ctx);
}
static void io_poll_complete_work(struct work_struct *work)
@@ -1240,9 +1199,11 @@
return;
}
list_del_init(&req->list);
+ io_poll_complete(ctx, req, mask);
spin_unlock_irq(&ctx->completion_lock);
- io_poll_complete(req, mask);
+ io_cqring_ev_posted(ctx);
+ io_put_req(req);
}
static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
@@ -1253,29 +1214,25 @@
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;
+ unsigned long flags;
/* for instances that support it check for an event match first: */
- if (mask) {
- unsigned long flags;
-
- if (!(mask & poll->events))
- return 0;
-
- /* try to complete the iocb inline if we can: */
- if (spin_trylock_irqsave(&ctx->completion_lock, flags)) {
- list_del(&req->list);
- spin_unlock_irqrestore(&ctx->completion_lock, flags);
-
- list_del_init(&poll->wait.entry);
- io_poll_complete(req, mask);
- return 1;
- }
- }
+ if (mask && !(mask & poll->events))
+ return 0;
list_del_init(&poll->wait.entry);
- queue_work(ctx->sqo_wq, &req->work);
+
+ if (mask && spin_trylock_irqsave(&ctx->completion_lock, flags)) {
+ list_del(&req->list);
+ io_poll_complete(ctx, req, mask);
+ spin_unlock_irqrestore(&ctx->completion_lock, flags);
+
+ io_cqring_ev_posted(ctx);
+ io_put_req(req);
+ } else {
+ queue_work(ctx->sqo_wq, &req->work);
+ }
+
return 1;
}
@@ -1305,36 +1262,23 @@
struct io_poll_iocb *poll = &req->poll;
struct io_ring_ctx *ctx = req->ctx;
struct io_poll_table ipt;
- unsigned flags;
+ bool cancel = false;
__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;
+ if (!poll->file)
+ return -EBADF;
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->nr_user_files))
- return -EBADF;
- poll->file = ctx->user_files[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->done = false;
poll->canceled = false;
ipt.pt._qproc = io_poll_queue_proc;
@@ -1346,56 +1290,44 @@
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);
+ if (likely(poll->head)) {
+ spin_lock(&poll->head->lock);
+ if (unlikely(list_empty(&poll->wait.entry))) {
+ if (ipt.error)
+ cancel = true;
+ ipt.error = 0;
+ mask = 0;
+ }
+ if (mask || ipt.error)
+ list_del_init(&poll->wait.entry);
+ else if (cancel)
+ WRITE_ONCE(poll->canceled, true);
+ else if (!poll->done) /* actually waiting for an event */
+ list_add_tail(&req->list, &ctx->cancel_list);
+ spin_unlock(&poll->head->lock);
}
- spin_unlock(&poll->head->lock);
+ if (mask) { /* no async, we'd stolen it */
+ req->error = mangle_poll(mask);
+ ipt.error = 0;
+ io_poll_complete(ctx, req, mask);
+ }
spin_unlock_irq(&ctx->completion_lock);
-out:
- if (unlikely(ipt.error)) {
- if (!(flags & IOSQE_FIXED_FILE))
- fput(poll->file);
- /*
- * Drop one of our refs to this req, __io_submit_sqe() will
- * drop the other one since we're returning an error.
- */
- io_free_req(req);
- return ipt.error;
+ if (mask) {
+ io_cqring_ev_posted(ctx);
+ io_put_req(req);
}
-
- if (mask)
- io_poll_complete(req, mask);
- io_free_req(req);
- return 0;
+ return ipt.error;
}
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)
{
- ssize_t ret;
- int opcode;
+ int ret, opcode;
if (unlikely(s->index >= ctx->sq_entries))
return -EINVAL;
@@ -1524,10 +1456,13 @@
break;
cond_resched();
} while (1);
+
+ /* drop submission reference */
+ io_put_req(req);
}
if (ret) {
io_cqring_add_event(ctx, sqe->user_data, ret, 0);
- io_free_req(req);
+ io_put_req(req);
}
/* async context always use a copy of the sqe */
@@ -1614,11 +1549,55 @@
return ret;
}
+static bool io_op_needs_file(const struct io_uring_sqe *sqe)
+{
+ int op = READ_ONCE(sqe->opcode);
+
+ switch (op) {
+ case IORING_OP_NOP:
+ case IORING_OP_POLL_REMOVE:
+ return false;
+ default:
+ return true;
+ }
+}
+
+static int io_req_set_file(struct io_ring_ctx *ctx, const struct sqe_submit *s,
+ struct io_submit_state *state, struct io_kiocb *req)
+{
+ unsigned flags;
+ int fd;
+
+ flags = READ_ONCE(s->sqe->flags);
+ fd = READ_ONCE(s->sqe->fd);
+
+ if (!io_op_needs_file(s->sqe)) {
+ req->file = NULL;
+ return 0;
+ }
+
+ if (flags & IOSQE_FIXED_FILE) {
+ if (unlikely(!ctx->user_files ||
+ (unsigned) fd >= ctx->nr_user_files))
+ return -EBADF;
+ req->file = ctx->user_files[fd];
+ req->flags |= REQ_F_FIXED_FILE;
+ } else {
+ if (s->needs_fixed_file)
+ return -EBADF;
+ req->file = io_file_get(state, fd);
+ if (unlikely(!req->file))
+ return -EBADF;
+ }
+
+ return 0;
+}
+
static int io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s,
struct io_submit_state *state)
{
struct io_kiocb *req;
- ssize_t ret;
+ int ret;
/* enforce forwards compatibility on users */
if (unlikely(s->sqe->flags & ~IOSQE_FIXED_FILE))
@@ -1628,7 +1607,9 @@
if (unlikely(!req))
return -EAGAIN;
- req->rw.ki_filp = NULL;
+ ret = io_req_set_file(ctx, s, state, req);
+ if (unlikely(ret))
+ goto out;
ret = __io_submit_sqe(ctx, req, s, true, state);
if (ret == -EAGAIN) {
@@ -1649,11 +1630,23 @@
INIT_WORK(&req->work, io_sq_wq_submit_work);
queue_work(ctx->sqo_wq, &req->work);
}
- ret = 0;
+
+ /*
+ * Queued up for async execution, worker will release
+ * submit reference when the iocb is actually
+ * submitted.
+ */
+ return 0;
}
}
+
+out:
+ /* drop submission reference */
+ io_put_req(req);
+
+ /* and drop final reference, if we failed */
if (ret)
- io_free_req(req);
+ io_put_req(req);
return ret;
}
diff --git a/fs/iomap.c b/fs/iomap.c
index 97cb9d4..abdd18e 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -1589,12 +1589,14 @@
if (should_dirty) {
bio_check_pages_dirty(bio);
} else {
- struct bio_vec *bvec;
- int i;
- struct bvec_iter_all iter_all;
+ if (!bio_flagged(bio, BIO_NO_PAGE_REF)) {
+ struct bvec_iter_all iter_all;
+ struct bio_vec *bvec;
+ int i;
- bio_for_each_segment_all(bvec, bio, i, iter_all)
- put_page(bvec->bv_page);
+ bio_for_each_segment_all(bvec, bio, i, iter_all)
+ put_page(bvec->bv_page);
+ }
bio_put(bio);
}
}
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index d66bf5f..791fee3 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -215,6 +215,7 @@
/*
* 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 */
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 87477e1..f184af1 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -23,14 +23,23 @@
};
enum iter_type {
- ITER_IOVEC = 0,
- ITER_KVEC = 2,
- ITER_BVEC = 4,
- ITER_PIPE = 8,
- ITER_DISCARD = 16,
+ /* set if ITER_BVEC doesn't hold a bv_page ref */
+ ITER_BVEC_FLAG_NO_REF = 2,
+
+ /* iter types */
+ ITER_IOVEC = 4,
+ ITER_KVEC = 8,
+ ITER_BVEC = 16,
+ ITER_PIPE = 32,
+ ITER_DISCARD = 64,
};
struct iov_iter {
+ /*
+ * Bit 0 is the read/write bit, set if we're writing.
+ * Bit 1 is the BVEC_FLAG_NO_REF bit, set if type is a bvec and
+ * the caller isn't expecting to drop a page reference when done.
+ */
unsigned int type;
size_t iov_offset;
size_t count;
@@ -84,6 +93,11 @@
return i->type & (READ | WRITE);
}
+static inline bool iov_iter_bvec_no_ref(const struct iov_iter *i)
+{
+ return (i->type & ITER_BVEC_FLAG_NO_REF) != 0;
+}
+
/*
* Total number of bytes covered by an iovec.
*
