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io_uring: add full-fledged dynamic buffers support
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Hook buffers into all rsrc infrastructure, including tagging and
updates.

Suggested-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/119ed51d68a491dae87eb55fb467a47870c86aad.1619356238.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Pavel Begunkov authored and Jens Axboe committed Apr 25, 2021
1 parent bd54b6f commit 634d00d
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Showing 2 changed files with 73 additions and 4 deletions.
76 changes: 72 additions & 4 deletions fs/io_uring.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -8114,8 +8114,8 @@ static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slo

static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
{
/* no updates yet, so not used */
WARN_ON_ONCE(1);
io_buffer_unmap(ctx, &prsrc->buf);
prsrc->buf = NULL;
}

static void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
Expand Down Expand Up @@ -8359,7 +8359,7 @@ static int io_buffer_validate(struct iovec *iov)
}

static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
unsigned int nr_args)
unsigned int nr_args, u64 __user *tags)
{
struct page *last_hpage = NULL;
struct io_rsrc_data *data;
Expand All @@ -8383,6 +8383,12 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
}

for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
u64 tag = 0;

if (tags && copy_from_user(&tag, &tags[i], sizeof(tag))) {
ret = -EFAULT;
break;
}
ret = io_copy_iov(ctx, &iov, arg, i);
if (ret)
break;
Expand All @@ -8394,6 +8400,7 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
&last_hpage);
if (ret)
break;
data->tags[i] = tag;
}

WARN_ON_ONCE(ctx->buf_data);
Expand All @@ -8406,6 +8413,62 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
return ret;
}

static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
struct io_uring_rsrc_update2 *up,
unsigned int nr_args)
{
u64 __user *tags = u64_to_user_ptr(up->tags);
struct iovec iov, __user *iovs = u64_to_user_ptr(up->data);
struct io_mapped_ubuf *imu;
struct page *last_hpage = NULL;
bool needs_switch = false;
__u32 done;
int i, err;

if (!ctx->buf_data)
return -ENXIO;
if (up->offset + nr_args > ctx->nr_user_bufs)
return -EINVAL;

for (done = 0; done < nr_args; done++) {
u64 tag = 0;

err = io_copy_iov(ctx, &iov, iovs, done);
if (err)
break;
if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) {
err = -EFAULT;
break;
}

i = array_index_nospec(up->offset + done, ctx->nr_user_bufs);
imu = ctx->user_bufs[i];
if (imu) {
err = io_queue_rsrc_removal(ctx->buf_data, up->offset + done,
ctx->rsrc_node, imu);
if (err)
break;
ctx->user_bufs[i] = NULL;
needs_switch = true;
}

if (iov.iov_base || iov.iov_len) {
err = io_buffer_validate(&iov);
if (err)
break;
err = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i],
&last_hpage);
if (err)
break;
ctx->buf_data->tags[up->offset + done] = tag;
}
}

if (needs_switch)
io_rsrc_node_switch(ctx, ctx->buf_data);
return done ? done : err;
}

static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg)
{
__s32 __user *fds = arg;
Expand Down Expand Up @@ -9807,6 +9870,8 @@ static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
switch (type) {
case IORING_RSRC_FILE:
return __io_sqe_files_update(ctx, up, nr_args);
case IORING_RSRC_BUFFER:
return __io_sqe_buffers_update(ctx, up, nr_args);
}
return -EINVAL;
}
Expand Down Expand Up @@ -9857,6 +9922,9 @@ static int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
case IORING_RSRC_FILE:
return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),
rr.nr, u64_to_user_ptr(rr.tags));
case IORING_RSRC_BUFFER:
return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data),
rr.nr, u64_to_user_ptr(rr.tags));
}
return -EINVAL;
}
Expand Down Expand Up @@ -9933,7 +10001,7 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,

switch (opcode) {
case IORING_REGISTER_BUFFERS:
ret = io_sqe_buffers_register(ctx, arg, nr_args);
ret = io_sqe_buffers_register(ctx, arg, nr_args, NULL);
break;
case IORING_UNREGISTER_BUFFERS:
ret = -EINVAL;
Expand Down
1 change: 1 addition & 0 deletions include/uapi/linux/io_uring.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -314,6 +314,7 @@ struct io_uring_files_update {

enum {
IORING_RSRC_FILE = 0,
IORING_RSRC_BUFFER = 1,
};

struct io_uring_rsrc_register {
Expand Down

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