ping
On 11/07/2019 04:07, Pavel Begunkov (Silence) wrote:
> From: Pavel Begunkov <asml.silence@xxxxxxxxx>
>
> It's quite tedious and error-prone to manually check before each call
> to io_{,un}account_mem() whether we need memory accounting. Instead,
> the functions can work directly with struct io_ring_ctx and handle
> checks themselves. In any case, they're perfectly inlined.
>
> Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
> ---
> fs/io_uring.c | 59 ++++++++++++++++++++++-----------------------------
> 1 file changed, 25 insertions(+), 34 deletions(-)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index 3fd884b4e0be..f47f7abe19eb 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -2704,14 +2704,19 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx,
> return ret;
> }
>
> -static void io_unaccount_mem(struct user_struct *user, unsigned long nr_pages)
> +static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
> {
> - atomic_long_sub(nr_pages, &user->locked_vm);
> + if (ctx->account_mem)
> + atomic_long_sub(nr_pages, &ctx->user->locked_vm);
> }
>
> -static int io_account_mem(struct user_struct *user, unsigned long nr_pages)
> +static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
> {
> unsigned long page_limit, cur_pages, new_pages;
> + struct user_struct *user = ctx->user;
> +
> + if (!ctx->account_mem)
> + return 0;
>
> /* Don't allow more pages than we can safely lock */
> page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
> @@ -2773,8 +2778,7 @@ static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx)
> for (j = 0; j < imu->nr_bvecs; j++)
> put_page(imu->bvec[j].bv_page);
>
> - if (ctx->account_mem)
> - io_unaccount_mem(ctx->user, imu->nr_bvecs);
> + io_unaccount_mem(ctx, imu->nr_bvecs);
> kvfree(imu->bvec);
> imu->nr_bvecs = 0;
> }
> @@ -2857,11 +2861,9 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
> start = ubuf >> PAGE_SHIFT;
> nr_pages = end - start;
>
> - if (ctx->account_mem) {
> - ret = io_account_mem(ctx->user, nr_pages);
> - if (ret)
> - goto err;
> - }
> + ret = io_account_mem(ctx, nr_pages);
> + if (ret)
> + goto err;
>
> ret = 0;
> if (!pages || nr_pages > got_pages) {
> @@ -2874,8 +2876,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
> GFP_KERNEL);
> if (!pages || !vmas) {
> ret = -ENOMEM;
> - if (ctx->account_mem)
> - io_unaccount_mem(ctx->user, nr_pages);
> + io_unaccount_mem(ctx, nr_pages);
> goto err;
> }
> got_pages = nr_pages;
> @@ -2885,8 +2886,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
> GFP_KERNEL);
> ret = -ENOMEM;
> if (!imu->bvec) {
> - if (ctx->account_mem)
> - io_unaccount_mem(ctx->user, nr_pages);
> + io_unaccount_mem(ctx, nr_pages);
> goto err;
> }
>
> @@ -2919,8 +2919,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
> for (j = 0; j < pret; j++)
> put_page(pages[j]);
> }
> - if (ctx->account_mem)
> - io_unaccount_mem(ctx->user, nr_pages);
> + io_unaccount_mem(ctx, nr_pages);
> kvfree(imu->bvec);
> goto err;
> }
> @@ -3009,9 +3008,7 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx)
> io_mem_free(ctx->cq_ring);
>
> percpu_ref_exit(&ctx->refs);
> - if (ctx->account_mem)
> - io_unaccount_mem(ctx->user,
> - ring_pages(ctx->sq_entries, ctx->cq_entries));
> + io_unaccount_mem(ctx, ring_pages(ctx->sq_entries, ctx->cq_entries));
> free_uid(ctx->user);
> kfree(ctx);
> }
> @@ -3253,7 +3250,6 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p)
> {
> struct user_struct *user = NULL;
> struct io_ring_ctx *ctx;
> - bool account_mem;
> int ret;
>
> if (!entries || entries > IORING_MAX_ENTRIES)
> @@ -3269,29 +3265,24 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p)
> p->cq_entries = 2 * p->sq_entries;
>
> user = get_uid(current_user());
> - account_mem = !capable(CAP_IPC_LOCK);
> -
> - if (account_mem) {
> - ret = io_account_mem(user,
> - ring_pages(p->sq_entries, p->cq_entries));
> - if (ret) {
> - free_uid(user);
> - return ret;
> - }
> - }
>
> ctx = io_ring_ctx_alloc(p);
> if (!ctx) {
> - if (account_mem)
> - io_unaccount_mem(user, ring_pages(p->sq_entries,
> - p->cq_entries));
> free_uid(user);
> return -ENOMEM;
> }
> +
> ctx->compat = in_compat_syscall();
> - ctx->account_mem = account_mem;
> + ctx->account_mem = !capable(CAP_IPC_LOCK);
> ctx->user = user;
>
> + ret = io_account_mem(ctx, ring_pages(p->sq_entries, p->cq_entries));
> + if (ret) {
> + free_uid(user);
> + kfree(ctx);
> + return ret;
> + }
> +
> ret = io_allocate_scq_urings(ctx, p);
> if (ret)
> goto err;
>
--
Yours sincerely,
Pavel Begunkov
Attachment:
signature.asc
Description: OpenPGP digital signature
