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Date: Thu, 11 Jul 2019 04:07:31 +0300
From: "Pavel Begunkov (Silence)" <asml.silence@...il.com>
To: Jens Axboe <axboe@...nel.dk>, linux-block@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Pavel Begunkov <asml.silence@...il.com>
Subject: [RFC][PATCH] io_uring: Incapsulate conditional mem accounting
From: Pavel Begunkov <asml.silence@...il.com>
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@...il.com>
---
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;
--
2.22.0
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