io_uring/zcrx: add user_struct and mm_struct to io_zcrx_ifq

In preparation for removing ifq->ctx and making ifq lifetime independent
of ring ctx, add user_struct and mm_struct to io_zcrx_ifq.

In the ifq cleanup path, these are the only fields used from the main
ring ctx to do accounting. Taking a copy in the ifq allows ifq->ctx to
be removed later, including the ctx->refs held by the ifq.

Signed-off-by: David Wei <dw@davidwei.uk>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c
index 5c90404283ff9ce50730dfc2e54efcd9c0a0fcb8..774efbce8cb6b8e104c5a8085ab50289ae81403a 100644 (file)
--- a/io_uring/zcrx.c
+++ b/io_uring/zcrx.c
@@ -200,7 +200,7 @@ static int io_import_umem(struct io_zcrx_ifq *ifq,
        }
 
        mem->account_pages = io_count_account_pages(pages, nr_pages);
-       ret = io_account_mem(ifq->ctx->user, ifq->ctx->mm_account, mem->account_pages);
+       ret = io_account_mem(ifq->user, ifq->mm_account, mem->account_pages);
        if (ret < 0)
                mem->account_pages = 0;
 
@@ -344,7 +344,8 @@ static void io_zcrx_get_niov_uref(struct net_iov *niov)
        atomic_inc(io_get_user_counter(niov));
 }
 
-static int io_allocate_rbuf_ring(struct io_zcrx_ifq *ifq,
+static int io_allocate_rbuf_ring(struct io_ring_ctx *ctx,
+                                struct io_zcrx_ifq *ifq,
                                 struct io_uring_zcrx_ifq_reg *reg,
                                 struct io_uring_region_desc *rd,
                                 u32 id)
@@ -362,7 +363,7 @@ static int io_allocate_rbuf_ring(struct io_zcrx_ifq *ifq,
        mmap_offset = IORING_MAP_OFF_ZCRX_REGION;
        mmap_offset += id << IORING_OFF_PBUF_SHIFT;
 
-       ret = io_create_region(ifq->ctx, &ifq->region, rd, mmap_offset);
+       ret = io_create_region(ctx, &ifq->region, rd, mmap_offset);
        if (ret < 0)
                return ret;
 
@@ -378,7 +379,7 @@ static int io_allocate_rbuf_ring(struct io_zcrx_ifq *ifq,
 
 static void io_free_rbuf_ring(struct io_zcrx_ifq *ifq)
 {
-       io_free_region(ifq->ctx->user, &ifq->region);
+       io_free_region(ifq->user, &ifq->region);
        ifq->rq_ring = NULL;
        ifq->rqes = NULL;
 }
@@ -390,7 +391,7 @@ static void io_zcrx_free_area(struct io_zcrx_ifq *ifq,
        io_release_area_mem(&area->mem);
 
        if (area->mem.account_pages)
-               io_unaccount_mem(area->ifq->ctx->user, area->ifq->ctx->mm_account,
+               io_unaccount_mem(ifq->user, ifq->mm_account,
                                 area->mem.account_pages);
 
        kvfree(area->freelist);
@@ -525,6 +526,9 @@ static void io_zcrx_ifq_free(struct io_zcrx_ifq *ifq)
 
        if (ifq->area)
                io_zcrx_free_area(ifq, ifq->area);
+       free_uid(ifq->user);
+       if (ifq->mm_account)
+               mmdrop(ifq->mm_account);
        if (ifq->dev)
                put_device(ifq->dev);
 
@@ -588,6 +592,14 @@ int io_register_zcrx_ifq(struct io_ring_ctx *ctx,
        ifq = io_zcrx_ifq_alloc(ctx);
        if (!ifq)
                return -ENOMEM;
+       if (ctx->user) {
+               get_uid(ctx->user);
+               ifq->user = ctx->user;
+       }
+       if (ctx->mm_account) {
+               mmgrab(ctx->mm_account);
+               ifq->mm_account = ctx->mm_account;
+       }
        ifq->rq_entries = reg.rq_entries;
 
        scoped_guard(mutex, &ctx->mmap_lock) {
@@ -597,7 +609,7 @@ int io_register_zcrx_ifq(struct io_ring_ctx *ctx,
                        goto ifq_free;
        }
 
-       ret = io_allocate_rbuf_ring(ifq, &reg, &rd, id);
+       ret = io_allocate_rbuf_ring(ctx, ifq, &reg, &rd, id);
        if (ret)
                goto err;
 

diff --git a/io_uring/zcrx.h b/io_uring/zcrx.h
index 33ef61503092df4e431eb7a8a5dc5b88beabae81..8d828dc9b0e416f67bbb74eba1dd4068dff2e6c5 100644 (file)
--- a/io_uring/zcrx.h
+++ b/io_uring/zcrx.h
@@ -42,6 +42,8 @@ struct io_zcrx_ifq {
        struct io_ring_ctx              *ctx;
        struct io_zcrx_area             *area;
        unsigned                        niov_shift;
+       struct user_struct              *user;
+       struct mm_struct                *mm_account;
 
        spinlock_t                      rq_lock ____cacheline_aligned_in_smp;
        struct io_uring                 *rq_ring;