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Diffstat (limited to 'io_uring/kbuf.c')
-rw-r--r--io_uring/kbuf.c160
1 files changed, 124 insertions, 36 deletions
diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c
index a90c820ce99e..2f0181521c98 100644
--- a/io_uring/kbuf.c
+++ b/io_uring/kbuf.c
@@ -137,7 +137,8 @@ static void __user *io_ring_buffer_select(struct io_kiocb *req, size_t *len,
return NULL;
head &= bl->mask;
- if (head < IO_BUFFER_LIST_BUF_PER_PAGE) {
+ /* mmaped buffers are always contig */
+ if (bl->is_mmap || head < IO_BUFFER_LIST_BUF_PER_PAGE) {
buf = &br->bufs[head];
} else {
int off = head & (IO_BUFFER_LIST_BUF_PER_PAGE - 1);
@@ -179,7 +180,7 @@ void __user *io_buffer_select(struct io_kiocb *req, size_t *len,
bl = io_buffer_get_list(ctx, req->buf_index);
if (likely(bl)) {
- if (bl->buf_nr_pages)
+ if (bl->is_mapped)
ret = io_ring_buffer_select(req, len, bl, issue_flags);
else
ret = io_provided_buffer_select(req, len, bl);
@@ -214,17 +215,28 @@ static int __io_remove_buffers(struct io_ring_ctx *ctx,
if (!nbufs)
return 0;
- if (bl->buf_nr_pages) {
- int j;
-
+ if (bl->is_mapped) {
i = bl->buf_ring->tail - bl->head;
- for (j = 0; j < bl->buf_nr_pages; j++)
- unpin_user_page(bl->buf_pages[j]);
- kvfree(bl->buf_pages);
- bl->buf_pages = NULL;
- bl->buf_nr_pages = 0;
+ if (bl->is_mmap) {
+ struct page *page;
+
+ page = virt_to_head_page(bl->buf_ring);
+ if (put_page_testzero(page))
+ free_compound_page(page);
+ bl->buf_ring = NULL;
+ bl->is_mmap = 0;
+ } else if (bl->buf_nr_pages) {
+ int j;
+
+ for (j = 0; j < bl->buf_nr_pages; j++)
+ unpin_user_page(bl->buf_pages[j]);
+ kvfree(bl->buf_pages);
+ bl->buf_pages = NULL;
+ bl->buf_nr_pages = 0;
+ }
/* make sure it's seen as empty */
INIT_LIST_HEAD(&bl->buf_list);
+ bl->is_mapped = 0;
return i;
}
@@ -304,7 +316,7 @@ int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags)
if (bl) {
ret = -EINVAL;
/* can't use provide/remove buffers command on mapped buffers */
- if (!bl->buf_nr_pages)
+ if (!bl->is_mapped)
ret = __io_remove_buffers(ctx, bl, p->nbufs);
}
io_ring_submit_unlock(ctx, issue_flags);
@@ -449,7 +461,7 @@ int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags)
}
}
/* can't add buffers via this command for a mapped buffer ring */
- if (bl->buf_nr_pages) {
+ if (bl->is_mapped) {
ret = -EINVAL;
goto err;
}
@@ -464,23 +476,87 @@ err:
return IOU_OK;
}
-int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
+static int io_pin_pbuf_ring(struct io_uring_buf_reg *reg,
+ struct io_buffer_list *bl)
{
struct io_uring_buf_ring *br;
- struct io_uring_buf_reg reg;
- struct io_buffer_list *bl, *free_bl = NULL;
struct page **pages;
int nr_pages;
+ pages = io_pin_pages(reg->ring_addr,
+ flex_array_size(br, bufs, reg->ring_entries),
+ &nr_pages);
+ if (IS_ERR(pages))
+ return PTR_ERR(pages);
+
+ br = page_address(pages[0]);
+#ifdef SHM_COLOUR
+ /*
+ * On platforms that have specific aliasing requirements, SHM_COLOUR
+ * is set and we must guarantee that the kernel and user side align
+ * nicely. We cannot do that if IOU_PBUF_RING_MMAP isn't set and
+ * the application mmap's the provided ring buffer. Fail the request
+ * if we, by chance, don't end up with aligned addresses. The app
+ * should use IOU_PBUF_RING_MMAP instead, and liburing will handle
+ * this transparently.
+ */
+ if ((reg->ring_addr | (unsigned long) br) & (SHM_COLOUR - 1)) {
+ int i;
+
+ for (i = 0; i < nr_pages; i++)
+ unpin_user_page(pages[i]);
+ return -EINVAL;
+ }
+#endif
+ bl->buf_pages = pages;
+ bl->buf_nr_pages = nr_pages;
+ bl->buf_ring = br;
+ bl->is_mapped = 1;
+ bl->is_mmap = 0;
+ return 0;
+}
+
+static int io_alloc_pbuf_ring(struct io_uring_buf_reg *reg,
+ struct io_buffer_list *bl)
+{
+ gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP;
+ size_t ring_size;
+ void *ptr;
+
+ ring_size = reg->ring_entries * sizeof(struct io_uring_buf_ring);
+ ptr = (void *) __get_free_pages(gfp, get_order(ring_size));
+ if (!ptr)
+ return -ENOMEM;
+
+ bl->buf_ring = ptr;
+ bl->is_mapped = 1;
+ bl->is_mmap = 1;
+ return 0;
+}
+
+int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
+{
+ struct io_uring_buf_reg reg;
+ struct io_buffer_list *bl, *free_bl = NULL;
+ int ret;
+
if (copy_from_user(&reg, arg, sizeof(reg)))
return -EFAULT;
- if (reg.pad || reg.resv[0] || reg.resv[1] || reg.resv[2])
+ if (reg.resv[0] || reg.resv[1] || reg.resv[2])
return -EINVAL;
- if (!reg.ring_addr)
- return -EFAULT;
- if (reg.ring_addr & ~PAGE_MASK)
+ if (reg.flags & ~IOU_PBUF_RING_MMAP)
return -EINVAL;
+ if (!(reg.flags & IOU_PBUF_RING_MMAP)) {
+ if (!reg.ring_addr)
+ return -EFAULT;
+ if (reg.ring_addr & ~PAGE_MASK)
+ return -EINVAL;
+ } else {
+ if (reg.ring_addr)
+ return -EINVAL;
+ }
+
if (!is_power_of_2(reg.ring_entries))
return -EINVAL;
@@ -497,7 +573,7 @@ int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
bl = io_buffer_get_list(ctx, reg.bgid);
if (bl) {
/* if mapped buffer ring OR classic exists, don't allow */
- if (bl->buf_nr_pages || !list_empty(&bl->buf_list))
+ if (bl->is_mapped || !list_empty(&bl->buf_list))
return -EEXIST;
} else {
free_bl = bl = kzalloc(sizeof(*bl), GFP_KERNEL);
@@ -505,22 +581,21 @@ int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
return -ENOMEM;
}
- pages = io_pin_pages(reg.ring_addr,
- flex_array_size(br, bufs, reg.ring_entries),
- &nr_pages);
- if (IS_ERR(pages)) {
- kfree(free_bl);
- return PTR_ERR(pages);
+ if (!(reg.flags & IOU_PBUF_RING_MMAP))
+ ret = io_pin_pbuf_ring(&reg, bl);
+ else
+ ret = io_alloc_pbuf_ring(&reg, bl);
+
+ if (!ret) {
+ bl->nr_entries = reg.ring_entries;
+ bl->mask = reg.ring_entries - 1;
+
+ io_buffer_add_list(ctx, bl, reg.bgid);
+ return 0;
}
- br = page_address(pages[0]);
- bl->buf_pages = pages;
- bl->buf_nr_pages = nr_pages;
- bl->nr_entries = reg.ring_entries;
- bl->buf_ring = br;
- bl->mask = reg.ring_entries - 1;
- io_buffer_add_list(ctx, bl, reg.bgid);
- return 0;
+ kfree(free_bl);
+ return ret;
}
int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
@@ -530,13 +605,15 @@ int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
if (copy_from_user(&reg, arg, sizeof(reg)))
return -EFAULT;
- if (reg.pad || reg.resv[0] || reg.resv[1] || reg.resv[2])
+ if (reg.resv[0] || reg.resv[1] || reg.resv[2])
+ return -EINVAL;
+ if (reg.flags)
return -EINVAL;
bl = io_buffer_get_list(ctx, reg.bgid);
if (!bl)
return -ENOENT;
- if (!bl->buf_nr_pages)
+ if (!bl->is_mapped)
return -EINVAL;
__io_remove_buffers(ctx, bl, -1U);
@@ -546,3 +623,14 @@ int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
}
return 0;
}
+
+void *io_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid)
+{
+ struct io_buffer_list *bl;
+
+ bl = io_buffer_get_list(ctx, bgid);
+ if (!bl || !bl->is_mmap)
+ return NULL;
+
+ return bl->buf_ring;
+}
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-01 02:36:53 +0300