This function is overly convoluted with a goto error path, and checks
under the mmap_read_lock() that don't need to be at all. Rearrange it
a bit so the checks and errors fall out naturally, rather than needing
to jump around for it.
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index d9c853d10587..7034be555334 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -1037,39 +1037,36 @@ struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages)
{
unsigned long start, end, nr_pages;
struct page **pages = NULL;
- int pret, ret = -ENOMEM;
+ int ret;
end = (ubuf + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
start = ubuf >> PAGE_SHIFT;
nr_pages = end - start;
+ WARN_ON(!nr_pages);
pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
if (!pages)
- goto done;
+ return ERR_PTR(-ENOMEM);
- ret = 0;
mmap_read_lock(current->mm);
- pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
- pages);
- if (pret == nr_pages)
+ ret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM, pages);
+ mmap_read_unlock(current->mm);
+
+ /* success, mapped all pages */
+ if (ret == nr_pages) {
*npages = nr_pages;
- else
- ret = pret < 0 ? pret : -EFAULT;
+ return pages;
+ }
- mmap_read_unlock(current->mm);
- if (ret) {
+ /* partial map, or didn't map anything */
+ if (ret >= 0) {
/* if we did partial map, release any pages we did get */
- if (pret > 0)
- unpin_user_pages(pages, pret);
- goto done;
- }
- ret = 0;
-done:
- if (ret < 0) {
- kvfree(pages);
- pages = ERR_PTR(ret);
+ if (ret)
+ unpin_user_pages(pages, ret);
+ ret = -EFAULT;
}
- return pages;
+ kvfree(pages);
+ return ERR_PTR(ret);
}
static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
--
Jens Axboe
