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authorJens Axboe <axboe@kernel.dk>2023-10-02 18:25:23 -0600
committerJens Axboe <axboe@kernel.dk>2023-10-02 18:25:23 -0600
commit922a2c78f13611e2c08fc48f615c0cd367dcb6da (patch)
treedbbc6aada738d873a49ef7c97b24deefc35021aa /io_uring
parent93b8cc60c37b9d17732b7a297e5dca29b50a990d (diff)
downloadlwn-922a2c78f13611e2c08fc48f615c0cd367dcb6da.tar.gz
lwn-922a2c78f13611e2c08fc48f615c0cd367dcb6da.zip
io_uring/rsrc: cleanup io_pin_pages()
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@kernel.dk>
Diffstat (limited to 'io_uring')
-rw-r--r--io_uring/rsrc.c37
1 files changed, 17 insertions, 20 deletions
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,