bcachefs: do_encrypt() now handles allocation failures

convert to darray, and add a fallback when allocation fails

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/checksum.c b/fs/bcachefs/checksum.c
index e7208bf1974e562616a3ee5a2a747f4da8389e27..6e6cc1d04b1c6ccee4720560f61ff3cf59a16961 100644 (file)
--- a/fs/bcachefs/checksum.c
+++ b/fs/bcachefs/checksum.c
@@ -100,13 +100,12 @@ static inline int do_encrypt_sg(struct crypto_sync_skcipher *tfm,
                                struct scatterlist *sg, size_t len)
 {
        SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm);
-       int ret;
 
        skcipher_request_set_sync_tfm(req, tfm);
        skcipher_request_set_callback(req, 0, NULL, NULL);
        skcipher_request_set_crypt(req, sg, sg, len, nonce.d);
 
-       ret = crypto_skcipher_encrypt(req);
+       int ret = crypto_skcipher_encrypt(req);
        if (ret)
                pr_err("got error %i from crypto_skcipher_encrypt()", ret);
 
@@ -128,28 +127,41 @@ static inline int do_encrypt(struct crypto_sync_skcipher *tfm,
                            len, offset_in_page(buf));
                return do_encrypt_sg(tfm, nonce, &sg, len);
        } else {
-               unsigned pages = buf_pages(buf, len);
-               struct scatterlist *sg;
-               size_t orig_len = len;
-               int ret, i;
-
-               sg = kmalloc_array(pages, sizeof(*sg), GFP_KERNEL);
-               if (!sg)
-                       return -BCH_ERR_ENOMEM_do_encrypt;
+               DARRAY_PREALLOCATED(struct scatterlist, 4) sgl;
+               size_t sgl_len = 0;
+               int ret;
 
-               sg_init_table(sg, pages);
+               darray_init(&sgl);
 
-               for (i = 0; i < pages; i++) {
+               while (len) {
                        unsigned offset = offset_in_page(buf);
-                       unsigned pg_len = min_t(size_t, len, PAGE_SIZE - offset);
+                       struct scatterlist sg = {
+                               .page_link      = (unsigned long) vmalloc_to_page(buf),
+                               .offset         = offset,
+                               .length         = min(len, PAGE_SIZE - offset),
+                       };
 
-                       sg_set_page(sg + i, vmalloc_to_page(buf), pg_len, offset);
-                       buf += pg_len;
-                       len -= pg_len;
+                       if (darray_push(&sgl, sg)) {
+                               sg_mark_end(&darray_last(sgl));
+                               ret = do_encrypt_sg(tfm, nonce, sgl.data, sgl_len);
+                               if (ret)
+                                       goto err;
+
+                               nonce = nonce_add(nonce, sgl_len);
+                               sgl_len = 0;
+                               sgl.nr = 0;
+                               BUG_ON(darray_push(&sgl, sg));
+                       }
+
+                       buf += sg.length;
+                       len -= sg.length;
+                       sgl_len += sg.length;
                }
 
-               ret = do_encrypt_sg(tfm, nonce, sg, orig_len);
-               kfree(sg);
+               sg_mark_end(&darray_last(sgl));
+               ret = do_encrypt_sg(tfm, nonce, sgl.data, sgl_len);
+err:
+               darray_exit(&sgl);
                return ret;
        }
 }