Re: [PATCH] crypto: af_alg - add async support to algif_aead

From: Stephan Mueller
Date: Thu Jan 28 2016 - 01:26:15 EST

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Am Mittwoch, 27. Januar 2016, 14:10:31 schrieb Tadeusz Struk:

Hi Tadeusz,

> Following the async change for algif_skcipher
> this patch adds similar async read to algif_aead.
>
> changes in v2:
> - change internal data structures from fixed size arrays, limited to
> RSGL_MAX_ENTRIES, to linked list model with no artificial limitation.

Thank you for the dynamic allocation support, but I do have a question.

> - use sock_kmalloc instead of kmalloc for memory allocation
> - use sock_hold instead of separate atomic ctr to wait for outstanding
> request
>
> Signed-off-by: Tadeusz Struk <tadeusz.struk@xxxxxxxxx>
> ---
> crypto/algif_aead.c | 278
> +++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 248
> insertions(+), 30 deletions(-)
>
> diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
> index 147069c..3fa1a95 100644
> --- a/crypto/algif_aead.c
> +++ b/crypto/algif_aead.c
> @@ -29,15 +29,24 @@ struct aead_sg_list {
> struct scatterlist sg[ALG_MAX_PAGES];
> };
>
> +struct aead_async_rsgl {
> + struct af_alg_sgl sgl;
> + struct list_head list;
> +};
> +
> +struct aead_async_req {
> + struct scatterlist *tsgl;
> + struct aead_async_rsgl first_rsgl;
> + struct list_head list;
> + struct kiocb *iocb;
> + unsigned int tsgls;
> + char iv[];
> +};
> +
> struct aead_ctx {
> struct aead_sg_list tsgl;
> - /*
> - * RSGL_MAX_ENTRIES is an artificial limit where user space at maximum
> - * can cause the kernel to allocate RSGL_MAX_ENTRIES * ALG_MAX_PAGES
> - * pages
> - */
> -#define RSGL_MAX_ENTRIES ALG_MAX_PAGES
> - struct af_alg_sgl rsgl[RSGL_MAX_ENTRIES];
> + struct aead_async_rsgl first_rsgl;
> + struct list_head list;
>
> void *iv;
>
> @@ -75,6 +84,17 @@ static inline bool aead_sufficient_data(struct aead_ctx
> *ctx) return ctx->used >= ctx->aead_assoclen + as;
> }
>
> +static void aead_reset_ctx(struct aead_ctx *ctx)
> +{
> + struct aead_sg_list *sgl = &ctx->tsgl;
> +
> + sg_init_table(sgl->sg, ALG_MAX_PAGES);
> + sgl->cur = 0;
> + ctx->used = 0;
> + ctx->more = 0;
> + ctx->merge = 0;
> +}
> +
> static void aead_put_sgl(struct sock *sk)
> {
> struct alg_sock *ask = alg_sk(sk);
> @@ -90,11 +110,6 @@ static void aead_put_sgl(struct sock *sk)
> put_page(sg_page(sg + i));
> sg_assign_page(sg + i, NULL);
> }
> - sg_init_table(sg, ALG_MAX_PAGES);
> - sgl->cur = 0;
> - ctx->used = 0;
> - ctx->more = 0;
> - ctx->merge = 0;
> }
>
> static void aead_wmem_wakeup(struct sock *sk)
> @@ -240,6 +255,7 @@ static int aead_sendmsg(struct socket *sock, struct
> msghdr *msg, size_t size) if (!aead_writable(sk)) {
> /* user space sent too much data */
> aead_put_sgl(sk);
> + aead_reset_ctx(ctx);
> err = -EMSGSIZE;
> goto unlock;
> }
> @@ -251,6 +267,7 @@ static int aead_sendmsg(struct socket *sock, struct
> msghdr *msg, size_t size)
>
> if (sgl->cur >= ALG_MAX_PAGES) {
> aead_put_sgl(sk);
> + aead_reset_ctx(ctx);
> err = -E2BIG;
> goto unlock;
> }
> @@ -287,6 +304,7 @@ static int aead_sendmsg(struct socket *sock, struct
> msghdr *msg, size_t size) ctx->more = msg->msg_flags & MSG_MORE;
> if (!ctx->more && !aead_sufficient_data(ctx)) {
> aead_put_sgl(sk);
> + aead_reset_ctx(ctx);
> err = -EMSGSIZE;
> }
>
> @@ -322,6 +340,7 @@ static ssize_t aead_sendpage(struct socket *sock, struct
> page *page, if (!aead_writable(sk)) {
> /* user space sent too much data */
> aead_put_sgl(sk);
> + aead_reset_ctx(ctx);
> err = -EMSGSIZE;
> goto unlock;
> }
> @@ -339,6 +358,7 @@ done:
> ctx->more = flags & MSG_MORE;
> if (!ctx->more && !aead_sufficient_data(ctx)) {
> aead_put_sgl(sk);
> + aead_reset_ctx(ctx);
> err = -EMSGSIZE;
> }
>
> @@ -349,23 +369,189 @@ unlock:
> return err ?: size;
> }
>
> -static int aead_recvmsg(struct socket *sock, struct msghdr *msg, size_t
> ignored, int flags) +#define GET_ASYM_REQ(req, tfm) (struct aead_async_req
> *) \
> + ((char *)req + sizeof(struct aead_request) + \
> + crypto_aead_reqsize(tfm))
> +
> + #define GET_REQ_SIZE(tfm) sizeof(struct aead_async_req) + \
> + crypto_aead_reqsize(tfm) + crypto_aead_ivsize(tfm) + \
> + sizeof(struct aead_request)
> +
> +static void aead_async_cb(struct crypto_async_request *_req, int err)
> +{
> + struct sock *sk = _req->data;
> + struct alg_sock *ask = alg_sk(sk);
> + struct aead_ctx *ctx = ask->private;
> + struct crypto_aead *tfm = crypto_aead_reqtfm(&ctx->aead_req);
> + struct aead_request *req = aead_request_cast(_req);
> + struct aead_async_req *areq = GET_ASYM_REQ(req, tfm);
> + struct scatterlist *sg = areq->tsgl;
> + struct aead_async_rsgl *rsgl;
> + struct kiocb *iocb = areq->iocb;
> + unsigned int i, reqlen = GET_REQ_SIZE(tfm);
> +
> + list_for_each_entry(rsgl, &areq->list, list) {
> + af_alg_free_sg(&rsgl->sgl);
> + if (rsgl != &areq->first_rsgl)
> + sock_kfree_s(sk, rsgl, sizeof(*rsgl));
> + }
> +
> + for (i = 0; i < areq->tsgls; i++)
> + put_page(sg_page(sg + i));

Shouldn't here be the same logic as in put_sgl? I.e.

for (i = 0; i < sgl->cur; i++) {
if (!sg_page(sg + i))
continue;

put_page(sg_page(sg + i));
sg_assign_page(sg + i, NULL);
}

> +
> + sock_kfree_s(sk, areq->tsgl, sizeof(*areq->tsgl) * areq->tsgls);
> + sock_kfree_s(sk, req, reqlen);
> + __sock_put(sk);
> + iocb->ki_complete(iocb, err, err);
> +}
> +
> +static int aead_recvmsg_async(struct socket *sock, struct msghdr *msg,
> + int flags)
> +{
> + struct sock *sk = sock->sk;
> + struct alg_sock *ask = alg_sk(sk);
> + struct aead_ctx *ctx = ask->private;
> + struct crypto_aead *tfm = crypto_aead_reqtfm(&ctx->aead_req);
> + struct aead_async_req *areq;
> + struct aead_request *req = NULL;
> + struct aead_sg_list *sgl = &ctx->tsgl;
> + struct aead_async_rsgl *last_rsgl = NULL, *rsgl;
> + unsigned int as = crypto_aead_authsize(tfm);
> + unsigned int i, reqlen = GET_REQ_SIZE(tfm);
> + int err = -ENOMEM;
> + unsigned long used;
> + size_t outlen;
> + size_t usedpages = 0;
> +
> + lock_sock(sk);
> + if (ctx->more) {
> + err = aead_wait_for_data(sk, flags);
> + if (err)
> + goto unlock;
> + }
> +
> + used = ctx->used;
> + outlen = used;
> +
> + if (!aead_sufficient_data(ctx))
> + goto unlock;
> +
> + req = sock_kmalloc(sk, reqlen, GFP_KERNEL);
> + if (unlikely(!req))
> + goto unlock;
> +
> + areq = GET_ASYM_REQ(req, tfm);
> + memset(&areq->first_rsgl, '\0', sizeof(areq->first_rsgl));
> + INIT_LIST_HEAD(&areq->list);
> + areq->iocb = msg->msg_iocb;
> + memcpy(areq->iv, ctx->iv, crypto_aead_ivsize(tfm));
> + aead_request_set_tfm(req, tfm);
> + aead_request_set_ad(req, ctx->aead_assoclen);
> + aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
> + aead_async_cb, sk);
> + used -= ctx->aead_assoclen + (ctx->enc ? as : 0);
> +
> + /* take over all tx sgls from ctx */
> + areq->tsgl = sock_kmalloc(sk, sizeof(*areq->tsgl) * sgl->cur,
> + GFP_KERNEL);
> + if (unlikely(!areq->tsgl))
> + goto free;
> +
> + sg_init_table(areq->tsgl, sgl->cur);
> + for (i = 0; i < sgl->cur; i++)
> + sg_set_page(&areq->tsgl[i], sg_page(&sgl->sg[i]),
> + sgl->sg[i].length, sgl->sg[i].offset);
> +
> + areq->tsgls = sgl->cur;
> +
> + /* create rx sgls */
> + while (iov_iter_count(&msg->msg_iter)) {
> + size_t seglen = min_t(size_t, iov_iter_count(&msg->msg_iter),
> + (outlen - usedpages));
> +
> + if (list_empty(&areq->list))
> + rsgl = &areq->first_rsgl;
> + else {
> + rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
> + if (unlikely(!rsgl)) {
> + err = -ENOMEM;
> + goto free;
> + }
> + }
> + rsgl->sgl.npages = 0;
> + list_add_tail(&rsgl->list, &areq->list);
> +
> + /* make one iovec available as scatterlist */
> + err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
> + if (err < 0)
> + goto free;
> +
> + usedpages += err;
> +
> + /* chain the new scatterlist with previous one */
> + if (last_rsgl)
> + af_alg_link_sg(&last_rsgl->sgl, &rsgl->sgl);
> +
> + last_rsgl = rsgl;
> +
> + /* we do not need more iovecs as we have sufficient memory */
> + if (outlen <= usedpages)
> + break;
> +
> + iov_iter_advance(&msg->msg_iter, err);
> + }
> + err = -EINVAL;
> + /* ensure output buffer is sufficiently large */
> + if (usedpages < outlen)
> + goto free;
> +
> + aead_request_set_crypt(req, areq->tsgl, areq->first_rsgl.sgl.sg, used,
> + areq->iv);
> + err = ctx->enc ? crypto_aead_encrypt(req) : crypto_aead_decrypt(req);
> + if (err) {
> + if (err == -EINPROGRESS) {
> + sock_hold(sk);
> + err = -EIOCBQUEUED;
> + aead_reset_ctx(ctx);
> + goto unlock;
> + } else if (err == -EBADMSG) {
> + aead_put_sgl(sk);
> + aead_reset_ctx(ctx);
> + }
> + goto free;
> + }
> + aead_put_sgl(sk);
> + aead_reset_ctx(ctx);
> +
> +free:
> + list_for_each_entry(rsgl, &areq->list, list) {
> + af_alg_free_sg(&rsgl->sgl);
> + if (rsgl != &areq->first_rsgl)
> + sock_kfree_s(sk, rsgl, sizeof(*rsgl));
> + }
> + if (areq->tsgl)
> + sock_kfree_s(sk, areq->tsgl, sizeof(*areq->tsgl) * areq-
>tsgls);
> + if (req)
> + sock_kfree_s(sk, req, reqlen);
> +unlock:
> + aead_wmem_wakeup(sk);
> + release_sock(sk);
> + return err ? err : outlen;
> +}
> +
> +static int aead_recvmsg_sync(struct socket *sock, struct msghdr *msg, int
> flags) {
> struct sock *sk = sock->sk;
> struct alg_sock *ask = alg_sk(sk);
> struct aead_ctx *ctx = ask->private;
> unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx-
>aead_req));
> struct aead_sg_list *sgl = &ctx->tsgl;
> - unsigned int i = 0;
> + struct aead_async_rsgl *last_rsgl = NULL;
> + struct aead_async_rsgl *rsgl, *tmp;
> int err = -EINVAL;
> unsigned long used = 0;
> size_t outlen = 0;
> size_t usedpages = 0;
> - unsigned int cnt = 0;
> -
> - /* Limit number of IOV blocks to be accessed below */
> - if (msg->msg_iter.nr_segs > RSGL_MAX_ENTRIES)
> - return -ENOMSG;
>
> lock_sock(sk);
>
> @@ -417,21 +603,33 @@ static int aead_recvmsg(struct socket *sock, struct
> msghdr *msg, size_t ignored, size_t seglen = min_t(size_t,
> iov_iter_count(&msg->msg_iter),
> (outlen - usedpages));
>
> + if (list_empty(&ctx->list))
> + rsgl = &ctx->first_rsgl;
> + else {
> + rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
> + if (unlikely(!rsgl)) {
> + err = -ENOMEM;
> + goto unlock;
> + }
> + }
> + rsgl->sgl.npages = 0;
> + list_add_tail(&rsgl->list, &ctx->list);
> +
> /* make one iovec available as scatterlist */
> - err = af_alg_make_sg(&ctx->rsgl[cnt], &msg->msg_iter,
> - seglen);
> + err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
> if (err < 0)
> goto unlock;
> usedpages += err;
> /* chain the new scatterlist with previous one */
> - if (cnt)
> - af_alg_link_sg(&ctx->rsgl[cnt-1], &ctx->rsgl[cnt]);
> + if (last_rsgl)
> + af_alg_link_sg(&last_rsgl->sgl, &rsgl->sgl);
> +
> + last_rsgl = rsgl;
>
> /* we do not need more iovecs as we have sufficient memory */
> if (outlen <= usedpages)
> break;
> iov_iter_advance(&msg->msg_iter, err);
> - cnt++;
> }
>
> err = -EINVAL;
> @@ -440,8 +638,7 @@ static int aead_recvmsg(struct socket *sock, struct
> msghdr *msg, size_t ignored, goto unlock;
>
> sg_mark_end(sgl->sg + sgl->cur - 1);
> -
> - aead_request_set_crypt(&ctx->aead_req, sgl->sg, ctx->rsgl[0].sg,
> + aead_request_set_crypt(&ctx->aead_req, sgl->sg, ctx-
>first_rsgl.sgl.sg,
> used, ctx->iv);
> aead_request_set_ad(&ctx->aead_req, ctx->aead_assoclen);
>
> @@ -452,25 +649,40 @@ static int aead_recvmsg(struct socket *sock, struct
> msghdr *msg, size_t ignored,
>
> if (err) {
> /* EBADMSG implies a valid cipher operation took place */
> - if (err == -EBADMSG)
> + if (err == -EBADMSG) {
> aead_put_sgl(sk);
> + aead_reset_ctx(ctx);
> + }
> goto unlock;
> }
>
> aead_put_sgl(sk);
> + aead_reset_ctx(ctx);
>
> err = 0;
>
> unlock:
> - for (i = 0; i < cnt; i++)
> - af_alg_free_sg(&ctx->rsgl[i]);
> -
> + list_for_each_entry_safe(rsgl, tmp, &ctx->list, list) {
> + af_alg_free_sg(&rsgl->sgl);
> + if (rsgl != &ctx->first_rsgl)
> + sock_kfree_s(sk, rsgl, sizeof(*rsgl));
> + list_del(&rsgl->list);
> + }
> + INIT_LIST_HEAD(&ctx->list);
> aead_wmem_wakeup(sk);
> release_sock(sk);
>
> return err ? err : outlen;
> }
>
> +static int aead_recvmsg(struct socket *sock, struct msghdr *msg, size_t
> ignored, + int flags)
> +{
> + return (msg->msg_iocb && !is_sync_kiocb(msg->msg_iocb)) ?
> + aead_recvmsg_async(sock, msg, flags) :
> + aead_recvmsg_sync(sock, msg, flags);
> +}
> +
> static unsigned int aead_poll(struct file *file, struct socket *sock,
> poll_table *wait)
> {
> @@ -539,7 +751,12 @@ static void aead_sock_destruct(struct sock *sk)
> struct aead_ctx *ctx = ask->private;
> unsigned int ivlen = crypto_aead_ivsize(
> crypto_aead_reqtfm(&ctx->aead_req));
> + int ctr = 0;
> +
> + while (atomic_read(&sk->sk_refcnt) != 0 && ctr++ < 10)
> + msleep(100);
>
> + WARN_ON(atomic_read(&sk->sk_refcnt) != 0);
> aead_put_sgl(sk);
> sock_kzfree_s(sk, ctx->iv, ivlen);
> sock_kfree_s(sk, ctx, ctx->len);
> @@ -574,6 +791,7 @@ static int aead_accept_parent(void *private, struct sock
> *sk) ctx->aead_assoclen = 0;
> af_alg_init_completion(&ctx->completion);
> sg_init_table(ctx->tsgl.sg, ALG_MAX_PAGES);
> + INIT_LIST_HEAD(&ctx->list);
>
> ask->private = ctx;

Ciao
Stephan

Next message: Junio C Hamano: "Re: [PULL] virtio: fixes, tests"
Previous message: Minfei Huang: "Re: [PATCH] kexec: unmap reserved pages for each error-return way"
In reply to: Fengguang Wu: "Re: [kbuild-all] [PATCH] crypto: af_alg - add async support to algif_aead"
Next in thread: Tadeusz Struk: "Re: [PATCH] crypto: af_alg - add async support to algif_aead"
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