ksmbd: keep common response iovecs in the work item

Most SMB responses need no more than four kvec entries, but every work
item currently allocates a separate four-entry array and frees it after
the response is sent.

Embed the common array in struct ksmbd_work and allocate a larger array
only when a response exceeds the inline capacity. This removes one
allocation and one free from the common request path while preserving
support for larger compound and read responses.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/smb/server/ksmbd_work.c b/fs/smb/server/ksmbd_work.c
index a5ab6799a65c50840d622f7fcc02f1a0aec53bcc..e2c2f45264beaf3356a78bd8340772acbde9e6a2 100644 (file)
--- a/fs/smb/server/ksmbd_work.c
+++ b/fs/smb/server/ksmbd_work.c
@@ -16,6 +16,36 @@
 static struct kmem_cache *work_cache;
 static struct workqueue_struct *ksmbd_wq;
 
+static int ksmbd_reserve_iov(struct ksmbd_work *work, int need_iov_cnt)
+{
+       struct kvec *new;
+       int new_alloc_cnt = work->iov_alloc_cnt;
+
+       if (work->iov_alloc_cnt >= work->iov_cnt + need_iov_cnt)
+               return 0;
+
+       do {
+               new_alloc_cnt += KSMBD_WORK_INLINE_IOVS;
+       } while (new_alloc_cnt < work->iov_cnt + need_iov_cnt);
+
+       if (work->iov == work->iov_inline) {
+               new = kcalloc(new_alloc_cnt, sizeof(*new), KSMBD_DEFAULT_GFP);
+               if (!new)
+                       return -ENOMEM;
+
+               memcpy(new, work->iov_inline, sizeof(work->iov_inline));
+       } else {
+               new = krealloc(work->iov, sizeof(*new) * new_alloc_cnt,
+                              KSMBD_DEFAULT_GFP | __GFP_ZERO);
+               if (!new)
+                       return -ENOMEM;
+       }
+
+       work->iov = new;
+       work->iov_alloc_cnt = new_alloc_cnt;
+       return 0;
+}
+
 struct ksmbd_work *ksmbd_alloc_work_struct(void)
 {
        struct ksmbd_work *work = kmem_cache_zalloc(work_cache, KSMBD_DEFAULT_GFP);
@@ -27,13 +57,8 @@ struct ksmbd_work *ksmbd_alloc_work_struct(void)
                INIT_LIST_HEAD(&work->async_request_entry);
                INIT_LIST_HEAD(&work->fp_entry);
                INIT_LIST_HEAD(&work->aux_read_list);
-               work->iov_alloc_cnt = 4;
-               work->iov = kzalloc_objs(struct kvec, work->iov_alloc_cnt,
-                                        KSMBD_DEFAULT_GFP);
-               if (!work->iov) {
-                       kmem_cache_free(work_cache, work);
-                       work = NULL;
-               }
+               work->iov_alloc_cnt = ARRAY_SIZE(work->iov_inline);
+               work->iov = work->iov_inline;
        }
        return work;
 }
@@ -55,7 +80,8 @@ void ksmbd_free_work_struct(struct ksmbd_work *work)
        kfree(work->tr_buf);
        kvfree(work->compress_buf);
        kvfree(work->request_buf);
-       kfree(work->iov);
+       if (work->iov != work->iov_inline)
+               kfree(work->iov);
 
        if (work->async_id)
                ksmbd_release_id(&work->conn->async_ida, work->async_id);
@@ -117,19 +143,9 @@ static int __ksmbd_iov_pin_rsp(struct ksmbd_work *work, void *ib, int len,
                        return -ENOMEM;
        }
 
-       if (work->iov_alloc_cnt < work->iov_cnt + need_iov_cnt) {
-               struct kvec *new;
-
-               work->iov_alloc_cnt += 4;
-               new = krealloc(work->iov,
-                              sizeof(struct kvec) * work->iov_alloc_cnt,
-                              KSMBD_DEFAULT_GFP | __GFP_ZERO);
-               if (!new) {
-                       kfree(ar);
-                       work->iov_alloc_cnt -= 4;
-                       return -ENOMEM;
-               }
-               work->iov = new;
+       if (ksmbd_reserve_iov(work, need_iov_cnt)) {
+               kfree(ar);
+               return -ENOMEM;
        }
 
        /* Plus rfc_length size on first iov */

diff --git a/fs/smb/server/ksmbd_work.h b/fs/smb/server/ksmbd_work.h
index 0da8cc0972d6d5c494fcd212de9d34382d266498..5368430561fb939596e0e86f82c873a25e19b450 100644 (file)
--- a/fs/smb/server/ksmbd_work.h
+++ b/fs/smb/server/ksmbd_work.h
@@ -13,6 +13,8 @@ struct ksmbd_conn;
 struct ksmbd_session;
 struct ksmbd_tree_connect;
 
+#define KSMBD_WORK_INLINE_IOVS 4
+
 enum {
        KSMBD_WORK_ACTIVE = 0,
        KSMBD_WORK_CANCELLED,
@@ -42,6 +44,7 @@ struct ksmbd_work {
        int                             iov_alloc_cnt;
        int                             iov_cnt;
        int                             iov_idx;
+       struct kvec                     iov_inline[KSMBD_WORK_INLINE_IOVS];
 
        /* Next cmd hdr in compound req buf*/
        int                             next_smb2_rcv_hdr_off;