cifs: allocate kvec array for cifs_readdata as a separate allocation

Eventually, we're going to want to append a list of pages to
cifs_readdata instead of a list of kvecs. To prepare for that, turn
the kvec array allocation into a separate one and just keep a
pointer to it in the readdata.

Signed-off-by: Jeff Layton <jlayton@redhat.com>

2 files changed, 13 insertions, 4 deletions

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index cc70ac0bac47..737289b50ca5 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -982,7 +982,7 @@ struct cifs_readdata {
         int (*marshal_iov) (struct cifs_readdata *rdata,
                             unsigned int remaining);
         unsigned int                    nr_iov;
-        struct kvec                     iov[1];
+        struct kvec                     *iov;
 };
 
 struct cifs_writedata;
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 8a781226ae33..61b7c834069f 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2410,19 +2410,27 @@ ssize_t cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov,
 }
 
 static struct cifs_readdata *
-cifs_readdata_alloc(unsigned int nr_vecs, work_func_t complete)
+cifs_readdata_alloc(unsigned int nr_pages, work_func_t complete)
 {
         struct cifs_readdata *rdata;
+        struct kvec *iov;
 
-        rdata = kzalloc(sizeof(*rdata) +
-                        sizeof(struct kvec) * nr_vecs, GFP_KERNEL);
+        iov = kzalloc(sizeof(*iov) * (nr_pages + 1), GFP_KERNEL);
+        if (!iov)
+                return (struct cifs_readdata *)iov;
+
+        rdata = kzalloc(sizeof(*rdata), GFP_KERNEL);
         if (rdata != NULL) {
                 kref_init(&rdata->refcount);
                 INIT_LIST_HEAD(&rdata->list);
                 init_completion(&rdata->done);
                 INIT_WORK(&rdata->work, complete);
                 INIT_LIST_HEAD(&rdata->pages);
+                rdata->iov = iov;
+        } else {
+                kfree(iov);
         }
+
         return rdata;
 }
 
@@ -2435,6 +2443,7 @@ cifs_readdata_release(struct kref *refcount)
         if (rdata->cfile)
                 cifsFileInfo_put(rdata->cfile);
 
+        kfree(rdata->iov);
         kfree(rdata);
 }