On Fri, Jan 05, 2024 at 06:53:05PM +0800, Hou Tao wrote: > From: Hou Tao <houtao1@xxxxxxxxxx> > > When invoking virtio_fs_enqueue_req() through kworker, both the > allocation of the sg array and the bounce buffer still use GFP_ATOMIC. > Considering the size of both the sg array and the bounce buffer may be > greater than PAGE_SIZE, use GFP_NOFS instead of GFP_ATOMIC to lower the > possibility of memory allocation failure. > What's the practical benefit of this patch. Looks like if memory allocation fails, we keep retrying at interval of 1ms and don't return error to user space. Thanks Vivek > Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx> > --- > Change log: > v2: > * pass gfp_t instead of bool to virtio_fs_enqueue_req() (Suggested by Matthew) > > v1: https://lore.kernel.org/linux-fsdevel/20240104015805.2103766-1-houtao@xxxxxxxxxxxxxxx > > fs/fuse/virtio_fs.c | 20 +++++++++++--------- > 1 file changed, 11 insertions(+), 9 deletions(-) > > diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c > index 3aac31d451985..8cf518624ce9e 100644 > --- a/fs/fuse/virtio_fs.c > +++ b/fs/fuse/virtio_fs.c > @@ -87,7 +87,8 @@ struct virtio_fs_req_work { > }; > > static int virtio_fs_enqueue_req(struct virtio_fs_vq *fsvq, > - struct fuse_req *req, bool in_flight); > + struct fuse_req *req, bool in_flight, > + gfp_t gfp); > > static const struct constant_table dax_param_enums[] = { > {"always", FUSE_DAX_ALWAYS }, > @@ -383,7 +384,7 @@ static void virtio_fs_request_dispatch_work(struct work_struct *work) > list_del_init(&req->list); > spin_unlock(&fsvq->lock); > > - ret = virtio_fs_enqueue_req(fsvq, req, true); > + ret = virtio_fs_enqueue_req(fsvq, req, true, GFP_NOFS); > if (ret < 0) { > if (ret == -ENOMEM || ret == -ENOSPC) { > spin_lock(&fsvq->lock); > @@ -488,7 +489,7 @@ static void virtio_fs_hiprio_dispatch_work(struct work_struct *work) > } > > /* Allocate and copy args into req->argbuf */ > -static int copy_args_to_argbuf(struct fuse_req *req) > +static int copy_args_to_argbuf(struct fuse_req *req, gfp_t gfp) > { > struct fuse_args *args = req->args; > unsigned int offset = 0; > @@ -502,7 +503,7 @@ static int copy_args_to_argbuf(struct fuse_req *req) > len = fuse_len_args(num_in, (struct fuse_arg *) args->in_args) + > fuse_len_args(num_out, args->out_args); > > - req->argbuf = kmalloc(len, GFP_ATOMIC); > + req->argbuf = kmalloc(len, gfp); > if (!req->argbuf) > return -ENOMEM; > > @@ -1119,7 +1120,8 @@ static unsigned int sg_init_fuse_args(struct scatterlist *sg, > > /* Add a request to a virtqueue and kick the device */ > static int virtio_fs_enqueue_req(struct virtio_fs_vq *fsvq, > - struct fuse_req *req, bool in_flight) > + struct fuse_req *req, bool in_flight, > + gfp_t gfp) > { > /* requests need at least 4 elements */ > struct scatterlist *stack_sgs[6]; > @@ -1140,8 +1142,8 @@ static int virtio_fs_enqueue_req(struct virtio_fs_vq *fsvq, > /* Does the sglist fit on the stack? */ > total_sgs = sg_count_fuse_req(req); > if (total_sgs > ARRAY_SIZE(stack_sgs)) { > - sgs = kmalloc_array(total_sgs, sizeof(sgs[0]), GFP_ATOMIC); > - sg = kmalloc_array(total_sgs, sizeof(sg[0]), GFP_ATOMIC); > + sgs = kmalloc_array(total_sgs, sizeof(sgs[0]), gfp); > + sg = kmalloc_array(total_sgs, sizeof(sg[0]), gfp); > if (!sgs || !sg) { > ret = -ENOMEM; > goto out; > @@ -1149,7 +1151,7 @@ static int virtio_fs_enqueue_req(struct virtio_fs_vq *fsvq, > } > > /* Use a bounce buffer since stack args cannot be mapped */ > - ret = copy_args_to_argbuf(req); > + ret = copy_args_to_argbuf(req, gfp); > if (ret < 0) > goto out; > > @@ -1245,7 +1247,7 @@ __releases(fiq->lock) > fuse_len_args(req->args->out_numargs, req->args->out_args)); > > fsvq = &fs->vqs[queue_id]; > - ret = virtio_fs_enqueue_req(fsvq, req, false); > + ret = virtio_fs_enqueue_req(fsvq, req, false, GFP_ATOMIC); > if (ret < 0) { > if (ret == -ENOMEM || ret == -ENOSPC) { > /* > -- > 2.29.2 >
