From: Hou Tao <houtao1@xxxxxxxxxx> Hi, The patch set aims to fix the warning related to an abnormal size parameter of kmalloc() in virtiofs. Patch #1 fixes it by introducing use_pages_for_kvec_io option in fuse_conn and enabling it in virtiofs. Beside the abnormal size parameter for kmalloc, the gfp parameter is also questionable: GFP_ATOMIC is used even when the allocation occurs in a kworker context. Patch #2 fixes it by using GFP_NOFS when the allocation is initiated by the kworker. For more details, please check the individual patches. As usual, comments are always welcome. Change Log: v3: * introduce use_pages_for_kvec_io for virtiofs. When the option is enabled, fuse will use iov_iter_extract_pages() to construct a page array and pass the pages array instead of a pointer to virtiofs. The benefit is twofold: the length of the data passed to virtiofs is limited by max_pages, and there is no memory copy compared with v2. v2: https://lore.kernel.org/linux-fsdevel/20240228144126.2864064-1-houtao@xxxxxxxxxxxxxxx/ * limit the length of ITER_KVEC dio by max_pages instead of the newly-introduced max_nopage_rw. Using max_pages make the ITER_KVEC dio being consistent with other rw operations. * replace kmalloc-allocated bounce buffer by using a bounce buffer backed by scattered pages when the length of the bounce buffer for KVEC_ITER dio is larger than PAG_SIZE, so even on hosts with fragmented memory, the KVEC_ITER dio can be handled normally by virtiofs. (Bernd Schubert) * merge the GFP_NOFS patch [1] into this patch-set and use memalloc_nofs_{save|restore}+GFP_KERNEL instead of GFP_NOFS (Benjamin Coddington) v1: https://lore.kernel.org/linux-fsdevel/20240103105929.1902658-1-houtao@xxxxxxxxxxxxxxx/ [1]: https://lore.kernel.org/linux-fsdevel/20240105105305.4052672-1-houtao@xxxxxxxxxxxxxxx/ Hou Tao (2): virtiofs: use pages instead of pointer for kernel direct IO virtiofs: use GFP_NOFS when enqueuing request through kworker fs/fuse/file.c | 12 ++++++++---- fs/fuse/fuse_i.h | 3 +++ fs/fuse/virtio_fs.c | 25 ++++++++++++++++--------- 3 files changed, 27 insertions(+), 13 deletions(-) -- 2.29.2
