On Wed, 2010-09-22 at 13:26 +0200, Boaz Harrosh wrote: > On 09/22/2010 10:02 AM, Nicholas A. Bellinger wrote: > > From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> > > > > Greetings all, > > > > This patch converts target_core_file.c fd_do_readv() and fd_do_writev() code to > > use dynamic allocation for *iov[] instead of local scope static memory to > > properly handle cases with TCM_Loop that can potentially exceed the 8K stack > > on 64-bit kernels with per 1:1 struct scatterlist <-> 512-byte block_size SGL length > > mapping up to the current FD_MAX_SECTORS=1024. For more information please see: > > > > http://lkml.org/lkml/2010/9/22/42 > > > > Many thanks to Fubo Chen for spotting this one! > > > > Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx> > > --- > > drivers/target/target_core_file.c | 20 ++++++++++++++++---- > > 1 files changed, 16 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c > > index 221b41e..93d3f63 100644 > > --- a/drivers/target/target_core_file.c > > +++ b/drivers/target/target_core_file.c > > @@ -476,12 +476,16 @@ static int fd_do_readv(struct fd_request *req, struct se_task *task) > > { > > struct file *fd = req->fd_dev->fd_file; > > struct scatterlist *sg = task->task_sg; > > - struct iovec iov[req->fd_sg_count]; > > + struct iovec *iov; > > mm_segment_t old_fs; > > loff_t pos = (req->fd_lba * DEV_ATTRIB(task->se_dev)->block_size); > > int ret = 0, i; > > > > - memset(iov, 0, sizeof(struct iovec) * req->fd_sg_count); > > + iov = kzalloc(sizeof(struct iovec) * req->fd_sg_count, GFP_KERNEL); > > A kzalloc allocation bigger then PAG_SIZE is very unstable, more so when > the system is up for a long time. > > Better prepare to loop here, up to PAG_SIZE iov at a time. > Hmmm, good point for the extreme TCM_Loop single 512-byte block per SGL case. Looks like we need to split up the struct iovec mappings for FILEIO into multiple allocations in fd_do_readv() and fd_do_writev()..? Best, --nab -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
