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. Boaz > + if (!(iov)) { > + printk(KERN_ERR "Unable to allocate fd_do_readv iov[]\n"); > + return -1; > + } > > for (i = 0; i < req->fd_sg_count; i++) { > iov[i].iov_len = sg[i].length; > @@ -492,6 +496,8 @@ static int fd_do_readv(struct fd_request *req, struct se_task *task) > set_fs(get_ds()); > ret = vfs_readv(fd, &iov[0], req->fd_sg_count, &pos); > set_fs(old_fs); > + > + kfree(iov); > /* > * Return zeros and GOOD status even if the READ did not return > * the expected virt_size for struct file w/o a backing struct > @@ -583,12 +589,16 @@ static int fd_do_writev(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, i = 0; > > - memset(iov, 0, sizeof(struct iovec) * req->fd_sg_count); > + iov = kzalloc(sizeof(struct iovec) * req->fd_sg_count, GFP_KERNEL); > + if (!(iov)) { > + printk(KERN_ERR "Unable to allocate fd_do_writev iov[]\n"); > + return -1; > + } > > for (i = 0; i < req->fd_sg_count; i++) { > iov[i].iov_len = sg[i].length; > @@ -600,6 +610,8 @@ static int fd_do_writev(struct fd_request *req, struct se_task *task) > ret = vfs_writev(fd, &iov[0], req->fd_sg_count, &pos); > set_fs(old_fs); > > + kfree(iov); > + > if (ret < 0 || ret != req->fd_size) { > printk(KERN_ERR "vfs_writev() returned %d\n", ret); > return -1; -- 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
