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); + 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; -- 1.5.6.5 -- 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
