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Message-Id: <1285142558-13219-1-git-send-email-nab@linux-iscsi.org>
Date: Wed, 22 Sep 2010 01:02:38 -0700
From: "Nicholas A. Bellinger" <nab@...ux-iscsi.org>
To: linux-kernel <linux-kernel@...r.kernel.org>,
linux-scsi <linux-scsi@...r.kernel.org>,
Christoph Hellwig <hch@....de>,
FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>,
Mike Christie <michaelc@...wisc.edu>
Cc: Fubo Chen <fubo.chen@...il.com>,
Nicholas Bellinger <nab@...ux-iscsi.org>
Subject: [PATCH] tcm/fileio: Convert to iov allocations for fd_do_readv() and fd_do_writev()
From: Nicholas Bellinger <nab@...ux-iscsi.org>
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@...ux-iscsi.org>
---
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
--
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