[ 108/173] target/file: Fix 32-bit highmem breakage for SGL -> iovec mapping
From: Ben Hutchings <hidden>
Date: 2012-12-28 19:43:00
Also in:
lkml
3.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
commit 40ff2c3b3da35dd3a00ac6722056a59b4b3f2caf upstream.
This patch changes vectored file I/O to use kmap + kunmap when mapping
incoming SGL memory -> struct iovec in order to properly support 32-bit
highmem configurations. This is because an extra bounce buffer may be
required when processing scatterlist pages allocated with GFP_KERNEL.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Nicholas Bellinger <redacted>
[bwh: Backported to 3.2: use task->task_sg{,_nents} for iteration]
Signed-off-by: Ben Hutchings <redacted>
---
drivers/target/target_core_file.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
--- a/drivers/target/target_core_file.c
+++ b/drivers/target/target_core_file.c@@ -300,7 +300,7 @@ static int fd_do_readv(struct se_task *t for_each_sg(task->task_sg, sg, task->task_sg_nents, i) { iov[i].iov_len = sg->length; - iov[i].iov_base = sg_virt(sg); + iov[i].iov_base = kmap(sg_page(sg)) + sg->offset; } old_fs = get_fs();
@@ -308,6 +308,8 @@ static int fd_do_readv(struct se_task *t ret = vfs_readv(fd, &iov[0], task->task_sg_nents, &pos); set_fs(old_fs); + for_each_sg(task->task_sg, sg, task->task_sg_nents, i) + kunmap(sg_page(sg)); kfree(iov); /* * Return zeros and GOOD status even if the READ did not return
@@ -353,7 +355,7 @@ static int fd_do_writev(struct se_task * for_each_sg(task->task_sg, sg, task->task_sg_nents, i) { iov[i].iov_len = sg->length; - iov[i].iov_base = sg_virt(sg); + iov[i].iov_base = kmap(sg_page(sg)) + sg->offset; } old_fs = get_fs();
@@ -361,6 +363,9 @@ static int fd_do_writev(struct se_task * ret = vfs_writev(fd, &iov[0], task->task_sg_nents, &pos); set_fs(old_fs); + for_each_sg(task->task_sg, sg, task->task_sg_nents, i) + kunmap(sg_page(sg)); + kfree(iov); if (ret < 0 || ret != task->task_size) {