| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.4 71/88] target/file: Fix 32-bit highmem breakage for SGL -> iovec mapping | Date | Mon, 9 Jun 2014 17:25:21 -0700 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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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 <nab@linux-iscsi.org> [bwh: Backported to 3.2: use task->task_sg{,_nents} for iteration] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Cc: Rui Xiang <rui.xiang@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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 @@ -299,7 +299,7 @@ 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(); @@ -307,6 +307,8 @@ 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 @@ -352,7 +354,7 @@ 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(); @@ -360,6 +362,9 @@ 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) {
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