target/file: Fix 32-bit highmem breakage for SGL -> iovec mapping

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>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Sebastian Andrzej Siewior 2012-12-05 12:08:29 +01:00 committed by Nicholas Bellinger
parent 0ff8754981
commit 40ff2c3b3d

View file

@ -236,7 +236,7 @@ static int fd_do_readv(struct se_cmd *cmd, struct scatterlist *sgl,
for_each_sg(sgl, sg, sgl_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();
@ -244,6 +244,8 @@ static int fd_do_readv(struct se_cmd *cmd, struct scatterlist *sgl,
ret = vfs_readv(fd, &iov[0], sgl_nents, &pos);
set_fs(old_fs);
for_each_sg(sgl, sg, sgl_nents, i)
kunmap(sg_page(sg));
kfree(iov);
/*
* Return zeros and GOOD status even if the READ did not return
@ -288,7 +290,7 @@ static int fd_do_writev(struct se_cmd *cmd, struct scatterlist *sgl,
for_each_sg(sgl, sg, sgl_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();
@ -296,6 +298,9 @@ static int fd_do_writev(struct se_cmd *cmd, struct scatterlist *sgl,
ret = vfs_writev(fd, &iov[0], sgl_nents, &pos);
set_fs(old_fs);
for_each_sg(sgl, sg, sgl_nents, i)
kunmap(sg_page(sg));
kfree(iov);
if (ret < 0 || ret != cmd->data_length) {