From 40ff2c3b3da35dd3a00ac6722056a59b4b3f2caf Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Wed, 5 Dec 2012 12:08:29 +0100 Subject: [PATCH] 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 Cc: stable@vger.kernel.org Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_file.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c index 8f6dae074c2c..1fc5825b3912 100644 --- a/drivers/target/target_core_file.c +++ b/drivers/target/target_core_file.c @@ -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) {