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Commit 40ff2c3b authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Nicholas Bellinger
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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: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 0ff87549

drivers/target/target_core_file.c

+7 −2
Original line number Diff line number Diff line
@@ -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) {