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Commit e2e21bd8 authored by Sagi Grimberg's avatar Sagi Grimberg Committed by Nicholas Bellinger
Browse files

target/user: Fix inconsistent kmap_atomic/kunmap_atomic 



Pointers that are mapped by kmap_atomic() + offset must
be unmapped without the offset. That would cause problems
if the SG element length exceeds the PAGE_SIZE limit.

Signed-off-by: default avatarSagi Grimberg <sagig@mellanox.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 7c0d0d51

drivers/target/target_core_user.c

+8 −6
Original line number Diff line number Diff line
@@ -260,7 +260,8 @@ static void alloc_and_scatter_data_area(struct tcmu_dev *udev, 


		/* Uh oh, we wrapped the buffer. Must split sg across 2 iovs. */

		if (sg->length != copy_bytes) {

			from += copy_bytes;

			void *from_skip = from + copy_bytes;



			copy_bytes = sg->length - copy_bytes;



			(*iov)->iov_len = copy_bytes;
@@ -270,7 +271,7 @@ static void alloc_and_scatter_data_area(struct tcmu_dev *udev, 
			if (copy_data) {

				to = (void *) udev->mb_addr +

					udev->data_off + udev->data_head;

				memcpy(to, from, copy_bytes);

				memcpy(to, from_skip, copy_bytes);

				tcmu_flush_dcache_range(to, copy_bytes);

			}
@@ -281,7 +282,7 @@ static void alloc_and_scatter_data_area(struct tcmu_dev *udev, 
				copy_bytes, udev->data_size);

		}



		kunmap_atomic(from);

		kunmap_atomic(from - sg->offset);

	}

}
@@ -309,18 +310,19 @@ static void gather_and_free_data_area(struct tcmu_dev *udev, 


		/* Uh oh, wrapped the data buffer for this sg's data */

		if (sg->length != copy_bytes) {

			void *to_skip = to + copy_bytes;



			from = (void *) udev->mb_addr +

				udev->data_off + udev->data_tail;

			WARN_ON(udev->data_tail);

			to += copy_bytes;

			copy_bytes = sg->length - copy_bytes;

			tcmu_flush_dcache_range(from, copy_bytes);

			memcpy(to, from, copy_bytes);

			memcpy(to_skip, from, copy_bytes);



			UPDATE_HEAD(udev->data_tail,

				copy_bytes, udev->data_size);

		}

		kunmap_atomic(to);

		kunmap_atomic(to - sg->offset);

	}

}