@@ -676,8 +676,10 @@ static void scatter_data_area(struct tcmu_dev *udev,
from = kmap_atomic(sg_page(sg)) + sg->offset;
while (sg_remaining > 0) {
if (block_remaining == 0) {
- if (to)
+ if (to) {
+ flush_dcache_page(page);
kunmap_atomic(to);
+ }
block_remaining = DATA_BLOCK_SIZE;
dbi = tcmu_cmd_get_dbi(tcmu_cmd);
@@ -722,7 +724,6 @@ static void scatter_data_area(struct tcmu_dev *udev,
memcpy(to + offset,
from + sg->length - sg_remaining,
copy_bytes);
- tcmu_flush_dcache_range(to, copy_bytes);
}
sg_remaining -= copy_bytes;
@@ -731,8 +732,10 @@ static void scatter_data_area(struct tcmu_dev *udev,
kunmap_atomic(from - sg->offset);
}
- if (to)
+ if (to) {
+ flush_dcache_page(page);
kunmap_atomic(to);
+ }
}
static void gather_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
@@ -778,13 +781,13 @@ static void gather_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
dbi = tcmu_cmd_get_dbi(cmd);
page = tcmu_get_block_page(udev, dbi);
from = kmap_atomic(page);
+ flush_dcache_page(page);
}
copy_bytes = min_t(size_t, sg_remaining,
block_remaining);
if (read_len < copy_bytes)
copy_bytes = read_len;
offset = DATA_BLOCK_SIZE - block_remaining;
- tcmu_flush_dcache_range(from, copy_bytes);
memcpy(to + sg->length - sg_remaining, from + offset,
copy_bytes);
(scatter|gather)_data_area() need to flush dcache after writing data to or before reading data from a page in uio data area. The two routines are able to handle data transfer to/from such a page in fragments and flush the cache after each fragment is copied by calling the wrapper tcmu_flush_dcache_range(). That means: 1) flush_dcache_page() can be called multiple times for the same page. 2) Calling flush_dcache_page() indirectly using the wrapper does not make sense, because each call of the wrapper is for one single page only and the calling routine already has the correct page pointer. Therefore I changed (scatter|gather)_data_area() such, that instead of calling tcmu_flush_dcache_range() before/after each memcpy, it now calls flush_dcache_page() before unmapping a page (when writing is complete for that page) or after mapping a page (when starting to read the page). Signed-off-by: Bodo Stroesser <bstroesser@ts.fujitsu.com> --- Since I have x86 machines only, where flush_dcache_page() is empty, this patch indeed is compile tested only. Therefore it needs thorough review or ideally a test on an architecture that has a non empty flush_dcache_page(). drivers/target/target_core_user.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)