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Subject[PATCH 1/3] btrfs: Replace kmap() with kmap_local_page() in inode.c
Date
The use of kmap() is being deprecated in favor of kmap_local_page() where
it is feasible. With kmap_local_page(), the mapping is per thread, CPU
local and not globally visible.

Therefore, use kmap_local_page() / kunmap_local() in inode.c wherever the
mappings are per thread and not globally visible.

Tested on QEMU + KVM 32 bits VM with 4GB of RAM and HIGHMEM64G enabled.

Suggested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
---
fs/btrfs/inode.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 81737eff92f3..7d84d57a0653 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -10779,15 +10779,15 @@ ssize_t btrfs_do_encoded_write(struct kiocb *iocb, struct iov_iter *from,
ret = -ENOMEM;
goto out_pages;
}
- kaddr = kmap(pages[i]);
+ kaddr = kmap_local_page(pages[i]);
if (copy_from_iter(kaddr, bytes, from) != bytes) {
- kunmap(pages[i]);
+ kunmap_local(kaddr);
ret = -EFAULT;
goto out_pages;
}
if (bytes < PAGE_SIZE)
memset(kaddr + bytes, 0, PAGE_SIZE - bytes);
- kunmap(pages[i]);
+ kunmap_local(kaddr);
}

for (;;) {
--
2.36.1
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