Messages in this thread Patch in this message | | | Date | Fri, 30 Jun 2023 03:20:07 +0530 | From | Deepak R Varma <> | Subject | [PATCH v3 2/6] gfs2: Replace kmap_atomic()+memcpy by memcpy_from_page() |
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kmap_atomic() is deprecated in favor of kmap_local_{folio,page}().
kmap_atomic() disables page-faults and preemption (the latter only for !PREEMPT_RT kernels), However, the code within the mapping/un-mapping in gfs2_internal_read() does not depend on the above-mentioned side effects.
Further, memcpy_{from,to}_page() wrappers combine the {kmap, unmap}_local_page() blocks when they are intended exclusively to copy contents from/to the temporary mapped page. So, replace the kmap_atomic()/kunmap_automic() block by the memcpy_from_page() API call. This change allows to tidy-up code and also eliminate unused variable p.
Suggested-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> Signed-off-by: Deepak R Varma <drv@mailo.com> --- Changes in v3: - Split as a separate patch for conversion in gfs2_internal_read() - Use memcpy_from_page() as suggested by Fabio and Andreas G - Included split version in patch set
Changes in v2: - Update patch description to correct the replacement function name from kmap_local_folio to kmap_local _page
fs/gfs2/aops.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c index 3eac4f2f5c27..f47fed657763 100644 --- a/fs/gfs2/aops.c +++ b/fs/gfs2/aops.c @@ -489,7 +489,6 @@ int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos, unsigned copied = 0; unsigned amt; struct page *page; - void *p; do { page = read_cache_page(mapping, index, gfs2_read_folio, NULL); @@ -498,12 +497,12 @@ int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos, continue; return PTR_ERR(page); } - p = kmap_atomic(page); - amt = size - copied; if (offset + size > PAGE_SIZE) amt = PAGE_SIZE - offset; - memcpy(buf + copied, p + offset, amt); - kunmap_atomic(p); + else + amt = size - copied; + + memcpy_from_page(buf, page, offset, amt); put_page(page); copied += amt; index++; -- 2.34.1
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