| Message ID | 20240424225449.1498244-3-mcgrof@kernel.org (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
| Series | mm/huge_memory: couple fixes and one cleanup | expand |
On 24 Apr 2024, at 18:54, Luis Chamberlain wrote: > Don't allow to query beyond a mapped file's length. Since this is just > a debugfs interface allow userspace to be lazy and use a large value so > we can just use the entire file. > > Without this we can end up wasting cycles looking for folios which > just don't exist for no good reason. > > Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> > --- > mm/huge_memory.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 8386d24a163e..86a8c7b3b8dc 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -3535,7 +3535,7 @@ static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, > struct file *candidate; > struct address_space *mapping; > int ret = -EINVAL; > - pgoff_t index; > + pgoff_t index, fsize; > int nr_pages = 1; > unsigned long total = 0, split = 0; > > @@ -3547,11 +3547,14 @@ static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, > if (IS_ERR(candidate)) > goto out; > > + mapping = candidate->f_mapping; > + fsize = i_size_read(mapping->host); > + if (off_end > fsize) > + off_end = fsize; > + > pr_debug("split file-backed THPs in file: %s, page offset: [0x%lx - 0x%lx]\n", > file_path, off_start, off_end); > > - mapping = candidate->f_mapping; > - > for (index = off_start; index < off_end; index += nr_pages) { > struct folio *folio = filemap_get_folio(mapping, index); LGTM. Reviewed-by: Zi Yan <ziy@nvidia.com> -- Best Regards, Yan, Zi
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 8386d24a163e..86a8c7b3b8dc 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3535,7 +3535,7 @@ static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, struct file *candidate; struct address_space *mapping; int ret = -EINVAL; - pgoff_t index; + pgoff_t index, fsize; int nr_pages = 1; unsigned long total = 0, split = 0; @@ -3547,11 +3547,14 @@ static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, if (IS_ERR(candidate)) goto out; + mapping = candidate->f_mapping; + fsize = i_size_read(mapping->host); + if (off_end > fsize) + off_end = fsize; + pr_debug("split file-backed THPs in file: %s, page offset: [0x%lx - 0x%lx]\n", file_path, off_start, off_end); - mapping = candidate->f_mapping; - for (index = off_start; index < off_end; index += nr_pages) { struct folio *folio = filemap_get_folio(mapping, index);
Don't allow to query beyond a mapped file's length. Since this is just a debugfs interface allow userspace to be lazy and use a large value so we can just use the entire file. Without this we can end up wasting cycles looking for folios which just don't exist for no good reason. Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> --- mm/huge_memory.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)