• Hugh Dickins's avatar
    tmpfs: add shmem_read_mapping_page_gfp · d9d90e5e
    Hugh Dickins authored
    Although it is used (by i915) on nothing but tmpfs, read_cache_page_gfp()
    is unsuited to tmpfs, because it inserts a page into pagecache before
    calling the filesystem's ->readpage: tmpfs may have pages in swapcache
    which only it knows how to locate and switch to filecache.
    At present tmpfs provides a ->readpage method, and copes with this by
    copying pages; but soon we can simplify it by removing its ->readpage.
    Provide shmem_read_mapping_page_gfp() now, ready for that transition,
    Export shmem_read_mapping_page_gfp() and add it to list in shmem_fs.h,
    with shmem_read_mapping_page() inline for the common mapping_gfp case.
    (shmem_read_mapping_page_gfp or shmem_read_cache_page_gfp? Generally the
    read_mapping_page functions use the mapping's ->readpage, and the
    read_cache_page functions use the supplied filler, so I think
    read_cache_page_gfp was slightly misnamed.)
    Signed-off-by: default avatarHugh Dickins <hughd@google.com>
    Cc: Christoph Hellwig <hch@infradead.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
shmem.c 78.3 KB